WO2014178330A1 - Method for driving electrophoretic display device, and electrophoretic display device - Google Patents

Method for driving electrophoretic display device, and electrophoretic display device Download PDF

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Publication number
WO2014178330A1
WO2014178330A1 PCT/JP2014/061604 JP2014061604W WO2014178330A1 WO 2014178330 A1 WO2014178330 A1 WO 2014178330A1 JP 2014061604 W JP2014061604 W JP 2014061604W WO 2014178330 A1 WO2014178330 A1 WO 2014178330A1
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WIPO (PCT)
Prior art keywords
pixel
driving
gradation
display
pixels
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Application number
PCT/JP2014/061604
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French (fr)
Japanese (ja)
Inventor
正史 阪上
藤沢　清志
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三菱鉛筆株式会社
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Priority claimed from JP2013095224A external-priority patent/JP2014215584A/en
Priority claimed from JP2013095223A external-priority patent/JP2014215583A/en
Application filed by 三菱鉛筆株式会社 filed Critical 三菱鉛筆株式会社
Publication of WO2014178330A1 publication Critical patent/WO2014178330A1/en

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3433—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices
    • G09G3/344—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices based on particles moving in a fluid or in a gas, e.g. electrophoretic devices
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0202—Addressing of scan or signal lines
    • G09G2310/0205—Simultaneous scanning of several lines in flat panels
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/06—Details of flat display driving waveforms
    • G09G2310/061—Details of flat display driving waveforms for resetting or blanking

Definitions

  • the present invention relates to an electrophoretic display device driving method and an electrophoretic display device that reversibly change a visual state by the action of an electric field or the like.
  • An electrophoretic display device that forms an image with electrophoretic display ink is known as a display device suitable for electronic paper.
  • display pixels are arranged in a matrix, and electrophoretic display ink is sealed in each display pixel and a pair of electrodes is provided.
  • a pixel signal is supplied from the data line driving circuit to one electrode (pixel electrode) of each display pixel via the data line and the TFT, and the pixel signal (driving voltage) is applied to the electrophoretic display ink of each display pixel.
  • a scanning signal is supplied from the scanning line driving circuit to the TFT of each display pixel (pixel electrode) through the scanning line.
  • the scanning signal is a signal (pulse signal) composed of a rectangular wave voltage, and each scanning line turns on the TFT for a period of the pulse width and applies the pixel signal to the pixel electrode. Only while the scanning line is selected (TFT on period), the potential difference between the pixel electrode and the common electrode is applied to each display pixel as a driving voltage.
  • the electrophoretic display device it is possible to improve the image quality (contrast and the like) by driving the electrophoretic display ink of each pixel at a higher voltage. For this reason, in a panel using switching elements, a method of applying a larger driving voltage by changing the common electrode potential is adopted (for example, see Patent Document 1).
  • the present invention has been made in view of such problems, and drives an electrophoretic display device capable of simultaneously improving display performance such as contrast and reflectance and improving precision gradation display performance. It is an object to provide a method and an electrophoretic display device.
  • An electrophoretic display device driving method includes a pair of substrates, at least one of which is light transmissive, a plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates, and the other substrate.
  • a common electrode disposed on the substrate surface so as to face the plurality of pixel electrodes, an electrophoretic display ink enclosed between the substrates and made of at least one or two or more types of electrophoretic particles, and the pixel electrodes arranged for each row
  • a first driving circuit that individually supplies pixel signals to a plurality of data lines connected to the plurality of data lines, and a pixel circuit that is provided on each of the plurality of data lines and that is supplied to the data lines in an on state.
  • a driving method of an electrophoretic display device comprising a plurality of storage capacitors connected in parallel between each pixel electrode and the common electrode, wherein all the electrodes are driven by a common swing that changes the potential of the common electrode.
  • the same display driving step for setting all pixels to the same display state, and the potential of the common electrode is fixed to an intermediate potential of the potential applied to the common electrode by common swing, and a plurality of data lines corresponding to the target pixel are provided.
  • a first voltage V1 is applied to the common electrode, and a second voltage V2 is applied to each data line as a pixel signal.
  • a common swing is applied, which includes applying a driving voltage to all the pixels at once using the plurality of scanning lines and changing all the pixels to the first display state to bring all the pixels into the same display state. May be.
  • a first voltage V1 is applied to the common electrode, and a second voltage V2 is applied to each data line as a pixel signal.
  • a common swing may be applied that includes driving the plurality of scanning lines sequentially to repeat one or a plurality of frames to bring all pixels into the same display state.
  • the same display driving step for all pixels is performed in a state where a first voltage V1 is applied to each data line as a pixel signal and a second voltage V2 is applied to the common electrode.
  • a first application operation for applying a driving voltage to all the pixels at once using the plurality of scanning lines to change all the pixels to the first display state, and each data using the second voltage V2 as a pixel signal.
  • a driving voltage is applied to all the pixels at once using the plurality of scanning lines in a state where the first voltage V1 is applied to the common electrode while applying the first voltage V1 to the common electrode.
  • a common swing may be applied including a series of operations in which a second application operation for changing to a different second display state is continuously performed as one set, and repeating this series of operations one or more sets. .
  • the same display driving step for all pixels is performed in a state where a first voltage V1 is applied to each data line as a pixel signal and a second voltage V2 is applied to the common electrode.
  • a first application operation for sequentially scanning the plurality of scanning lines to change all pixels to a first display state; and applying the second voltage V2 to the data lines as a pixel signal;
  • the plurality of scanning lines are sequentially scanned to continuously perform a second application operation for changing all pixels to a second display state different from the first display state.
  • a common swing including repeating a series of operations as one set or a plurality of sets may be applied.
  • the gray scale display driving step includes a step of driving the target pixel repeatedly with a driving voltage of the first polarity and changing the target pixel to a desired gray scale while the first target pixel is applied to the target pixel.
  • a driving voltage having a second polarity opposite to the polarity may be applied.
  • the gradation display driving step includes dividing the number of scans necessary for expressing the gradation into several blocks separated by a pause period corresponding to one frame or a plurality of frames.
  • the target pixel may be scanned in units of blocks.
  • the pixel electrode of the target pixel and the common electrode may be sequentially short-circuited in the pause period between the blocks.
  • the pixel electrodes of the target pixel may be sequentially opened in the pause period between the blocks.
  • the target pixel has the first polarity in the middle of changing the gradation by repeatedly driving the target pixel with the driving voltage having the first polarity in one of the blocks.
  • a drive voltage having the second polarity in the reverse direction may be applied.
  • the stop step may be short-circuited to the target pixel electrode with the same potential as the common electrode after the target pixel reaches a desired gradation.
  • the stop step may sequentially short-circuit between the pixel electrode and the common electrode of all the pixels after all the pixels reach a desired gradation.
  • the stop step may simultaneously short-circuit between the pixel electrode and the common electrode of all the pixels after all the pixels reach a desired gradation.
  • a pause period may be provided between the gradation display drive step and the stop step.
  • An electrophoretic display device driving method includes a pair of substrates, at least one of which is light transmissive, a plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates, and the other substrate.
  • a common electrode disposed on the substrate surface so as to face the plurality of pixel electrodes, an electrophoretic display ink enclosed between the substrates and made of at least one or two or more types of electrophoretic particles, and the pixel electrodes arranged for each row
  • a first driving circuit that individually supplies pixel signals to a plurality of data lines connected to the plurality of data lines, and a pixel circuit that is provided on each of the plurality of data lines and that is supplied to the data lines in an on state.
  • a driving method of an electrophoretic display device comprising a plurality of storage capacitors connected in parallel between each pixel electrode and the common electrode, wherein all the electrodes are driven by a common swing that changes the potential of the common electrode.
  • the same display driving step for setting all pixels to the same display state, and the potential of the common electrode is fixed to an intermediate potential of the potential applied to the common electrode by common swing, and a plurality of data lines corresponding to the target pixel are provided.
  • a gradation display driving step for controlling the number of scans so that the target pixel has a desired gradation in a state where the pixel signal is applied, and after the target pixel reaches the desired gradation, the pixel of the target pixel And a stop step of opening the electrode.
  • a first voltage V1 is applied to the common electrode, and a second voltage V2 is applied to each data line as a pixel signal.
  • a common swing is applied, which includes applying a driving voltage to all the pixels at once using the plurality of scanning lines and changing all the pixels to the first display state to bring all the pixels into the same display state. May be.
  • a first voltage V1 is applied to the common electrode, and a second voltage V2 is applied to each data line as a pixel signal.
  • a common swing may be applied that includes driving the plurality of scanning lines sequentially to repeat one or a plurality of frames to bring all pixels into the same display state.
  • the same display driving step for all pixels is performed in a state where a first voltage V1 is applied to each data line as a pixel signal and a second voltage V2 is applied to the common electrode.
  • a first application operation for applying a driving voltage to all the pixels at once using the plurality of scanning lines to change all the pixels to the first display state, and each data using the second voltage V2 as a pixel signal.
  • a driving voltage is applied to all the pixels at once using the plurality of scanning lines in a state where the first voltage V1 is applied to the common electrode while applying the first voltage V1 to the common electrode.
  • a common swing may be applied including a series of operations in which a second application operation for changing to a different second display state is continuously performed as one set, and repeating this series of operations one or more sets. .
  • the same display driving step for all pixels is performed in a state where a first voltage V1 is applied to each data line as a pixel signal and a second voltage V2 is applied to the common electrode.
  • a first application operation for sequentially scanning the plurality of scanning lines to change all pixels to a first display state; and applying the second voltage V2 to the data lines as a pixel signal;
  • the plurality of scanning lines are sequentially scanned to continuously perform a second application operation for changing all pixels to a second display state different from the first display state.
  • a common swing including repeating a series of operations as one set or a plurality of sets may be applied.
  • the gray scale display driving step includes a step of driving the target pixel repeatedly with a driving voltage of the first polarity and changing the target pixel to a desired gray scale while the first target pixel is applied to the target pixel.
  • a driving voltage having a second polarity opposite to the polarity may be applied.
  • the gradation display driving step includes dividing the number of scans necessary for expressing the gradation into several blocks separated by a pause period corresponding to one frame or a plurality of frames.
  • the target pixel may be scanned in units of blocks.
  • the pixel electrode of the target pixel and the common electrode may be sequentially short-circuited in the pause period between the blocks.
  • the pixel electrodes of the target pixel may be sequentially opened in the pause period between the blocks.
  • the target pixel has the first polarity in the middle of changing the gradation by repeatedly driving the target pixel with the driving voltage having the first polarity in one of the blocks.
  • a drive voltage having the second polarity in the reverse direction may be applied.
  • an erasure drive may be performed to prevent an afterimage phenomenon in which the currently displayed image appears blurry after the next image is written.
  • This afterimage erasing drive may be performed by simultaneous selection of all scanning lines using the above-mentioned common swing, or may be performed by sequential selection of scanning lines. Further, it may be realized by such driving without using the common swing. In addition, any means other than these may be used as long as the driving can prevent the afterimage phenomenon.
  • An electrophoretic display device includes a pair of substrates, at least one of which is light transmissive, a plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates, and a substrate surface of the other substrate.
  • a common electrode disposed opposite to the plurality of pixel electrodes, an electrophoretic display ink sealed between the substrates, in which one or more types of electrophoretic particles are dispersed, and the pixel electrodes are connected for each row.
  • a first driving circuit for individually supplying pixel signals to the plurality of data lines; and the pixels corresponding to the pixel signals provided on the plurality of data lines and supplied to the data lines in the ON state, respectively.
  • an electrophoretic display device capable of simultaneously improving display performance such as contrast and reflectance and improving precision gradation display performance and further extending the life of the display device.
  • a driving method and an electrophoretic display device can be provided.
  • FIG. 1 is an overall configuration diagram of an electrophoretic display device according to a first embodiment. It is a circuit diagram which shows the electrical structure of the pixel in the said electrophoretic display device. It is a fragmentary sectional view of the display part in the above-mentioned electrophoretic display device. It is explanatory drawing of the all pixel same display drive step using the common swing by the pulse system by all the scanning line simultaneous selection in the said electrophoretic display device. It is explanatory drawing of the all pixel same display drive step using the common swing by the pulse system by the scanning line sequential selection in the said electrophoretic display device. It is explanatory drawing of the all pixel same display drive step using the common swing by the swing pulse system by all the scanning line sequential selection in the said electrophoretic display device.
  • FIG. 1 is an overall configuration diagram of an electrophoretic display device according to an embodiment of the present invention.
  • the electrophoretic display device 1 includes a display unit 2 in which display pixels are arranged in a matrix, a data line driving circuit 3 that supplies pixel signals to the display unit 2, and a rectangular shape on the display unit 2.
  • a scanning line driving circuit 4 for supplying a scanning signal composed of a pulse signal of a wave, a common potential supply circuit 5 for applying a common potential to each display pixel of the display unit 2, and a controller 6 for controlling the operation of the entire apparatus. Configured.
  • the controller 6 controls the data line driving circuit 3, the scanning line driving circuit 4, and the common potential supply circuit 5 to erase the current image and set all pixels to the same display state (all white or all black).
  • the discharging stop step is executed every time one image is displayed.
  • the same display drive step, gradation display drive step, and stop step for all pixels are performed by the pixel signal supplied from the data line drive circuit 3, the scan signal supplied from the scan line drive circuit 4, and the common potential supply circuit. This is realized by a combination of voltages supplied from 5.
  • n data lines X 1 to Xn extending in parallel in the column direction (Y direction) extend from the data line driving circuit 3, and intersect with these data lines from the scanning line driving circuit 4.
  • the m scanning lines Y1 to Ym extend in parallel in the row direction (X direction).
  • display pixels 20 are formed at each intersection where the data lines (X1, X2,... Xn) and the scanning lines (Y1, Y2,... Ym) intersect.
  • the display unit 2 has a plurality of display pixels 20 arranged in a matrix of n rows and m columns.
  • the data line driving circuit 3 supplies pixel signals to the data lines (X1, X2,... Xn) based on the timing signal supplied from the controller 6.
  • the data line driving circuit 3 has a high potential V1 (for example, 15 V), a low potential V2 (for example, ⁇ 15 V), three potentials Vmid (for example, 0 V) that is an intermediate voltage between V1 and V2, and a high impedance state. It is configured to be selectable.
  • the scanning line driving circuit 4 supplies a scanning signal having an arbitrary pulse width simultaneously or sequentially to each scanning line (Y1, Y2,... Ym) based on the timing signal supplied from the controller 6. Thereby, a scanning signal is supplied to the display pixel 20 to be driven. Since a pixel to be subjected to gradation control is selected by the scanning signal, the scanning signal can also be called a selection signal.
  • the common potential Vcom is applied from the common potential supply circuit 5 via the common potential line 11 to each display pixel 20 constituting the display unit 2.
  • the common potential supply circuit 5 includes, as the common potential Vcom, three potentials of a high potential V1 (for example, 15V), a low potential V2 (for example, ⁇ 15V), and Vmid (for example, 0V) that is an intermediate voltage between V1 and V2.
  • the high impedance state can be selected. That is, the common potential supply circuit 5 is configured to be able to select the same voltage as the three voltages V1, V2, and Vmin that the data line driving circuit 3 can select as pixel signals.
  • the controller 6 supplies timing signals such as a clock signal and a start pulse to the data line driving circuit 3, the scanning line driving circuit 4, and the common potential supply circuit 5 to control each circuit.
  • the controller 6 supplies the gradation data of the display target pixel to the data line driving circuit 3 or the common potential supply circuit 5.
  • the data line driving circuit 3 or the common potential supply circuit 5 determines the number of application times of the write pulse and the voltage value according to the gradation data, and synchronizes with the frame scanning (pixel row selection) operation of the scanning line driving circuit 4.
  • a pixel signal or a common potential is supplied to the pixel.
  • FIG. 2 is an equivalent circuit diagram showing an electrical configuration of the display pixel 20.
  • positioned at the display part 2 at the matrix form is the same structure, each part which comprises the display pixel 20 attaches
  • the display pixel 20 includes a pixel electrode 21, a common electrode 22, an electrophoretic display ink 23, a pixel switching transistor 24, and a storage capacitor 25.
  • the pixel switching transistor 24 can be configured by, for example, a TFT (Thin Film Transistor).
  • the gate of the pixel switching transistor 24 is electrically connected to the scanning line (Y1, Y2,... Ym) of the corresponding row.
  • the source of the pixel switching transistor 24 is electrically connected to the data line (X1, X2,... Xn) of the corresponding column.
  • the drain of the pixel switching transistor 24 is electrically connected to the pixel electrode 21 and the storage capacitor 25.
  • the pixel switching transistor 24 receives the pixel signal supplied from the data line driving circuit 3 via the data lines (X1, X2,... Xn) and the scanning line (Y1, Y2, Y2) of the corresponding row from the scanning line driving circuit 4. ..., Ym), and output to the pixel electrode 21 and the storage capacitor 25 at a timing corresponding
  • a pixel signal is supplied to the pixel electrode 21 from the data line driving circuit 3 through the data lines (X1, X2,... Xn) and the pixel switching transistor 24.
  • the pixel electrode 21 is disposed opposite to the common electrode 22 with the electrophoretic display ink 23 interposed therebetween.
  • the common electrode 22 is electrically connected to the common potential line 11 to which the common potential Vcom is supplied.
  • the electrophoretic display ink 23 is a liquid material in which at least one type of electrophoretic particles is dispersed, and is held between the electrodes so as not to leak with a sealing material (not shown).
  • the storage capacitor 25 is made up of a pair of electrodes arranged opposite to each other with a dielectric film therebetween, one electrode is electrically connected to the pixel electrode 21 and the pixel switching transistor 24, and the other electrode is connected to the common potential line 11. Electrically connected.
  • the storage capacitor 25 continues to move the electrophoretic particles in a direction corresponding to the drive voltage for a longer time than a predetermined period even after the drive voltage generated between the electrodes of the display pixel 20 is turned off by one selection. It has a capacity size that can be stored.
  • FIG. 3 is a partial cross-sectional view of the display unit 2 in the electrophoretic display device 1.
  • the display unit 2 has a configuration in which an element substrate 28 and a counter substrate 29 are arranged to face each other via a spacer (not shown), and an electrophoretic display ink 23 is sealed between the substrates. .
  • description will be made on the assumption that an image is displayed on the counter substrate 29 side.
  • the element substrate 28 is a substrate made of, for example, glass or plastic. Although not shown here on the element substrate 28, the pixel switching transistor 24, the storage capacitor 25, the scanning lines (Y1, Y2,... Ym), and the data lines (X1, X2) described above with reference to FIG. ,... Xn), and a laminated structure in which the common potential line 11 is formed. A plurality of pixel electrodes 21 are provided in a matrix on the upper layer side of the stacked structure.
  • the counter substrate 29 is a light-transmitting substrate made of, for example, glass or plastic.
  • the common electrode 22 is formed so as to face the plurality of pixel electrodes 21.
  • the common electrode 22 is formed of a transparent conductive material such as magnesium silver (MgAg), indium tin oxide (ITO), indium zinc oxide (IZO), for example.
  • the electrophoretic display ink 23 includes at least a positively or negatively charged electrophoretic particle having a first color and a dispersion medium colored in a second color so that contrast display is possible.
  • the first electrophoretic particles having a negatively charged first color and the second color having a charging characteristic different from that of the first electrophoretic particles and capable of displaying contrast with the first color.
  • a description will be given by taking as an example a configuration including positively charged black particles 83, negatively charged white particles 82, and a dispersion medium 81 in which the black particles 83 and the white particles 82 are dispersed.
  • the present invention is not limited to this. That is, by arbitrarily selecting white and black particles within a range in which contrast display is possible, for example, by changing the particles to red, green, blue, or the like, the display surface of the display unit 2 is displayed in red, green, blue It can be displayed.
  • the positively charged black particles 83 are attracted to the common electrode 22 side by the Coulomb force, and the negatively charged white particles 82 are attracted to the pixel electrode 21 side by the Coulomb force. As a result, the black particles 83 gather on the display surface side (common electrode 22 side), and the display surface of the display unit 2 is displayed in black.
  • the drive operation for displaying the gradation image on the electrophoretic display device 1 is divided into the above-described all-pixel identical display drive step, gradation display drive step, and stop step.
  • the same display drive, gradation display drive step, and stop step for all the pixels will be described in order.
  • the driving method is not particularly limited as long as it is a driving method that can perform common swinging so that all the pixels of the electrophoretic display device are once in the same display state.
  • the driving method is not particularly limited as long as it is a driving method that can perform common swinging so that all the pixels of the electrophoretic display device are once in the same display state.
  • the effect of the present invention can be effectively achieved.
  • a common swing that changes the common potential Vcom applied to the common electrode 22 is applied, and all the display pixels 20 are set to the same display state.
  • the common electrode 22 is set to a high potential with respect to the pixel electrode 21 to change all the display pixels 20 to the first display state (for example, all white state).
  • a second application operation for setting all the display pixels 20 to a second display state (for example, an all black state) by setting the common electrode 22 to a low potential with respect to the pixel electrode 21 hereinafter, referred to as “the second application operation”.
  • the above driving method is referred to as “pulse method”.) All the pixels are brought into the same display state by at least one of the operations.
  • each display pixel 20 (more specifically, the pixel electrode 21) can be secured.
  • a large driving voltage can be applied between the electrode and the common electrode 22.
  • larger kinetic energy can be given to the electrophoretic particles (white particles 82, black particles 83) in the electrophoretic display ink 23.
  • the electrophoretic particles can be efficiently moved to the display surface side and the back surface side, and the white and black electrophoretic particles can be separated cleanly, and display performance such as black-and-white contrast and reflectance. Is improved.
  • the pulse-type application operation is not limited to once, but the first application operation may be repeated a plurality of times.
  • the second application operation may be repeated a plurality of times.
  • a method of repeating the set once or a plurality of times hereinafter referred to as “swing pulse method”. It may be used. Note that the number of times of the first application operation and the second application operation performed by the swing pulse method may be different.
  • all scanning lines Y1 to Ym are simultaneously supplied with scanning signals to perform all display.
  • a method of simultaneously applying a driving voltage to the pixels 20 (a pulse method by simultaneous selection of all scanning lines and a swing pulse method by simultaneous selection of all scanning lines) and a scanning signal are sequentially supplied to each of the scanning lines Y1 to Ym.
  • a method of sequentially applying a driving voltage to all the display pixels 20 (a pulse method by scanning line sequential selection and a swing pulse method by scanning line order selection) can be selected.
  • FIG. 4 is an explanatory diagram of the all pixel identical display driving step using the common swing by the pulse method by the simultaneous selection of all the scanning lines in the electrophoretic display device 1 according to the present embodiment.
  • FIG. 5 is an explanatory diagram of the all pixel identical display driving step using the common swing by the pulse method by the scanning line sequential selection in the electrophoretic display device 1 according to the present embodiment.
  • FIG. 6 is an explanatory diagram of the all pixel identical display driving step using the common swing by the swing pulse method by the simultaneous selection of all the scanning lines in the electrophoretic display device 1 according to the present embodiment.
  • FIG. 7 is an explanatory diagram of the all pixel identical display driving step using the common swing by the swing pulse method by the scanning line sequential selection in the electrophoretic display device 1 according to the present embodiment.
  • 15V is used as the high potential voltage V1 applied to the pixel electrode 21 and the common electrode 22, while ⁇ 15V is used as the low potential voltage V2.
  • 0V is used as the intermediate voltage Vmid.
  • a voltage V1 of 15V is applied to the common electrode 22 and a voltage V2 of ⁇ 15V is applied to the pixel electrode 21.
  • a scanning signal (ON potential) is simultaneously supplied to all the scanning lines Y1 to Ym.
  • a drive voltage of V1-V2 that is, 30V is applied to the electrophoretic display ink 23 of each display pixel 20.
  • a scanning signal (ON potential) is sequentially supplied to each scanning line Y1 to Ym, and this scanning signal is supplied.
  • the voltage V2 is applied to the corresponding pixel electrode 21 and the voltage V1 is applied to the common electrode 22 at the timing, which is different from the common swing using the swing pulse method by simultaneous selection of all scanning lines shown in FIG. 5A shows the case where the scanning signal is supplied to the scanning line Y1 at the beginning of the frame, and FIG. 5B shows the case where the scanning signal is supplied to the scanning line Ym at the end of the frame.
  • the scanning signal is supplied at a timing that is sequentially shifted between the scanning signal supply timing for the scanning line Y1 and the scanning signal supply timing for Ym.
  • a voltage V2 of ⁇ 15 V is applied to the common electrode 22, and a voltage V1 of 15 V is applied to the pixel electrode 21.
  • the second application operation in which the scanning signal (ON potential) is simultaneously supplied to all the scanning lines Y1 to Ym is performed.
  • a voltage of V2-V1 that is, ⁇ 30 V is applied to the electrophoretic display ink 23 of each display pixel 20.
  • the scanning electrode (on potential) is simultaneously applied to all the scanning lines Y1 to Ym with the potential of the common electrode 22 changed to the voltage V1 of 15V and the potential of the pixel electrode 21 changed to the voltage V2 of -15V.
  • the first application operation is performed.
  • a drive voltage of V1-V2 (that is, 30V) is applied to the electrophoretic display ink 23 of each display pixel 20.
  • FIG. 6 shows a case where two sets are applied with this series of application operations as one set. The number of times of repeating these application operations can be arbitrarily selected, and can be set to three times or more.
  • a voltage V2 of ⁇ 15 V is applied to the common electrode 22, and a voltage V1 of 15 V is applied to the pixel electrode 21.
  • a second application operation in which a scanning signal (ON potential) is sequentially supplied to all the scanning lines Y1 to Ym is performed.
  • a voltage of V2-V1 that is, ⁇ 30 V is sequentially applied to the electrophoretic display ink 23 of each display pixel 20.
  • the scanning electrode (on potential) is sequentially applied to all the scanning lines Y1 to Ym in a state where the potential of the common electrode 22 is changed to the voltage V1 of 15V and the potential of the pixel electrode 21 is changed to the voltage V2 of -15V.
  • the first application operation is performed.
  • the drive voltage of V1-V2 (that is, 30V) is sequentially applied to the electrophoretic display ink 23 of each display pixel 20.
  • FIG. 7 shows a case where two sets are applied with one set of the application operation in which the second application operation is repeated twice after the first application operation is repeated twice.
  • the number of times of repeating these application operations can be arbitrarily selected, and can be set to three or more. It is also possible to set a different number of times.
  • the dotted line portion of the voltage applied to the ink shown in FIG. 4 to FIG. 7 shows the voltage waveform after the all-pixels identical display drive step, but in the present invention, all the pixels are the same to which the above common swing is applied.
  • the process proceeds to a gradation display operation in which a gradation image is displayed using each display pixel 20. This gradation display operation step will be described later.
  • This afterimage erasing drive may be performed by simultaneous selection of all scanning lines using the above-mentioned common swing, or may be performed by sequential selection of scanning lines. Further, it may be realized by such driving without using the common swing. In addition, any means other than these may be used as long as it can drive the afterimage phenomenon.
  • the supply of the scanning signal to a specific scanning line takes time required to scan all the scanning lines Y1 to Ym once (select all scanning lines continuously). Assuming one frame period, the period is one frame. That is, when the scanning signal is continuously supplied to the scanning line Y1, after the scanning signal is supplied at a certain timing, the next scanning signal is supplied after one frame has elapsed from the supply timing (see FIG. 5). Therefore, the period in which the driving voltage is continuously applied to the display pixels 20 selected by the scanning line Y1 is also one frame period.
  • the electrophoretic display of each display pixel 20 connected to the scanning line Y1 to which the scanning signal is supplied in the first application operation A voltage V1-V2 (ie, 30V) is instantaneously applied to the ink 23.
  • the applied drive voltage charges the storage capacitor 25, and the charge accumulated in the storage capacitor 25 is gradually discharged thereafter.
  • a voltage of V2-V1 that is, ⁇ 30 V
  • the applied drive voltage charges the storage capacitor 25 with a reverse voltage, and the charge accumulated in the storage capacitor 25 is then gradually discharged.
  • the gradation display driving step in the electrophoretic display device 1 will be described.
  • the gradation display driving step pixels corresponding to the display image are displayed on the plurality of data lines X1 to Xn in a state in which the potential of the common electrode 22 is fixed to the intermediate potential Vmid of the voltages V1 and V2 applied by the common swing.
  • the target display pixel 20 is adjusted to a desired gradation according to the number of times of application.
  • the pixel electrode is brought into a high impedance state after at least the last scan, and each pixel shifts from the gradation display driving step to the stop step when a desired gradation is obtained.
  • the gradation display driving step in the electrophoretic display device 1 unlike the same display driving step for all the pixels, driving for each pixel electrode 21 is performed with the potential applied to the common electrode 22 being fixed to the intermediate potential Vmid without switching. Is controlled.
  • the gradation level (color tone) that changes with one drive control increases as the potential difference applied to the electrophoretic display ink 23 increases. For this reason, when common swing is performed as in the above-described all-pixel same display driving step, the potential difference applied to the electrophoretic display ink 23 becomes large and is not necessarily suitable for gradation display control.
  • the driving of each pixel electrode 21 is controlled in a state of being fixed at the intermediate potential Vmid.
  • gradation display can be adjusted with a relatively small potential difference, and the precision gradation display performance in the electrophoretic display device 1 can be improved.
  • the display pixel 20 corresponding to the gradation display control object corresponds to the display pixel 20 until reaching a desired gradation.
  • a sequential grayscale driving method for sequentially driving the display pixels 20 by sequentially supplying scanning signals to the scanning lines in one frame period, and the number of times the display pixels 20 are driven (the number of scans) required to express a desired grayscale Apply one of the block scan gradation driving method that divides the block into several blocks separated by a pause period corresponding to one frame or a plurality of frames and drives the display pixels 20 to be subjected to gradation display control on a block basis. To do.
  • FIG. 8 is an explanatory diagram of the gradation display driving step using the sequential gradation driving method.
  • FIG. 9 is an explanatory diagram of a gradation display driving step using the block scan gradation driving method.
  • the potential applied to the common electrode 22 is fixed to the intermediate potential Vmid, and the pixel signal applied to the pixel electrode 21 and the scanning supplied to the scanning line are used.
  • the gray scale display in the display pixel 20 is adjusted by the number of times of signal supply (the number of scans or the number of driving).
  • a voltage is applied to the display pixel 20.
  • gradation driving can be performed with a driving voltage that is half of the driving voltage in the same display driving step for all pixels. it can.
  • precise gradation display performance can be improved. Specifically, as shown in FIG. 8, when the supply of the pixel signal and the scanning signal to the display pixel 20 that is the target of gradation control is stopped twice, the gradation of the display pixel 20 is changed to the gradation C. Is set.
  • the gradation of the display pixel 20 is set to the gradation B. Furthermore, when the supply of the pixel signal and the scanning signal to the display pixel 20 that is the target of gradation control is stopped at seven times, the gradation of the display pixel 20 is set to the gradation A. Note that when the gradation of the display pixel 20 is set to gradations C and B, the pixel signal potentials at the third time and the sixth time are Vmid or a high impedance state, respectively, but in FIG. The case where the pixel signal and the scanning signal are supplied seven times is shown. The high impedance state will be described later.
  • the display pixel 20 is adjusted by adjusting the number of scans (also referred to as the number of simultaneous application of the pixel signal and the scan signal or the number of gradation drives) for the display pixel 20 to be subjected to gradation control.
  • the gradation display at is adjusted.
  • the case where all the pixels are set to white in the same display driving step for all the pixels has been described, so that the density in the display pixel 20 can be expressed deeply as the number of scans increases, and the density in the display pixel 20 decreases as the number of scans decreases. Can express thinly. In the example shown in FIG.
  • the density of gradation C set by the number of times of scanning twice is the smallest, and the number of times of scanning five times (simultaneous application of pixel signal and scanning signal).
  • the density of gradation A set by is the highest.
  • pixel signals and scanning signals are continuously supplied to the display pixels 20 to be subjected to gradation control, and the number of times of supply is adjusted to adjust the level of the display pixels 20. Adjust the key display.
  • the number of times of driving (scanning number of times) of the display pixel 20 necessary for expressing a desired gradation is separated in a pause period corresponding to one frame or a plurality of frames. Dividing into several blocks, the display pixels 20 are driven in units of blocks.
  • gradation B shown in FIG. 8 when gradation B shown in FIG. 8 is expressed by gradation, as shown in FIG. 9, for example, a pause period of one frame or a plurality of frames (regions A1, A2 shown in FIG. 8). , A3 to A6) are divided into a plurality of blocks (B1 to B3, B4 to B8 shown in the figure), and the display pixels 20 are driven in units of blocks.
  • the display pixel 20 is driven by three blocks B1 to B3 separated by a one-frame pause period A1 and a three-frame pause period A2.
  • the display pixel 20 is driven by five blocks B4 to B8 separated by four one-frame pause periods A3 to A6.
  • the display pixels 20 are driven in units of blocks as described above, a pause period of at least one frame is inserted between the blocks. Therefore, like the sequential gradation driving method shown in FIG. Compared to the case where the same display pixel 20 is continuously driven, the total movement amount of the electrophoretic particles (white particles 82 and black particles 83) in the electrophoretic display ink 23 changes.
  • the gradation of the display pixel 20 can be finely adjusted in the block scan gradation driving method. For example, in the block scan gradation driving method shown in the middle part of FIG. 9, gradation B ′ having a gradation slightly thinner than gradation B shown in the upper part of FIG. In the scan gradation driving method, a gradation B ′′ having a gradation slightly thinner than the gradation B ′ is expressed.
  • FIG. 10 is an explanatory diagram of drive energy when the block scan gradation driving method and the sequential gradation driving method are used in the electrophoretic display device 1 according to the present embodiment.
  • FIG. 10A shows an enlarged view of a region surrounded by a broken line C shown in FIG.
  • the waveform on the left side shown in FIG. 10A shows a waveform (hereinafter referred to as “primary waveform” for convenience) when the drive voltage is first applied to the display pixel 20 from the initial state where the drive voltage is not applied.
  • the waveform on the right side shown in FIG. 10B is a waveform when the subsequent drive voltage is applied after the charge due to the drive voltage applied in advance is accumulated in the storage capacitor 25 and all the charges are not discharged (hereinafter referred to as the waveform). For convenience, it is referred to as a “secondary waveform”.
  • the drive voltage application time t in the primary waveform and the secondary waveform is the same time.
  • the drive voltage in the primary waveform rises from the intermediate voltage Vmid
  • the drive voltage in the secondary waveform rises from a voltage value between the intermediate voltage Vmid and the high potential voltage V2. For this reason, the rise of the secondary waveform rises more rapidly than the primary waveform.
  • FIG. 10B shows drive voltages S V1 and S V2 corresponding to the application time t of the primary waveform and the secondary waveform.
  • FIG. 10C shows a comparison result of these drive voltages S V1 and S V2 .
  • the vertical axis represents voltage and the horizontal axis represents time.
  • the drive voltage S V2 of the secondary waveform with a voltage higher than the driving voltage S V1 of the primary wave at the beginning time portion. For this reason, it can be seen that the drive energy based on the drive voltage S V2 of the secondary waveform is larger by ⁇ S than the drive energy based on the drive voltage S V1 of the primary waveform.
  • the total amount of drive energy when the display pixel 20 is driven by the sequential gradation drive method shown in the upper part of FIG. 9 is a value obtained by adding four ⁇ S to the drive voltage S V1 for five times (that is, 5 ⁇ S V1 + 4 ⁇ It can be seen that ⁇ S).
  • the total amount of driving energy when the display pixel 20 is driven by the block scan gradation driving method shown in the lower part of FIG. 9 is a value obtained by summing the five driving voltages S V1 (that is, 5 ⁇ S V1 ). I understand that. That is, the driving energy is smaller by two ⁇ S than the total amount of driving energy when the display pixel 20 is driven by the block scan gradation driving method shown in the middle stage of FIG. For this reason, the gradation B ′′ is a gradation slightly thinner than the gradation B ′.
  • the pixel electrode 21 may be short-circuited by applying a voltage equal to that of the common electrode 22, and the common electrode 22 is opened in a high impedance state.
  • the pixel electrode can be appropriately selected within a range in which the pixel electrode can be brought into a high impedance state after the last scan.
  • each pixel shifts from the gradation display drive step to the stop step when a desired gradation is obtained.
  • a gradation is obtained by applying a reverse voltage to the display pixel 20 to be controlled in the middle of changing to a desired gradation. It is preferable as an embodiment to adjust the value.
  • Such a method of applying a reverse voltage to the display pixel 20 in the middle of changing to a desired gradation is hereinafter referred to as a “reverse scan insertion drive method”.
  • FIGS. 11 and 12 are explanatory diagrams of gradation drive control using the reverse scan insertion drive method in the electrophoretic display device 1 according to the present embodiment.
  • the case where the drive voltage is applied only five times (FIG. 11) or twice to the display pixel 20 that is the target of gradation control is illustrated. Note that, in the gradations G1 to G5 shown in FIG. 11, the gradation G1 has the lowest density and the density gradually increases toward the gradation G5.
  • FIG. 11 shows the gradation change of two types of ink (electrophoretic particles 82 and 83) A and B whose gradation display is controlled.
  • the gradation G5 shown in FIG. 11 is a desired gradation.
  • Ink A has an electrical characteristic that a gradation G5 can be obtained by driving five times (application of a driving voltage) from a white (or black) state.
  • the ink B has an electrical characteristic that a gradation G5 can be obtained by driving twice (applying a driving voltage) from a white (or black) state.
  • the gradation changes by 4 gradations by applying the driving voltage in the direction of increasing the gradation, whereas only 3 gradations are applied by applying the driving voltage in the direction of decreasing the gradation. It is assumed that it has electrical characteristics in which gradation changes.
  • the sequential gradation driving method when the sequential gradation driving method is applied, in the ink A, the three gradations G2 to G4 can be sequentially obtained as intermediate gradations between the gradations G1 to G5.
  • the ink B the gradation of the display pixel 20 reaches the gradation G5 only by applying the driving voltage once from the state of the gradation G1. That is, in the ink B, the intermediate gradations G2 to G4 cannot be obtained. Therefore, the gradation expression performance of the ink B having such electrical characteristics is improved by controlling the gradation drive by applying the reverse scan insertion drive method.
  • the preceding drive voltage is applied to the pixel electrode 21 of the display pixel 20 that has reached the gradation G5 by the second drive voltage application.
  • a drive voltage (pixel signal in the direction of decreasing gradation) having a voltage opposite to that of the pixel signal in the direction of increasing darkness is applied (third drive).
  • the gradation G2 can be obtained.
  • a pixel signal in the direction of increasing the gradation is applied to the pixel electrode 21 of the display pixel 20 (fourth driving). Thereby, in this display pixel 20, the gradation G6 can be obtained.
  • the gradation G6 indicates a darker gradation than the gradation G5. Further, a pixel signal in a direction of decreasing the gradation is applied to the pixel electrode 21 of the display pixel 20 (fifth drive). Thereby, in the display pixel 20, the gradation G3 can be obtained.
  • a drive voltage having a reverse voltage is applied in the middle of changing the display pixel 20 to be a gradation control target to a desired gradation.
  • Use to adjust the gradation As a result, even when ink (electrophoretic particles 82 and 83) having electrical characteristics with a large gradation change is used, intermediate gradations such as the gradations G2 to G4 described above can be obtained. Tonal expression can be realized.
  • the stop step in the electrophoretic display device 1 will be described.
  • the stopping step after each display pixel 20 reaches a desired gradation, the potential of the pixel electrode 21 for each pixel is set to the same potential as the common electrode 22.
  • each scanning line there is a sequential short-circuit method for each scanning line in which the pixel electrodes 21 and the common electrodes 22 of all the display pixels 20 are sequentially short-circuited.
  • Each short-circuiting method may be performed after a certain period of time has elapsed from the end of the gradation display driving step (sequential short-circuiting after every pause, simultaneous short-circuiting after each pause, and sequential short-circuiting after every scanning line).
  • FIG. 13 is an explanatory diagram of a short-circuit operation and an open operation when the gradation drive control is finished in the electrophoretic display device 1 according to the present embodiment.
  • 13A shows a short-circuit operation at the stop step
  • FIG. 13B shows an open operation during the gradation display driving step
  • FIG. 13C shows an open operation at the stop step.
  • the scanning signal for the scanning line Y is turned on, and the voltage applied to the pixel electrode 21 via the data line X is the same as the voltage applied to the common electrode 22. Set to potential.
  • the data line X is set to a high impedance state by some method as shown in FIG. 13B, or the scanning line Y is set to an off potential as shown in FIG. Set to state.
  • the former is different in that the scanning signal for the scanning line Y is on-potential, while the latter is the scanning signal for the scanning line Y is off-potential.
  • the pixel-by-pixel sequential short-circuit method is a method of short-circuiting pixels that have finished the gradation display driving step at the next operation timing. For example, as shown in FIG. 14A, a fifth scanning signal is supplied to the display pixel 20.
  • the pixel electrode 21 and the common electrode 22 are set to the same voltage (here, Vmid (0 V)) at the timing corresponding to this scanning signal, the electrophoretic display is performed at the timing when the fifth scanning signal is supplied. In this method, charges accumulated in the ink 23 and the holding capacitor 25 are removed.
  • the pixel-by-pixel sequential short-circuit method after the pause is a method in which the short-circuit operation is performed after inserting the open operation for supplying the scanning signal one or more times with the pixel electrode 21 in the high impedance state between the fourth and fifth times in FIG. 14A. is there.
  • the sequential short-circuit method for each pixel after the pause since the timing until the stop can be set for each pixel, it is possible to obtain richer gradation display performance.
  • FIG. 15 is an explanatory diagram of a stop step using the simultaneous short-circuit method.
  • FIG. 16 is an explanatory diagram of the stop step using the sequential short-circuit method for each scanning line. 15 and 16 show lines L1 to Lm controlled in accordance with the scanning signals for the scanning lines Y1 to Ym.
  • the simultaneous short-circuit method as shown in FIG. 15, immediately after all the pixels of the display unit 2 including the display pixels 20 have finished the gradation display driving step, the potential applied to the pixel electrodes 21 all at once. By making the potential applied to the common electrode 22 the same potential, all the scanning lines Y1 to Ym are short-circuited simultaneously. According to the stop step using the simultaneous short-circuit method, since the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are forcibly removed, the amount of charge consumed in the electrophoretic display ink 23 is reduced. Can be reduced. Thereby, since the damage which the electrophoretic display ink 23 receives can be reduced, it becomes possible to realize the lifetime improvement of the display part 2. In particular, in the simultaneous short-circuit method, since all the scanning lines Y1 to Ym can be short-circuited at a time, it is possible to shorten the processing time required for the stop step without requiring complicated control.
  • the scanning lines Y1 to Ym are sequentially formed immediately after all the pixels of the display unit composed of the display pixels 20 have finished the gradation display driving step. Is supplied with a scanning signal, and the potential applied to the pixel electrode 21 and the potential applied to the common electrode 22 in each pixel are set to the same potential.
  • the stop step using the sequential short-circuit method for each scanning line as in the simultaneous short-circuit method, the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are forcibly removed. The amount of charge consumed in the ink 23 can be reduced.
  • the short-circuit operation is performed immediately after all the pixels of the display unit 2 have finished the gradation display drive step.
  • these short-circuiting operations may be performed after a fixed period of time has elapsed after the image has been written (post-stop short-circuiting method).
  • the rest period can be set to a period in which the movement of the particles (white particles 82, black particles 83) in the electrophoretic display ink 23 ends.
  • the short-circuit operation is performed with the pause period interposed therebetween, it is possible to ensure the long life of the display unit 2 while maintaining the gradation expression performance.
  • FIG. 14 is an explanatory diagram of a stop step in a pixel for which the gradation driving step has been completed in the electrophoretic display device 1 according to the present embodiment.
  • FIG. 14A shows a waveform when a pixel for which the gradation display driving step has been completed by the sequential short circuit method for each pixel is short-circuited at the next scanning timing, and in FIG. 14B, the gradation display is performed by the sequential opening method for each pixel.
  • the waveform in the case where the pixel for which the driving step has been completed is opened at the timing of the next search is shown.
  • the fifth scanning signal is supplied to the display pixel 20 as shown in FIG. 14A.
  • the pixel electrode 21 and the common electrode 22 are set to the same voltage (here, Vmid (0 V)). In this case, the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are removed at the timing when the fifth scanning signal is supplied.
  • the pixel electrode 21 is placed in a high impedance state at the timing when the fifth and subsequent scanning signals are supplied to the display pixel 20. As driven. As a result, the charge accumulated in the storage capacitor 25 in the fourth scan is gradually discharged.
  • the drive voltage is held until the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are naturally discharged. Therefore, the memory performance in the display unit 2 can be improved.
  • an image is displayed on the display unit 2 by sequentially executing the same pixel display driving step, gradation display driving step, and stop step.
  • a gradation display driving step is performed across the same display driving step for all pixels, and a stop step is performed.
  • the common swing is applied in the same display driving step for all pixels, a high contrast white or black display can be realized.
  • the gradation display driving step since the driving of each pixel electrode 21 is controlled in a state where it is fixed to the intermediate potential Vmid without applying the common swing, a fine gradation change can be realized. As a result, it is possible to improve the black and white binary display performance and improve the gradation expression performance.
  • a substrate (hereinafter referred to as ITO-PET) on which a transparent electrode having a surface resistance of 250 ⁇ / ⁇ is formed on indium tin oxide (tin-doped indium oxide) on a PET film. Used).
  • the common electrode 22 is formed with microcells having a height of 20 ⁇ m and a pitch of 300 ⁇ m for partitioning ink.
  • the periphery of the electrophoretic display ink 23 was sealed with a UV curable adhesive so that the distance between the electrodes (between the pixel electrode 21 and the common electrode 22) was 20 ⁇ m and the display area was 50 mm ⁇ 40 mm.
  • One panel configured as described above is hereinafter referred to as a single cell.
  • the electrical characteristics of the ink are a volume resistivity of 10 10 ( ⁇ cm) and a relative dielectric constant of 3.
  • the electrophoretic display ink 23 includes white particles 82 and black particles 83.
  • the white particles 82 are negatively charged.
  • the common electrode 22 has a higher voltage than the pixel electrode 21, the white particles 82 gather on the common electrode 22 side, and the display surface side (the common electrode 22 side) displays white.
  • the black particles 83 are positively charged.
  • the common electrode 22 has a lower voltage than the pixel electrode 21, the black particles 83 gather on the common electrode 22 side, and the display surface side (common electrode 22 side) is black. Become.
  • a holding experiment 25 having a capacitance of 14.7 ⁇ F was connected in parallel to one single cell, and this was regarded as one pixel, and a verification experiment was conducted.
  • the scanning line selection time was set to 20 ⁇ s.
  • the time required to supply the scanning signal for one frame is 4.8 ms. Accordingly, a voltage of 20 ⁇ s is applied to the single cell within one frame of 4.8 ms.
  • the number of frames was changed in accordance with the gradation.
  • one frame is set to 100 ms, and the voltage is applied to all the pixels for 100 ms.
  • the common electrode 22 is set to 0 V, and +15 V is applied to the pixel electrode 21, so that the common electrode 22 side (display surface side) is white.
  • a potential difference of 15 V was obtained as a voltage for moving the particles 82.
  • a potential difference of 15V was obtained as a voltage for moving the black particles 83 to the common electrode 22 side (display surface side).
  • Example 1 In the same display driving step for all the pixels, the scanning operation for sequentially selecting the scanning lines in a state where +15 V is applied to the common electrode 22 and ⁇ 15 V is applied to the pixel electrode 21 is repeated 20 times to change the display state of all pixels to white. Later, 0V is applied to the common electrode 22, + 15V is applied to the pixel electrode 21 according to the next display image data, + 15V is applied to the pixel whose display state is to be changed, and 0V is applied to the pixel whose display state is not changed.
  • a gradation display driving step for repeating a scanning operation for sequentially selecting lines 60 times is performed, and a stop step for applying the same potential as the common electrode by applying 0 V to the pixel electrode 21 of the pixel that has reached the gradation to be displayed is performed. It was.
  • Example 2 After repeating the scanning operation of sequentially selecting scanning lines with -15V applied to the common electrode 22 and + 15V applied to the pixel electrode, + 15V is applied to the common electrode 22 and -15V is applied to the pixel electrode 21.
  • a scan operation for sequentially selecting scanning lines in a state where voltage is applied is repeated 20 times to change the display state of all pixels to white. After all pixels are in the same display driving step, 0 V is applied to the common electrode 22 and applied to the pixel electrode 21.
  • Example 3 In the same display driving step for all pixels, the display state of all pixels is changed to white by the operation of selecting all scanning lines simultaneously for 100 ms with +15 V applied to the common electrode 22 and ⁇ 15 V applied to the pixel electrode 21. Later, 0V is applied to the common electrode 22, + 15V is applied to the pixel electrode 21 according to the next display image data, + 15V is applied to the pixel whose display state is to be changed, and 0V is applied to the pixel whose display state is not changed.
  • a gradation display driving step for repeating a scanning operation for sequentially selecting lines 60 times is performed, and a stop step for applying the same potential as the common electrode by applying 0 V to the pixel electrode 21 of the pixel that has reached the gradation to be displayed is performed. It was.
  • Example 4 After -15V is applied to the common electrode 22 and + 15V is applied to the pixel electrode, all scanning lines are simultaneously selected for 100 ms, and then + 15V is applied to the common electrode 22 and -15V is applied to the pixel electrode 21. In the state where all the scanning lines are simultaneously applied for 100 ms in a state where voltage is applied, 0 V is applied to the common electrode 22 after the same pixel display driving step for changing the display state of all pixels to white by the operation of selecting all the scanning lines.
  • Example 5 In the gradation display driving step of Example 2, the scanning operation was repeated 31 times so that all the pixels were displayed in the intermediate gradation 1 display state.
  • Example 6 In the gradation display driving step of Example 2, the scanning operation was repeated 30 times so that all the pixels were in the display state of intermediate gradation 2.
  • Example 7 In the gradation display driving step of Example 2, the scanning operation was repeated 29 times to bring all pixels into the display state of intermediate gradation 3.
  • Example 8 Reverse scan insertion drive
  • the scan operation is repeated 15 times, then the scan operation is performed once with + 15V applied to the pixel electrode, and then the scan operation is performed with ⁇ 15V applied to the pixel electrode again.
  • the scan operation is performed with + 15V applied to the pixel electrode again.
  • Example 9 Block scan driving
  • a pause period of 10 scan operations is provided, and then the scan operation is repeated 15 times so that all pixels are in a display state of intermediate grayscale 5.
  • Example 10 Combination of reverse scan insertion drive and block scan drive
  • a scan operation is performed once in a state where +15 V is applied to the pixel electrode after providing a pause period of 10 scan operations. After a pause period of 10 operations, the scan operation was repeated 15 times with -15 V applied to the pixel electrode, so that all the pixels were set to the display state of the intermediate gradation 5.
  • Example 3 In the stop step, display was performed by driving different from that in Example 2 only that the pixel electrode was in a high impedance state.
  • the reflectance (Y value) was measured using a spectrocolorimeter “SC-P” manufactured by Suga Test Instruments Co., Ltd.
  • the light source used for the measurement was D65, a 10 ° field of view, the measurement hole was ⁇ 15, and the specular reflection was excluded.
  • evaluation item C gradation display performance
  • the number of scans required to shift from the reflectance obtained in evaluation A to the reflectance obtained in evaluation B is the maximum value of the intermediate gradation that can be expressed.
  • the number of scans required was defined as gradation display performance.
  • the scanning was changed from 1 to 60 times in the gradation display driving step and stopped, and the reflectance after the application of each scanning number was measured and evaluated.
  • scanning number is 64 times or more: A” “scanning number is 32 times or more and less than 64 times: ⁇ ” “scanning number is 16 times or more and less than 32 times: ⁇ ” “scanning number is 15 times or less: x” did.
  • the electrophoretic display device according to the second embodiment differs from the electrophoretic display device according to the first embodiment in the stopping step.
  • the electrophoretic display device according to the second embodiment has the same configuration as the electrophoretic display device according to the first embodiment.
  • the electrophoretic display device according to the second embodiment is the same as the electrophoretic display device according to the first embodiment except for the stop step (all pixel identical display drive step and gradation display drive step). ).
  • stop step all pixel identical display drive step and gradation display drive step.
  • the potential of the pixel electrode 21 for each pixel is set to a high impedance state to scan a signal.
  • An opening operation is performed to supply (see FIG. 13B). Since the pixel electrode of the target pixel is opened in the stop step after the gradation display driving step is completed, the driving voltage is held until the charge accumulated in the target pixel is spontaneously discharged. Memory performance can be improved.
  • FIG. 13 is an explanatory diagram of a short-circuit operation and an open operation when the gradation drive control is finished in the electrophoretic display device 1 according to the present embodiment.
  • 13A shows a short-circuit operation at the stop step
  • FIG. 13B shows an open operation during the gradation display driving step
  • FIG. 13C shows an open operation at the stop step.
  • the scanning signal for the scanning line Y is turned on, and the voltage applied to the pixel electrode 21 via the data line X is the same as the voltage applied to the common electrode 22. Set to potential.
  • the data line X is set to a high impedance state by some method as shown in FIG. 13B, or the scanning line Y is set to an off potential as shown in FIG. Set to state.
  • the former is different in that the scanning signal for the scanning line Y is on-potential, while the latter is the scanning signal for the scanning line Y is off-potential.
  • FIG. 14 is an explanatory diagram of a stop step in a pixel for which the gradation driving step has been completed in the electrophoretic display device 1 according to the present embodiment.
  • FIG. 14A shows a waveform when a pixel for which the gradation display driving step has been completed by the sequential short circuit method for each pixel is short-circuited at the next scanning timing, and in FIG. 14B, the gradation display is performed by the sequential opening method for each pixel.
  • the waveform in the case where the pixel for which the driving step has been completed is opened at the timing of the next search is shown.
  • the fifth scanning signal is supplied to the display pixel 20 as shown in FIG. 14A.
  • the pixel electrode 21 and the common electrode 22 are set to the same voltage (here, Vmid (0 V)). In this case, the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are removed at the timing when the fifth scanning signal is supplied.
  • the pixel electrode 21 is placed in a high impedance state at the timing when the fifth and subsequent scanning signals are supplied to the display pixel 20. As driven. As a result, the charge accumulated in the storage capacitor 25 in the fourth scan is gradually discharged.
  • the drive voltage is held until the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are naturally discharged. Therefore, the memory performance in the display unit 2 can be improved.
  • an image is displayed on the display unit 2 by sequentially executing the same pixel display driving step, gradation display driving step, and stop step.
  • a gradation display driving step is once performed across the same display driving step for all pixels, and a stop step is performed.
  • the common swing is applied in the same display driving step for all pixels, a high contrast white or black display can be realized.
  • the gradation display driving step since the driving of each pixel electrode 21 is controlled in a state where it is fixed to the intermediate potential Vmid without applying the common swing, a fine gradation change can be realized.
  • the memory performance in the display device can be improved. It becomes. As a result, it is possible to improve the black and white binary display performance and improve the gradation expression performance.
  • an erasing driving may be performed to prevent an afterimage phenomenon in which the currently displayed image appears to remain dull after the next image is written.
  • This afterimage erasing drive may be performed by simultaneous selection of all scanning lines using the above-mentioned common swing, or may be performed by sequential selection of scanning lines. Further, it may be realized by such driving without using the common swing. In addition, any means other than these may be used as long as the driving can prevent the afterimage phenomenon.
  • a substrate (hereinafter referred to as ITO-PET) on which a transparent electrode having a surface resistance of 250 ⁇ / ⁇ is formed on indium tin oxide (tin-doped indium oxide) on a PET film. Used).
  • the common electrode 22 is formed with microcells having a height of 20 ⁇ m and a pitch of 300 ⁇ m for partitioning ink.
  • the periphery of the electrophoretic display ink 23 was sealed with a UV curable adhesive so that the distance between the electrodes (between the pixel electrode 21 and the common electrode 22) was 20 ⁇ m and the display area was 50 mm ⁇ 40 mm.
  • One panel configured as described above is hereinafter referred to as a single cell.
  • the electrical characteristics of the ink are a volume resistivity of 10 10 ( ⁇ cm) and a relative dielectric constant of 3.
  • the electrophoretic display ink 23 includes white particles 82 and black particles 83.
  • the white particles 82 are negatively charged.
  • the common electrode 22 has a higher voltage than the pixel electrode 21, the white particles 82 gather on the common electrode 22 side, and the display surface side (the common electrode 22 side) displays white.
  • the black particles 83 are positively charged.
  • the common electrode 22 has a lower voltage than the pixel electrode 21, the black particles 83 gather on the common electrode 22 side, and the display surface side (common electrode 22 side) is black.
  • the single cell was connected to a holding capacitor 25 having a capacitance of 14.7 ⁇ F in parallel, and this was regarded as one pixel, and a verification experiment was performed.
  • the scanning line selection time was set to 20 ⁇ s.
  • the time required to supply the scanning signal for one frame is 4.8 ms. Accordingly, a voltage of 20 ⁇ s is applied to the single cell within one frame of 4.8 ms.
  • the number of frames was changed in accordance with the gradation.
  • one frame is set to 100 ms, and the voltage is applied to all the pixels for 100 ms.
  • the common electrode 22 is set to 0 V, and +15 V is applied to the pixel electrode 21, so that the common electrode 22 side (display surface side) is white.
  • a potential difference of 15 V was obtained as a voltage for moving the particles 82.
  • a potential difference of 15V was obtained as a voltage for moving the black particles 83 to the common electrode 22 side (display surface side).
  • Example 11 In the same display driving step for all the pixels, the scanning operation for sequentially selecting the scanning lines in a state where +15 V is applied to the common electrode 22 and ⁇ 15 V is applied to the pixel electrode 21 is repeated 20 times to change the display state of all pixels to white. Later, 0V is applied to the common electrode 22, + 15V is applied to the pixel electrode 21 according to the next display image data, + 15V is applied to the pixel whose display state is to be changed, and 0V is applied to the pixel whose display state is not changed.
  • a gradation display driving step in which the scanning operation for sequentially selecting lines is repeated 60 times is performed, and a stop step is performed in which the pixel electrode 21 of the pixel that has reached the gradation to be displayed is brought into a high impedance state.
  • Example 12 After repeating the scanning operation of sequentially selecting scanning lines with -15V applied to the common electrode 22 and + 15V applied to the pixel electrode, + 15V is applied to the common electrode 22 and -15V is applied to the pixel electrode 21.
  • a scan operation for sequentially selecting scanning lines in a state where voltage is applied is repeated 20 times to change the display state of all pixels to white.
  • 0 V is applied to the common electrode 22 and applied to the pixel electrode 21.
  • Is a gradation display drive in which + 15V is applied to a pixel whose display state is to be changed in accordance with the next display image data, and 0V is applied to a pixel whose display state is not to be changed to sequentially select a scanning line 60 times.
  • a step was performed to stop the pixel electrode 21 of the pixel that reached the gradation to be displayed in a high impedance state.
  • Example 13 In the same display driving step for all pixels, the display state of all pixels is changed to white by the operation of selecting all scanning lines simultaneously for 100 ms with +15 V applied to the common electrode 22 and ⁇ 15 V applied to the pixel electrode 21. Later, 0V is applied to the common electrode 22, + 15V is applied to the pixel electrode 21 according to the next display image data, + 15V is applied to the pixel whose display state is to be changed, and 0V is applied to the pixel whose display state is not changed.
  • a gradation display driving step in which the scanning operation for sequentially selecting lines is repeated 60 times is performed, and a stop step is performed in which the pixel electrode 21 of the pixel that has reached the gradation to be displayed is brought into a high impedance state.
  • Example 14 After -15V is applied to the common electrode 22 and + 15V is applied to the pixel electrode, all scanning lines are simultaneously selected for 100 ms, and then + 15V is applied to the common electrode 22 and -15V is applied to the pixel electrode 21. In the state where all the scanning lines are simultaneously applied for 100 ms in a state where voltage is applied, 0 V is applied to the common electrode 22 after the same pixel display driving step for changing the display state of all pixels to white by the operation of selecting all the scanning lines.
  • a step was performed to stop the pixel electrode 21 of the pixel that reached the gradation to be displayed in a high impedance state.
  • Example 15 In the gradation display driving step of Example 12, the scanning operation was repeated 31 times so that all the pixels were displayed in the intermediate gradation 1 display state.
  • Example 16 In the gradation display driving step of Example 12, the scanning operation was repeated 30 times to bring all pixels into the display state of intermediate gradation 2.
  • Example 17 In the gradation display driving step of Example 12, the scanning operation was repeated 29 times to bring all the pixels into the display state of the intermediate gradation 3.
  • Example 18 Reverse scan insertion drive
  • the scan operation was performed once with + 15V applied to the pixel electrode, and then the scan operation was performed with ⁇ 15V applied again to the pixel electrode. was repeated 15 times to bring all the pixels into the display state of the intermediate gradation 4.
  • Example 19 Block scan drive
  • a scanning operation is repeated 15 times, and then a pause period for 10 scanning operations is provided, and then the scanning operation is repeated 15 times to bring all pixels into the display state of intermediate gradation 5.
  • Example 20 Combination of reverse scan insertion drive and block scan drive
  • a scan operation is performed once in a state in which +15 V is applied to the pixel electrode after providing a pause period for 10 scan operations. After a pause period of 10 operations, the scan operation was repeated 15 times with -15 V applied to the pixel electrode, so that all the pixels were set to the display state of the intermediate gradation 5.
  • the reflectance (Y value) was measured using a spectrocolorimeter “SC-P” manufactured by Suga Test Instruments Co., Ltd.
  • the light source used for the measurement was D65, a 10 ° field of view, the measurement hole was ⁇ 15, and the specular reflection was excluded.
  • the scanning was changed from 1 to 60 times in the gradation display driving step and stopped, and the reflectance after the application of each scanning number was measured and evaluated.
  • scanning number is 64 times or more: A” “scanning number is 32 times or more and less than 64 times: ⁇ ” “scanning number is 16 times or more and less than 32 times: ⁇ ” “scanning number is 15 times or less: x” did.
  • a display device using electrophoretic ink can maintain the display without giving energy after displaying the image, but the position of the particles slightly changes due to the discharge of electric charges stored in the particles and the influence of gravity, etc. There is a phenomenon that decreases. Specifically, the reflectance of the white display portion is reduced, and the reflectance of the black display portion is increased. In order to evaluate the degree of deterioration in display quality, the deterioration state was judged by looking at the display after being left for 3 days after the display rewriting. In the table, “change in display performance cannot be realized: ⁇ ”, “display deterioration can be realized: ⁇ ”, “display performance is significantly reduced: ⁇ ”.
  • FIG. 19 shows the reflectance after the gradation display driving step of evaluation in Examples 15 to 20.
  • the electrophoretic display ink 23 is composed of an electrophoretic display liquid composed of white particles 82, black particles 83, and a dispersion medium 81, and this is used as electronic ink has been described.
  • the electrophoretic display ink 23 used in the electrophoretic display device 1 according to the present invention is not limited to this and can be appropriately changed.
  • a configuration in which electronic ink is filled in a microcapsule can be employed.

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Abstract

In order to simultaneously achieve an improvement in display performance such as contrast and reflectance, and an improvement in precision gradation display performance, an electrophoretic display device and a method for driving the electrophoretic display device are provided, said device and method being characterized by being provided with: a step for identically driving all pixels, wherein all pixel electrodes (21) are placed in an identical display state by a common swing that changes the potential of common electrodes (22); a gradation display drive step, wherein the potential of the common electrodes (22) is fixed at an intermediate potential of the potential applied by the common swing to the common electrodes (22), a number of scans is controlled in such a manner that target pixels attain a desired gradation, while pixel signals are applied to a plurality of data lines (X) corresponding to the target pixels, and the aforementioned pixel electrodes are placed in a high impedance state after the final scan; and a stopping step, wherein a short circuit is produced between the pixel electrodes (21) and the common electrodes (22) of the target pixels once the target pixels have attained the desired gradation.

Description

電気泳動表示装置の駆動方法及び電気泳動表示装置Electrophoretic display device driving method and electrophoretic display device
　本発明は、電界等の作用により可逆的に視認状態を変化させる電気泳動表示装置の駆動方法及び電気泳動表示装置に関する。 The present invention relates to an electrophoretic display device driving method and an electrophoretic display device that reversibly change a visual state by the action of an electric field or the like.
　電子ペーパーに適した表示装置として、電気泳動表示インクにより画像を形成する電気泳動表示装置が知られている。一般的な電気泳動表示装置は、表示画素がマトリクス状に配置され、各表示画素に電気泳動表示インクが封入されると共に一対の電極が設けられる。データ線駆動回路からデータ線及びＴＦＴを介して各表示画素の一方の電極（画素電極）に画素信号を供給し、各表示画素の電気泳動表示インクに画素信号（駆動電圧）が印加されるように走査線駆動回路から各表示画素（画素電極）のＴＦＴに走査線を介して走査信号を供給する。走査信号は矩形波の電圧からなる信号（パルス信号）であり、各走査線はパルス幅の期間だけＴＦＴをオンして画素電極に画素信号が印加される。走査線が選択されている間（ＴＦＴオン期間）のみ、各表示画素には画素電極と共通電極の電位差が駆動電圧として印加される。 An electrophoretic display device that forms an image with electrophoretic display ink is known as a display device suitable for electronic paper. In a general electrophoretic display device, display pixels are arranged in a matrix, and electrophoretic display ink is sealed in each display pixel and a pair of electrodes is provided. A pixel signal is supplied from the data line driving circuit to one electrode (pixel electrode) of each display pixel via the data line and the TFT, and the pixel signal (driving voltage) is applied to the electrophoretic display ink of each display pixel. In addition, a scanning signal is supplied from the scanning line driving circuit to the TFT of each display pixel (pixel electrode) through the scanning line. The scanning signal is a signal (pulse signal) composed of a rectangular wave voltage, and each scanning line turns on the TFT for a period of the pulse width and applies the pixel signal to the pixel electrode. Only while the scanning line is selected (TFT on period), the potential difference between the pixel electrode and the common electrode is applied to each display pixel as a driving voltage.
　電気泳動表示装置では、各画素の電気泳動表示インクを、より高い電圧にて駆動した方が画像品質（コントラスト等）を向上可能である。このため、スイッチング素子を用いたパネルにおいて、共通電極電位を変動させることでより大きな駆動電圧を印加させる方法などが採用されている（例えば、特許文献１参照）。 In the electrophoretic display device, it is possible to improve the image quality (contrast and the like) by driving the electrophoretic display ink of each pixel at a higher voltage. For this reason, in a panel using switching elements, a method of applying a larger driving voltage by changing the common electrode potential is adopted (for example, see Patent Document 1).
特開２００２－１４９１１５号公報JP 2002-149115 A
　上記のとおり、電気泳動表示装置では、より高い電圧を用いて駆動することで高速書換や高白反射率、高コントラストが達成されるものであるが、その後に階調表示する用途を想定した場合、次のような問題がある。すなわち、高い電圧を用いて階調表示しようとすると、画素電極と共通電極の間に印加される駆動電圧が大きいために電気泳動粒子の移動速度が速くなり、電気泳動粒子の位置（分布）の制御が難しくなって階調表示性能が大幅に低下するなどの問題があった。 As described above, in an electrophoretic display device, high-speed rewriting, high white reflectance, and high contrast can be achieved by driving using a higher voltage, but when an application for gradation display is assumed thereafter There are the following problems. That is, when attempting to display gradation using a high voltage, the moving voltage of the electrophoretic particles increases because the drive voltage applied between the pixel electrode and the common electrode is large, and the position (distribution) of the electrophoretic particles There are problems such as difficulty in control and a significant reduction in gradation display performance.
　本発明は、このような問題点に鑑みてなされたものであり、コントラストや反射率などの表示性能の向上と精密な階調表示性能の向上を同時に実現することができる電気泳動表示装置の駆動方法及び電気泳動表示装置を提供することを目的とする。 The present invention has been made in view of such problems, and drives an electrophoretic display device capable of simultaneously improving display performance such as contrast and reflectance and improving precision gradation display performance. It is an object to provide a method and an electrophoretic display device.
　本発明の電気泳動表示装置の駆動方法は、少なくとも一方が光透過性を有する一対の基板と、一方の前記基板の基板面にマトリクス状に配置された複数の画素電極と、他方の前記基板の基板面に前記複数の画素電極に対向して配置された共通電極と、前記基板間に封入され、少なくとも１又は２種類以上の電気泳動粒子からなる電気泳動表示インクと、前記画素電極が行毎に接続された複数のデータ線に対して個別に画素信号を供給する第１の駆動回路と、前記複数のデータ線上に夫々設けられ、オン状態において当該データ線に供給される前記画素信号を対応する前記画素電極に印加する複数のスイッチと、前記スイッチが列毎に接続された複数の走査線を、前記スイッチをオン状態にする走査信号によって走査する第２の駆動回路と、前記各画素電極と前記共通電極との間にそれぞれ並列に接続された複数の保持容量と、を具備した電気泳動表示装置の駆動方法であって、前記共通電極の電位を変化させるコモン振りによって全画素を同一の表示状態にする全画素同一表示駆動ステップと、前記共通電極の電位を当該共通電極にコモン振りで印加された電位の中間電位に固定され、対象画素に対応した複数のデータ線に画素信号が印加された状態で、対象画素が所望の階調となるように走査回数を制御し、最後の走査後に前記画素電極をハイインピーダンス状態とする階調表示駆動ステップと、対象画素が所望の階調に到達した後、当該対象画素の前記画素電極と前記共通電極との間を短絡する停止ステップと、を具備したことを特徴とする。 An electrophoretic display device driving method according to the present invention includes a pair of substrates, at least one of which is light transmissive, a plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates, and the other substrate. A common electrode disposed on the substrate surface so as to face the plurality of pixel electrodes, an electrophoretic display ink enclosed between the substrates and made of at least one or two or more types of electrophoretic particles, and the pixel electrodes arranged for each row A first driving circuit that individually supplies pixel signals to a plurality of data lines connected to the plurality of data lines, and a pixel circuit that is provided on each of the plurality of data lines and that is supplied to the data lines in an on state. A plurality of switches to be applied to the pixel electrodes, a second drive circuit that scans a plurality of scanning lines to which the switches are connected for each column by a scanning signal for turning on the switches, A driving method of an electrophoretic display device comprising a plurality of storage capacitors connected in parallel between each pixel electrode and the common electrode, wherein all the electrodes are driven by a common swing that changes the potential of the common electrode. The same display driving step for setting all pixels to the same display state, and the potential of the common electrode is fixed to an intermediate potential of the potential applied to the common electrode by common swing, and a plurality of data lines corresponding to the target pixel are provided. A gradation display driving step of controlling the number of scans so that the target pixel has a desired gradation in a state where the pixel signal is applied, and setting the pixel electrode in a high impedance state after the last scan, and the target pixel is desired And a stop step of short-circuiting between the pixel electrode and the common electrode of the target pixel after reaching the gradation.
　この構成により、コモン振りによる高い電圧で、例えば白や黒の表示をはっきりと出した後、通常駆動の低い電圧で色の階調表示を制御することが可能となり、コントラストや反射率などの表示性能の向上と精密な階調表示性能の向上とを同時に実現することができることとなる。一般的に、通常よりも大きい駆動電圧で画素を駆動した場合、電気泳動粒子をより高密度で表示面に集めることとなるため粒子間の凝集力や電極面との付着力も高まってしまう。この凝集や付着をほぐすために同じ駆動電圧で階調表示駆動を実施するのが一般的だが、複数回走査による階調駆動を組み合わせることで、高い駆動電圧を印加することなしに、凝集や付着を解消することが可能となる。さらに、階調表示後の停止ステップにおいて、共通電極と画素電極の電位を等しくして短絡状態を作り、各画素の電気泳動インクと保持容量に蓄えられた電荷を除去することで、パネルの長寿命化を達成することができる。 With this configuration, it is possible to control color gradation display with a low voltage of normal driving after clearly displaying, for example, white or black display with a high voltage due to common swing, and display contrast, reflectance, etc. Improvement in performance and improvement in precise gradation display performance can be realized at the same time. In general, when a pixel is driven with a driving voltage larger than usual, electrophoretic particles are collected on the display surface at a higher density, so that the cohesive force between the particles and the adhesion force with the electrode surface are also increased. In order to loosen this aggregation and adhesion, it is common to perform gradation display drive at the same drive voltage, but by combining gradation drive by scanning multiple times, aggregation and adhesion can be done without applying a high drive voltage. Can be eliminated. Furthermore, in the stop step after gradation display, the potentials of the common electrode and the pixel electrode are made equal to create a short-circuit state, and the charge stored in the electrophoretic ink and the storage capacitor of each pixel is removed, thereby increasing the length of the panel. Life expectancy can be achieved.
　上記電気泳動表示装置の駆動方法において、前記全画素同一表示駆動ステップは、第１の電圧Ｖ１を前記共通電極に印加し、第２の電圧Ｖ２を画素信号として前記各データ線に印加した状態で前記複数の走査線を用いて全画素に一斉に駆動電圧を印加して全画素を第１の表示状態に変化させる駆動により全画素を同一の表示状態にすること、を含むコモン振りが適用されてもよい。 In the driving method of the electrophoretic display device, in the same display driving step for all pixels, a first voltage V1 is applied to the common electrode, and a second voltage V2 is applied to each data line as a pixel signal. A common swing is applied, which includes applying a driving voltage to all the pixels at once using the plurality of scanning lines and changing all the pixels to the first display state to bring all the pixels into the same display state. May be.
　上記電気泳動表示装置の駆動方法において、前記全画素同一表示駆動ステップは、第１の電圧Ｖ１を前記共通電極に印加し、第２の電圧Ｖ２を画素信号として前記各データ線に印加した状態で前記複数の走査線を順次走査する駆動を、１または複数フレーム繰り返すことで全画素を同一の表示状態にすること、を含むコモン振りが適用されてもよい。 In the driving method of the electrophoretic display device, in the same display driving step for all pixels, a first voltage V1 is applied to the common electrode, and a second voltage V2 is applied to each data line as a pixel signal. A common swing may be applied that includes driving the plurality of scanning lines sequentially to repeat one or a plurality of frames to bring all pixels into the same display state.
　上記電気泳動表示装置の駆動方法において、前記全画素同一表示駆動ステップは、第１の電圧Ｖ１を画素信号として前記各データ線に印加し、第２の電圧Ｖ２を前記共通電極に印加した状態で前記複数の走査線を用いて全画素に一斉に駆動電圧を印加して全画素を第１の表示状態に変化させる第１の印加動作と、前記第２の電圧Ｖ２を画素信号として前記各データ線に印加し、前記第１の電圧Ｖ１を前記共通電極に印加した状態で前記複数の走査線を用いて全画素に一斉に駆動電圧を印加し、全画素を前記第１の表示状態とは異なる第２の表示状態に変化させる第２の印加動作とを連続して行う一連の動作を１セットとして、この一連の動作を１または複数セット繰り返すこと、を含むコモン振りが適用されてもよい。 In the driving method of the electrophoretic display device, the same display driving step for all pixels is performed in a state where a first voltage V1 is applied to each data line as a pixel signal and a second voltage V2 is applied to the common electrode. A first application operation for applying a driving voltage to all the pixels at once using the plurality of scanning lines to change all the pixels to the first display state, and each data using the second voltage V2 as a pixel signal. A driving voltage is applied to all the pixels at once using the plurality of scanning lines in a state where the first voltage V1 is applied to the common electrode while applying the first voltage V1 to the common electrode. A common swing may be applied including a series of operations in which a second application operation for changing to a different second display state is continuously performed as one set, and repeating this series of operations one or more sets. .
　上記電気泳動表示装置の駆動方法において、前記全画素同一表示駆動ステップは、第１の電圧Ｖ１を画素信号として前記各データ線に印加し、第２の電圧Ｖ２を前記共通電極に印加した状態で前記複数の走査線を順次走査して全画素を第１の表示状態に変化させる第１の印加動作と、前記第２の電圧Ｖ２を画素信号として前記各データ線に印加し、前記第１の電圧Ｖ１を前記共通電極に印加した状態で前記複数の走査線を順次走査して全画素を前記第１の表示状態とは異なる第２の表示状態に変化させる第２の印加動作とを連続して行う一連の動作を１セットとして、この一連の動作を１または複数セット繰り返すこと、を含むコモン振りが適用されてもよい。 In the driving method of the electrophoretic display device, the same display driving step for all pixels is performed in a state where a first voltage V1 is applied to each data line as a pixel signal and a second voltage V2 is applied to the common electrode. A first application operation for sequentially scanning the plurality of scanning lines to change all pixels to a first display state; and applying the second voltage V2 to the data lines as a pixel signal; With the voltage V1 applied to the common electrode, the plurality of scanning lines are sequentially scanned to continuously perform a second application operation for changing all pixels to a second display state different from the first display state. A common swing including repeating a series of operations as one set or a plurality of sets may be applied.
　上記電気泳動表示装置の駆動方法において、前記階調表示駆動ステップは、対象画素を第１の極性の駆動電圧で繰り返し駆動して所望の階調に変化させる途中で、当該対象画素に第１の極性とは逆向きの第２の極性の駆動電圧を印加してもよい。 In the driving method of the electrophoretic display device, the gray scale display driving step includes a step of driving the target pixel repeatedly with a driving voltage of the first polarity and changing the target pixel to a desired gray scale while the first target pixel is applied to the target pixel. A driving voltage having a second polarity opposite to the polarity may be applied.
　上記電気泳動表示装置の駆動方法において、前記階調表示駆動ステップは、階調を表現するために必要な走査回数を、１フレーム又は複数フレームに相当する休止期間で分離されるいくつかのブロックに分け、前記ブロック単位で対象画素を走査してもよい。 In the driving method of the electrophoretic display device, the gradation display driving step includes dividing the number of scans necessary for expressing the gradation into several blocks separated by a pause period corresponding to one frame or a plurality of frames. The target pixel may be scanned in units of blocks.
　上記電気泳動表示装置の駆動方法において、前記ブロックと前記ブロックの間の前記休止期間において、対象画素の前記画素電極と前記共通電極との間を順次短絡してもよい。 In the driving method of the electrophoretic display device, the pixel electrode of the target pixel and the common electrode may be sequentially short-circuited in the pause period between the blocks.
　上記電気泳動表示装置の駆動方法において、前記ブロックと前記ブロックの間の前記休止期間において、対象画素の前記画素電極を順次開放してもよい。 In the driving method of the electrophoretic display device, the pixel electrodes of the target pixel may be sequentially opened in the pause period between the blocks.
　上記電気泳動表示装置の駆動方法において、前記ブロックの１つのブロック内で対象画素を第１の極性の駆動電圧で繰り返し駆動して階調変化させる途中で、当該対象画素に第１の極性とは逆向きの第２の極性の駆動電圧を印加してもよい。 In the driving method of the electrophoretic display device, the target pixel has the first polarity in the middle of changing the gradation by repeatedly driving the target pixel with the driving voltage having the first polarity in one of the blocks. A drive voltage having the second polarity in the reverse direction may be applied.
　上記電気泳動表示装置の駆動方法において、前記停止ステップは、対象画素が所望の階調に到達した後、前記対象画素電極に前記共通電極と同電位として短絡してもよい。 In the driving method of the electrophoretic display device, the stop step may be short-circuited to the target pixel electrode with the same potential as the common electrode after the target pixel reaches a desired gradation.
　上記電気泳動表示装置の駆動方法において、前記停止ステップは、全画素が所望の階調に到達した後、全画素の前記画素電極と前記共通電極との間を順次短絡してもよい。 In the driving method of the electrophoretic display device, the stop step may sequentially short-circuit between the pixel electrode and the common electrode of all the pixels after all the pixels reach a desired gradation.
　上記電気泳動表示装置の駆動方法において、前記停止ステップは、全画素が所望の階調に到達した後、全画素の前記画素電極と前記共通電極との間を一斉に短絡してもよい。 In the driving method of the electrophoretic display device, the stop step may simultaneously short-circuit between the pixel electrode and the common electrode of all the pixels after all the pixels reach a desired gradation.
　上記電気泳動表示装置の駆動方法において、前記階調表示駆動ステップと前記停止ステップの間に、休止期間を設けてもよい。 In the driving method of the electrophoretic display device, a pause period may be provided between the gradation display drive step and the stop step.
　本発明の電気泳動表示装置の駆動方法は、少なくとも一方が光透過性を有する一対の基板と、一方の前記基板の基板面にマトリクス状に配置された複数の画素電極と、他方の前記基板の基板面に前記複数の画素電極に対向して配置された共通電極と、前記基板間に封入され、少なくとも１又は２種類以上の電気泳動粒子からなる電気泳動表示インクと、前記画素電極が行毎に接続された複数のデータ線に対して個別に画素信号を供給する第１の駆動回路と、前記複数のデータ線上に夫々設けられ、オン状態において当該データ線に供給される前記画素信号を対応する前記画素電極に印加する複数のスイッチと、前記スイッチが列毎に接続された複数の走査線を、前記スイッチをオン状態にする走査信号によって走査する第２の駆動回路と、前記各画素電極と前記共通電極との間にそれぞれ並列に接続された複数の保持容量と、を具備した電気泳動表示装置の駆動方法であって、前記共通電極の電位を変化させるコモン振りによって全画素を同一の表示状態にする全画素同一表示駆動ステップと、前記共通電極の電位を当該共通電極にコモン振りで印加された電位の中間電位に固定され、対象画素に対応した複数のデータ線に画素信号が印加された状態で、対象画素が所望の階調となるように走査回数を制御する階調表示駆動ステップと、対象画素が所望の階調に到達した後、当該対象画素の前記画素電極を開放する停止ステップと、を具備したことを特徴とする。 An electrophoretic display device driving method according to the present invention includes a pair of substrates, at least one of which is light transmissive, a plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates, and the other substrate. A common electrode disposed on the substrate surface so as to face the plurality of pixel electrodes, an electrophoretic display ink enclosed between the substrates and made of at least one or two or more types of electrophoretic particles, and the pixel electrodes arranged for each row A first driving circuit that individually supplies pixel signals to a plurality of data lines connected to the plurality of data lines, and a pixel circuit that is provided on each of the plurality of data lines and that is supplied to the data lines in an on state. A plurality of switches to be applied to the pixel electrodes, a second drive circuit that scans a plurality of scanning lines to which the switches are connected for each column by a scanning signal for turning on the switches, A driving method of an electrophoretic display device comprising a plurality of storage capacitors connected in parallel between each pixel electrode and the common electrode, wherein all the electrodes are driven by a common swing that changes the potential of the common electrode. The same display driving step for setting all pixels to the same display state, and the potential of the common electrode is fixed to an intermediate potential of the potential applied to the common electrode by common swing, and a plurality of data lines corresponding to the target pixel are provided. A gradation display driving step for controlling the number of scans so that the target pixel has a desired gradation in a state where the pixel signal is applied, and after the target pixel reaches the desired gradation, the pixel of the target pixel And a stop step of opening the electrode.
　この構成により、コモン振りによる高い電圧で、例えば白や黒の表示をはっきりと出した後、通常駆動の低い電圧で色の階調表示を制御することが可能となり、コントラストや反射率などの表示性能の向上と精密な階調表示性能の向上とを同時に実現することができることとなる。一般的に、通常よりも大きい駆動電圧で画素を駆動した場合、電気泳動粒子をより高密度で表示面に集めることとなるため粒子間の凝集力や電極面との付着力も高まってしまう。この凝集や付着をほぐすために同じ駆動電圧で階調表示駆動を実施するのが一般的だが、複数回走査による階調駆動を組み合わせることで、高い駆動電圧を印加することなしに、凝集や付着を解消することが可能となる。さらに、階調表示できた後の停止ステップにおいて、対象画素の画素電極を開放することから、対象画素に蓄積された電荷が自然放電されるまで駆動電圧が保持されることから、表示装置におけるメモリ性を向上することが可能となる。この結果、コントラストや反射率などの表示性能の向上と精密な階調表示性能の向上を同時に実現することができ、さらに表示装置のメモリ性の向上を図ることができる。 With this configuration, it is possible to control color gradation display with a low voltage of normal driving after clearly displaying, for example, white or black display with a high voltage due to common swing, and display contrast, reflectance, etc. Improvement in performance and improvement in precise gradation display performance can be realized at the same time. In general, when a pixel is driven with a driving voltage larger than usual, electrophoretic particles are collected on the display surface at a higher density, so that the cohesive force between the particles and the adhesion force with the electrode surface are also increased. In order to loosen this aggregation and adhesion, it is common to perform gradation display drive at the same drive voltage, but by combining gradation drive by scanning multiple times, aggregation and adhesion can be done without applying a high drive voltage. Can be eliminated. Further, since the pixel electrode of the target pixel is opened in the stop step after the gradation display can be performed, the drive voltage is held until the electric charge accumulated in the target pixel is naturally discharged. It becomes possible to improve the property. As a result, it is possible to simultaneously improve display performance such as contrast and reflectance, and improve precision gradation display performance, and further improve memory performance of the display device.
　上記電気泳動表示装置の駆動方法において、前記全画素同一表示駆動ステップは、第１の電圧Ｖ１を前記共通電極に印加し、第２の電圧Ｖ２を画素信号として前記各データ線に印加した状態で前記複数の走査線を用いて全画素に一斉に駆動電圧を印加して全画素を第１の表示状態に変化させる駆動により全画素を同一の表示状態にすること、を含むコモン振りが適用されてもよい。 In the driving method of the electrophoretic display device, in the same display driving step for all pixels, a first voltage V1 is applied to the common electrode, and a second voltage V2 is applied to each data line as a pixel signal. A common swing is applied, which includes applying a driving voltage to all the pixels at once using the plurality of scanning lines and changing all the pixels to the first display state to bring all the pixels into the same display state. May be.
　上記電気泳動表示装置の駆動方法において、前記全画素同一表示駆動ステップは、第１の電圧Ｖ１を前記共通電極に印加し、第２の電圧Ｖ２を画素信号として前記各データ線に印加した状態で前記複数の走査線を順次走査する駆動を、１または複数フレーム繰り返すことで全画素を同一の表示状態にすること、を含むコモン振りが適用されてもよい。 In the driving method of the electrophoretic display device, in the same display driving step for all pixels, a first voltage V1 is applied to the common electrode, and a second voltage V2 is applied to each data line as a pixel signal. A common swing may be applied that includes driving the plurality of scanning lines sequentially to repeat one or a plurality of frames to bring all pixels into the same display state.
　上記電気泳動表示装置の駆動方法において、前記全画素同一表示駆動ステップは、第１の電圧Ｖ１を画素信号として前記各データ線に印加し、第２の電圧Ｖ２を前記共通電極に印加した状態で前記複数の走査線を用いて全画素に一斉に駆動電圧を印加して全画素を第１の表示状態に変化させる第１の印加動作と、前記第２の電圧Ｖ２を画素信号として前記各データ線に印加し、前記第１の電圧Ｖ１を前記共通電極に印加した状態で前記複数の走査線を用いて全画素に一斉に駆動電圧を印加し、全画素を前記第１の表示状態とは異なる第２の表示状態に変化させる第２の印加動作とを連続して行う一連の動作を１セットとして、この一連の動作を１または複数セット繰り返すこと、を含むコモン振りが適用されてもよい。 In the driving method of the electrophoretic display device, the same display driving step for all pixels is performed in a state where a first voltage V1 is applied to each data line as a pixel signal and a second voltage V2 is applied to the common electrode. A first application operation for applying a driving voltage to all the pixels at once using the plurality of scanning lines to change all the pixels to the first display state, and each data using the second voltage V2 as a pixel signal. A driving voltage is applied to all the pixels at once using the plurality of scanning lines in a state where the first voltage V1 is applied to the common electrode while applying the first voltage V1 to the common electrode. A common swing may be applied including a series of operations in which a second application operation for changing to a different second display state is continuously performed as one set, and repeating this series of operations one or more sets. .
　上記電気泳動表示装置の駆動方法において、前記全画素同一表示駆動ステップは、第１の電圧Ｖ１を画素信号として前記各データ線に印加し、第２の電圧Ｖ２を前記共通電極に印加した状態で前記複数の走査線を順次走査して全画素を第１の表示状態に変化させる第１の印加動作と、前記第２の電圧Ｖ２を画素信号として前記各データ線に印加し、前記第１の電圧Ｖ１を前記共通電極に印加した状態で前記複数の走査線を順次走査して全画素を前記第１の表示状態とは異なる第２の表示状態に変化させる第２の印加動作とを連続して行う一連の動作を１セットとして、この一連の動作を１または複数セット繰り返すこと、を含むコモン振りが適用されてもよい。 In the driving method of the electrophoretic display device, the same display driving step for all pixels is performed in a state where a first voltage V1 is applied to each data line as a pixel signal and a second voltage V2 is applied to the common electrode. A first application operation for sequentially scanning the plurality of scanning lines to change all pixels to a first display state; and applying the second voltage V2 to the data lines as a pixel signal; With the voltage V1 applied to the common electrode, the plurality of scanning lines are sequentially scanned to continuously perform a second application operation for changing all pixels to a second display state different from the first display state. A common swing including repeating a series of operations as one set or a plurality of sets may be applied.
　上記電気泳動表示装置の駆動方法において、前記階調表示駆動ステップは、対象画素を第１の極性の駆動電圧で繰り返し駆動して所望の階調に変化させる途中で、当該対象画素に第１の極性とは逆向きの第２の極性の駆動電圧を印加してもよい。 In the driving method of the electrophoretic display device, the gray scale display driving step includes a step of driving the target pixel repeatedly with a driving voltage of the first polarity and changing the target pixel to a desired gray scale while the first target pixel is applied to the target pixel. A driving voltage having a second polarity opposite to the polarity may be applied.
　上記電気泳動表示装置の駆動方法において、前記階調表示駆動ステップは、階調を表現するために必要な走査回数を、１フレーム又は複数フレームに相当する休止期間で分離されるいくつかのブロックに分け、前記ブロック単位で対象画素を走査してもよい。 In the driving method of the electrophoretic display device, the gradation display driving step includes dividing the number of scans necessary for expressing the gradation into several blocks separated by a pause period corresponding to one frame or a plurality of frames. The target pixel may be scanned in units of blocks.
　上記電気泳動表示装置の駆動方法において、前記ブロックと前記ブロックの間の前記休止期間において、対象画素の前記画素電極と前記共通電極との間を順次短絡してもよい。 In the driving method of the electrophoretic display device, the pixel electrode of the target pixel and the common electrode may be sequentially short-circuited in the pause period between the blocks.
　上記電気泳動表示装置の駆動方法において、前記ブロックと前記ブロックの間の前記休止期間において、対象画素の前記画素電極を順次開放してもよい。 In the driving method of the electrophoretic display device, the pixel electrodes of the target pixel may be sequentially opened in the pause period between the blocks.
　上記電気泳動表示装置の駆動方法において、前記ブロックの１つのブロック内で対象画素を第１の極性の駆動電圧で繰り返し駆動して階調変化させる途中で、当該対象画素に第１の極性とは逆向きの第２の極性の駆動電圧を印加してもよい。 In the driving method of the electrophoretic display device, the target pixel has the first polarity in the middle of changing the gradation by repeatedly driving the target pixel with the driving voltage having the first polarity in one of the blocks. A drive voltage having the second polarity in the reverse direction may be applied.
　上記全画素同一表示駆動に先立って、現在表示されている画像が次の画像を書き込んだ後もぼんやりと残って見える残像現象を防ぐための消去駆動が行われてもよい。この残像消去駆動は上記コモン振りを用いて全走査線同時選択によってなされてもよいし、走査線順次選択によってなされてもよい。また、コモン振りを用いないこれらの駆動にて実現してもよい。また、これら以外の方法でも、残像現象を防ぐことが可能な駆動であればどのような手段を用いてもよい。 Prior to the same display drive for all the pixels, an erasure drive may be performed to prevent an afterimage phenomenon in which the currently displayed image appears blurry after the next image is written. This afterimage erasing drive may be performed by simultaneous selection of all scanning lines using the above-mentioned common swing, or may be performed by sequential selection of scanning lines. Further, it may be realized by such driving without using the common swing. In addition, any means other than these may be used as long as the driving can prevent the afterimage phenomenon.
　本発明の電気泳動表示装置は、少なくとも一方が光透過性を有する一対の基板と、一方の前記基板の基板面にマトリクス状に配置された複数の画素電極と、他方の前記基板の基板面に前記複数の画素電極に対向して配置された共通電極と、前記基板間に封入され、１又は２種類以上の電気泳動粒子が分散する電気泳動表示インクと、前記画素電極が行毎に接続された複数のデータ線に対して個別に画素信号を供給する第１の駆動回路と、前記複数のデータ線上に夫々設けられ、オン状態において当該データ線に供給される前記画素信号を対応する前記画素電極に印加する複数のスイッチと、前記スイッチが列毎に接続された複数の走査線を、前記スイッチをオン状態にする走査信号によって走査する第２の駆動回路と、前記各画素電極と前記共通電極との間にそれぞれ並列に接続された複数の保持容量と、具備し、前記共通電極の電位を変化させるコモン振りによって全画素を同一の表示状態にした後、前記共通電極の電位を当該共通電極にコモン振りで印加された電位の中間電位に固定して、対象画素に対応した複数のデータ線に画素信号を印加した状態で、対象画素が所望の階調となるように走査回数を制御して階調表示し、対象画素が所望の階調に到達した後、当該対象画素の前記画素電極を開放することを特徴とする。 An electrophoretic display device according to the present invention includes a pair of substrates, at least one of which is light transmissive, a plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates, and a substrate surface of the other substrate. A common electrode disposed opposite to the plurality of pixel electrodes, an electrophoretic display ink sealed between the substrates, in which one or more types of electrophoretic particles are dispersed, and the pixel electrodes are connected for each row. A first driving circuit for individually supplying pixel signals to the plurality of data lines; and the pixels corresponding to the pixel signals provided on the plurality of data lines and supplied to the data lines in the ON state, respectively. A plurality of switches to be applied to the electrodes; a second drive circuit that scans a plurality of scanning lines to which the switches are connected for each column by a scanning signal for turning on the switches; A plurality of storage capacitors connected in parallel with the common electrode, respectively, and after making all pixels in the same display state by a common swing that changes the potential of the common electrode, the potential of the common electrode is The number of scans is adjusted so that the target pixel has a desired gradation in a state where the pixel signal is applied to a plurality of data lines corresponding to the target pixel while being fixed to an intermediate potential applied to the common electrode by common swing. Gradation is controlled to display, and after the target pixel reaches a desired gradation, the pixel electrode of the target pixel is opened.
　本発明によれば、コントラストや反射率などの表示性能の向上と精密な階調表示性能の向上を同時に実現することができ、さらに表示装置の長寿命化を図ることができる電気泳動表示装置の駆動方法及び電気泳動表示装置を提供できる。 According to the present invention, an electrophoretic display device capable of simultaneously improving display performance such as contrast and reflectance and improving precision gradation display performance and further extending the life of the display device. A driving method and an electrophoretic display device can be provided.
第１の実施の形態に係る電気泳動表示装置の全体構成図である。1 is an overall configuration diagram of an electrophoretic display device according to a first embodiment. 上記電気泳動表示装置における画素の電気的な構成を示す回路図である。It is a circuit diagram which shows the electrical structure of the pixel in the said electrophoretic display device. 上記電気泳動表示装置における表示部の部分断面図である。It is a fragmentary sectional view of the display part in the above-mentioned electrophoretic display device. 上記電気泳動表示装置における全走査線同時選択によるパルス方式によるコモン振りを用いた全画素同一表示駆動ステップの説明図である。It is explanatory drawing of the all pixel same display drive step using the common swing by the pulse system by all the scanning line simultaneous selection in the said electrophoretic display device. 上記電気泳動表示装置における走査線順次選択によるパルス方式によるコモン振りを用いた全画素同一表示駆動ステップの説明図である。It is explanatory drawing of the all pixel same display drive step using the common swing by the pulse system by the scanning line sequential selection in the said electrophoretic display device. 上記電気泳動表示装置における全走査線順次選択によるスイングパルス方式によるコモン振りを用いた全画素同一表示駆動ステップの説明図である。It is explanatory drawing of the all pixel same display drive step using the common swing by the swing pulse system by all the scanning line sequential selection in the said electrophoretic display device. 上記電気泳動表示装置における走査線順次選択によるスイングパルス方式によるコモン振りを用いた全画素同一表示駆動ステップの変更例の説明図である。It is explanatory drawing of the example of a change of the all pixel same display drive step using the common swing by the swing pulse system by the scanning line sequential selection in the said electrophoretic display device. 上記電気泳動表示装置における順次階調駆動方式を用いた階調表示駆動ステップの説明図である。It is explanatory drawing of the gradation display drive step using the sequential gradation drive system in the said electrophoretic display device. 上記電気泳動表示装置におけるブロックスキャン階調駆動方式を用いた階調表示駆動ステップの説明図である。It is explanatory drawing of the gradation display drive step using the block scan gradation drive system in the said electrophoretic display device. 上記電気泳動表示装置でブロックスキャン階調駆動方式と順次階調駆動方式とを用いた場合の駆動エネルギーの説明図である。It is explanatory drawing of the drive energy at the time of using a block scan gradation drive system and a sequential gradation drive system in the said electrophoretic display device. 上記電気泳動表示装置における逆スキャン挿入駆動方式を用いた階調駆動制御の説明図である。It is explanatory drawing of the gradation drive control using the reverse scan insertion drive system in the said electrophoretic display device. 上記電気泳動表示装置における逆スキャン挿入駆動方式を用いた階調駆動制御の説明図である。It is explanatory drawing of the gradation drive control using the reverse scan insertion drive system in the said electrophoretic display device. 上記電気泳動表示装置における階調駆動制御を終了する場合の短絡動作及び開放動作の説明図である。It is explanatory drawing of the short circuit operation | movement and open | release operation | movement in the case of complete | finishing the gradation drive control in the said electrophoretic display device. 上記電気泳動表示装置における階調駆動制御を終了する場合の波形の説明図である。It is explanatory drawing of the waveform in the case of complete | finishing the gradation drive control in the said electrophoretic display device. 上記電気泳動表示装置における一斉短絡方式を用いた停止ステップの説明図である。It is explanatory drawing of the stop step using the simultaneous short circuit system in the said electrophoretic display device. 上記電気泳動表示装置における順次短絡方式を用いた停止ステップの説明図である。It is explanatory drawing of the stop step using the sequential short circuit system in the said electrophoretic display device. 上記電気泳動表示装置における階調駆動制御を終了する場合の波形の説明図である。It is explanatory drawing of the waveform in the case of complete | finishing the gradation drive control in the said electrophoretic display device. 第１の実施の形態に係る電気泳動表示装置の実施例における駆動動作に関する検証結果の説明図である。It is explanatory drawing of the verification result regarding the drive operation in the Example of the electrophoretic display device which concerns on 1st Embodiment. 第２の実施の形態に係る電気泳動表示装置の実施例における駆動動作に関する検証結果の説明図である。It is explanatory drawing of the verification result regarding the drive operation in the Example of the electrophoretic display device which concerns on 2nd Embodiment.
（第１の実施の形態）
　以下、本発明の実施の形態について添付図面を参照して詳細に説明する。
　図１は、本発明の実施の形態に係る電気泳動表示装置の全体構成図である。図１に示すように、この電気泳動表示装置１は、マトリクス状に表示画素が配置された表示部２と、表示部２に画素信号を供給するデータ線駆動回路３と、表示部２に矩形波のパルス信号からなる走査信号を供給する走査線駆動回路４と、表示部２の各表示画素に共通電位を与える共通電位供給回路５と、装置全体の動作を制御するコントローラ６と、を備えて構成される。 (First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an overall configuration diagram of an electrophoretic display device according to an embodiment of the present invention. As shown in FIG. 1, the electrophoretic display device 1 includes a display unit 2 in which display pixels are arranged in a matrix, a data line driving circuit 3 that supplies pixel signals to the display unit 2, and a rectangular shape on the display unit 2. A scanning line driving circuit 4 for supplying a scanning signal composed of a pulse signal of a wave, a common potential supply circuit 5 for applying a common potential to each display pixel of the display unit 2, and a controller 6 for controlling the operation of the entire apparatus. Configured.
　コントローラ６は、データ線駆動回路３、走査線駆動回路４及び共通電位供給回路５を制御することで、現在ある画像を消去して全画素を同一の表示状態（全白又は全黒）にする全画素同一表示駆動ステップと、表示したい画像の階調データに応じてスキャン回数を変化させて階調画像を表示させる階調表示駆動ステップと、短絡動作を入れて画素が保持している電荷を放電する停止ステップと、を１画像表示する度に実行する。後述するように、全画素同一表示駆動ステップ、階調表示駆動ステップ及び停止ステップは、データ線駆動回路３から供給される画素信号、走査線駆動回路４から供給される走査信号、共通電位供給回路５から供給される電圧の組み合わせによって実現される。 The controller 6 controls the data line driving circuit 3, the scanning line driving circuit 4, and the common potential supply circuit 5 to erase the current image and set all pixels to the same display state (all white or all black). The same display driving step for all pixels, the gradation display driving step for displaying the gradation image by changing the number of scans according to the gradation data of the image to be displayed, and the charge held by the pixel by the short-circuit operation The discharging stop step is executed every time one image is displayed. As will be described later, the same display drive step, gradation display drive step, and stop step for all pixels are performed by the pixel signal supplied from the data line drive circuit 3, the scan signal supplied from the scan line drive circuit 4, and the common potential supply circuit. This is realized by a combination of voltages supplied from 5.
　表示部２には、データ線駆動回路３から列方向（Ｙ方向）に並列に伸びるｎ本のデータ線Ｘ１からＸｎが延在するとともに、これらのデータ線と交差して走査線駆動回路４から行方向（Ｘ方向）に並列に伸びるｍ本の走査線Ｙ１からＹｍが延在している。表示部２において、データ線（Ｘ１，Ｘ２，…Ｘｎ）と、走査線（Ｙ１，Ｙ２，…Ｙｍ）とが交差する各交差部に表示画素２０がそれぞれ形成されている。このように、表示部２には、ｎ行ｍ列のマトリクス状に複数の表示画素２０が配置されている。 In the display unit 2, n data lines X 1 to Xn extending in parallel in the column direction (Y direction) extend from the data line driving circuit 3, and intersect with these data lines from the scanning line driving circuit 4. The m scanning lines Y1 to Ym extend in parallel in the row direction (X direction). In the display unit 2, display pixels 20 are formed at each intersection where the data lines (X1, X2,... Xn) and the scanning lines (Y1, Y2,... Ym) intersect. Thus, the display unit 2 has a plurality of display pixels 20 arranged in a matrix of n rows and m columns.
　データ線駆動回路３は、コントローラ６から供給されるタイミング信号に基づいて、各データ線（Ｘ１，Ｘ２，…Ｘｎ）に画素信号を供給する。データ線駆動回路３は、高電位Ｖ１（例えば、１５Ｖ）、低電位Ｖ２（例えば、－１５Ｖ）、Ｖ１とＶ２の中間電圧であるＶｍｉｄ（例えば、０Ｖ）の３つの電位、およびハイインピーダンス状態を選択可能に構成されている。 The data line driving circuit 3 supplies pixel signals to the data lines (X1, X2,... Xn) based on the timing signal supplied from the controller 6. The data line driving circuit 3 has a high potential V1 (for example, 15 V), a low potential V2 (for example, −15 V), three potentials Vmid (for example, 0 V) that is an intermediate voltage between V1 and V2, and a high impedance state. It is configured to be selectable.
　走査線駆動回路４は、コントローラ６から供給されるタイミング信号に基づいて、各走査線（Ｙ１，Ｙ２，…Ｙｍ）に任意のパルス幅の走査信号を同時に又は順番に供給する。これにより、駆動対象となる表示画素２０に対して、走査信号が供給される。走査信号によって階調制御対象となる画素を選択するので、走査信号のことを選択信号と呼ぶこともできる。 The scanning line driving circuit 4 supplies a scanning signal having an arbitrary pulse width simultaneously or sequentially to each scanning line (Y1, Y2,... Ym) based on the timing signal supplied from the controller 6. Thereby, a scanning signal is supplied to the display pixel 20 to be driven. Since a pixel to be subjected to gradation control is selected by the scanning signal, the scanning signal can also be called a selection signal.
　表示部２を構成する各表示画素２０には、共通電位供給回路５から共通電位線１１を介して共通電位Ｖｃｏｍが印加される。共通電位供給回路５は、共通電位Ｖｃｏｍとして、高電位Ｖ１（例えば、１５Ｖ）、低電位Ｖ２（例えば、－１５Ｖ）、Ｖ１とＶ２の中間電圧であるＶｍｉｄ（例えば、０Ｖ）の３つの電位、およびハイインピーダンス状態を選択可能に構成されている。すなわち、共通電位供給回路５は、データ線駆動回路３が画素信号として選択可能な３つの電圧Ｖ１，Ｖ２，Ｖｍｉｎと同一電圧を選択可能に構成されている。 The common potential Vcom is applied from the common potential supply circuit 5 via the common potential line 11 to each display pixel 20 constituting the display unit 2. The common potential supply circuit 5 includes, as the common potential Vcom, three potentials of a high potential V1 (for example, 15V), a low potential V2 (for example, −15V), and Vmid (for example, 0V) that is an intermediate voltage between V1 and V2. The high impedance state can be selected. That is, the common potential supply circuit 5 is configured to be able to select the same voltage as the three voltages V1, V2, and Vmin that the data line driving circuit 3 can select as pixel signals.
　コントローラ６は、クロック信号、スタートパルス等のタイミング信号を、データ線駆動回路３、走査線駆動回路４及び共通電位供給回路５に供給して各回路を制御する。例えば、コントローラ６は、表示対象画素の階調データをデータ線駆動回路３または共通電位供給回路５に供給する。データ線駆動回路３または共通電位供給回路５は、階調データに応じて書込みパルスの印加回数及び電圧値を決定し、走査線駆動回路４のフレーム走査（画素行選択）動作に同期して対象画素に画素信号または共通電位を供給する。 The controller 6 supplies timing signals such as a clock signal and a start pulse to the data line driving circuit 3, the scanning line driving circuit 4, and the common potential supply circuit 5 to control each circuit. For example, the controller 6 supplies the gradation data of the display target pixel to the data line driving circuit 3 or the common potential supply circuit 5. The data line driving circuit 3 or the common potential supply circuit 5 determines the number of application times of the write pulse and the voltage value according to the gradation data, and synchronizes with the frame scanning (pixel row selection) operation of the scanning line driving circuit 4. A pixel signal or a common potential is supplied to the pixel.
　図２は、表示画素２０の電気的な構成を示す等価回路図である。なお、表示部２にマトリクス状に配置された各表示画素２０は同一構成であるので、表示画素２０を構成する各部には共通の符号を付して説明する。 FIG. 2 is an equivalent circuit diagram showing an electrical configuration of the display pixel 20. In addition, since each display pixel 20 arrange | positioned at the display part 2 at the matrix form is the same structure, each part which comprises the display pixel 20 attaches | subjects a common code | symbol, and demonstrates it.
　表示画素２０は、画素電極２１と、共通電極２２と、電気泳動表示インク２３と、画素スイッチング用トランジスタ２４と、保持容量２５と、を備えている。画素スイッチング用トランジスタ２４は、例えばＴＦＴ（Ｔｈｉｎ　Ｆｉｌｍ　Ｔｒａｎｓｉｓｔｏｒ）で構成することができる。画素スイッチング用トランジスタ２４のゲートは、対応する行の走査線（Ｙ１，Ｙ２，…Ｙｍ）に電気的に接続されている。画素スイッチング用トランジスタ２４のソースは、対応する列のデータ線（Ｘ１，Ｘ２，…Ｘｎ）に電気的に接続されている。また、画素スイッチング用トランジスタ２４のドレインは、画素電極２１及び保持容量２５に電気的に接続されている。画素スイッチング用トランジスタ２４は、データ線駆動回路３からデータ線（Ｘ１，Ｘ２，…Ｘｎ）を介して供給される画素信号を、走査線駆動回路４から対応する行の走査線（Ｙ１，Ｙ２，…Ｙｍ）を介して供給される走査信号に応じたタイミングで、画素電極２１及び保持容量２５に出力する。 The display pixel 20 includes a pixel electrode 21, a common electrode 22, an electrophoretic display ink 23, a pixel switching transistor 24, and a storage capacitor 25. The pixel switching transistor 24 can be configured by, for example, a TFT (Thin Film Transistor). The gate of the pixel switching transistor 24 is electrically connected to the scanning line (Y1, Y2,... Ym) of the corresponding row. The source of the pixel switching transistor 24 is electrically connected to the data line (X1, X2,... Xn) of the corresponding column. The drain of the pixel switching transistor 24 is electrically connected to the pixel electrode 21 and the storage capacitor 25. The pixel switching transistor 24 receives the pixel signal supplied from the data line driving circuit 3 via the data lines (X1, X2,... Xn) and the scanning line (Y1, Y2, Y2) of the corresponding row from the scanning line driving circuit 4. ..., Ym), and output to the pixel electrode 21 and the storage capacitor 25 at a timing corresponding to the scanning signal supplied via.
　画素電極２１には、データ線駆動回路３からデータ線（Ｘ１，Ｘ２，…Ｘｎ）及び画素スイッチング用トランジスタ２４を介して、画素信号が供給される。画素電極２１は、電気泳動表示インク２３を介して共通電極２２と互いに対向して配置されている。共通電極２２は、共通電位Ｖｃｏｍが供給される共通電位線１１に電気的に接続されている。 A pixel signal is supplied to the pixel electrode 21 from the data line driving circuit 3 through the data lines (X1, X2,... Xn) and the pixel switching transistor 24. The pixel electrode 21 is disposed opposite to the common electrode 22 with the electrophoretic display ink 23 interposed therebetween. The common electrode 22 is electrically connected to the common potential line 11 to which the common potential Vcom is supplied.
　電気泳動表示インク２３は、少なくとも１種類の電気泳動粒子が分散された液状体であり、電極間に図示しない封止材にて漏れ出さないように保持されている。 The electrophoretic display ink 23 is a liquid material in which at least one type of electrophoretic particles is dispersed, and is held between the electrodes so as not to leak with a sealing material (not shown).
　保持容量２５は、誘電体膜を介して対向配置された一対の電極からなり、一方の電極が画素電極２１及び画素スイッチング用トランジスタ２４に電気的に接続され、他方の電極が共通電位線１１に電気的に接続されている。例えば、保持容量２５は、１回の選択で表示画素２０の電極間に生じる駆動電圧がオフした後も電気泳動粒子を所定期間よりも長い時間に亘り駆動電圧に応じた方向へ移動させ続ける電荷を蓄積可能な容量サイズを有する。 The storage capacitor 25 is made up of a pair of electrodes arranged opposite to each other with a dielectric film therebetween, one electrode is electrically connected to the pixel electrode 21 and the pixel switching transistor 24, and the other electrode is connected to the common potential line 11. Electrically connected. For example, the storage capacitor 25 continues to move the electrophoretic particles in a direction corresponding to the drive voltage for a longer time than a predetermined period even after the drive voltage generated between the electrodes of the display pixel 20 is turned off by one selection. It has a capacity size that can be stored.
　次に、電気泳動表示装置１の表示部２の具体的な構成について、図３に基づいて説明する。図３は、電気泳動表示装置１における表示部２の部分断面図である。図３に示すように、表示部２は、素子基板２８と、対向基板２９とが、図示しないスペーサを介して対向配置され、基板間に電気泳動表示インク２３が封入された構成となっている。なお、本実施の形態では、対向基板２９側に画像を表示することを前提として説明する。 Next, a specific configuration of the display unit 2 of the electrophoretic display device 1 will be described with reference to FIG. FIG. 3 is a partial cross-sectional view of the display unit 2 in the electrophoretic display device 1. As shown in FIG. 3, the display unit 2 has a configuration in which an element substrate 28 and a counter substrate 29 are arranged to face each other via a spacer (not shown), and an electrophoretic display ink 23 is sealed between the substrates. . In the present embodiment, description will be made on the assumption that an image is displayed on the counter substrate 29 side.
　素子基板２８は、例えば、ガラス又はプラスチック等からなる基板である。素子基板２８上には、ここでは図示を省略するが、図２を参照して上述した画素スイッチング用トランジスタ２４、保持容量２５、走査線（Ｙ１，Ｙ２，…Ｙｍ）、データ線（Ｘ１，Ｘ２，…Ｘｎ）、共通電位線１１などが作り込まれた積層構造が形成されている。この積層構造の上層側に、複数の画素電極２１がマトリクス状に設けられている。 The element substrate 28 is a substrate made of, for example, glass or plastic. Although not shown here on the element substrate 28, the pixel switching transistor 24, the storage capacitor 25, the scanning lines (Y1, Y2,... Ym), and the data lines (X1, X2) described above with reference to FIG. ,... Xn), and a laminated structure in which the common potential line 11 is formed. A plurality of pixel electrodes 21 are provided in a matrix on the upper layer side of the stacked structure.
　対向基板２９は、例えば、ガラス又はプラスチック等からなる光透過性の基板である。対向基板２９における素子基板２８との対向面上には、共通電極２２が、複数の画素電極２１と対向して形成されている。共通電極２２は、例えば、マグネシウム銀（ＭｇＡｇ）、インジウムスズ酸化物（ＩＴＯ）、インジウム亜鉛酸化物（ＩＺＯ）などの透明導電材料から形成されている。 The counter substrate 29 is a light-transmitting substrate made of, for example, glass or plastic. On the surface of the counter substrate 29 facing the element substrate 28, the common electrode 22 is formed so as to face the plurality of pixel electrodes 21. The common electrode 22 is formed of a transparent conductive material such as magnesium silver (MgAg), indium tin oxide (ITO), indium zinc oxide (IZO), for example.
　電気泳動表示インク２３は、少なくとも正又は負に帯電した第１の色を有する電気泳動粒子とそれとコントラスト表示可能となるような第２の色に着色された分散媒とからなる構成や、少なくとも正又は負に帯電した第１の色を有する第１の電気泳動粒子と、第１の電気泳動粒子とは異なる帯電特性を有し、第１の色とコントラスト表示可能となるような第２の色を有する第２の電気泳動粒子と分散媒とからなる構成をとることが可能である。本実施の形態では、正に帯電した黒色粒子８３と、負に帯電した白色粒子８２と、これらの黒色粒子８３及び白色粒子８２を分散させる分散媒８１と、からなる構成を例にとって説明するが、これに限定されるものではない。すなわち、白色、黒色の粒子をコントラスト表示可能な範囲で任意に選択することにより、例えば、赤色、緑色、青色などの粒子に変えることによって、表示部２の表示面を赤色表示、緑色表示、青色表示などにすることができるものである。 The electrophoretic display ink 23 includes at least a positively or negatively charged electrophoretic particle having a first color and a dispersion medium colored in a second color so that contrast display is possible. Alternatively, the first electrophoretic particles having a negatively charged first color and the second color having a charging characteristic different from that of the first electrophoretic particles and capable of displaying contrast with the first color. It is possible to take a configuration comprising the second electrophoretic particles having a dispersion medium. In the present embodiment, a description will be given by taking as an example a configuration including positively charged black particles 83, negatively charged white particles 82, and a dispersion medium 81 in which the black particles 83 and the white particles 82 are dispersed. However, the present invention is not limited to this. That is, by arbitrarily selecting white and black particles within a range in which contrast display is possible, for example, by changing the particles to red, green, blue, or the like, the display surface of the display unit 2 is displayed in red, green, blue It can be displayed.
　画素電極２１と共通電極２２との間に、相対的に共通電極２２の電位が高くなるように電圧が印加された場合には、正に帯電した黒色粒子８３は、クーロン力によって画素電極２１側に引き寄せられるとともに、負に帯電した白色粒子８２は、クーロン力によって共通電極２２側に引き寄せられる。この結果、表示面側（共通電極２２側）には、白色粒子８２が集まり、表示部２の表示面は白色表示となる。一方、画素電極２１と共通電極２２との間に、相対的に画素電極２１の電位が高くなるように（相対的に共通電極２２の電位が低くなるように）電圧が印加された場合には、正に帯電した黒色粒子８３は、クーロン力によって共通電極２２側に引き寄せられるとともに、負に帯電した白色粒子８２は、クーロン力によって画素電極２１側に引き寄せられる。この結果、表示面側（共通電極２２側）には、黒色粒子８３が集まり、表示部２の表示面は黒色表示となる。 When a voltage is applied between the pixel electrode 21 and the common electrode 22 so that the potential of the common electrode 22 is relatively high, the positively charged black particles 83 are moved to the pixel electrode 21 side by Coulomb force. The negatively charged white particles 82 are attracted to the common electrode 22 side by the Coulomb force. As a result, white particles 82 gather on the display surface side (the common electrode 22 side), and the display surface of the display unit 2 displays white. On the other hand, when a voltage is applied between the pixel electrode 21 and the common electrode 22 such that the potential of the pixel electrode 21 is relatively high (so that the potential of the common electrode 22 is relatively low). The positively charged black particles 83 are attracted to the common electrode 22 side by the Coulomb force, and the negatively charged white particles 82 are attracted to the pixel electrode 21 side by the Coulomb force. As a result, the black particles 83 gather on the display surface side (common electrode 22 side), and the display surface of the display unit 2 is displayed in black.
　次に、以上のように構成された電気泳動表示装置１における駆動動作について説明する。階調画像を電気泳動表示装置１に表示させる駆動動作は、上述した全画素同一表示駆動ステップ、階調表示駆動ステップ及び停止ステップの３つに分割される。以下、これらの全画素同一表示駆動、階調表示駆動ステップ及び停止ステップについて、順番に説明する。 Next, the driving operation in the electrophoretic display device 1 configured as described above will be described. The drive operation for displaying the gradation image on the electrophoretic display device 1 is divided into the above-described all-pixel identical display drive step, gradation display drive step, and stop step. Hereinafter, the same display drive, gradation display drive step, and stop step for all the pixels will be described in order.
　まず、電気泳動表示装置１における全画素同一表示駆動ステップについて説明する。全画素同一表示駆動ステップでは、コモン振りを行って電気泳動表示装置の画素を一旦全て同一の表示状態にできる駆動方法であれば特に限定されるものではないが、以下に示す方法を用いることで、効果的に本発明の効果を奏することができるものである。 First, the same pixel display driving step in the electrophoretic display device 1 will be described. In the same display driving step for all pixels, the driving method is not particularly limited as long as it is a driving method that can perform common swinging so that all the pixels of the electrophoretic display device are once in the same display state. However, by using the following method, The effect of the present invention can be effectively achieved.
　全画素同一表示駆動ステップにおいては、共通電極２２に印加される共通電位Ｖｃｏｍを変化させるコモン振りが適用され、全ての表示画素２０が同一の表示状態に設定される。例えば、全画素同一表示駆動ステップにおいては、共通電極２２を画素電極２１に対して高電位に設定して全ての表示画素２０を第１の表示状態（例えば、全白状態）に変化させる第１の印加動作、もしくは共通電極２２を画素電極２１に対して低電位に設定して全ての表示画素２０を第２の表示状態（例えば、全黒状態）に変化させる第２の印加動作（以下、上記のような駆動方式を「パルス方式」と呼ぶ。）の少なくともどちらか一方の動作によって全画素を同一の表示状態とする。 In the same display driving step for all pixels, a common swing that changes the common potential Vcom applied to the common electrode 22 is applied, and all the display pixels 20 are set to the same display state. For example, in the same display driving step for all pixels, the common electrode 22 is set to a high potential with respect to the pixel electrode 21 to change all the display pixels 20 to the first display state (for example, all white state). Or a second application operation for setting all the display pixels 20 to a second display state (for example, an all black state) by setting the common electrode 22 to a low potential with respect to the pixel electrode 21 (hereinafter, referred to as “the second application operation”). The above driving method is referred to as “pulse method”.) All the pixels are brought into the same display state by at least one of the operations.
　このように、全画素同一表示駆動ステップにコモン振りを適用することにより、画素電極２１と共通電極２２との間に大きな電位差を確保でき、各表示画素２０（より具体的には、画素電極２１と共通電極２２との電極間）に大きな駆動電圧を印加できる。これにより、電気泳動表示インク２３内の電気泳動粒子（白粒子８２、黒粒子８３）に、より大きな運動エネルギーを与えることができる。この結果、電気泳動粒子を効率よく表示面側や背面側に移動させることができ、また、白及び黒の電気泳動粒子をきれいに分離することが可能となり、白黒のコントラストや反射率などの表示性能の向上が図られる。 Thus, by applying the common swing to the same display driving step for all the pixels, a large potential difference can be secured between the pixel electrode 21 and the common electrode 22, and each display pixel 20 (more specifically, the pixel electrode 21) can be secured. A large driving voltage can be applied between the electrode and the common electrode 22. Thereby, larger kinetic energy can be given to the electrophoretic particles (white particles 82, black particles 83) in the electrophoretic display ink 23. As a result, the electrophoretic particles can be efficiently moved to the display surface side and the back surface side, and the white and black electrophoretic particles can be separated cleanly, and display performance such as black-and-white contrast and reflectance. Is improved.
　全画素同一表示駆動ステップにコモン振りを適用することで得られる作用をより効果的に得るために、パルス方式の印加動作は１回だけではなく、前記第１の印加動作を複数回繰り返すことや、前記第２の印加動作を複数回繰り返し行っても良い。また、第１の印加動作と第２の印加動作を連続して行う一連の動作（セット）として、そのセットを１回又は複数回繰り返し行う方式（以下、「スイングパルス方式」と呼ぶ。）を用いても良い。なお、スイングパルス方式にて行われる第１の印加動作と第２の印加動作は、その回数がそれぞれ異なっていてもよい。 In order to more effectively obtain the action obtained by applying the common swing to the same display driving step for all pixels, the pulse-type application operation is not limited to once, but the first application operation may be repeated a plurality of times. The second application operation may be repeated a plurality of times. In addition, as a series of operations (sets) in which the first application operation and the second application operation are continuously performed, a method of repeating the set once or a plurality of times (hereinafter referred to as “swing pulse method”). It may be used. Note that the number of times of the first application operation and the second application operation performed by the swing pulse method may be different.
　本実施の形態に係る電気泳動表示装置１においては、全画素同一表示駆動ステップに適用されるコモン振りとして、例えば、全ての走査線Ｙ１～Ｙｍに対して同時に走査信号を供給して全ての表示画素２０に同時に駆動電圧を印加する方式（全走査線同時選択によるパルス方式、及び全走査線同時選択によるスイングパルス方式）と、各走査線Ｙ１～Ｙｍに対して順次に走査信号を供給して全ての表示画素２０に駆動電圧を順番に印加する方式（走査線順次選択によるパルス方式、及び走査線順選択によるスイングパルス方式）と、を選択できる。 In the electrophoretic display device 1 according to the present embodiment, as a common swing applied to the same display driving step for all pixels, for example, all scanning lines Y1 to Ym are simultaneously supplied with scanning signals to perform all display. A method of simultaneously applying a driving voltage to the pixels 20 (a pulse method by simultaneous selection of all scanning lines and a swing pulse method by simultaneous selection of all scanning lines) and a scanning signal are sequentially supplied to each of the scanning lines Y1 to Ym. A method of sequentially applying a driving voltage to all the display pixels 20 (a pulse method by scanning line sequential selection and a swing pulse method by scanning line order selection) can be selected.
　以下、全走査線同時選択によるパルス方式、走査線順次選択によるパルス方式、全走査線同時選択によるスイングパルス方式、走査線順次選択によるスイングパルス方式を用いたコモン振りについて、図４、図５、図６及び図７に基づいて説明する。図４は、本実施の形態に係る電気泳動表示装置１における全走査線同時選択によるパルス方式によるコモン振りを用いた全画素同一表示駆動ステップの説明図である。図５は、本実施の形態に係る電気泳動表示装置１における走査線順次選択によるパルス方式によるコモン振りを用いた全画素同一表示駆動ステップの説明図である。図６は、本実施の形態に係る電気泳動表示装置１における全走査線同時選択によるスイングパルス方式によるコモン振りを用いた全画素同一表示駆動ステップの説明図である。図７は、本実施の形態に係る電気泳動表示装置１における走査線順次選択によるスイングパルス方式によるコモン振りを用いた全画素同一表示駆動ステップの説明図である。 Hereinafter, a common pulse using a pulse method by simultaneous selection of all scanning lines, a pulse method by sequential selection of scanning lines, a swing pulse method by simultaneous selection of all scanning lines, and a swing pulse method by sequential selection of scanning lines will be described with reference to FIGS. This will be described with reference to FIGS. FIG. 4 is an explanatory diagram of the all pixel identical display driving step using the common swing by the pulse method by the simultaneous selection of all the scanning lines in the electrophoretic display device 1 according to the present embodiment. FIG. 5 is an explanatory diagram of the all pixel identical display driving step using the common swing by the pulse method by the scanning line sequential selection in the electrophoretic display device 1 according to the present embodiment. FIG. 6 is an explanatory diagram of the all pixel identical display driving step using the common swing by the swing pulse method by the simultaneous selection of all the scanning lines in the electrophoretic display device 1 according to the present embodiment. FIG. 7 is an explanatory diagram of the all pixel identical display driving step using the common swing by the swing pulse method by the scanning line sequential selection in the electrophoretic display device 1 according to the present embodiment.
　図４、図５、図６、及び図７に示すコモン振りにおいては、画素電極２１及び共通電極２２に印加される高電位の電圧Ｖ１として１５Ｖを用いる一方、低電位の電圧Ｖ２として－１５Ｖを用い、これらの中間電圧Ｖｍｉｄとして０Ｖを用いて説明する。 In the common swing shown in FIGS. 4, 5, 6 and 7, 15V is used as the high potential voltage V1 applied to the pixel electrode 21 and the common electrode 22, while −15V is used as the low potential voltage V2. In the following description, 0V is used as the intermediate voltage Vmid.
　図４に示すように、全走査線同時選択によるパルス方式を用いたコモン振りにおいては、共通電極２２に１５Ｖの電圧Ｖ１が印加され、画素電極２１に－１５Ｖの電圧Ｖ２が印加される。また、全ての走査線Ｙ１～Ｙｍに対して同時に走査信号（オン電位）が供給される。これにより、各表示画素２０の電気泳動表示インク２３には、Ｖ１－Ｖ２の駆動電圧（すなわち、３０Ｖ）が印加される。 As shown in FIG. 4, in the common swing using the pulse method by simultaneous selection of all scanning lines, a voltage V1 of 15V is applied to the common electrode 22 and a voltage V2 of −15V is applied to the pixel electrode 21. A scanning signal (ON potential) is simultaneously supplied to all the scanning lines Y1 to Ym. As a result, a drive voltage of V1-V2 (that is, 30V) is applied to the electrophoretic display ink 23 of each display pixel 20.
　図５に示すように、走査線順次選択によるパルス方式を用いたコモン振りにおいては、各走査線Ｙ１～Ｙｍに対して順次に走査信号（オン電位）が供給され、この走査信号が供給されるタイミングで該当する画素電極２１に電圧Ｖ２、共通電極２２に電圧Ｖ１が印加される点で、図４に示した全走査線同時選択によるスイングパルス方式を用いたコモン振りと相違する。図５Ａにおいては、フレーム先頭の走査線Ｙ１に対して走査信号が供給された場合について示し、図５Ｂにおいては、フレーム最後の走査線Ｙｍに対して走査信号が供給された場合について示している。なお、走査線Ｙ２～Ｙ（ｍ－１）については、走査線Ｙ１に対する走査信号の供給タイミングと、Ｙｍに対する走査信号の供給タイミングとの間で、順次シフトしたタイミングで走査信号が供給される。 As shown in FIG. 5, in the common oscillation using the pulse system by sequential scanning line selection, a scanning signal (ON potential) is sequentially supplied to each scanning line Y1 to Ym, and this scanning signal is supplied. The voltage V2 is applied to the corresponding pixel electrode 21 and the voltage V1 is applied to the common electrode 22 at the timing, which is different from the common swing using the swing pulse method by simultaneous selection of all scanning lines shown in FIG. 5A shows the case where the scanning signal is supplied to the scanning line Y1 at the beginning of the frame, and FIG. 5B shows the case where the scanning signal is supplied to the scanning line Ym at the end of the frame. For the scanning lines Y2 to Y (m−1), the scanning signal is supplied at a timing that is sequentially shifted between the scanning signal supply timing for the scanning line Y1 and the scanning signal supply timing for Ym.
　図６に示すように、全走査線同時選択によるスイングパルス方式を用いたコモン振りにおいては、まず、共通電極２２に－１５Ｖの電圧Ｖ２が印加され、画素電極２１に１５Ｖの電圧Ｖ１が印加された状態で全ての走査線Ｙ１～Ｙｍに対して同時に走査信号（オン電位）が供給される第２の印加動作を行う。これにより、各表示画素２０の電気泳動表示インク２３には、Ｖ２－Ｖ１の電圧（すなわち、－３０Ｖ）が印加される。その後に共通電極２２の電位を１５Ｖの電圧Ｖ１に変更し、画素電極２１の電位を－１５Ｖの電圧Ｖ２に変更した状態で、全ての走査線Ｙ１～Ｙｍに対して同時に走査信号（オン電位）が供給される第１の印加動作を行う。これにより、各表示画素２０の電気泳動表示インク２３には、Ｖ１－Ｖ２の駆動電圧（すなわち、３０Ｖ）が印加される。図６ではこの一連の印加動作を１セットとして、２セット印加した場合を示している。これらの印加動作を繰り返す回数については任意に選択可能であり、３回以上に設定することができる。 As shown in FIG. 6, in the common swing using the swing pulse method by simultaneous selection of all scanning lines, first, a voltage V2 of −15 V is applied to the common electrode 22, and a voltage V1 of 15 V is applied to the pixel electrode 21. In this state, the second application operation in which the scanning signal (ON potential) is simultaneously supplied to all the scanning lines Y1 to Ym is performed. As a result, a voltage of V2-V1 (that is, −30 V) is applied to the electrophoretic display ink 23 of each display pixel 20. Thereafter, the scanning electrode (on potential) is simultaneously applied to all the scanning lines Y1 to Ym with the potential of the common electrode 22 changed to the voltage V1 of 15V and the potential of the pixel electrode 21 changed to the voltage V2 of -15V. The first application operation is performed. As a result, a drive voltage of V1-V2 (that is, 30V) is applied to the electrophoretic display ink 23 of each display pixel 20. FIG. 6 shows a case where two sets are applied with this series of application operations as one set. The number of times of repeating these application operations can be arbitrarily selected, and can be set to three times or more.
　図７に示すように、走査線順次選択によるスイングパルス方式を用いたコモン振りにおいては、まず、共通電極２２に－１５Ｖの電圧Ｖ２が印加され、画素電極２１に１５Ｖの電圧Ｖ１が印加された状態で全ての走査線Ｙ１～Ｙｍに対して順次走査信号（オン電位）が供給される第２の印加動作を行う。これにより、各表示画素２０の電気泳動表示インク２３には、Ｖ２－Ｖ１の電圧（すなわち、－３０Ｖ）が順次印加される。その後に共通電極２２の電位を１５Ｖの電圧Ｖ１に変更し、画素電極２１の電位を－１５Ｖの電圧Ｖ２に変更した状態で、全ての走査線Ｙ１～Ｙｍに対して順次走査信号（オン電位）が供給される第１の印加動作を行う。これにより、各表示画素２０の電気泳動表示インク２３には、Ｖ１－Ｖ２の駆動電圧（すなわち、３０Ｖ）が順次印加される。図７では、第１の印加動作を２回繰り返した後に第２の印加動作を二回繰り返した印加動作を１セットとして、２セット印加した場合を示している。これらの印加動作を繰り返す回数については任意に選択可能であり、それぞれ３回以上に設定することができる。またそれぞれ異なる回数に設定することもできる。 As shown in FIG. 7, in the common swing using the swing pulse method by sequential scanning line selection, first, a voltage V2 of −15 V is applied to the common electrode 22, and a voltage V1 of 15 V is applied to the pixel electrode 21. In this state, a second application operation in which a scanning signal (ON potential) is sequentially supplied to all the scanning lines Y1 to Ym is performed. As a result, a voltage of V2-V1 (that is, −30 V) is sequentially applied to the electrophoretic display ink 23 of each display pixel 20. Thereafter, the scanning electrode (on potential) is sequentially applied to all the scanning lines Y1 to Ym in a state where the potential of the common electrode 22 is changed to the voltage V1 of 15V and the potential of the pixel electrode 21 is changed to the voltage V2 of -15V. The first application operation is performed. As a result, the drive voltage of V1-V2 (that is, 30V) is sequentially applied to the electrophoretic display ink 23 of each display pixel 20. FIG. 7 shows a case where two sets are applied with one set of the application operation in which the second application operation is repeated twice after the first application operation is repeated twice. The number of times of repeating these application operations can be arbitrarily selected, and can be set to three or more. It is also possible to set a different number of times.
　図４から図７に示すインクにかかる電圧の点線部は全画素同一表示駆動ステップを終えた後の電圧波形を示しているが、本発明においては、上記のコモン振りが適用される全画素同一表示駆動ステップが行われた後、各表示画素２０を用いて階調画像を表示させる諧調表示動作に移行する。なお、この諧調表示動作ステップについては後述する。 The dotted line portion of the voltage applied to the ink shown in FIG. 4 to FIG. 7 shows the voltage waveform after the all-pixels identical display drive step, but in the present invention, all the pixels are the same to which the above common swing is applied. After the display driving step is performed, the process proceeds to a gradation display operation in which a gradation image is displayed using each display pixel 20. This gradation display operation step will be described later.
　以上に記載した全画素同一表示駆動ステップに先立って、現在表示されている画像（書換前の画像）が次の画像（書換後の画像）を書き込んだ後もぼんやりと残って見える現象（残像現象）を解消するための消去駆動が行われてもよい。この残像消去駆動は、上記コモン振りを用いて全走査線同時選択によってなされてもよいし、走査線順次選択によってなされてもよい。また、コモン振りを用いないこれらの駆動にて実現してもよい。また、これら以外の方法でも、残像現象を解消することが可能な駆動であればどのような手段を用いてもよい。 Prior to the all-pixel identical display driving step described above, a phenomenon in which the currently displayed image (image before rewriting) appears to remain dull after writing the next image (image after rewriting) (afterimage phenomenon) ) May be performed to eliminate the problem. This afterimage erasing drive may be performed by simultaneous selection of all scanning lines using the above-mentioned common swing, or may be performed by sequential selection of scanning lines. Further, it may be realized by such driving without using the common swing. In addition, any means other than these may be used as long as it can drive the afterimage phenomenon.
　なお、図５、図７に示すように、特定の走査線に対する走査信号の供給は、全ての走査線Ｙ１～Ｙｍを１回走査（連続して全走査線を選択）するのに要する時間を１フレーム期間とすると、１フレーム周期で行われる。すなわち、走査線Ｙ１に走査信号を連続して供給する場合、あるタイミングで走査信号を供給した後、その供給タイミングから１フレーム経過した後に次の走査信号が供給される（図５参照）。したがって、走査線Ｙ１にて選択される表示画素２０に連続して駆動電圧が印加される周期も１フレーム周期となる。 As shown in FIGS. 5 and 7, the supply of the scanning signal to a specific scanning line takes time required to scan all the scanning lines Y1 to Ym once (select all scanning lines continuously). Assuming one frame period, the period is one frame. That is, when the scanning signal is continuously supplied to the scanning line Y1, after the scanning signal is supplied at a certain timing, the next scanning signal is supplied after one frame has elapsed from the supply timing (see FIG. 5). Therefore, the period in which the driving voltage is continuously applied to the display pixels 20 selected by the scanning line Y1 is also one frame period.
　このように各走査線Ｙ１～Ｙｍに対して順次に走査信号を供給することにより、第１の印加動作において、走査信号が供給された走査線Ｙ１に接続された各表示画素２０の電気泳動表示インク２３には、瞬時的にＶ１－Ｖ２の電圧（すなわち、３０Ｖ）が印加される。そして、印加された駆動電圧は、保持容量２５を充電し、保持容量２５に蓄積された電荷は、その後、漸次放電されていく。一方、第２の印加動作において、走査信号が供給された各表示画素２０の電気泳動表示インク２３には、瞬時的にＶ２－Ｖ１の電圧（すなわち、－３０Ｖ）が印加される。そして、印加された駆動電圧は、保持容量２５を逆電圧で充電し、保持容量２５に蓄積された電荷は、その後、漸次放電されていく。 Thus, by sequentially supplying the scanning signals to the respective scanning lines Y1 to Ym, the electrophoretic display of each display pixel 20 connected to the scanning line Y1 to which the scanning signal is supplied in the first application operation. A voltage V1-V2 (ie, 30V) is instantaneously applied to the ink 23. The applied drive voltage charges the storage capacitor 25, and the charge accumulated in the storage capacitor 25 is gradually discharged thereafter. On the other hand, in the second application operation, a voltage of V2-V1 (that is, −30 V) is instantaneously applied to the electrophoretic display ink 23 of each display pixel 20 to which the scanning signal is supplied. The applied drive voltage charges the storage capacitor 25 with a reverse voltage, and the charge accumulated in the storage capacitor 25 is then gradually discharged.
　次に、電気泳動表示装置１における階調表示駆動ステップについて説明する。階調表示駆動ステップにおいては、共通電極２２の電位を、コモン振りで印加された電圧Ｖ１、Ｖ２の中間電位Ｖｍｉｄに固定した状態にて、複数のデータ線Ｘ１～Ｘｎに表示画像に対応した画素信号を印加すると共に、複数の走査線Ｙ１～Ｙｍを所定パターンで選択することにより、対象となる表示画素２０が印加回数に応じて所望の階調に調整される。さらに、階調表示駆動ステップにおいては少なくとも最後の走査後に前記画素電極をハイインピーダンス状態とし、各画素は所望の階調を得た時点で階調表示駆動ステップから停止ステップへ移行する。 Next, the gradation display driving step in the electrophoretic display device 1 will be described. In the gradation display driving step, pixels corresponding to the display image are displayed on the plurality of data lines X1 to Xn in a state in which the potential of the common electrode 22 is fixed to the intermediate potential Vmid of the voltages V1 and V2 applied by the common swing. By applying a signal and selecting a plurality of scanning lines Y1 to Ym in a predetermined pattern, the target display pixel 20 is adjusted to a desired gradation according to the number of times of application. Further, in the gradation display driving step, the pixel electrode is brought into a high impedance state after at least the last scan, and each pixel shifts from the gradation display driving step to the stop step when a desired gradation is obtained.
　電気泳動表示装置１における階調表示駆動ステップにおいては、全画素同一表示駆動ステップと異なり、共通電極２２に印加される電位を切り替えることなく、中間電位Ｖｍｉｄに固定した状態で各画素電極２１に対する駆動が制御される。一般に各表示画素２０における階調表現においては、電気泳動表示インク２３に印加される電位差が大きいほど１回の駆動制御で変化する階調度（色味）が大きくなる。このため、上述した全画素同一表示駆動ステップのようにコモン振りを行う場合には、電気泳動表示インク２３に印加される電位差が大きくなり、階調表示制御には必ずしも適さない。このため、階調表示駆動ステップにおいては、中間電位Ｖｍｉｄに固定した状態で各画素電極２１に対する駆動を制御している。これにより、相対的に小さい電位差により階調表示を調節でき、電気泳動表示装置１における精密な階調表示性能を向上することが可能となる。 In the gradation display driving step in the electrophoretic display device 1, unlike the same display driving step for all the pixels, driving for each pixel electrode 21 is performed with the potential applied to the common electrode 22 being fixed to the intermediate potential Vmid without switching. Is controlled. In general, in the gradation expression in each display pixel 20, the gradation level (color tone) that changes with one drive control increases as the potential difference applied to the electrophoretic display ink 23 increases. For this reason, when common swing is performed as in the above-described all-pixel same display driving step, the potential difference applied to the electrophoretic display ink 23 becomes large and is not necessarily suitable for gradation display control. For this reason, in the gradation display driving step, the driving of each pixel electrode 21 is controlled in a state of being fixed at the intermediate potential Vmid. As a result, gradation display can be adjusted with a relatively small potential difference, and the precision gradation display performance in the electrophoretic display device 1 can be improved.
　本実施の形態に係る電気泳動表示装置１においては、階調表示駆動ステップとして、例えば、階調表示制御対象となる表示画素２０が所望の階調に到達するまで、当該表示画素２０に対応する走査線に走査信号を１フレーム周期で順次供給して表示画素２０を駆動する順次階調駆動方式と、所望の階調を表現するために必要な表示画素２０の駆動回数（走査回数）を、１フレーム又は複数フレームに相当する休止期間で分離されるいくつかのブロックに分け、ブロック単位で階調表示制御対象となる表示画素２０を駆動するブロックスキャン階調駆動方式と、のいずれかを適用する。 In the electrophoretic display device 1 according to the present embodiment, as the gradation display driving step, for example, the display pixel 20 corresponding to the gradation display control object corresponds to the display pixel 20 until reaching a desired gradation. A sequential grayscale driving method for sequentially driving the display pixels 20 by sequentially supplying scanning signals to the scanning lines in one frame period, and the number of times the display pixels 20 are driven (the number of scans) required to express a desired grayscale, Apply one of the block scan gradation driving method that divides the block into several blocks separated by a pause period corresponding to one frame or a plurality of frames and drives the display pixels 20 to be subjected to gradation display control on a block basis. To do.
　以下、順次階調駆動方式、又はブロックスキャン階調駆動方式を用いた階調表示駆動ステップについて図８及び図９に基づいて説明する。図８は、順次階調駆動方式を用いた階調表示駆動ステップの説明図である。図９は、ブロックスキャン階調駆動方式を用いた階調表示駆動ステップの説明図である。 Hereinafter, the gradation display driving step using the sequential gradation driving method or the block scan gradation driving method will be described with reference to FIGS. FIG. 8 is an explanatory diagram of the gradation display driving step using the sequential gradation driving method. FIG. 9 is an explanatory diagram of a gradation display driving step using the block scan gradation driving method.
　図８に示すように、順次階調駆動方式においては、共通電極２２に印加される電位が中間電位Ｖｍｉｄに固定されると共に、画素電極２１に印加される画素信号及び走査線に供給される走査信号の供給回数（走査回数または駆動回数）によって表示画素２０における階調表示が調節される。対象画素となる特定の表示画素２０を１回走査した場合を考える。すなわち、対象画素となる表示画素２０の画素電極２１に画素信号（例えばＶ２＝－１５Ｖ）を印加し、共通電極２２に中間電位Ｖｍｉｄ（例えばＶｍｉｄ＝０Ｖ）が印加されていれば、Ｖ２の駆動電圧が表示画素２０に印加される。これは、図４に示すコモン振りと比較して半分の駆動電圧で表示画素２０が駆動されていることになる。階調表示駆動ステップの中では、コモン振りを適用しないことで（共通電極２２に中間電位Ｖｍｉｄに固定）、全画素同一表示駆動ステップ時の駆動電圧の半分の駆動電圧で階調駆動することができる。小さな駆動電圧を用いて走査回数を調整することで精密な階調表示性能を向上することができる。具体的には、図８に示すように、階調制御対象となる表示画素２０に対する画素信号及び走査信号の供給が２回で停止された場合、当該表示画素２０の階調は階調Ｃに設定される。また、階調制御対象となる表示画素２０に対する画素信号及び走査信号の供給が５回で停止された場合、当該表示画素２０の階調は階調Ｂに設定される。さらに、階調制御対象となる表示画素２０に対する画素信号及び走査信号の供給が７回で停止された場合、当該表示画素２０の階調は階調Ａに設定される。なお、表示画素２０の階調が階調Ｃ、Ｂに設定される場合、それぞれ３回目、６回目以降の画素信号電位はＶｍｉｄもしくはハイインピーダンス状態となるが、図８においては、説明の便宜上、画素信号及び走査信号が７回供給される場合について示している。なお、ハイインピーダンス状態については後述する。 As shown in FIG. 8, in the sequential gradation driving method, the potential applied to the common electrode 22 is fixed to the intermediate potential Vmid, and the pixel signal applied to the pixel electrode 21 and the scanning supplied to the scanning line are used. The gray scale display in the display pixel 20 is adjusted by the number of times of signal supply (the number of scans or the number of driving). Consider a case where a specific display pixel 20 as a target pixel is scanned once. That is, if a pixel signal (for example, V2 = −15V) is applied to the pixel electrode 21 of the display pixel 20 that is the target pixel and an intermediate potential Vmid (for example, Vmid = 0V) is applied to the common electrode 22, driving of V2 is performed. A voltage is applied to the display pixel 20. This means that the display pixel 20 is driven with a driving voltage half that of the common swing shown in FIG. In the gradation display driving step, by applying no common swing (fixed to the common electrode 22 at the intermediate potential Vmid), gradation driving can be performed with a driving voltage that is half of the driving voltage in the same display driving step for all pixels. it can. By adjusting the number of scans using a small drive voltage, precise gradation display performance can be improved. Specifically, as shown in FIG. 8, when the supply of the pixel signal and the scanning signal to the display pixel 20 that is the target of gradation control is stopped twice, the gradation of the display pixel 20 is changed to the gradation C. Is set. In addition, when the supply of the pixel signal and the scanning signal to the display pixel 20 that is the target of gradation control is stopped five times, the gradation of the display pixel 20 is set to the gradation B. Furthermore, when the supply of the pixel signal and the scanning signal to the display pixel 20 that is the target of gradation control is stopped at seven times, the gradation of the display pixel 20 is set to the gradation A. Note that when the gradation of the display pixel 20 is set to gradations C and B, the pixel signal potentials at the third time and the sixth time are Vmid or a high impedance state, respectively, but in FIG. The case where the pixel signal and the scanning signal are supplied seven times is shown. The high impedance state will be described later.
　順次階調駆動方式においては、階調制御対象となる表示画素２０に対する走査回数（画素信号及び走査信号の同時印加回数又は階調駆動回数ということもできる）を調節することで、当該表示画素２０における階調表示が調節される。この図では全画素同一表示駆動ステップにおいて全画素を白にした場合について説明しているので、走査回数が多いほど表示画素２０における濃度を濃く表現でき、走査回数が少ないほど表示画素２０における濃度を薄く表現できる。図８に示す例では、２回の走査回数（画素信号及び走査信号の同時印加）により設定される階調Ｃの濃度が最も薄く、５回の走査回数（画素信号及び走査信号の同時印加）により設定される階調Ａの濃度が最も濃くなる。 In the sequential gradation drive method, the display pixel 20 is adjusted by adjusting the number of scans (also referred to as the number of simultaneous application of the pixel signal and the scan signal or the number of gradation drives) for the display pixel 20 to be subjected to gradation control. The gradation display at is adjusted. In this figure, the case where all the pixels are set to white in the same display driving step for all the pixels has been described, so that the density in the display pixel 20 can be expressed deeply as the number of scans increases, and the density in the display pixel 20 decreases as the number of scans decreases. Can express thinly. In the example shown in FIG. 8, the density of gradation C set by the number of times of scanning twice (simultaneous application of pixel signal and scanning signal) is the smallest, and the number of times of scanning five times (simultaneous application of pixel signal and scanning signal). The density of gradation A set by is the highest.
　図８に示す順次階調駆動方式においては、階調制御対象となる表示画素２０に対して画素信号及び走査信号を連続して供給し、その供給回数を調節することで当該表示画素２０における階調表示を調節する。これに対し、ブロックスキャン階調駆動方式においては、所望の階調を表現するために必要な表示画素２０の駆動回数（走査回数）を、１フレーム又は複数フレームに相当する休止期間で分離されるいくつかのブロックに分け、ブロック単位で表示画素２０を駆動する。 In the sequential gradation driving method shown in FIG. 8, pixel signals and scanning signals are continuously supplied to the display pixels 20 to be subjected to gradation control, and the number of times of supply is adjusted to adjust the level of the display pixels 20. Adjust the key display. On the other hand, in the block scan gradation driving method, the number of times of driving (scanning number of times) of the display pixel 20 necessary for expressing a desired gradation is separated in a pause period corresponding to one frame or a plurality of frames. Dividing into several blocks, the display pixels 20 are driven in units of blocks.
　ブロックスキャン階調駆動方式においては、図８に示す階調Ｂを階調表現する場合において、図９に示すように、例えば、１フレーム又は複数フレームの休止期間（同図に示す領域Ａ１、Ａ２、Ａ３～Ａ６）で分離される複数のブロック（同図に示すＢ１～Ｂ３、Ｂ４～Ｂ８）に分け、このブロック単位で表示画素２０を駆動する。なお、図９の中段に示すブロックスキャン階調駆動方式においては、１フレームの休止期間Ａ１及び３フレームの休止期間Ａ２で分離される３つのブロックＢ１～Ｂ３で表示画素２０を駆動する。一方、図９の下段に示すブロックスキャン階調駆動方式においては、４つの１フレームの休止期間Ａ３～Ａ６で分離される５つのブロックＢ４～Ｂ８で表示画素２０を駆動する。 In the block scan gradation driving method, when gradation B shown in FIG. 8 is expressed by gradation, as shown in FIG. 9, for example, a pause period of one frame or a plurality of frames (regions A1, A2 shown in FIG. 8). , A3 to A6) are divided into a plurality of blocks (B1 to B3, B4 to B8 shown in the figure), and the display pixels 20 are driven in units of blocks. In the block scan gradation driving method shown in the middle stage of FIG. 9, the display pixel 20 is driven by three blocks B1 to B3 separated by a one-frame pause period A1 and a three-frame pause period A2. On the other hand, in the block scan gradation driving method shown in the lower part of FIG. 9, the display pixel 20 is driven by five blocks B4 to B8 separated by four one-frame pause periods A3 to A6.
　このようにブロック単位で表示画素２０を駆動する場合には、ブロック間に少なくとも１フレーム以上の休止期間が挿入されることから、図８に示す順次階調駆動方式のように、１フレーム周期で連続して同一表示画素２０を駆動する場合と比較して電気泳動表示インク２３内の電気泳動粒子（白粒子８２、黒粒子８３）の総移動量が変化する。この特性を利用することにより、ブロックスキャン階調駆動方式においては、表示画素２０の階調の微調整を行うことができる。例えば、図９の中段に示すブロックスキャン階調駆動方式においては、同図の上段に示す階調Ｂよりも僅かに薄い階調を有する階調Ｂ´が表現され、同図の下段に示すブロックスキャン階調駆動方式においては、この階調Ｂ´よりも僅かに薄い階調を有する階調Ｂ´´が表現される。 When the display pixels 20 are driven in units of blocks as described above, a pause period of at least one frame is inserted between the blocks. Therefore, like the sequential gradation driving method shown in FIG. Compared to the case where the same display pixel 20 is continuously driven, the total movement amount of the electrophoretic particles (white particles 82 and black particles 83) in the electrophoretic display ink 23 changes. By utilizing this characteristic, the gradation of the display pixel 20 can be finely adjusted in the block scan gradation driving method. For example, in the block scan gradation driving method shown in the middle part of FIG. 9, gradation B ′ having a gradation slightly thinner than gradation B shown in the upper part of FIG. In the scan gradation driving method, a gradation B ″ having a gradation slightly thinner than the gradation B ′ is expressed.
　ここで、ブロックスキャン階調駆動方式を用いる場合に順次階調駆動方式と比べて表示画素２０の階調の微調整が可能となる理由について説明する。図１０は、本実施の形態に係る電気泳動表示装置１でブロックスキャン階調駆動方式と順次階調駆動方式とを用いた場合の駆動エネルギーの説明図である。 Here, the reason why the gradation of the display pixel 20 can be finely adjusted when using the block scan gradation driving method as compared with the sequential gradation driving method will be described. FIG. 10 is an explanatory diagram of drive energy when the block scan gradation driving method and the sequential gradation driving method are used in the electrophoretic display device 1 according to the present embodiment.
　図１０Ａは、図９に示す破線Ｃで囲んだ領域の拡大図を示している。図１０Ａに示す左方側の波形は、表示画素２０に駆動電圧が印加されていない初期状態から最初に駆動電圧が印加された場合の波形（以下、便宜上「一次波形」という）を示し、図１０Ｂに示す右方側の波形は、先行して印加された駆動電圧による電荷を保持容量２５に蓄積後、その全てが放電されていない状態で後続する駆動電圧が印加された場合の波形（以下、便宜上「二次波形」という）を示している。 FIG. 10A shows an enlarged view of a region surrounded by a broken line C shown in FIG. The waveform on the left side shown in FIG. 10A shows a waveform (hereinafter referred to as “primary waveform” for convenience) when the drive voltage is first applied to the display pixel 20 from the initial state where the drive voltage is not applied. The waveform on the right side shown in FIG. 10B is a waveform when the subsequent drive voltage is applied after the charge due to the drive voltage applied in advance is accumulated in the storage capacitor 25 and all the charges are not discharged (hereinafter referred to as the waveform). For convenience, it is referred to as a “secondary waveform”.
　図１０Ａに示すように、一次波形及び二次波形における駆動電圧の印加時間ｔは同一の時間である。しかしながら、一次波形における駆動電圧が中間電圧Ｖｍｉｄから立ち上がるのに対し、二次波形における駆動電圧は中間電圧Ｖｍｉｄと高電位の電圧Ｖ２との間の電圧値から立ち上がる。このため、二次波形の立ち上がりは、一次波形と比較して急速に立ち上がる。 As shown in FIG. 10A, the drive voltage application time t in the primary waveform and the secondary waveform is the same time. However, the drive voltage in the primary waveform rises from the intermediate voltage Vmid, whereas the drive voltage in the secondary waveform rises from a voltage value between the intermediate voltage Vmid and the high potential voltage V2. For this reason, the rise of the secondary waveform rises more rapidly than the primary waveform.
　図１０Ｂは、一次波形及び二次波形の印加時間ｔに対応する駆動電圧ＳＶ１、ＳＶ２を示している。図１０Ｃは、これらの駆動電圧ＳＶ１、ＳＶ２の比較結果を示している。なお、図１０Ｃにおいては、縦軸に電圧を示し、横軸に時間を示している。図１０Ｃに示すように、二次波形の駆動電圧ＳＶ２は、その先頭時間部分にて一次波形の駆動電圧ＳＶ１よりも高い電圧値を有する。このため、二次波形の駆動電圧ＳＶ２に基づく駆動エネルギーは、一次波形の駆動電圧ＳＶ１に基づく駆動エネルギーよりもΔＳだけ大きいことが分かる。なお、このΔＳは、以下の式により求められる。
　ΔＳ　＝　ＳＶ２　－　ＳＶ１ FIG. 10B shows drive voltages S V1 and S V2 corresponding to the application time t of the primary waveform and the secondary waveform. FIG. 10C shows a comparison result of these drive voltages S V1 and S V2 . In FIG. 10C, the vertical axis represents voltage and the horizontal axis represents time. As shown in FIG. 10C, the drive voltage S V2 of the secondary waveform, with a voltage higher than the driving voltage S V1 of the primary wave at the beginning time portion. For this reason, it can be seen that the drive energy based on the drive voltage S V2 of the secondary waveform is larger by ΔS than the drive energy based on the drive voltage S V1 of the primary waveform. This ΔS is obtained by the following equation.
ΔS = S V2 -S V1
　ここで、図９に示す例で説明する。図９の上段に示す順次階調駆動方式で表示画素２０を駆動した場合における駆動エネルギーの総量は、５回の駆動電圧ＳＶ１に４つのΔＳを付加した値（すなわち、５×ＳＶ１＋４×ΔＳ）であることが分かる。 Here, an example shown in FIG. 9 will be described. The total amount of drive energy when the display pixel 20 is driven by the sequential gradation drive method shown in the upper part of FIG. 9 is a value obtained by adding four ΔS to the drive voltage S V1 for five times (that is, 5 × S V1 + 4 × It can be seen that ΔS).
　一方、図９の中段に示すブロックスキャン階調駆動方式で表示画素２０を駆動した場合における駆動エネルギーの総量は、５回の駆動電圧ＳＶ１に２つのΔＳを付加した値（すなわち、５×ＳＶ１＋２×ΔＳ）であることが分かる。すなわち、図９の上段に示す順次階調駆動方式で表示画素２０を駆動した場合における駆動エネルギーの総量よりも２つのΔＳ分だけ駆動エネルギーが小さい。このため、階調Ｂ´は、階調Ｂよりも僅かに薄い階調に変化することになる。 On the other hand, the total amount of drive energy in case of driving the display pixel 20 in the block scan gradation driving scheme shown in the middle of FIG. 9, 5 times of the drive voltage values obtained by adding the two ΔS in S V1 (i.e., 5 × S V1 + 2 × ΔS). That is, the driving energy is smaller by two ΔS than the total amount of driving energy when the display pixel 20 is driven by the sequential gradation driving method shown in the upper part of FIG. For this reason, the gradation B ′ changes to a gradation slightly thinner than the gradation B.
　また、図９の下段に示すブロックスキャン階調駆動方式で表示画素２０を駆動した場合における駆動エネルギーの総量は、５回の駆動電圧ＳＶ１を合計した値（すなわち、５×ＳＶ１）であることが分かる。すなわち、図９の中段に示すブロックスキャン階調駆動方式で表示画素２０を駆動した場合における駆動エネルギーの総量よりも更に２つのΔＳ分だけ駆動エネルギーが小さい。このため、階調Ｂ´´は、階調Ｂ´よりも僅かに薄い階調となる。 Further, the total amount of driving energy when the display pixel 20 is driven by the block scan gradation driving method shown in the lower part of FIG. 9 is a value obtained by summing the five driving voltages S V1 (that is, 5 × S V1 ). I understand that. That is, the driving energy is smaller by two ΔS than the total amount of driving energy when the display pixel 20 is driven by the block scan gradation driving method shown in the middle stage of FIG. For this reason, the gradation B ″ is a gradation slightly thinner than the gradation B ′.
　なお、ブロックスキャン階調駆動方式における二つの前記ブロックの間の期間においては、画素電極２１に共通電極２２と等しい電圧を印加することで短絡させてもよく、共通電極２２をハイインピーダンス状態として開放してもよく、最後の走査後に前記画素電極をハイインピーダンス状態とすることが可能な範囲で適宜選択することができる。順次階調駆動方式およびブロックスキャン駆動方式において、各画素は所望の階調を得た時点で階調表示駆動ステップから停止ステップへ移行する。 In the period between the two blocks in the block scan gradation driving method, the pixel electrode 21 may be short-circuited by applying a voltage equal to that of the common electrode 22, and the common electrode 22 is opened in a high impedance state. Alternatively, the pixel electrode can be appropriately selected within a range in which the pixel electrode can be brought into a high impedance state after the last scan. In the sequential gradation drive method and block scan drive method, each pixel shifts from the gradation display drive step to the stop step when a desired gradation is obtained.
　また、これらの順次階調駆動方式及びブロックスキャン階調駆動方式において、所望の階調に変化させる途中で、階調制御対象の表示画素２０に対して逆向きの電圧を印加することで階調を調節することは、実施の形態として好ましい。このように所望の階調に変化させる途中で表示画素２０に逆向きの電圧を印加する方式を、以下「逆スキャン挿入駆動方式」と呼ぶものとする。 Further, in these sequential gradation driving method and block scan gradation driving method, a gradation is obtained by applying a reverse voltage to the display pixel 20 to be controlled in the middle of changing to a desired gradation. It is preferable as an embodiment to adjust the value. Such a method of applying a reverse voltage to the display pixel 20 in the middle of changing to a desired gradation is hereinafter referred to as a “reverse scan insertion drive method”.
　以下、この逆スキャン挿入駆動方式を用いた階調駆動制御について図１１及び図１２に基づいて説明する。図１１及び図１２は、本実施の形態に係る電気泳動表示装置１における逆スキャン挿入駆動方式を用いた階調駆動制御の説明図である。階調制御対象となる表示画素２０に対して駆動電圧を５回（図１１）又は２回だけ印加する場合について例示している。なお、図１１に示す階調Ｇ１～Ｇ５においては、階調Ｇ１の濃度が最も薄く、階調Ｇ５に向けて次第に濃度が濃くなる階調を示している。 Hereinafter, gradation drive control using this reverse scan insertion drive method will be described with reference to FIGS. 11 and 12 are explanatory diagrams of gradation drive control using the reverse scan insertion drive method in the electrophoretic display device 1 according to the present embodiment. The case where the drive voltage is applied only five times (FIG. 11) or twice to the display pixel 20 that is the target of gradation control is illustrated. Note that, in the gradations G1 to G5 shown in FIG. 11, the gradation G1 has the lowest density and the density gradually increases toward the gradation G5.
　図１１においては、階調表示制御される２種類のインク（電気泳動粒子８２，８３）Ａ、Ｂの階調変化について示している。ここでは、図１１に示す階調Ｇ５が所望の階調であるものとする。インクＡにおいては、白（又は黒）の状態から５回の駆動（駆動電圧の印加）で階調Ｇ５が得られる電気特性を有する。一方、インクＢにおいては、白（又は黒）の状態から２回の駆動（駆動電圧の印加）で階調Ｇ５が得られる電気特性を有する。また、インクＢにおいては、階調を濃くする方向の駆動電圧の印加により４階調分だけ階調が変化するのに対し、階調を薄くする方向の駆動電圧の印加により３階調分だけ階調が変化する電気特性を有するものとする。 FIG. 11 shows the gradation change of two types of ink (electrophoretic particles 82 and 83) A and B whose gradation display is controlled. Here, it is assumed that the gradation G5 shown in FIG. 11 is a desired gradation. Ink A has an electrical characteristic that a gradation G5 can be obtained by driving five times (application of a driving voltage) from a white (or black) state. On the other hand, the ink B has an electrical characteristic that a gradation G5 can be obtained by driving twice (applying a driving voltage) from a white (or black) state. In ink B, the gradation changes by 4 gradations by applying the driving voltage in the direction of increasing the gradation, whereas only 3 gradations are applied by applying the driving voltage in the direction of decreasing the gradation. It is assumed that it has electrical characteristics in which gradation changes.
　順次階調駆動方式を適用した場合、インクＡにおいては、階調Ｇ１から階調Ｇ５までの間の中間階調として３つの階調Ｇ２～Ｇ４を順に得ることができる。一方、インクＢにおいては、階調Ｇ１の状態から駆動電圧を１回だけ印加しただけで、表示画素２０の階調は階調Ｇ５に達する。すなわち、インクＢにおいては、中間階調Ｇ２～Ｇ４を得ることができない。そこで、逆スキャン挿入駆動方式を適用して階調駆動制御することで、このような電気特性を有するインクＢの階調表現性能を向上するものである。 When the sequential gradation driving method is applied, in the ink A, the three gradations G2 to G4 can be sequentially obtained as intermediate gradations between the gradations G1 to G5. On the other hand, in the ink B, the gradation of the display pixel 20 reaches the gradation G5 only by applying the driving voltage once from the state of the gradation G1. That is, in the ink B, the intermediate gradations G2 to G4 cannot be obtained. Therefore, the gradation expression performance of the ink B having such electrical characteristics is improved by controlling the gradation drive by applying the reverse scan insertion drive method.
　図１２に示す逆スキャン挿入駆動方式を用いた階調駆動制御においては、２回目の駆動電圧の印加により階調Ｇ５に達した表示画素２０の画素電極２１に対し、先行する駆動電圧（階調を濃くする方向の画素信号）とは逆向きの電圧を有する駆動電圧（階調を薄くする方向の画素信号）を印加する（３回目の駆動）。これにより、この表示画素２０においては、階調Ｇ２を得ることができる。さらに、表示画素２０の画素電極２１に対して階調を濃くする方向の画素信号を印加する（４回目の駆動）。これにより、この表示画素２０においては、階調Ｇ６を得ることができる。なお、この階調Ｇ６は、階調Ｇ５よりも濃い階調を示す。さらに、表示画素２０の画素電極２１に対して階調を薄くする方向の画素信号を印加する（５回目の駆動）。これにより、この表示画素２０においては、階調Ｇ３を得ることができる。 In the gradation drive control using the reverse scan insertion drive method shown in FIG. 12, the preceding drive voltage (gradation) is applied to the pixel electrode 21 of the display pixel 20 that has reached the gradation G5 by the second drive voltage application. A drive voltage (pixel signal in the direction of decreasing gradation) having a voltage opposite to that of the pixel signal in the direction of increasing darkness is applied (third drive). Thereby, in this display pixel 20, the gradation G2 can be obtained. Further, a pixel signal in the direction of increasing the gradation is applied to the pixel electrode 21 of the display pixel 20 (fourth driving). Thereby, in this display pixel 20, the gradation G6 can be obtained. Note that the gradation G6 indicates a darker gradation than the gradation G5. Further, a pixel signal in a direction of decreasing the gradation is applied to the pixel electrode 21 of the display pixel 20 (fifth drive). Thereby, in the display pixel 20, the gradation G3 can be obtained.
　このように逆スキャン挿入駆動方式を用いた階調駆動制御においては、階調制御対象となる表示画素２０を所望の階調に変化させる途中で、逆向きの電圧を有する駆動電圧を印加することで階調を調節する。これにより、階調の変化が大きい電気特性を有するインク（電気泳動粒子８２，８３）を用いる場合においても、上述した階調Ｇ２～Ｇ４のような中間階調を得ることできるので、豊かな階調表現を実現することが可能となる。 As described above, in the gradation drive control using the reverse scan insertion drive method, a drive voltage having a reverse voltage is applied in the middle of changing the display pixel 20 to be a gradation control target to a desired gradation. Use to adjust the gradation. As a result, even when ink (electrophoretic particles 82 and 83) having electrical characteristics with a large gradation change is used, intermediate gradations such as the gradations G2 to G4 described above can be obtained. Tonal expression can be realized.
　次に、電気泳動表示装置１における停止ステップについて説明する。本実施の形態に係る電気泳動表示装置１においては、停止ステップとして、それぞれの表示画素２０が所望の階調に達した後、各画素ごとの画素電極２１の電位を共通電極２２と同電位として短絡する画素毎順次短絡方式と、表示画素すべての表示画素２０が所望の階調に到達した後、全ての表示画素２０の画素電極２１と共通電極２２との間を一斉に短絡する一斉短絡方式と、全ての表示画素２０の画素電極２１と共通電極２２との間を順次に短絡する走査線毎順次短絡方式と、がある。それぞれの短絡方式は階調表示駆動ステップ終了後から一定時間が経過してから行ってもよい（休止後画素毎順次短絡方式、休止後一斉短絡方式、休止後走査線毎順次短絡方式）。 Next, the stop step in the electrophoretic display device 1 will be described. In the electrophoretic display device 1 according to the present embodiment, as the stopping step, after each display pixel 20 reaches a desired gradation, the potential of the pixel electrode 21 for each pixel is set to the same potential as the common electrode 22. A sequential short-circuit method for each pixel to be short-circuited and a simultaneous short-circuit method in which the pixel electrodes 21 and the common electrodes 22 of all the display pixels 20 are short-circuited at once after the display pixels 20 of all the display pixels reach a desired gradation. In addition, there is a sequential short-circuit method for each scanning line in which the pixel electrodes 21 and the common electrodes 22 of all the display pixels 20 are sequentially short-circuited. Each short-circuiting method may be performed after a certain period of time has elapsed from the end of the gradation display driving step (sequential short-circuiting after every pause, simultaneous short-circuiting after each pause, and sequential short-circuiting after every scanning line).
　ここで、短絡動作および開放動作について図１３に基づいて説明する。図１３は、本実施の形態に係る電気泳動表示装置１における階調駆動制御を終了する場合の短絡動作及び開放動作の説明図である。図１３Ａにおいては、停止ステップの短絡動作を示し、図１３Ｂにおいては階調表示駆動ステップ中の開放動作について示し、図１３Ｃにおいては、停止ステップの開放動作を示している。 Here, the short circuit operation and the open operation will be described with reference to FIG. FIG. 13 is an explanatory diagram of a short-circuit operation and an open operation when the gradation drive control is finished in the electrophoretic display device 1 according to the present embodiment. 13A shows a short-circuit operation at the stop step, FIG. 13B shows an open operation during the gradation display driving step, and FIG. 13C shows an open operation at the stop step.
　短絡動作においては、図１３Ａに示すように、走査線Ｙに対する走査信号をオン電位とし、データ線Ｘを介して画素電極２１に印加される電圧と、共通電極２２に印加される電圧とが同電位に設定される。一方、開放動作においては、図１３Ｂに示すように、データ線Ｘを何らかの方法によりハイインピーダンス状態に設定し、或いは、図１３Ｃに示すように、走査線Ｙをオフ電位に設定することでハイインピーダンス状態に設定する。前者が走査線Ｙに対する走査信号がオン電位であるのに対し、後者が走査線Ｙに対する走査信号がオフ電位である点で相違する。 In the short-circuit operation, as shown in FIG. 13A, the scanning signal for the scanning line Y is turned on, and the voltage applied to the pixel electrode 21 via the data line X is the same as the voltage applied to the common electrode 22. Set to potential. On the other hand, in the open operation, the data line X is set to a high impedance state by some method as shown in FIG. 13B, or the scanning line Y is set to an off potential as shown in FIG. Set to state. The former is different in that the scanning signal for the scanning line Y is on-potential, while the latter is the scanning signal for the scanning line Y is off-potential.
　以下、画素毎順次短絡方式と休止後画素毎順次短絡方式を用いた停止ステップについて説明する。画素毎順次短絡方式は、階調表示駆動ステップを終えた画素を次の操作タイミングで短絡とする方式で、図１４Ａに示すように、例えば、表示画素２０に５回目の走査信号が供給される一方、この走査信号に対応するタイミングにて、画素電極２１及び共通電極２２が同一電圧（ここでは、Ｖｍｉｄ（０Ｖ））に設定することで５回目の走査信号が供給されたタイミングで電気泳動表示インク２３及び保持容量２５に蓄積された電荷が除去する方式である。休止後画素毎順次短絡方式は、図１４Ａの４回目と５回目の間に画素電極２１をハイインピーダンス状態にして走査信号を供給する開放動作を１または複数回挿入した後に短絡動作を行う方式である。特に休止後画素毎順次短絡方式においては、停止までのタイミングを画素毎に設定できるためにより豊かな階調表示性能を得ることが可能となる。 Hereinafter, the stop step using the sequential short circuit method for each pixel and the sequential short circuit method for each pixel after the pause will be described. The pixel-by-pixel sequential short-circuit method is a method of short-circuiting pixels that have finished the gradation display driving step at the next operation timing. For example, as shown in FIG. 14A, a fifth scanning signal is supplied to the display pixel 20. On the other hand, when the pixel electrode 21 and the common electrode 22 are set to the same voltage (here, Vmid (0 V)) at the timing corresponding to this scanning signal, the electrophoretic display is performed at the timing when the fifth scanning signal is supplied. In this method, charges accumulated in the ink 23 and the holding capacitor 25 are removed. The pixel-by-pixel sequential short-circuit method after the pause is a method in which the short-circuit operation is performed after inserting the open operation for supplying the scanning signal one or more times with the pixel electrode 21 in the high impedance state between the fourth and fifth times in FIG. 14A. is there. In particular, in the sequential short-circuit method for each pixel after the pause, since the timing until the stop can be set for each pixel, it is possible to obtain richer gradation display performance.
　以下、一斉短絡方式及び順次短絡方式を用いた停止ステップについて図１５及び図１６に基づいて説明する。図１５は、一斉短絡方式を用いた停止ステップの説明図である。図１６は、走査線毎順次短絡方式を用いた停止ステップの説明図である。なお、図１５及び図１６においては、走査線Ｙ１～Ｙｍに対する走査信号に応じて制御されるラインＬ１～Ｌｍを示している。 Hereinafter, the stop step using the simultaneous short-circuit method and the sequential short-circuit method will be described with reference to FIGS. 15 and 16. FIG. 15 is an explanatory diagram of a stop step using the simultaneous short-circuit method. FIG. 16 is an explanatory diagram of the stop step using the sequential short-circuit method for each scanning line. 15 and 16 show lines L1 to Lm controlled in accordance with the scanning signals for the scanning lines Y1 to Ym.
　一斉短絡方式においては、図１５に示すように、各表示画素２０から構成される表示部２のすべての画素が階調表示駆動ステップを終えた直後、一斉に画素電極２１に印加される電位と共通電極２２に印加される電位とを同電位とすることで、全ての走査線Ｙ１～Ｙｍを同時に短絡する。この一斉短絡方式を用いた停止ステップによれば、電気泳動表示インク２３及び保持容量２５に蓄積された電荷が強制的に除去されることから、電気泳動表示インク２３において消費される電荷の量を低減できる。これにより、電気泳動表示インク２３が受けるダメージを低減できるので、表示部２の長寿命化を実現することが可能となる。特に、一斉短絡方式においては、全ての走査線Ｙ１～Ｙｍを一括的に短絡できるので、複雑な制御を必要とすることなく、停止ステップに必要な処理時間を短縮することが可能となる。 In the simultaneous short-circuit method, as shown in FIG. 15, immediately after all the pixels of the display unit 2 including the display pixels 20 have finished the gradation display driving step, the potential applied to the pixel electrodes 21 all at once. By making the potential applied to the common electrode 22 the same potential, all the scanning lines Y1 to Ym are short-circuited simultaneously. According to the stop step using the simultaneous short-circuit method, since the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are forcibly removed, the amount of charge consumed in the electrophoretic display ink 23 is reduced. Can be reduced. Thereby, since the damage which the electrophoretic display ink 23 receives can be reduced, it becomes possible to realize the lifetime improvement of the display part 2. In particular, in the simultaneous short-circuit method, since all the scanning lines Y1 to Ym can be short-circuited at a time, it is possible to shorten the processing time required for the stop step without requiring complicated control.
　一方、走査線毎順次短絡方式においては、図１６に示すように、各表示画素２０から構成される表示部のすべての画素が階調表示駆動ステップを終えた直後、順次に走査線Ｙ１～Ｙｍに走査信号を与えて各画素における画素電極２１に印加される電位と共通電極２２に印加される電位とを同電位とする。この走査線毎順次短絡方式を用いた停止ステップによれば、一斉短絡方式と同様に、電気泳動表示インク２３及び保持容量２５に蓄積された電荷が強制的に除去されることから、電気泳動表示インク２３において消費される電荷の量を低減できる。これにより、電気泳動表示インク２３が受けるダメージを低減できるので、表示部２の長寿命化を実現することが可能となる。特に、順次短絡方式においては、走査線Ｙ１～Ｙｍ毎に表示画素２０に対する駆動電圧の印加時間を揃えることが可能となる。 On the other hand, in the sequential short-circuiting method for each scanning line, as shown in FIG. 16, the scanning lines Y1 to Ym are sequentially formed immediately after all the pixels of the display unit composed of the display pixels 20 have finished the gradation display driving step. Is supplied with a scanning signal, and the potential applied to the pixel electrode 21 and the potential applied to the common electrode 22 in each pixel are set to the same potential. According to the stop step using the sequential short-circuit method for each scanning line, as in the simultaneous short-circuit method, the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are forcibly removed. The amount of charge consumed in the ink 23 can be reduced. Thereby, since the damage which the electrophoretic display ink 23 receives can be reduced, it becomes possible to realize the lifetime improvement of the display part 2. In particular, in the sequential short-circuit method, it is possible to align the drive voltage application time for the display pixels 20 for each of the scanning lines Y1 to Ym.
　なお、図１５及び図１６に示す一斉短絡方式及び順次短絡方式においては、表示部２のすべての画素が階調表示駆動ステップを終えた直後に短絡動作を行う場合について説明している。しかしながら、これらの短絡動作については、画像を書き込んだ後、一定時間の休止期間の経過後に行うようにしてもよい（休止後短絡方式）。この休止後短絡方式においては、例えば、休止期間として、電気泳動表示インク２３内の粒子（白粒子８２、黒粒子８３）の移動が終了する期間に設定することができる。この場合には、休止期間を挟んで短絡動作が行われることから、階調表現性能を維持しながら表示部２の長寿命化を確保することが可能となる。 In the simultaneous short-circuit method and the sequential short-circuit method shown in FIGS. 15 and 16, the case where the short-circuit operation is performed immediately after all the pixels of the display unit 2 have finished the gradation display drive step is described. However, these short-circuiting operations may be performed after a fixed period of time has elapsed after the image has been written (post-stop short-circuiting method). In the short circuit after rest, for example, the rest period can be set to a period in which the movement of the particles (white particles 82, black particles 83) in the electrophoretic display ink 23 ends. In this case, since the short-circuit operation is performed with the pause period interposed therebetween, it is possible to ensure the long life of the display unit 2 while maintaining the gradation expression performance.
　次に、本実施の形態に係る電気泳動表示装置１における停止ステップの波形について説明する。図１４は、本実施の形態に係る電気泳動表示装置１における階調駆動ステップが終了した画素における停止ステップの説明図である。図１４Ａにおいては、画素毎順次短絡方式により階調表示駆動ステップが終了した画素を次の走査のタイミングで短絡とする場合の波形を示し、図１４Ｂにおいては、画素毎順次開放方式により階調表示駆動ステップが終了した画素を次の捜査のタイミングで開放とする場合の波形を示している。 Next, the waveform of the stop step in the electrophoretic display device 1 according to the present embodiment will be described. FIG. 14 is an explanatory diagram of a stop step in a pixel for which the gradation driving step has been completed in the electrophoretic display device 1 according to the present embodiment. FIG. 14A shows a waveform when a pixel for which the gradation display driving step has been completed by the sequential short circuit method for each pixel is short-circuited at the next scanning timing, and in FIG. 14B, the gradation display is performed by the sequential opening method for each pixel. The waveform in the case where the pixel for which the driving step has been completed is opened at the timing of the next search is shown.
　階調表示駆動ステップを終えた画素を次の操作タイミングで短絡とする画素毎順次短絡方式を適用する停止ステップでは、図１４Ａに示すように、例えば、表示画素２０に５回目の走査信号が供給される一方、この走査信号に対応するタイミングにて、画素電極２１及び共通電極２２が同一電圧（ここでは、Ｖｍｉｄ（０Ｖ））に設定される。この場合、５回目の走査信号が供給されたタイミングで電気泳動表示インク２３及び保持容量２５に蓄積された電荷が除去される。 In the stop step of applying the pixel-by-pixel sequential short-circuit method in which the pixels that have finished the gradation display drive step are short-circuited at the next operation timing, for example, the fifth scanning signal is supplied to the display pixel 20 as shown in FIG. 14A. On the other hand, at the timing corresponding to this scanning signal, the pixel electrode 21 and the common electrode 22 are set to the same voltage (here, Vmid (0 V)). In this case, the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are removed at the timing when the fifth scanning signal is supplied.
　このように停止ステップに画素毎順次短絡方式を適用する場合には、電気泳動表示インク２３及び保持容量２５に蓄積された電荷が強制的に除去されることから、電気泳動表示インク２３において消費される電荷の量を低減できる。これにより、電気泳動表示インク２３が受けるダメージを低減できるので、表示部２の長寿命化を実現することが可能となる。 In this way, when the pixel-by-pixel sequential short-circuit method is applied to the stop step, the charges accumulated in the electrophoretic display ink 23 and the storage capacitor 25 are forcibly removed, and thus are consumed in the electrophoretic display ink 23. The amount of charge to be reduced can be reduced. Thereby, since the damage which the electrophoretic display ink 23 receives can be reduced, it becomes possible to realize the lifetime improvement of the display part 2.
　一方、停止ステップで画素毎順次開放方式を適用する場合には、図１４Ｂに示すように、例えば、表示画素２０に５回目以降の走査信号が供給されるタイミングにて画素電極２１をハイインピーダンス状態として駆動される。その結果、４回目の走査で保持容量２５に蓄積された電荷が徐々に放電される。 On the other hand, when the pixel-by-pixel sequential opening method is applied in the stop step, as shown in FIG. 14B, for example, the pixel electrode 21 is placed in a high impedance state at the timing when the fifth and subsequent scanning signals are supplied to the display pixel 20. As driven. As a result, the charge accumulated in the storage capacitor 25 in the fourth scan is gradually discharged.
　このように階調駆動制御を終了する際に画素電極２１を順次開放する場合には、電気泳動表示インク２３及び保持容量２５に蓄積された電荷が自然放電されるまで駆動電圧が保持されることから、表示部２におけるメモリ性を向上することが可能となる。 Thus, when the pixel electrodes 21 are sequentially opened when the gradation drive control is finished, the drive voltage is held until the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are naturally discharged. Therefore, the memory performance in the display unit 2 can be improved.
　同様に、ブロックスキャン階調駆動方式を用いて階調駆動制御を行う場合において、順次短絡、又は順次開放により階調駆動制御を終了する場合の波形について図９に示す例を用いて説明する。ブロックスキャン階調駆動方式を用いた階調駆動制御を順次短絡方式により終了する場合、図９に示すように、最後のブロック（階調Ｂ´のブロックＢ３、階調Ｂ´´のブロックＢ８）にて電気泳動表示インク２３及び保持容量２５に蓄積された電荷は、強制的に除去される。一方、ブロックスキャン階調駆動方式を用いた階調駆動制御を順次開放方式により終了する場合には、図１７に示すように、上述した順次短絡方式のように除去されずに保持され、時間経過に伴って自然放電される。 Similarly, in the case of performing gradation drive control using the block scan gradation drive method, a waveform when gradation drive control is terminated by sequential short-circuiting or sequential opening will be described using an example shown in FIG. When the gradation drive control using the block scan gradation drive method is sequentially terminated by the short-circuit method, as shown in FIG. 9, the last block (the block B3 of the gradation B ′ and the block B8 of the gradation B ″) The charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are forcibly removed. On the other hand, when the gradation drive control using the block scan gradation drive method is sequentially ended by the open method, as shown in FIG. Accompanied by spontaneous discharge.
　ブロックスキャン階調駆動方式を用いた階調駆動制御を終了する場合においても、順次短絡方式を適用する場合には、電気泳動表示インク２３及び保持容量２５に蓄積された電荷が強制的に除去されることから、電気泳動表示インク２３で消費される電荷量の低減を通じて電気泳動表示インク２３が受けるダメージを低減できるので、表示部２の長寿命化を実現することが可能となる。一方、順次開放方式を適用する場合には、電気泳動表示インク２３及び保持容量２５に蓄積された電荷を階調表現に有効に活用できるので、表示部２におけるメモリ性を向上することが可能となる。 Even when the gradation drive control using the block scan gradation drive method is terminated, when the short-circuit method is applied sequentially, the charges accumulated in the electrophoretic display ink 23 and the storage capacitor 25 are forcibly removed. As a result, damage to the electrophoretic display ink 23 can be reduced through a reduction in the amount of charge consumed by the electrophoretic display ink 23, and thus the life of the display unit 2 can be extended. On the other hand, when the sequential opening method is applied, the charges stored in the electrophoretic display ink 23 and the storage capacitor 25 can be effectively used for gradation expression, so that the memory performance in the display unit 2 can be improved. Become.
　以上説明したように、本実施の形態に係る電気泳動表示装置１においては、全画素同一表示駆動ステップ、階調表示駆動ステップ及び停止ステップを順次実行することで表示部２に画像を表示させる。ある画像を表示部２に表示した後、新たな別の画像を表示する場合には、全画素同一表示駆動ステップを挟んで階調表示駆動ステップが行われ、停止ステップが行われる。この場合において、全画素同一表示駆動ステップではコモン振りが適用されることから、高コントラストの白又は黒の表示を実現できる。一方、階調表示駆動ステップではコモン振りを適用することなく中間電位Ｖｍｉｄに固定した状態で各画素電極２１に対する駆動が制御されることから、細かい階調の変化を実現できる。この結果、白黒二値の表示性能を向上すると共に、階調表現性能を向上することが可能となる。 As described above, in the electrophoretic display device 1 according to the present embodiment, an image is displayed on the display unit 2 by sequentially executing the same pixel display driving step, gradation display driving step, and stop step. When a new image is displayed after a certain image is displayed on the display unit 2, a gradation display driving step is performed across the same display driving step for all pixels, and a stop step is performed. In this case, since the common swing is applied in the same display driving step for all pixels, a high contrast white or black display can be realized. On the other hand, in the gradation display driving step, since the driving of each pixel electrode 21 is controlled in a state where it is fixed to the intermediate potential Vmid without applying the common swing, a fine gradation change can be realized. As a result, it is possible to improve the black and white binary display performance and improve the gradation expression performance.
　以下に実施例を挙げて本発明をさらに詳しく説明するが、本発明はこれら実施例のみに限られるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
　以下、本実施の形態に係る電気泳動表示装置１における駆動動作に関する検証実験について説明する。ここでは、共通電極２２と画素電極２１の素材には、酸化インジウムスズ（スズドープ酸化インジウム）によって表面抵抗が２５０Ω／□となる透明な電極がＰＥＴフィルム上に形成された基板（以下ＩＴＯ－ＰＥＴと呼ぶ）を使用した。また、共通電極２２には、インクを仕切るための高さ２０μｍ、ピッチ３００μｍのマイクロセルが形成されている。電気泳動表示インク２３を電極間（画素電極２１－共通電極２２間）が２０μｍ、表示エリアが５０ｍｍ×４０ｍｍとなるようにＵＶ硬化接着剤で周囲を封止した。上記のように構成されたパネル１枚を以下単セルと呼称する。 Hereinafter, a verification experiment regarding the driving operation in the electrophoretic display device 1 according to the present embodiment will be described. Here, as a material for the common electrode 22 and the pixel electrode 21, a substrate (hereinafter referred to as ITO-PET) on which a transparent electrode having a surface resistance of 250 Ω / □ is formed on indium tin oxide (tin-doped indium oxide) on a PET film. Used). The common electrode 22 is formed with microcells having a height of 20 μm and a pitch of 300 μm for partitioning ink. The periphery of the electrophoretic display ink 23 was sealed with a UV curable adhesive so that the distance between the electrodes (between the pixel electrode 21 and the common electrode 22) was 20 μm and the display area was 50 mm × 40 mm. One panel configured as described above is hereinafter referred to as a single cell.
　インク（電気泳動表示インク２３）の電気的特性は、体積固有抵抗が１０１０（Ωｃｍ）、比誘電率が３である。電気泳動表示インク２３は、白色粒子８２及び黒色粒子８３を含む。白色粒子８２は、負に帯電しており、共通電極２２が画素電極２１と比較して高電圧の場合に共通電極２２側に集まり、表示面側（共通電極２２側）が白色表示となる。一方、黒色粒子８３は、正に帯電しており、共通電極２２が画素電極２１と比較して低電圧の場合に共通電極２２側に集まり、表示面側（共通電極２２側）が黒色表示となる。 The electrical characteristics of the ink (electrophoretic display ink 23) are a volume resistivity of 10 10 (Ωcm) and a relative dielectric constant of 3. The electrophoretic display ink 23 includes white particles 82 and black particles 83. The white particles 82 are negatively charged. When the common electrode 22 has a higher voltage than the pixel electrode 21, the white particles 82 gather on the common electrode 22 side, and the display surface side (the common electrode 22 side) displays white. On the other hand, the black particles 83 are positively charged. When the common electrode 22 has a lower voltage than the pixel electrode 21, the black particles 83 gather on the common electrode 22 side, and the display surface side (common electrode 22 side) is black. Become.
　前記単セル１枚に静電容量が１４．７μFの保持容量２５を並列に接続しこれを１画素とみなして検証実験を実施した。 A holding experiment 25 having a capacitance of 14.7 μF was connected in parallel to one single cell, and this was regarded as one pixel, and a verification experiment was conducted.
　検証実験においては、データ線数が３２０本であり、走査線数が２４０本の一般的なＱＶＧＡパネル（表示部２）を想定した。 In the verification experiment, a general QVGA panel (display unit 2) having 320 data lines and 240 scanning lines was assumed.
　走査線順次選択方式にて駆動する場合、走査線の選択時間を２０μｓとした。この場合、走査線数が２４０本であるので、１フレームの走査信号の供給に要する時間は、４．８ｍｓである。したがって前記単セルには、１フレーム４．８ｍｓのうちに２０μｓだけ電圧が印加される。なお、階調表示駆動ステップでは、階調に合わせてフレーム数を変化させた。 When driving by the scanning line sequential selection method, the scanning line selection time was set to 20 μs. In this case, since the number of scanning lines is 240, the time required to supply the scanning signal for one frame is 4.8 ms. Accordingly, a voltage of 20 μs is applied to the single cell within one frame of 4.8 ms. In the gradation display driving step, the number of frames was changed in accordance with the gradation.
　また、全走査線同時選択駆動方式にて駆動する場合は、１フレームを１００ｍｓとして全画素が１００ｍｓの期間、電圧が印加されるようにした。 In the case of driving by the all-scan line simultaneous selection driving method, one frame is set to 100 ms, and the voltage is applied to all the pixels for 100 ms.
　全画素同一表示駆動ステップに適用されるコモン振りにおいては、共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加することで、共通電極２２側（表示面側）に白色粒子８２を移動させる電圧として電位差３０Ｖを得た。一方、共通電極２２に－１５Ｖを印加し、画素電極２１に＋１５Ｖを印加することで、共通電極２２側（表示面側）に黒色粒子８３を移動させる電圧として電位差３０Ｖを得た。 In the common swing applied to the same display driving step for all the pixels, + 15V is applied to the common electrode 22 and −15V is applied to the pixel electrode 21, so that the white particles 82 are applied to the common electrode 22 side (display surface side). A potential difference of 30 V was obtained as the voltage to be moved. On the other hand, by applying -15V to the common electrode 22 and + 15V to the pixel electrode 21, a potential difference of 30V was obtained as a voltage for moving the black particles 83 to the common electrode 22 side (display surface side).
　コモン振りを適用しない階調表示駆動ステップ（階調表示駆動）においては、共通電極２２を０Ｖに設定し、画素電極２１に＋１５Ｖを印加することで、共通電極２２側（表示面側）に白色粒子８２を移動させる電圧として電位差１５Ｖを得た。一方、共通電極２２を０Ｖに設定し、画素電極２１に－１５Ｖを印加することで、共通電極２２側（表示面側）に黒色粒子８３を移動させる電圧として電位差１５Ｖを得た。 In the gradation display driving step (gradation display driving) in which the common swing is not applied, the common electrode 22 is set to 0 V, and +15 V is applied to the pixel electrode 21, so that the common electrode 22 side (display surface side) is white. A potential difference of 15 V was obtained as a voltage for moving the particles 82. On the other hand, by setting the common electrode 22 to 0V and applying -15V to the pixel electrode 21, a potential difference of 15V was obtained as a voltage for moving the black particles 83 to the common electrode 22 side (display surface side).
（実施例１）
　共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加した状態で走査線を順次選択するスキャン動作を２０回繰り返して全画素の表示状態を白に変化させる全画素同一表示駆動ステップの後に、共通電極２２に０Ｖを印加し、画素電極２１には、次表示画像データに従って表示状態を変化させたい画素には＋１５Ｖを印加し、表示状態を変化させない画素には０Ｖを印加させて走査線を順次選択するスキャン動作を６０回繰り返す階調表示駆動ステップを行い、表示したい階調に到達した画素の画素電極２１に０Ｖを印加することで、共通電極と同電位とする停止ステップを行った。 (Example 1)
In the same display driving step for all the pixels, the scanning operation for sequentially selecting the scanning lines in a state where +15 V is applied to the common electrode 22 and −15 V is applied to the pixel electrode 21 is repeated 20 times to change the display state of all pixels to white. Later, 0V is applied to the common electrode 22, + 15V is applied to the pixel electrode 21 according to the next display image data, + 15V is applied to the pixel whose display state is to be changed, and 0V is applied to the pixel whose display state is not changed. A gradation display driving step for repeating a scanning operation for sequentially selecting lines 60 times is performed, and a stop step for applying the same potential as the common electrode by applying 0 V to the pixel electrode 21 of the pixel that has reached the gradation to be displayed is performed. It was.
（実施例２）
　共通電極２２に－１５Ｖを印加し、画素電極に＋１５Ｖを印加した状態で走査線を順次選択するスキャン動作を２０回繰り返したのちに、共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加した状態で走査線を順次選択するスキャン動作を２０回繰り返して全画素の表示状態を白に変化させる全画素同一表示駆動ステップの後に、共通電極２２に０Ｖを印加し、画素電極２１には、次表示画像データに従って表示状態を変化させたい画素には＋１５Ｖを印加し、表示状態を変化させない画素には０Ｖを印加させて走査線を順次選択するスキャン動作を６０回繰り返す階調表示駆動ステップを行い、表示したい階調に到達した画素の画素電極２１に０Ｖを印加することで、共通電極と同電位とする停止ステップを行った。 (Example 2)
After repeating the scanning operation of sequentially selecting scanning lines with -15V applied to the common electrode 22 and + 15V applied to the pixel electrode, + 15V is applied to the common electrode 22 and -15V is applied to the pixel electrode 21. A scan operation for sequentially selecting scanning lines in a state where voltage is applied is repeated 20 times to change the display state of all pixels to white. After all pixels are in the same display driving step, 0 V is applied to the common electrode 22 and applied to the pixel electrode 21. Is a gradation display drive in which + 15V is applied to a pixel whose display state is to be changed in accordance with the next display image data, and 0V is applied to a pixel whose display state is not to be changed to sequentially select a scanning line 60 times. Steps were performed, and a stop step of applying the same potential as the common electrode by applying 0 V to the pixel electrode 21 of the pixel that reached the gradation to be displayed was performed.
（実施例３）
　共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加した状態で全走査線を同時に１００ｍｓの間、選択する動作によって全画素の表示状態を白に変化させる全画素同一表示駆動ステップの後に、共通電極２２に０Ｖを印加し、画素電極２１には、次表示画像データに従って表示状態を変化させたい画素には＋１５Ｖを印加し、表示状態を変化させない画素には０Ｖを印加させて走査線を順次選択するスキャン動作を６０回繰り返す階調表示駆動ステップを行い、表示したい階調に到達した画素の画素電極２１に０Ｖを印加することで、共通電極と同電位とする停止ステップを行った。 (Example 3)
In the same display driving step for all pixels, the display state of all pixels is changed to white by the operation of selecting all scanning lines simultaneously for 100 ms with +15 V applied to the common electrode 22 and −15 V applied to the pixel electrode 21. Later, 0V is applied to the common electrode 22, + 15V is applied to the pixel electrode 21 according to the next display image data, + 15V is applied to the pixel whose display state is to be changed, and 0V is applied to the pixel whose display state is not changed. A gradation display driving step for repeating a scanning operation for sequentially selecting lines 60 times is performed, and a stop step for applying the same potential as the common electrode by applying 0 V to the pixel electrode 21 of the pixel that has reached the gradation to be displayed is performed. It was.
（実施例４）
　共通電極２２に－１５Ｖを印加し、画素電極に＋１５Ｖを印加した状態で全走査線を同時に１００ｍｓの間、選択する動作ののちに、共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加した状態で全走査線を同時に１００ｍｓの間、選択する動作によって全画素の表示状態を白に変化させる全画素同一表示駆動ステップの後に、共通電極２２に０Ｖを印加し、画素電極２１には、次表示画像データに従って表示状態を変化させたい画素には＋１５Ｖを印加し、表示状態を変化させない画素には０Ｖを印加させて走査線を順次選択するスキャン動作を６０回繰り返す階調表示駆動ステップを行い、表示したい階調に到達した画素の画素電極２１に０Ｖを印加することで、共通電極と同電位とする停止ステップを行った。 Example 4
After -15V is applied to the common electrode 22 and + 15V is applied to the pixel electrode, all scanning lines are simultaneously selected for 100 ms, and then + 15V is applied to the common electrode 22 and -15V is applied to the pixel electrode 21. In the state where all the scanning lines are simultaneously applied for 100 ms in a state where voltage is applied, 0 V is applied to the common electrode 22 after the same pixel display driving step for changing the display state of all pixels to white by the operation of selecting all the scanning lines. Is a gradation display drive in which + 15V is applied to a pixel whose display state is to be changed in accordance with the next display image data, and 0V is applied to a pixel whose display state is not to be changed to sequentially select a scanning line 60 times. Steps were performed, and a stop step of applying the same potential as the common electrode by applying 0 V to the pixel electrode 21 of the pixel that reached the gradation to be displayed was performed.
（実施例５）
　実施例２の、階調表示駆動ステップにおいて、スキャン動作を３１回繰り返して全画素を中間階調１の表示状態にした。 (Example 5)
In the gradation display driving step of Example 2, the scanning operation was repeated 31 times so that all the pixels were displayed in the intermediate gradation 1 display state.
（実施例６）
　実施例２の、階調表示駆動ステップにおいて、スキャン動作を３０回繰り返して全画素を中間階調２の表示状態にした。 (Example 6)
In the gradation display driving step of Example 2, the scanning operation was repeated 30 times so that all the pixels were in the display state of intermediate gradation 2.
（実施例７）
　実施例２の、階調表示駆動ステップにおいて、スキャン動作を２９回繰り返して全画素を中間階調３の表示状態にした。 (Example 7)
In the gradation display driving step of Example 2, the scanning operation was repeated 29 times to bring all pixels into the display state of intermediate gradation 3.
（実施例８：逆スキャン挿入駆動）
　実施例６の、階調表示駆動ステップにおいて、スキャン動作を１５回繰り返した後に画素電極に＋１５Ｖを印加した状態でスキャン動作を１回行い、その後再び画素電極に－１５Ｖを印加した状態でスキャン動作を１５回繰り返して全画素を中間階調４の表示状態にした。 (Example 8: Reverse scan insertion drive)
In the gradation display driving step of Example 6, the scan operation is repeated 15 times, then the scan operation is performed once with + 15V applied to the pixel electrode, and then the scan operation is performed with −15V applied to the pixel electrode again. Was repeated 15 times to bring all the pixels into the display state of the intermediate gradation 4.
（実施例９：ブロックスキャン駆動）
　実施例６の、階調表示駆動ステップにおいて、スキャン動作を１５回繰り返した後にスキャン動作１０回分の休止期間を設け、その後スキャン動作を１５回繰り返して全画素を中間階調５の表示状態にした。 (Example 9: Block scan driving)
In the grayscale display driving step of Example 6, after a scan operation is repeated 15 times, a pause period of 10 scan operations is provided, and then the scan operation is repeated 15 times so that all pixels are in a display state of intermediate grayscale 5. .
（実施例１０：逆スキャン挿入駆動とブロックスキャン駆動の組合わせ）
　実施例６の、階調表示駆動ステップにおいて、スキャン動作を１５回繰り返した後にスキャン動作１０回分の休止期間を設けたのちに画素電極に＋１５Ｖを印加した状態でスキャン動作を１回行い、再びスキャン動作１０回分の休止期間を設けた後に画素電極に－１５Ｖを印加した状態でスキャン動作を１５回繰り返して全画素を中間階調５の表示状態にした。 (Example 10: Combination of reverse scan insertion drive and block scan drive)
In the gradation display driving step of Example 6, after the scan operation is repeated 15 times, a scan operation is performed once in a state where +15 V is applied to the pixel electrode after providing a pause period of 10 scan operations. After a pause period of 10 operations, the scan operation was repeated 15 times with -15 V applied to the pixel electrode, so that all the pixels were set to the display state of the intermediate gradation 5.
（比較例１）
　全画素同一表示駆動ステップにおいて、共通電極２２には常に０Ｖが印加されていることのみ実施例２と異なる駆動にて表示を行った。 (Comparative Example 1)
In the same display driving step for all pixels, display was performed by driving different from that in Example 2 only that 0 V was always applied to the common electrode 22.
（比較例２）
　全画素同一表示駆動ステップにおいて、共通電極２２には常に０Ｖが印加され、階調表示駆動において、共通電極２２には常に－１５Ｖが印加されていることのみ実施例２と異なる駆動にて表示を行った。 (Comparative Example 2)
In the same display driving step for all pixels, 0V is always applied to the common electrode 22, and in the gradation display driving, −15V is always applied to the common electrode 22. went.
（比較例３）
　停止ステップにおいて、画素電極がハイインピーダンス状態となることのみ実施例２と異なる駆動にて表示を行った。 (Comparative Example 3)
In the stop step, display was performed by driving different from that in Example 2 only that the pixel electrode was in a high impedance state.
（比較例４）
　階調表示駆動において、共通電極２２には常に－１５Ｖが印加されていることのみ実施例２と異なる駆動にて表示を行った。 (Comparative Example 4)
In gradation display driving, display was performed by driving different from that in Example 2 only that −15 V was always applied to the common electrode 22.
（評価方法）
　駆動後の評価にはスガ試験機社製の分光測色計「ＳＣ－Ｐ」を用いて反射率（Ｙ値）を測定した。測定に使用した光源はＤ６５、１０°視野、測定孔はφ１５、正反射を除いて測定した。 (Evaluation methods)
For evaluation after driving, the reflectance (Y value) was measured using a spectrocolorimeter “SC-P” manufactured by Suga Test Instruments Co., Ltd. The light source used for the measurement was D65, a 10 ° field of view, the measurement hole was φ15, and the specular reflection was excluded.
（評価項目Ａ：全画素同一表示反射率）
　各実施例及び比較例の駆動において全画素同一表示駆動ステップ後に駆動を停止して反射率を計測し全画素同一表示反射率とした。本実施例では白反射率となり、数値が高いほど性能がよい。今回は「反射率４５以上：◎」「反射率４０以上４５未満：○」「反射率３５以上４０未満：△」「反射率３５未満：×」と表現した。 (Evaluation item A: All pixels have the same display reflectance)
In the driving of each example and comparative example, the driving was stopped after the same pixel display driving step, and the reflectance was measured to obtain the same display reflectance of all pixels. In this embodiment, the white reflectance is obtained, and the higher the numerical value, the better the performance. This time, it was expressed as “reflectance 45 or higher: ◎” “reflectivity 40 or higher and lower than 45: ◯” “reflectivity 35 or higher but lower than 40: Δ” “reflectivity 35 lower than 35: x”.
（評価項目Ｂ：階調駆動表示時最終反射率）
　各実施例及び比較例の駆動において、階調表示駆動ステップでスキャンを６０回繰り返した後の反射率を計測し、階調駆動表示時最終反射率とした。本実施例ではこの状態が最も黒い状態を得た場合の反射率となり、数値が低いほど性能がよい。今回は「反射率４．０未満：◎」「反射率４．０以上４．５未満：○」「反射率４．５以上５．０未満：△」「反射率５．０以上：×」と表現した。 (Evaluation item B: Final reflectance during gradation drive display)
In the driving of each example and comparative example, the reflectivity after the scan was repeated 60 times in the gradation display driving step was measured to obtain the final reflectance at the gradation driving display. In this embodiment, this is the reflectance when this state is the blackest, and the lower the value, the better the performance. This time, “reflectance less than 4.0: ◎” “reflectance 4.0 or more and less than 4.5: ○” “reflectance 4.5 or more and less than 5.0: Δ” “reflectance 5.0 or more: x” Expressed.
（評価項目Ｃ：階調表示性能）
　スキャン回数階調においては、スキャンのたびに粒子は反対側電極へ移動することとなり、逆方向への移動はない。したがって、評価Ａで得られた反射率から評価Ｂで得られた反射率へ移行するのに必要となるスキャン回数が、表現できる中間階調の最大値となる。本実施例においては、「スキャン回数を一回増加しても反射率変動が、スキャン回数増加前の反射率から５％以上変化しない」時点で粒子の移動が終了したと判断し、それまでに要したスキャン回数を階調表示性能とした。各実施例及び比較例の駆動において、階調表示駆動ステップでスキャンを１回から６０回まで変化させて停止し、各スキャン回数印加後の反射率を計測して評価した。今回は「スキャン回数が６４回以上：◎」「スキャン回数が３２回以上６４回未満：○」「スキャン回数が１６回以上３２回未満：△」「スキャン回数が１５回以下：×」と表現した。 (Evaluation item C: gradation display performance)
In the scanning frequency gradation, each time a scan is performed, the particles move to the opposite electrode, and there is no movement in the reverse direction. Therefore, the number of scans required to shift from the reflectance obtained in evaluation A to the reflectance obtained in evaluation B is the maximum value of the intermediate gradation that can be expressed. In this example, it is determined that the movement of the particles has been completed at the time “the reflectance fluctuation does not change by 5% or more from the reflectance before the increase in the number of scans even if the number of scans is increased by one”. The number of scans required was defined as gradation display performance. In the driving of each example and comparative example, the scanning was changed from 1 to 60 times in the gradation display driving step and stopped, and the reflectance after the application of each scanning number was measured and evaluated. This time, “scanning number is 64 times or more: A” “scanning number is 32 times or more and less than 64 times: ○” “scanning number is 16 times or more and less than 32 times: Δ” “scanning number is 15 times or less: x” did.
（評価項目Ｄ：書換耐久性）
　表示書換駆動を繰り返していくと「全画素同一表示の反射率」は低下し、「階調駆動表示時最終反射率」は上昇する。また「中間階調反射率」は変動するといった表示性能劣化が発生する。今回は書換駆動２０万回後の表示を見て劣化状態を判断した。「表示性能の変化が実感できない：○」「表示の低下が実感できる：△」「表示性能が著しく低下する：×」と表現した。 (Evaluation item D: Rewriting durability)
As the display rewriting drive is repeated, the “reflectance of the same display for all pixels” decreases, and the “final reflectivity during gradation drive display” increases. In addition, display performance deterioration such as “half-tone reflectance” fluctuates. This time, the deterioration state was judged by looking at the display 200,000 times after the rewriting drive. It was expressed as “cannot feel a change in display performance: ○” “can feel a drop in display: Δ” “remarkably deteriorates in display performance: x”.
（評価の結果その１）
　実施例１～４及び比較例１～４の評価の結果を表１に示した。
Figure JPOXMLDOC01-appb-T000001
 (As a result of evaluation 1)
The evaluation results of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
（評価の結果その１の考察）
　実施例１～４は、評価４項目すべてにおいて○以上の結果となった。これに対し、比較例１と２では、評価項目Ａ及び評価項目Ｂで○とならない。このことから、全画素同一表示駆動ステップにおいて共通電極２２を０Ｖとする駆動（コモンを振らない駆動）を実施した場合、白及び黒の表示性能が低下し、パネルのコントラストが低下する。比較例４では、評価項目Ｃでは△となる。このことから全画素同一表示駆動ステップ及び階調表示駆動ステップの両方でコモン振りによる駆動を実施した場合、階調表示性能が低下することがわかる。比較例３は評価項目Ｄにて△となる。このことから、停止ステップにおいて画素電極をハイインピーダンス状態とする駆動は書換耐久性が低下することがわかる。 (Consideration of evaluation result 1)
In Examples 1 to 4, results of ◯ or more were obtained in all four evaluation items. On the other hand, in the comparative examples 1 and 2, the evaluation item A and the evaluation item B are not good. For this reason, when the drive for setting the common electrode 22 to 0 V (drive without shaking the common) is performed in the same display drive step for all the pixels, the display performance of white and black is lowered, and the contrast of the panel is lowered. In Comparative Example 4, the evaluation item C is Δ. From this, it is understood that the gradation display performance deteriorates when driving by common swing is performed in both the same pixel display driving step and the gradation display driving step. In Comparative Example 3, the evaluation item D is Δ. From this, it can be seen that the driving to bring the pixel electrode to the high impedance state in the stop step has a low rewrite durability.
（評価の結果その２）
　実施例５～１０の評価の階調表示駆動ステップ後の反射率を図１８に示した。 (As a result of evaluation 2)
The reflectance after the gradation display driving step of evaluation of Examples 5 to 10 is shown in FIG.
（評価結果その２の考察）
　実施例５～７は階調表示駆動ステップにおいてスキャン回数が１ずつ異なる駆動である。したがって、従来技術のスキャン回数階調方式を用いる場合、この間の反射率を得ることはできない。しかし、実施例８の逆スキャンを挿入する駆動や実施例９の休止を挿入する駆動、また、実施例１０の、逆スキャンとブロックスキャンを組み合わせた駆動により、実施例５～７の間の反射率を得ることができた。このことから、逆スキャン挿入駆動およびブロックスキャン駆動を用いることで階調表示の微調整を行うことが可能となることがわかる。 (Consideration of evaluation result 2)
In the fifth to seventh embodiments, the number of scans is different by one in the gradation display driving step. Therefore, when using the conventional scanning frequency gradation method, the reflectance during this period cannot be obtained. However, the reflection between the fifth to seventh embodiments by the drive for inserting the reverse scan of the eighth embodiment, the drive for inserting the pause of the ninth embodiment, and the drive of the tenth embodiment combining the reverse scan and the block scan. I was able to get a rate. From this, it can be understood that the gradation display can be finely adjusted by using the reverse scan insertion drive and the block scan drive.
　なお、上記の効果を、ＴＦＴを用いたＱＶＧＡの表示パネルにて検証した結果、同様の結果が得られた。 As a result of verifying the above effect with a QVGA display panel using TFTs, the same result was obtained.
（第２の実施の形態）
　第２の実施の形態に係る電気泳動表示装置は、停止ステップにおいて、第１の実施の形態に係る電気泳動表示装置と相違する。第２の実施の形態に係る電気泳動表示装置は、第１の実施の形態に係る電気泳動表示装置と共通の構成を有している。また、第２の実施の形態に係る電気泳動表示装置は、停止ステップを除き、第１の実施の形態に係る電気泳動表示装置と同一のステップ（全画素同一表示駆動ステップ及び階調表示駆動ステップ）を実行する。なお、以下においては、第１の実施の形態に係る電気泳動表示装置と共通する構成要素について同一の符号を用いて説明を行う。 (Second Embodiment)
The electrophoretic display device according to the second embodiment differs from the electrophoretic display device according to the first embodiment in the stopping step. The electrophoretic display device according to the second embodiment has the same configuration as the electrophoretic display device according to the first embodiment. The electrophoretic display device according to the second embodiment is the same as the electrophoretic display device according to the first embodiment except for the stop step (all pixel identical display drive step and gradation display drive step). ). In the following description, components common to the electrophoretic display device according to the first embodiment will be described using the same reference numerals.
　第２の実施の形態に係る電気泳動表示装置においては、停止ステップとして、それぞれの表示画素２０が所望の階調に達した後、各画素ごとの画素電極２１の電位をハイインピーダンス状態として走査信号を供給する開放動作を行う（図１３Ｂ参照）。階調表示駆動ステップが終了した後の停止ステップにおいて、対象画素の画素電極を開放することから、対象画素に蓄積された電荷が自然放電されるまで駆動電圧が保持されることとなり、表示装置におけるメモリ性を向上することが可能となる。 In the electrophoretic display device according to the second embodiment, as a stop step, after each display pixel 20 reaches a desired gradation, the potential of the pixel electrode 21 for each pixel is set to a high impedance state to scan a signal. An opening operation is performed to supply (see FIG. 13B). Since the pixel electrode of the target pixel is opened in the stop step after the gradation display driving step is completed, the driving voltage is held until the charge accumulated in the target pixel is spontaneously discharged. Memory performance can be improved.
　ここで、短絡動作および開放動作について図１３に基づいて説明する。図１３は、本実施の形態に係る電気泳動表示装置１における階調駆動制御を終了する場合の短絡動作及び開放動作の説明図である。図１３Ａにおいては、停止ステップの短絡動作を示し、図１３Ｂにおいては階調表示駆動ステップ中の開放動作について示し、図１３Ｃにおいては、停止ステップの開放動作を示している。 Here, the short circuit operation and the open operation will be described with reference to FIG. FIG. 13 is an explanatory diagram of a short-circuit operation and an open operation when the gradation drive control is finished in the electrophoretic display device 1 according to the present embodiment. 13A shows a short-circuit operation at the stop step, FIG. 13B shows an open operation during the gradation display driving step, and FIG. 13C shows an open operation at the stop step.
　短絡動作においては、図１３Ａに示すように、走査線Ｙに対する走査信号をオン電位とし、データ線Ｘを介して画素電極２１に印加される電圧と、共通電極２２に印加される電圧とが同電位に設定される。一方、開放動作においては、図１３Ｂに示すように、データ線Ｘを何らかの方法によりハイインピーダンス状態に設定し、或いは、図１３Ｃに示すように、走査線Ｙをオフ電位に設定することでハイインピーダンス状態に設定する。前者が走査線Ｙに対する走査信号がオン電位であるのに対し、後者が走査線Ｙに対する走査信号がオフ電位である点で相違する。 In the short-circuit operation, as shown in FIG. 13A, the scanning signal for the scanning line Y is turned on, and the voltage applied to the pixel electrode 21 via the data line X is the same as the voltage applied to the common electrode 22. Set to potential. On the other hand, in the open operation, the data line X is set to a high impedance state by some method as shown in FIG. 13B, or the scanning line Y is set to an off potential as shown in FIG. Set to state. The former is different in that the scanning signal for the scanning line Y is on-potential, while the latter is the scanning signal for the scanning line Y is off-potential.
　次に、本実施の形態に係る電気泳動表示装置１における停止ステップの波形について説明する。図１４は、本実施の形態に係る電気泳動表示装置１における階調駆動ステップが終了した画素における停止ステップの説明図である。図１４Ａにおいては、画素毎順次短絡方式により階調表示駆動ステップが終了した画素を次の走査のタイミングで短絡とする場合の波形を示し、図１４Ｂにおいては、画素毎順次開放方式により階調表示駆動ステップが終了した画素を次の捜査のタイミングで開放とする場合の波形を示している。 Next, the waveform of the stop step in the electrophoretic display device 1 according to the present embodiment will be described. FIG. 14 is an explanatory diagram of a stop step in a pixel for which the gradation driving step has been completed in the electrophoretic display device 1 according to the present embodiment. FIG. 14A shows a waveform when a pixel for which the gradation display driving step has been completed by the sequential short circuit method for each pixel is short-circuited at the next scanning timing, and in FIG. 14B, the gradation display is performed by the sequential opening method for each pixel. The waveform in the case where the pixel for which the driving step has been completed is opened at the timing of the next search is shown.
　階調表示駆動ステップを終えた画素を次の操作タイミングで短絡とする画素毎順次短絡方式を適用する停止ステップでは、図１４Ａに示すように、例えば、表示画素２０に５回目の走査信号が供給される一方、この走査信号に対応するタイミングにて、画素電極２１及び共通電極２２が同一電圧（ここでは、Ｖｍｉｄ（０Ｖ））に設定される。この場合、５回目の走査信号が供給されたタイミングで電気泳動表示インク２３及び保持容量２５に蓄積された電荷が除去される。 In the stop step of applying the pixel-by-pixel sequential short-circuit method in which the pixels that have finished the gradation display drive step are short-circuited at the next operation timing, for example, the fifth scanning signal is supplied to the display pixel 20 as shown in FIG. 14A. On the other hand, at the timing corresponding to this scanning signal, the pixel electrode 21 and the common electrode 22 are set to the same voltage (here, Vmid (0 V)). In this case, the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are removed at the timing when the fifth scanning signal is supplied.
　このように停止ステップに画素毎順次短絡方式を適用する場合には、電気泳動表示インク２３及び保持容量２５に蓄積された電荷が強制的に除去されることから、電気泳動表示インク２３において消費される電荷の量を低減できる。これにより、電気泳動表示インク２３が受けるダメージを低減できるので、表示部２の長寿命化を実現することが可能となる。 In this way, when the pixel-by-pixel sequential short-circuit method is applied to the stop step, the charges accumulated in the electrophoretic display ink 23 and the storage capacitor 25 are forcibly removed, and thus are consumed in the electrophoretic display ink 23. The amount of charge to be reduced can be reduced. Thereby, since the damage which the electrophoretic display ink 23 receives can be reduced, it becomes possible to realize the lifetime improvement of the display part 2.
　一方、停止ステップで画素毎順次開放方式を適用する場合には、図１４Ｂに示すように、例えば、表示画素２０に５回目以降の走査信号が供給されるタイミングにて画素電極２１をハイインピーダンス状態として駆動される。その結果、４回目の走査で保持容量２５に蓄積された電荷が徐々に放電される。 On the other hand, when the pixel-by-pixel sequential opening method is applied in the stop step, as shown in FIG. 14B, for example, the pixel electrode 21 is placed in a high impedance state at the timing when the fifth and subsequent scanning signals are supplied to the display pixel 20. As driven. As a result, the charge accumulated in the storage capacitor 25 in the fourth scan is gradually discharged.
　このように階調駆動制御を終了する際に画素電極２１を順次開放する場合には、電気泳動表示インク２３及び保持容量２５に蓄積された電荷が自然放電されるまで駆動電圧が保持されることから、表示部２におけるメモリ性を向上することが可能となる。 Thus, when the pixel electrodes 21 are sequentially opened when the gradation drive control is finished, the drive voltage is held until the charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are naturally discharged. Therefore, the memory performance in the display unit 2 can be improved.
　同様に、ブロックスキャン階調駆動方式を用いて階調駆動制御を行う場合において、順次短絡、又は順次開放により階調駆動制御を終了する場合の波形について図９に示す例を用いて説明する。ブロックスキャン階調駆動方式を用いた階調駆動制御を順次短絡方式により終了する場合、図９に示すように、最後のブロック（階調Ｂ´のブロックＢ３、階調Ｂ´´のブロックＢ８）にて電気泳動表示インク２３及び保持容量２５に蓄積された電荷は、強制的に除去される。一方、ブロックスキャン階調駆動方式を用いた階調駆動制御を順次開放方式により終了する場合には、図１７に示すように、上述した順次短絡方式のように除去されずに保持され、時間経過に伴って自然放電される。 Similarly, in the case of performing gradation drive control using the block scan gradation drive method, a waveform when gradation drive control is terminated by sequential short-circuiting or sequential opening will be described using an example shown in FIG. When the gradation drive control using the block scan gradation drive method is sequentially terminated by the short-circuit method, as shown in FIG. 9, the last block (the block B3 of the gradation B ′ and the block B8 of the gradation B ″) The charges accumulated in the electrophoretic display ink 23 and the holding capacitor 25 are forcibly removed. On the other hand, when the gradation drive control using the block scan gradation drive method is sequentially ended by the open method, as shown in FIG. Accompanied by spontaneous discharge.
　ブロックスキャン階調駆動方式を用いた階調駆動制御を終了する場合においても、順次短絡方式を適用する場合には、電気泳動表示インク２３及び保持容量２５に蓄積された電荷が強制的に除去されることから、電気泳動表示インク２３で消費される電荷量の低減を通じて電気泳動表示インク２３が受けるダメージを低減できるので、表示部２の長寿命化を実現することが可能となる。一方、順次開放方式を適用する場合には、電気泳動表示インク２３及び保持容量２５に蓄積された電荷を階調表現に有効に活用できるので、表示部２におけるメモリ性を向上することが可能となる。 Even when the gradation drive control using the block scan gradation drive method is terminated, when the short-circuit method is applied sequentially, the charges accumulated in the electrophoretic display ink 23 and the storage capacitor 25 are forcibly removed. As a result, damage to the electrophoretic display ink 23 can be reduced through a reduction in the amount of charge consumed by the electrophoretic display ink 23, and thus the life of the display unit 2 can be extended. On the other hand, when the sequential opening method is applied, the charges stored in the electrophoretic display ink 23 and the storage capacitor 25 can be effectively used for gradation expression, so that the memory performance in the display unit 2 can be improved. Become.
　以上説明したように、本実施の形態に係る電気泳動表示装置１においては、全画素同一表示駆動ステップ、階調表示駆動ステップ及び停止ステップを順次実行することで表示部２に画像を表示させる。ある画像を表示部２に表示した後、新たな別の画像を表示する場合には、一旦、全画素同一表示駆動ステップを挟んで階調表示駆動ステップが行われ、停止ステップが行われる。この場合において、全画素同一表示駆動ステップではコモン振りが適用されることから、高コントラストの白又は黒の表示を実現できる。一方、階調表示駆動ステップではコモン振りを適用することなく中間電位Ｖｍｉｄに固定した状態で各画素電極２１に対する駆動が制御されることから、細かい階調の変化を実現できる。また、停止ステップにおいて、対象画素の画素電極を開放することから、対象画素に蓄積された電荷が自然放電されるまで駆動電圧が保持されることから、表示装置におけるメモリ性を向上することが可能となる。この結果、白黒二値の表示性能を向上すると共に、階調表現性能を向上することが可能となる。 As described above, in the electrophoretic display device 1 according to the present embodiment, an image is displayed on the display unit 2 by sequentially executing the same pixel display driving step, gradation display driving step, and stop step. When a new image is displayed after a certain image is displayed on the display unit 2, a gradation display driving step is once performed across the same display driving step for all pixels, and a stop step is performed. In this case, since the common swing is applied in the same display driving step for all pixels, a high contrast white or black display can be realized. On the other hand, in the gradation display driving step, since the driving of each pixel electrode 21 is controlled in a state where it is fixed to the intermediate potential Vmid without applying the common swing, a fine gradation change can be realized. In addition, since the pixel electrode of the target pixel is opened in the stop step, and the drive voltage is held until the charge accumulated in the target pixel is naturally discharged, the memory performance in the display device can be improved. It becomes. As a result, it is possible to improve the black and white binary display performance and improve the gradation expression performance.
　また、上記全画素同一表示駆動に先立って、現在表示されている画像が次の画像を書き込んだ後もぼんやりと残って見える残像現象を防ぐための消去駆動が行われてもよい。この残像消去駆動は上記コモン振りを用いて全走査線同時選択によってなされてもよいし、走査線順次選択によってなされてもよい。また、コモン振りを用いないこれらの駆動にて実現してもよい。また、これら以外の方法でも、残像現象を防ぐことが可能な駆動であればどのような手段を用いてもよい。 In addition, prior to the above-described all-pixel identical display driving, an erasing driving may be performed to prevent an afterimage phenomenon in which the currently displayed image appears to remain dull after the next image is written. This afterimage erasing drive may be performed by simultaneous selection of all scanning lines using the above-mentioned common swing, or may be performed by sequential selection of scanning lines. Further, it may be realized by such driving without using the common swing. In addition, any means other than these may be used as long as the driving can prevent the afterimage phenomenon.
　以下、本実施の形態に係る電気泳動表示装置１における駆動動作に関する検証実験について説明する。ここでは、共通電極２２と画素電極２１の素材には、酸化インジウムスズ（スズドープ酸化インジウム）によって表面抵抗が２５０Ω／□となる透明な電極がＰＥＴフィルム上に形成された基板（以下ＩＴＯ－ＰＥＴと呼ぶ）を使用した。また、共通電極２２には、インクを仕切るための高さ２０μｍ、ピッチ３００μｍのマイクロセルが形成されている。電気泳動表示インク２３を電極間（画素電極２１－共通電極２２間）が２０μｍ、表示エリアが５０ｍｍ×４０ｍｍとなるようにＵＶ硬化接着剤で周囲を封止した。上記のように構成されたパネル１枚を以下単セルと呼称する。 Hereinafter, a verification experiment regarding the driving operation in the electrophoretic display device 1 according to the present embodiment will be described. Here, as a material for the common electrode 22 and the pixel electrode 21, a substrate (hereinafter referred to as ITO-PET) on which a transparent electrode having a surface resistance of 250 Ω / □ is formed on indium tin oxide (tin-doped indium oxide) on a PET film. Used). The common electrode 22 is formed with microcells having a height of 20 μm and a pitch of 300 μm for partitioning ink. The periphery of the electrophoretic display ink 23 was sealed with a UV curable adhesive so that the distance between the electrodes (between the pixel electrode 21 and the common electrode 22) was 20 μm and the display area was 50 mm × 40 mm. One panel configured as described above is hereinafter referred to as a single cell.
　インク（電気泳動表示インク２３）の電気的特性は、体積固有抵抗が１０１０（Ωｃｍ）、比誘電率が３である。電気泳動表示インク２３は、白色粒子８２及び黒色粒子８３を含む。白色粒子８２は、負に帯電しており、共通電極２２が画素電極２１と比較して高電圧の場合に共通電極２２側に集まり、表示面側（共通電極２２側）が白色表示となる。一方、黒色粒子８３は、正に帯電しており、共通電極２２が画素電極２１と比較して低電圧の場合に共通電極２２側に集まり、表示面側（共通電極２２側）が黒色表示となる。前記単セル１枚に静電容量が１４．７μFの保持容量２５を並列に接続しこれを１画素とみなして検証実験を実施した。 The electrical characteristics of the ink (electrophoretic display ink 23) are a volume resistivity of 10 10 (Ωcm) and a relative dielectric constant of 3. The electrophoretic display ink 23 includes white particles 82 and black particles 83. The white particles 82 are negatively charged. When the common electrode 22 has a higher voltage than the pixel electrode 21, the white particles 82 gather on the common electrode 22 side, and the display surface side (the common electrode 22 side) displays white. On the other hand, the black particles 83 are positively charged. When the common electrode 22 has a lower voltage than the pixel electrode 21, the black particles 83 gather on the common electrode 22 side, and the display surface side (common electrode 22 side) is black. Become. The single cell was connected to a holding capacitor 25 having a capacitance of 14.7 μF in parallel, and this was regarded as one pixel, and a verification experiment was performed.
　検証実験においては、データ線数が３２０本であり、走査線数が２４０本の一般的なＱＶＧＡパネル（表示部２）を想定した。 In the verification experiment, a general QVGA panel (display unit 2) having 320 data lines and 240 scanning lines was assumed.
　走査線順次選択方式にて駆動する場合、走査線の選択時間を２０μｓとした。この場合、走査線数が２４０本であるので、１フレームの走査信号の供給に要する時間は、４．８ｍｓである。したがって前記単セルには、１フレーム４．８ｍｓのうちに２０μｓだけ電圧が印加される。なお、階調表示駆動ステップでは、階調に合わせてフレーム数を変化させた。 When driving by the scanning line sequential selection method, the scanning line selection time was set to 20 μs. In this case, since the number of scanning lines is 240, the time required to supply the scanning signal for one frame is 4.8 ms. Accordingly, a voltage of 20 μs is applied to the single cell within one frame of 4.8 ms. In the gradation display driving step, the number of frames was changed in accordance with the gradation.
　また、全走査線同時選択駆動方式にて駆動する場合は、１フレームを１００ｍｓとして全画素が１００ｍｓの期間、電圧が印加されるようにした。 In the case of driving by the all-scan line simultaneous selection driving method, one frame is set to 100 ms, and the voltage is applied to all the pixels for 100 ms.
　全画素同一表示駆動ステップに適用されるコモン振りにおいては、共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加することで、共通電極２２側（表示面側）に白色粒子８２を移動させる電圧として電位差３０Ｖを得た。一方、共通電極２２に－１５Ｖを印加し、画素電極２１に＋１５Ｖを印加することで、共通電極２２側（表示面側）に黒色粒子８３を移動させる電圧として電位差３０Ｖを得た。 In the common swing applied to the same display driving step for all the pixels, + 15V is applied to the common electrode 22 and −15V is applied to the pixel electrode 21, whereby white particles 82 are applied to the common electrode 22 side (display surface side). A potential difference of 30 V was obtained as the voltage to be moved. On the other hand, by applying -15V to the common electrode 22 and + 15V to the pixel electrode 21, a potential difference of 30V was obtained as a voltage for moving the black particles 83 to the common electrode 22 side (display surface side).
　コモン振りを適用しない階調表示駆動ステップ（階調表示駆動）においては、共通電極２２を０Ｖに設定し、画素電極２１に＋１５Ｖを印加することで、共通電極２２側（表示面側）に白色粒子８２を移動させる電圧として電位差１５Ｖを得た。一方、共通電極２２を０Ｖに設定し、画素電極２１に－１５Ｖを印加することで、共通電極２２側（表示面側）に黒色粒子８３を移動させる電圧として電位差１５Ｖを得た。 In the gradation display driving step (gradation display driving) in which the common swing is not applied, the common electrode 22 is set to 0 V, and +15 V is applied to the pixel electrode 21, so that the common electrode 22 side (display surface side) is white. A potential difference of 15 V was obtained as a voltage for moving the particles 82. On the other hand, by setting the common electrode 22 to 0V and applying -15V to the pixel electrode 21, a potential difference of 15V was obtained as a voltage for moving the black particles 83 to the common electrode 22 side (display surface side).
（実施例１１）
　共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加した状態で走査線を順次選択するスキャン動作を２０回繰り返して全画素の表示状態を白に変化させる全画素同一表示駆動ステップの後に、共通電極２２に０Ｖを印加し、画素電極２１には、次表示画像データに従って表示状態を変化させたい画素には＋１５Ｖを印加し、表示状態を変化させない画素には０Ｖを印加させて走査線を順次選択するスキャン動作を６０回繰り返す階調表示駆動ステップを行い、表示したい階調に到達した画素の画素電極２１をハイインピーダンス状態とする停止ステップを行った。 (Example 11)
In the same display driving step for all the pixels, the scanning operation for sequentially selecting the scanning lines in a state where +15 V is applied to the common electrode 22 and −15 V is applied to the pixel electrode 21 is repeated 20 times to change the display state of all pixels to white. Later, 0V is applied to the common electrode 22, + 15V is applied to the pixel electrode 21 according to the next display image data, + 15V is applied to the pixel whose display state is to be changed, and 0V is applied to the pixel whose display state is not changed. A gradation display driving step in which the scanning operation for sequentially selecting lines is repeated 60 times is performed, and a stop step is performed in which the pixel electrode 21 of the pixel that has reached the gradation to be displayed is brought into a high impedance state.
（実施例１２）
　共通電極２２に－１５Ｖを印加し、画素電極に＋１５Ｖを印加した状態で走査線を順次選択するスキャン動作を２０回繰り返したのちに、共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加した状態で走査線を順次選択するスキャン動作を２０回繰り返して全画素の表示状態を白に変化させる全画素同一表示駆動ステップの後に、共通電極２２に０Ｖを印加し、画素電極２１には、次表示画像データに従って表示状態を変化させたい画素には＋１５Ｖを印加し、表示状態を変化させない画素には０Ｖを印加させて走査線を順次選択するスキャン動作を６０回繰り返す階調表示駆動ステップを行い、表示したい階調に到達した画素の画素電極２１をハイインピーダンス状態とする停止ステップを行った。 Example 12
After repeating the scanning operation of sequentially selecting scanning lines with -15V applied to the common electrode 22 and + 15V applied to the pixel electrode, + 15V is applied to the common electrode 22 and -15V is applied to the pixel electrode 21. A scan operation for sequentially selecting scanning lines in a state where voltage is applied is repeated 20 times to change the display state of all pixels to white. After all pixels are in the same display driving step, 0 V is applied to the common electrode 22 and applied to the pixel electrode 21. Is a gradation display drive in which + 15V is applied to a pixel whose display state is to be changed in accordance with the next display image data, and 0V is applied to a pixel whose display state is not to be changed to sequentially select a scanning line 60 times. A step was performed to stop the pixel electrode 21 of the pixel that reached the gradation to be displayed in a high impedance state.
（実施例１３）
　共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加した状態で全走査線を同時に１００ｍｓの間、選択する動作によって全画素の表示状態を白に変化させる全画素同一表示駆動ステップの後に、共通電極２２に０Ｖを印加し、画素電極２１には、次表示画像データに従って表示状態を変化させたい画素には＋１５Ｖを印加し、表示状態を変化させない画素には０Ｖを印加させて走査線を順次選択するスキャン動作を６０回繰り返す階調表示駆動ステップを行い、表示したい階調に到達した画素の画素電極２１をハイインピーダンス状態とする停止ステップを行った。 (Example 13)
In the same display driving step for all pixels, the display state of all pixels is changed to white by the operation of selecting all scanning lines simultaneously for 100 ms with +15 V applied to the common electrode 22 and −15 V applied to the pixel electrode 21. Later, 0V is applied to the common electrode 22, + 15V is applied to the pixel electrode 21 according to the next display image data, + 15V is applied to the pixel whose display state is to be changed, and 0V is applied to the pixel whose display state is not changed. A gradation display driving step in which the scanning operation for sequentially selecting lines is repeated 60 times is performed, and a stop step is performed in which the pixel electrode 21 of the pixel that has reached the gradation to be displayed is brought into a high impedance state.
（実施例１４）
　共通電極２２に－１５Ｖを印加し、画素電極に＋１５Ｖを印加した状態で全走査線を同時に１００ｍｓの間、選択する動作ののちに、共通電極２２に＋１５Ｖを印加し、画素電極２１に－１５Ｖを印加した状態で全走査線を同時に１００ｍｓの間、選択する動作によって全画素の表示状態を白に変化させる全画素同一表示駆動ステップの後に、共通電極２２に０Ｖを印加し、画素電極２１には、次表示画像データに従って表示状態を変化させたい画素には＋１５Ｖを印加し、表示状態を変化させない画素には０Ｖを印加させて走査線を順次選択するスキャン動作を６０回繰り返す階調表示駆動ステップを行い、表示したい階調に到達した画素の画素電極２１をハイインピーダンス状態とする停止ステップを行った。 (Example 14)
After -15V is applied to the common electrode 22 and + 15V is applied to the pixel electrode, all scanning lines are simultaneously selected for 100 ms, and then + 15V is applied to the common electrode 22 and -15V is applied to the pixel electrode 21. In the state where all the scanning lines are simultaneously applied for 100 ms in a state where voltage is applied, 0 V is applied to the common electrode 22 after the same pixel display driving step for changing the display state of all pixels to white by the operation of selecting all the scanning lines. Is a gradation display drive in which + 15V is applied to a pixel whose display state is to be changed in accordance with the next display image data, and 0V is applied to a pixel whose display state is not to be changed to sequentially select a scanning line 60 times. A step was performed to stop the pixel electrode 21 of the pixel that reached the gradation to be displayed in a high impedance state.
（実施例１５）
　実施例１２の、階調表示駆動ステップにおいて、スキャン動作を３１回繰り返して全画素を中間階調１の表示状態にした。 (Example 15)
In the gradation display driving step of Example 12, the scanning operation was repeated 31 times so that all the pixels were displayed in the intermediate gradation 1 display state.
（実施例１６）
　実施例１２の、階調表示駆動ステップにおいて、スキャン動作を３０回繰り返して全画素を中間階調２の表示状態にした。 (Example 16)
In the gradation display driving step of Example 12, the scanning operation was repeated 30 times to bring all pixels into the display state of intermediate gradation 2.
（実施例１７）
　実施例１２の、階調表示駆動ステップにおいて、スキャン動作を２９回繰り返して全画素を中間階調３の表示状態にした。 (Example 17)
In the gradation display driving step of Example 12, the scanning operation was repeated 29 times to bring all the pixels into the display state of the intermediate gradation 3.
（実施例１８：逆スキャン挿入駆動）
　実施例１６の、階調表示駆動ステップにおいて、スキャン動作を１５回繰り返した後に画素電極に＋１５Ｖを印加した状態でスキャン動作を１回行い、その後再び画素電極に－１５Ｖを印加した状態でスキャン動作を１５回繰り返して全画素を中間階調４の表示状態にした。 (Example 18: Reverse scan insertion drive)
In the gradation display driving step of Example 16, after the scan operation was repeated 15 times, the scan operation was performed once with + 15V applied to the pixel electrode, and then the scan operation was performed with −15V applied again to the pixel electrode. Was repeated 15 times to bring all the pixels into the display state of the intermediate gradation 4.
（実施例１９：ブロックスキャン駆動）
　実施例１６の、階調表示駆動ステップにおいて、スキャン動作を１５回繰り返した後にスキャン動作１０回分の休止期間を設け、その後スキャン動作を１５回繰り返して全画素を中間階調５の表示状態にした。 (Example 19: Block scan drive)
In the gradation display driving step of Example 16, a scanning operation is repeated 15 times, and then a pause period for 10 scanning operations is provided, and then the scanning operation is repeated 15 times to bring all pixels into the display state of intermediate gradation 5. .
（実施例２０：逆スキャン挿入駆動とブロックスキャン駆動の組合わせ）
　実施例１６の、階調表示駆動ステップにおいて、スキャン動作を１５回繰り返した後にスキャン動作１０回分の休止期間を設けたのちに画素電極に＋１５Ｖを印加した状態でスキャン動作を１回行い、再びスキャン動作１０回分の休止期間を設けた後に画素電極に－１５Ｖを印加した状態でスキャン動作を１５回繰り返して全画素を中間階調５の表示状態にした。 (Example 20: Combination of reverse scan insertion drive and block scan drive)
In the gradation display driving step of Example 16, after a scan operation is repeated 15 times, a scan operation is performed once in a state in which +15 V is applied to the pixel electrode after providing a pause period for 10 scan operations. After a pause period of 10 operations, the scan operation was repeated 15 times with -15 V applied to the pixel electrode, so that all the pixels were set to the display state of the intermediate gradation 5.
（比較例１１）
　全画素同一表示駆動ステップにおいて、共通電極２２には常に０Ｖが印加されていることのみ実施例１２と異なる駆動にて表示を行った。 (Comparative Example 11)
In the same display driving step for all pixels, display was performed by driving different from that in Example 12 only that 0 V was always applied to the common electrode 22.
（比較例１２）
　全画素同一表示駆動ステップにおいて、共通電極２２には常に０Ｖが印加され、階調表示駆動において、共通電極２２には常に－１５Ｖが印加されていることのみ実施例１２と異なる駆動にて表示を行った。 (Comparative Example 12)
In the same display driving step for all the pixels, 0V is always applied to the common electrode 22, and in the gradation display driving, −15V is always applied to the common electrode 22, and display is performed by driving different from that in the twelfth embodiment. went.
（比較例１３）
　停止ステップにおいて、表示したい階調に到達した画素の画素電極２１に０Ｖを印加することで、共通電極と同電位とする停止ステップを行った。 (Comparative Example 13)
In the stop step, 0 V was applied to the pixel electrode 21 of the pixel that reached the gradation to be displayed, so that the stop step was set to the same potential as the common electrode.
（比較例１４）
　階調表示駆動において、共通電極２２には常に－１５Ｖが印加されていることのみ実施例１２と異なる駆動にて表示を行った。 (Comparative Example 14)
In gradation display driving, display was performed by driving different from that in Example 12 only that −15 V was always applied to the common electrode 22.
（評価方法）
　駆動後の評価にはスガ試験機社製の分光測色計「ＳＣ－Ｐ」を用いて反射率（Ｙ値）を測定した。測定に使用した光源はＤ６５、１０°視野、測定孔はφ１５、正反射を除いて測定した。 (Evaluation methods)
For evaluation after driving, the reflectance (Y value) was measured using a spectrocolorimeter “SC-P” manufactured by Suga Test Instruments Co., Ltd. The light source used for the measurement was D65, a 10 ° field of view, the measurement hole was φ15, and the specular reflection was excluded.
（評価項目Ａ：全画素同一表示反射率）
　各実施例及び比較例の駆動において全画素同一表示駆動ステップ後に駆動を停止して反射率を計測し全画素同一表示反射率とした。本実施例では白反射率となり、数値が高いほど性能がよい。今回は「反射率４５以上：◎」「反射率４０以上４５未満：○」「反射率３５以上４０未満：△」「反射率３５未満：×」と表現した。 (Evaluation item A: All pixels have the same display reflectance)
In the driving of each example and comparative example, the driving was stopped after the same pixel display driving step, and the reflectance was measured to obtain the same display reflectance of all pixels. In this embodiment, the white reflectance is obtained, and the higher the numerical value, the better the performance. This time, it was expressed as “reflectance 45 or higher: ◎” “reflectivity 40 or higher and lower than 45: ◯” “reflectivity 35 or higher but lower than 40: Δ” “reflectivity 35 lower than 35: x”.
（評価項目Ｂ：階調駆動表示時最終反射率）
　各実施例及び比較例の駆動において、階調表示駆動ステップでスキャンを６０回繰り返した後の反射率を計測し、階調駆動表示時最終反射率とした。本実施例ではこの状態が最も黒い状態を得た場合の反射率となり、数値が低いほど性能がよい。今回は「反射率４．０未満：◎」「反射率４．０以上４．５未満：○」「反射率４．５以上５．０未満：△」「反射率５．０以上：×」と表現した。 (Evaluation item B: Final reflectance during gradation drive display)
In the driving of each example and comparative example, the reflectivity after the scan was repeated 60 times in the gradation display driving step was measured to obtain the final reflectance at the gradation driving display. In this embodiment, this is the reflectance when this state is the blackest, and the lower the value, the better the performance. This time, “reflectance less than 4.0: ◎” “reflectance 4.0 or more and less than 4.5: ○” “reflectance 4.5 or more and less than 5.0: Δ” “reflectance 5.0 or more: x” Expressed.
（評価項目Ｃ：階調表示性能評価）
　スキャン回数階調においては、スキャンのたびに粒子は反対側電極へ移動することとなり、逆方向への移動はない。したがって、評価Ａで得られた反射率から評価Ｂで得られた反射率へ移行するのに必要となるスキャン回数が、表現できる中間階調の最大値となる。今回は、「スキャン回数を一回増加しても反射率変動が、スキャン回数増加前の反射率から５％以上変化しない」時点で粒子の移動が終了したと判断し、それまでに要したスキャン回数を階調表示性能とした。各実施例及び比較例の駆動において、階調表示駆動ステップでスキャンを１回から６０回まで変化させて停止し、各スキャン回数印加後の反射率を計測して評価した。今回は「スキャン回数が６４回以上：◎」「スキャン回数が３２回以上６４回未満：○」「スキャン回数が１６回以上３２回未満：△」「スキャン回数が１５回以下：×」と表現した。 (Evaluation item C: gradation display performance evaluation)
In the scanning frequency gradation, each time a scan is performed, the particles move to the opposite electrode, and there is no movement in the reverse direction. Therefore, the number of scans required to shift from the reflectance obtained in evaluation A to the reflectance obtained in evaluation B is the maximum value of the intermediate gradation that can be expressed. This time, it was judged that the movement of particles was completed at the time when “the reflectance fluctuation does not change more than 5% from the reflectance before the increase in the number of scans even if the number of scans is increased once”, and the scan required until then The number of times was defined as gradation display performance. In the driving of each example and comparative example, the scanning was changed from 1 to 60 times in the gradation display driving step and stopped, and the reflectance after the application of each scanning number was measured and evaluated. This time, “scanning number is 64 times or more: A” “scanning number is 32 times or more and less than 64 times: ○” “scanning number is 16 times or more and less than 32 times: Δ” “scanning number is 15 times or less: x” did.
（評価項目Ｄ：画像保持性能）
　電気泳動インクを用いた表示装置は画像表示後にはエネルギーを与えることなく表示を維持可能であるが、粒子に蓄えられた電荷の放電や重力の影響などにより粒子の位置が若干変動し、表示品質が低下する現象がある。具体的には白表示部は反射率が低下し、黒表示部は反射率が上昇する。この表示品質低下の度合いを評価するために表示書換を実施後３日間放置した後の表示を見て劣化状態を判断した。表では「表示性能の変化が実感できない：○」「表示の低下が実感できる：△」「表示性能が著しく低下する：×」と表現した。 (Evaluation item D: Image holding performance)
A display device using electrophoretic ink can maintain the display without giving energy after displaying the image, but the position of the particles slightly changes due to the discharge of electric charges stored in the particles and the influence of gravity, etc. There is a phenomenon that decreases. Specifically, the reflectance of the white display portion is reduced, and the reflectance of the black display portion is increased. In order to evaluate the degree of deterioration in display quality, the deterioration state was judged by looking at the display after being left for 3 days after the display rewriting. In the table, “change in display performance cannot be realized: ○”, “display deterioration can be realized: Δ”, “display performance is significantly reduced: ×”.
（評価の結果その１）
　実施例１１～１４及び比較例１１～１４の評価の結果を表２に示した。
Figure JPOXMLDOC01-appb-T000002
 (As a result of evaluation 1)
The evaluation results of Examples 11 to 14 and Comparative Examples 11 to 14 are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
（評価の結果その１の考察）
　実施例１１～１４は評価４項目すべてにおいて○以上の結果となった。これに対し、比較例１１と比較例１２で評価項目Ａで○とならない。このことから、全画素同一表示駆動ステップにおいて共通電極２２を０Ｖとする駆動（コモンを振らない駆動）を実施した場合、白の表示性能が低下し、パネルのコントラストが低下する。比較例１４では評価項目Ｃが×となる。このことから全画素同一表示駆動ステップ及び階調表示駆動ステップの両方でコモン振りによる駆動を実施した場合、階調表示性能が低下することがわかる。比較例１３は評価項目Ｄにて△となる。このことから、停止ステップにおいて画素電極を短絡状態とする駆動は画像保持性能が低下することがわかる。 (Consideration of evaluation result 1)
In Examples 11 to 14, results of ◯ or more were obtained in all four evaluation items. On the other hand, in the comparative example 11 and the comparative example 12, the evaluation item A is not good. For this reason, when the drive for setting the common electrode 22 to 0 V (drive without shaking the common) is performed in the same display drive step for all the pixels, the white display performance is lowered and the panel contrast is lowered. In Comparative Example 14, the evaluation item C is x. From this, it is understood that the gradation display performance deteriorates when driving by common swing is performed in both the same pixel display driving step and the gradation display driving step. In Comparative Example 13, the evaluation item D is Δ. From this, it can be seen that in the stop step, the image holding performance deteriorates when the pixel electrode is short-circuited.
（評価の結果その２）
　実施例１５～２０の評価の階調表示駆動ステップ後の反射率を図１９に示した。 (As a result of evaluation 2)
FIG. 19 shows the reflectance after the gradation display driving step of evaluation in Examples 15 to 20.
（評価結果その２の考察）
　実施例１５～１７は階調表示駆動ステップにおいてスキャン回数が１ずつ異なる駆動である。したがって、従来技術のスキャン回数階調方式を用いる場合、この間の反射率を得ることはできない。しかし、実施例１８の逆スキャンを挿入する駆動や実施例１９の休止を挿入する駆動、また、実施例２０の、逆スキャンとブロックスキャンを組み合わせた駆動により、実施例１５～１７の間の反射率を得ることができた。このことから、逆スキャン挿入駆動およびブロックスキャン駆動を用いることで階調表示の微調整を行うことが可能となることがわかる。 (Consideration of evaluation result 2)
In the fifteenth to seventeenth embodiments, the number of scans is different by one in the gradation display driving step. Therefore, when using the conventional scanning frequency gradation method, the reflectance during this period cannot be obtained. However, the reflection between the embodiments 15 to 17 by the drive for inserting the reverse scan of the embodiment 18, the drive for inserting the pause of the embodiment 19, and the drive of the embodiment 20 combining the reverse scan and the block scan. I was able to get a rate. From this, it can be understood that the gradation display can be finely adjusted by using the reverse scan insertion drive and the block scan drive.
　なお、上記の効果を、ＴＦＴを用いたＱＶＧＡの表示パネルにて検証した結果、同様の結果が得られた。 As a result of verifying the above effect with a QVGA display panel using TFTs, the same result was obtained.
　なお、本発明は上記実施の形態に限定されず、さまざまに変更して実施可能である。上記実施の形態において、添付図面に図示されている大きさや形状などについては、これに限定されず、本発明の効果を発揮する範囲内で適宜変更が可能である。その他、本発明の目的の範囲を逸脱しない限りにおいて適宜変更して実施可能である。 It should be noted that the present invention is not limited to the above embodiment, and can be implemented with various modifications. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited thereto, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.
　例えば、上記実施の形態においては、電気泳動表示インク２３が白色粒子８２、黒色粒子８３及び分散媒８１からなる電気泳動表示用液で構成され、これを電子インクとして用いる場合について説明している。しかしながら、本発明に係る電気泳動表示装置１で用いられる電気泳動表示インク２３については、これに限定されるものではなく適宜変更が可能である。例えば、電子インクをマイクロカプセル内に充填した構成を採用することも可能である。 For example, in the above embodiment, the case where the electrophoretic display ink 23 is composed of an electrophoretic display liquid composed of white particles 82, black particles 83, and a dispersion medium 81, and this is used as electronic ink has been described. However, the electrophoretic display ink 23 used in the electrophoretic display device 1 according to the present invention is not limited to this and can be appropriately changed. For example, a configuration in which electronic ink is filled in a microcapsule can be employed.
　本出願は、２０１３年４月３０日出願の特願２０１３－０９５２２３及び特願２０１３－０９５２２４に基づく。この内容は、全てここに含めておく。
  This application is based on Japanese Patent Application Nos. 2013-095223 and 2013-095224 filed on Apr. 30, 2013. All this content is included here.

Claims (16)

  1. 　少なくとも一方が光透過性を有する一対の基板と、
    　一方の前記基板の基板面にマトリクス状に配置された複数の画素電極と、
    　他方の前記基板の基板面に前記複数の画素電極に対向して配置された共通電極と、
    　前記基板間に封入され、１又は２種類以上の電気泳動粒子が分散された電気泳動表示インクと、
    　前記画素電極が行毎に接続された複数のデータ線に対して個別に画素信号を供給する第１の駆動回路と、
    　前記複数のデータ線上に夫々設けられ、オン状態において当該データ線に供給される前記画素信号を対応する前記画素電極に印加する複数のスイッチと、
    　前記スイッチが列毎に接続された複数の走査線を、前記スイッチをオン状態にする走査信号によって走査する第２の駆動回路と、
    　前記各画素電極と前記共通電極との間にそれぞれ並列に接続された複数の保持容量と、
    を具備した電気泳動表示装置の駆動方法であって、
    　前記共通電極の電位を変化させるコモン振りによって全画素を同一の表示状態にする全画素同一表示駆動ステップと、
    　前記共通電極の電位を当該共通電極にコモン振りで印加された電位の中間電位に固定され、対象画素に対応した複数のデータ線に画素信号が印加された状態で、対象画素が所望の階調となるように走査回数を制御し、最後の走査後に前記画素電極をハイインピーダンス状態とする階調表示駆動ステップと、
    　対象画素が所望の階調に到達した後、当該対象画素の前記画素電極と前記共通電極との間を短絡する停止ステップと、
    を具備したことを特徴とする電気泳動表示装置の駆動方法。     A pair of substrates, at least one of which is light transmissive,
    A plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates;
    A common electrode disposed opposite to the plurality of pixel electrodes on the substrate surface of the other substrate;
    An electrophoretic display ink enclosed between the substrates and having one or more types of electrophoretic particles dispersed therein;
    A first drive circuit that individually supplies pixel signals to a plurality of data lines to which the pixel electrodes are connected for each row;
    A plurality of switches that are respectively provided on the plurality of data lines and apply the pixel signals supplied to the data lines to the corresponding pixel electrodes in an on state;
    A second drive circuit that scans a plurality of scanning lines to which the switch is connected for each column by a scanning signal that turns on the switch;
    A plurality of storage capacitors connected in parallel between each of the pixel electrodes and the common electrode;
    A method for driving an electrophoretic display device comprising:
    The same display driving step for all the pixels to make all the pixels in the same display state by the common swing changing the potential of the common electrode;
    The potential of the common electrode is fixed to an intermediate potential of the potential applied to the common electrode by a common swing, and the target pixel has a desired gradation in a state where pixel signals are applied to a plurality of data lines corresponding to the target pixel. A gradation display driving step for controlling the number of scans so that the pixel electrode is in a high impedance state after the last scan;
    A stop step of short-circuiting between the pixel electrode and the common electrode of the target pixel after the target pixel reaches a desired gradation;
    A method for driving an electrophoretic display device, comprising:
  2. 　前記全画素同一表示駆動ステップは、
    　第１の電圧Ｖ１を前記共通電極に印加し、第２の電圧Ｖ２を画素信号として前記各データ線に印加した状態で、前記複数の走査線を用いて全画素に一斉に駆動電圧を印加して全画素を第１の表示状態に変化させる駆動により全画素を同一の表示状態にすること
    を含むコモン振りが適用されることを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The same display driving step for all pixels includes:
    In the state where the first voltage V1 is applied to the common electrode and the second voltage V2 is applied to each data line as a pixel signal, a driving voltage is applied to all the pixels simultaneously using the plurality of scanning lines. 2. The method of driving an electrophoretic display device according to claim 1, wherein common swinging is applied, which includes bringing all pixels into the same display state by driving to change all pixels to the first display state.
  3. 　前記全画素同一表示駆動ステップは、
    　第１の電圧Ｖ１を前記共通電極に印加し、第２の電圧Ｖ２を画素信号として前記各データ線に印加した状態で、前記複数の走査線を順次走査する駆動を１または複数フレーム繰り返すことで全画素を同一の表示状態にすること
    を含むコモン振りが適用されることを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The same display driving step for all pixels includes:
    By repeating the driving of sequentially scanning the plurality of scanning lines for one or a plurality of frames in a state where the first voltage V1 is applied to the common electrode and the second voltage V2 is applied to each data line as a pixel signal. 2. The method for driving an electrophoretic display device according to claim 1, wherein common swinging including bringing all pixels into the same display state is applied.
  4. 　前記全画素同一表示駆動ステップは、
    　第１の電圧Ｖ１を前記共通電極に印加し、第２の電圧Ｖ２を画素信号として前記各データ線に印加した状態で、前記複数の走査線を用いて全画素に一斉に駆動電圧を印加して全画素を第１の表示状態に変化させる第１の印加動作と、
    　前記第２の電圧Ｖ２を前記共通電極に印加し、前記第１の電圧Ｖ１を画素信号として前記各データ線に印加した状態で、前記複数の走査線を用いて全画素に一斉に駆動電圧を印加し、全画素を前記第１の表示状態とは異なる第２の表示状態に変化させる第２の印加動作と、
    　を連続して行う一連の動作を１セットとして、
    　この一連の動作を１または複数セット繰り返すこと
    を含むコモン振りが適用されることを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The same display driving step for all pixels includes:
    In the state where the first voltage V1 is applied to the common electrode and the second voltage V2 is applied to each data line as a pixel signal, a driving voltage is applied to all the pixels simultaneously using the plurality of scanning lines. A first application operation for changing all the pixels to the first display state;
    In the state where the second voltage V2 is applied to the common electrode and the first voltage V1 is applied to each data line as a pixel signal, a driving voltage is applied to all the pixels at once using the plurality of scanning lines. Applying a second application operation to change all pixels to a second display state different from the first display state;
    As a set, a series of operations to perform
    2. The method for driving an electrophoretic display device according to claim 1, wherein a common swing including repeating one or a plurality of sets of the series of operations is applied.
  5. 　前記全画素同一表示駆動ステップは、
    　第１の電圧Ｖ１を前記共通電極に印加し、第２の電圧Ｖ２を画素信号として前記各データ線に印加した状態で、前記複数の走査線を順次走査して全画素を第１の表示状態に変化させる第１の印加動作と、
    　前記第２の電圧Ｖ２を前記共通電極に印加し、前記第１の電圧Ｖ１を画素信号として前記各データ線に印加した状態で、前記複数の走査線を順次走査して全画素を前記第１の表示状態とは異なる第２の表示状態に変化させる第２の印加動作と、
    　を連続して行う一連の動作を１セットとして、
    　この一連の動作を１または複数セット繰り返すこと
    を含むコモン振りが適用されることを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The same display driving step for all pixels includes:
    In a state where the first voltage V1 is applied to the common electrode and the second voltage V2 is applied to the data lines as a pixel signal, the plurality of scanning lines are sequentially scanned so that all the pixels are in the first display state. A first application operation to change to
    In a state where the second voltage V2 is applied to the common electrode and the first voltage V1 is applied to each data line as a pixel signal, the plurality of scanning lines are sequentially scanned so that all the pixels are the first. A second application operation for changing to a second display state different from the display state of
    As a set, a series of operations to perform
    2. The method for driving an electrophoretic display device according to claim 1, wherein a common swing including repeating one or a plurality of sets of the series of operations is applied.
  6. 　前記階調表示駆動ステップは、
    　対象画素を第１の極性の駆動電圧で繰り返し駆動して所望の階調に変化させる途中で、当該対象画素に第１の極性とは逆向きの第２の極性の駆動電圧を印加することを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The gradation display driving step includes:
    In the middle of changing the target pixel to the desired gradation by repeatedly driving the target pixel with the drive voltage of the first polarity, applying the drive voltage of the second polarity opposite to the first polarity to the target pixel. The method for driving an electrophoretic display device according to claim 1.
  7. 　前記階調表示駆動ステップは、
    　階調を表現するために必要な走査回数を、１フレーム又は複数フレームに相当する休止期間で分離されるいくつかのブロックに分け、前記ブロック単位で対象画素を走査することを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The gradation display driving step includes:
    The number of scans necessary to express gradation is divided into several blocks separated in a pause period corresponding to one frame or a plurality of frames, and the target pixel is scanned in units of the blocks. 2. A method for driving an electrophoretic display device according to 1.
  8. 　前記ブロックと前記ブロックの間の前記休止期間において、対象画素の前記画素電極と前記共通電極との間を順次短絡することを特徴とする請求項７記載の電気泳動表示装置の駆動方法。 The method for driving an electrophoretic display device according to claim 7, wherein the pixel electrode and the common electrode of a target pixel are sequentially short-circuited in the pause period between the blocks.
  9. 　前記ブロックと前記ブロックの間の前記休止期間において、対象画素の前記画素電極を順次開放することを特徴とする請求項７記載の電気泳動表示装置の駆動方法。 The method for driving an electrophoretic display device according to claim 7, wherein the pixel electrodes of the target pixel are sequentially opened during the pause period between the blocks.
  10. 　前記ブロックの１つのブロック内で対象画素を第１の極性の駆動電圧で繰り返し駆動して階調変化させる途中で、当該対象画素に第１の極性とは逆向きの第２の極性の駆動電圧を印加することを特徴とする請求項７記載の電気泳動表示装置の駆動方法。 In the course of changing the gradation by repeatedly driving the target pixel with the drive voltage of the first polarity in one block of the block, the drive voltage of the second polarity opposite to the first polarity is applied to the target pixel. The method for driving an electrophoretic display device according to claim 7, wherein: is applied.
  11. 　前記停止ステップは、
    　対象画素が所望の階調に到達した後、前記対象画素電極に前記共通電極と同電位として短絡することを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The stopping step includes
    2. The method for driving an electrophoretic display device according to claim 1, wherein after the target pixel reaches a desired gradation, the target pixel electrode is short-circuited with the same potential as the common electrode.
  12. 　前記停止ステップは、
    　全画素が所望の階調に到達した後、全画素の前記画素電極と前記共通電極との間を順次短絡することを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The stopping step includes
    The method of driving an electrophoretic display device according to claim 1, wherein after all pixels reach a desired gradation, the pixel electrode and the common electrode of all pixels are sequentially short-circuited.
  13. 　前記停止ステップは、
    　全画素が所望の階調に到達した後、全画素の前記画素電極と前記共通電極との間を一斉に短絡することを特徴とする請求項１記載の電気泳動表示装置の駆動方法。     The stopping step includes
    The method of driving an electrophoretic display device according to claim 1, wherein after all pixels reach a desired gradation, the pixel electrode and the common electrode of all the pixels are short-circuited simultaneously.
  14. 　前記階調表示駆動ステップと前記停止ステップの間に、休止期間を設けることを特徴とする請求項１記載の電気泳動表示装置の駆動方法。 The driving method of the electrophoretic display device according to claim 1, wherein a pause period is provided between the gradation display driving step and the stopping step.
  15. 　少なくとも一方が光透過性を有する一対の基板と、
    　一方の前記基板の基板面にマトリクス状に配置された複数の画素電極と、
    　他方の前記基板の基板面に前記複数の画素電極に対向して配置された共通電極と、
    　前記基板間に封入され、少なくとも１又は２種類以上の電気泳動粒子からなる電気泳動表示インクと、前記画素電極が行毎に接続された複数のデータ線に対して個別に画素信号を供給する第１の駆動回路と、
    　前記複数のデータ線上に夫々設けられ、オン状態において当該データ線に供給される前記画素信号を対応する前記画素電極に印加する複数のスイッチと、
    　前記スイッチが列毎に接続された複数の走査線を、前記スイッチをオン状態にする走査信号によって走査する第２の駆動回路と、
    　前記各画素電極と前記共通電極との間にそれぞれ並列に接続された複数の保持容量と、
    を具備し、
    　前記共通電極の電位を変化させるコモン振りによって全画素を同一の表示状態にした後、前記共通電極の電位を当該共通電極にコモン振りで印加された電位の中間電位に固定して、対象画素に対応した複数のデータ線に画素信号を印加した状態で、対象画素が所望の階調となるように走査回数を制御し、最後の走査後に前記画素電極をハイインピーダンス状態として階調表示し、対象画素が所望の階調に到達した後、当該対象画素の前記画素電極と前記共通電極との間を短絡することを特徴とする電気泳動表示装置。     A pair of substrates, at least one of which is light transmissive,
    A plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates;
    A common electrode disposed opposite to the plurality of pixel electrodes on the substrate surface of the other substrate;
    A pixel signal is individually supplied to an electrophoretic display ink encapsulated between the substrates and made of at least one or two or more types of electrophoretic particles, and a plurality of data lines in which the pixel electrodes are connected for each row. 1 driving circuit;
    A plurality of switches that are respectively provided on the plurality of data lines and apply the pixel signals supplied to the data lines to the corresponding pixel electrodes in an on state;
    A second drive circuit that scans a plurality of scanning lines to which the switch is connected for each column by a scanning signal that turns on the switch;
    A plurality of storage capacitors connected in parallel between each of the pixel electrodes and the common electrode;
    Comprising
    After making all the pixels in the same display state by common swing that changes the potential of the common electrode, the potential of the common electrode is fixed to an intermediate potential of the potential applied to the common electrode by common swing, In a state where pixel signals are applied to a plurality of corresponding data lines, the number of scans is controlled so that the target pixel has a desired gradation, and after the last scan, the pixel electrode is in a high impedance state and displayed in gradation. An electrophoretic display device comprising: short-circuiting between the pixel electrode and the common electrode of the target pixel after the pixel reaches a desired gradation.
  16. 　少なくとも一方が光透過性を有する一対の基板と、
    　一方の前記基板の基板面にマトリクス状に配置された複数の画素電極と、
    　他方の前記基板の基板面に前記複数の画素電極に対向して配置された共通電極と、
    　前記基板間に封入され、少なくとも１又は２種類以上の電気泳動粒子からなる電気泳動表示インクと、
    　前記画素電極が行毎に接続された複数のデータ線に対して個別に画素信号を供給する第１の駆動回路と、
    　前記複数のデータ線上に夫々設けられ、オン状態において当該データ線に供給される前記画素信号を対応する前記画素電極に印加する複数のスイッチと、
    　前記スイッチが列毎に接続された複数の走査線を、前記スイッチをオン状態にする走査信号によって走査する第２の駆動回路と、
    　前記各画素電極と前記共通電極との間にそれぞれ並列に接続された複数の保持容量と、
    　を具備した電気泳動表示装置の駆動方法であって、
    　前記共通電極の電位を変化させるコモン振りによって全画素を同一の表示状態にする全画素同一表示駆動ステップと、
    　前記共通電極の電位を当該共通電極にコモン振りで印加された電位の中間電位に固定され、対象画素に対応した複数のデータ線に画素信号が印加された状態で、対象画素が所望の階調となるように走査回数を制御する階調表示駆動ステップと、
    　対象画素が所望の階調に到達した後、当該対象画素の前記画素電極を開放する停止ステップと、
    を具備したことを特徴とする電気泳動表示装置の駆動方法。     A pair of substrates, at least one of which is light transmissive,
    A plurality of pixel electrodes arranged in a matrix on the substrate surface of one of the substrates;
    A common electrode disposed opposite to the plurality of pixel electrodes on the substrate surface of the other substrate;
    An electrophoretic display ink enclosed between the substrates and made of at least one or two or more types of electrophoretic particles;
    A first drive circuit that individually supplies pixel signals to a plurality of data lines to which the pixel electrodes are connected for each row;
    A plurality of switches that are respectively provided on the plurality of data lines and apply the pixel signals supplied to the data lines to the corresponding pixel electrodes in an on state;
    A second drive circuit that scans a plurality of scanning lines to which the switch is connected for each column by a scanning signal that turns on the switch;
    A plurality of storage capacitors connected in parallel between each of the pixel electrodes and the common electrode;
    A method for driving an electrophoretic display device comprising:
    The same display driving step for all the pixels to make all the pixels in the same display state by the common swing changing the potential of the common electrode;
    The potential of the common electrode is fixed to an intermediate potential of the potential applied to the common electrode by a common swing, and the target pixel has a desired gradation in a state where pixel signals are applied to a plurality of data lines corresponding to the target pixel. A gradation display driving step for controlling the number of scans so that
    A stop step of opening the pixel electrode of the target pixel after the target pixel reaches a desired gradation;
    A method for driving an electrophoretic display device, comprising:
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