CN110992900A - Liquid crystal display screen, backlight circuit and backlight driving method thereof - Google Patents
Liquid crystal display screen, backlight circuit and backlight driving method thereof Download PDFInfo
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- CN110992900A CN110992900A CN201911300567.XA CN201911300567A CN110992900A CN 110992900 A CN110992900 A CN 110992900A CN 201911300567 A CN201911300567 A CN 201911300567A CN 110992900 A CN110992900 A CN 110992900A
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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
- G09G3/3406—Control of illumination source
- G09G3/3413—Details of control of colour illumination sources
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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
- G09G3/36—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 liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3648—Control of matrices with row and column drivers using an active matrix
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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
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0626—Adjustment of display parameters for control of overall brightness
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- Liquid Crystal Display Device Control (AREA)
Abstract
The invention relates to a liquid crystal display screen, a backlight circuit and a backlight driving method thereof, wherein the backlight circuit comprises a plurality of data signal lines for accessing scanning signals; a plurality of scanning signal lines for accessing data signals; a plurality of emission control signal lines for accessing the emission control signals; a plurality of light emitting cells arranged in an array, each light emitting cell comprising 2nA plurality of light emitting elements, n is 1 or more; and a plurality of light-emitting drive circuits, each light-emitting element is connected with a light-emitting drive circuit; each light-emitting drive circuit is connected with one data signal line, one scanning signal line and one emission control signal line, and is used for accessing scanning signals and data signals to control the light-emitting time of the light-emitting elements so as to control the brightness gray scale of the light-emitting elements, and accessing emission control signals to control the enabling or closing of each light-emitting element in each light-emitting unit, and the light-emitting time is divided and the selection of the light-emitting area is combinedThe gray scale level of the display screen can be improved.
Description
Technical Field
The invention relates to the technical field of display, in particular to a liquid crystal display screen, a backlight circuit and a backlight driving method thereof.
Background
The Local Dimming (Local Dimming) is a method of dividing a display area of an image into a plurality of blocks and adjusting the brightness of a backlight for each block based on an image signal.
At present, a double-tube light-emitting drive circuit is generally adopted to control light-emitting of a light-emitting diode, the light-emitting time of the light-emitting diode determines the size of gray scale, generally, the longer the light-emitting time is, the higher the brightness is, and the higher the gray scale is, one transistor in the double-tube light-emitting drive circuit is used for addressing, and the other transistor is used for providing current for the light-emitting diode. At present, the refresh frequency of the display screen is generally 60HZ, the light-emitting driving circuit can only achieve 64 gray scale display by splitting the light-emitting time, and in order to achieve a higher image level of the display screen, the display screen is generally required to achieve higher-level gray scale display, such as 256 gray scale display. It is difficult to achieve higher-order gray scale display by further dividing the light emitting time, because the human visual system is insensitive to fast bright and dark flashes and thus cannot distinguish gray scales. And if the refresh frequency is increased and the time of each frame is shorter and shorter, the manner of dividing the light-emitting time can make the visual system more difficult to distinguish the gray scale. Therefore, it is difficult to divide the light emitting time into such a plurality of gray levels and to finely control the gray levels at a high refresh frequency of the display panel.
Disclosure of Invention
In view of the above, it is desirable to provide a liquid crystal display panel, a backlight circuit and a backlight driving method thereof.
In a first aspect, a backlight circuit is provided, the backlight circuit comprising:
a plurality of data signal lines for accessing scanning signals;
a plurality of scanning signal lines for accessing data signals;
a plurality of emission control signal lines for accessing the emission control signals;
a plurality of light emitting cells arranged in an array, each light emitting cell comprising 2nA plurality of light emitting elements, n is 1 or more; and
the light-emitting drive circuits are connected with the light-emitting elements;
each light-emitting drive circuit is connected with one data signal line, one scanning signal line and one emission control signal line, and the light-emitting drive circuit is used for accessing scanning signals and data signals to control the light-emitting time of the light-emitting elements so as to control the brightness gray scale of the light-emitting elements and accessing emission control signals to control the enabling or closing of the light-emitting elements in each light-emitting unit.
In the backlight circuit, the light emitting duration of each light emitting unit is controlled by the scanning signal and the data signal, and the brightness gray scale of the light emitting elements is controlled in time, so that the gray scale division of the display screen can be realized in time, and each light emitting unit comprises 2nThe light emitting unit of the light emitting diode can select the size of the light emitting area under the control of the emission control signal, so that the gray scale can be further distinguished in space, and finally, the gray scale level of the display screen is improved by segmenting the light emitting time and selecting the light emitting area.
In a second aspect, a liquid crystal display panel is provided, comprising a liquid crystal cell and a backlight circuit as described above, the backlight circuit being disposed on a back side of the liquid crystal cell for illuminating the liquid crystal cell.
In the backlight circuit of the liquid crystal display panel, the light emitting duration of each light emitting unit is controlled by the scanning signal and the data signal, and the brightness gray scale of the light emitting elements is controlled in time, so that the gray scale division of the display panel can be realized in time, and each light emitting unit comprises 2nThe light emitting unit of the light emitting diode can select the size of the light emitting area under the control of the emission control signal, so that the gray scale can be further distinguished in space, and finally, the gray scale level of the display screen is improved by segmenting the light emitting time and combining the selection of the light emitting area.
In a third aspect, a backlight driving method of a backlight circuit is provided, where the backlight circuit includes:
a plurality of data signal lines for accessing scanning signals;
a plurality of scanning signal lines for accessing data signals;
a plurality of emission control signal lines for accessing the emission control signals;
a plurality of light emitting cells arranged in an array, each light emitting cell comprising 2nA plurality of light emitting elements, n is 1 or more; and
the light-emitting drive circuits are connected with the light-emitting elements;
each light-emitting drive circuit is connected with one data signal line, one scanning signal line and one emission control signal line, and is used for accessing scanning signals and data signals to control the light-emitting time of the light-emitting elements so as to control the brightness gray scale of the light-emitting elements and accessing emission control signals to control the enabling or closing of each light-emitting element in each light-emitting unit;
the backlight driving method includes the steps of:
providing a data signal through a data signal line, providing a scanning signal through a scanning signal line, and providing an emission control signal through an emission control signal line;
and determining the light-emitting element needing to emit light in each light-emitting unit according to the emission control signal, controlling the enabling or closing of the light-emitting element in each light-emitting unit, and controlling the light-emitting time of the light-emitting element in each light-emitting unit according to the data signal and the scanning signal.
In the backlight driving method of the backlight circuit, each light emitting unit of the backlight circuit can realize 64 gray scale display of the display screen by controlling the light emitting time of the light emitting diode through the scanning signal and the data signal in the backlight driving process, and each light emitting unit comprises 2nThe light emitting unit of the light emitting diode can select the size of the light emitting area under the control of the emission control signal, so that the gray scale can be further distinguished in space, and finally, the gray scale level of the display screen is improved by segmenting the light emitting time and combining the selection of the light emitting area.
Drawings
FIG. 1 is a schematic diagram of a light-emitting driving circuit of a light-emitting diode in the prior art;
fig. 2 is an operation timing diagram of the light emission driving circuit based on fig. 1;
FIG. 3 is a schematic structural diagram of a backlight circuit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a backlight circuit according to another embodiment of the present invention;
fig. 5 is a schematic structural diagram of a light-emitting driving circuit according to an embodiment of the invention;
fig. 6 is a schematic structural diagram of a light-emitting driving circuit according to a second embodiment of the invention;
fig. 7 is a schematic structural diagram of a light-emitting driving circuit according to a third embodiment of the invention;
fig. 8 is an operation timing chart based on the light emission driving circuit of fig. 5, 6 or 7;
FIG. 9 is a schematic layout diagram of LEDs in a light-emitting unit;
fig. 10 is a flowchart illustrating a backlight driving method of a backlight circuit according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As described in the background art, a dual-transistor light-emitting driving circuit is generally used to control the light-emitting diode to emit light, the light-emitting time of the light-emitting diode determines the gray scale, and generally, the longer the light-emitting time is, the higher the luminance is, and the higher the gray scale is, one transistor in the dual-transistor light-emitting driving circuit is used for addressing, and the other transistor is used for providing current for the light-emitting diode. Fig. 1 is a light emission driving circuit including a thin film transistor T1, a thin film transistor T2, and a capacitor Cs, in which for the thin film transistor T1, a drain thereof is connected to a constant voltage high level (VDD) signal line through a light emitting diode, and a source thereof is grounded; for the thin film transistor T2, the drain thereof is connected to a digital (Date) signal line, the source thereof is connected to the gate of the thin film transistor T1, and is also grounded via the capacitor Cs, and the gate thereof is connected to a Scan (Scan) signal line for supplying a digital signal, the Scan signal line for supplying a Scan signal, the Scan signal including an address signal. Each light emitting diode adopts a common anode design, the thin film transistor T1 works in a linear region, when a scanning signal and a digital signal are at high level simultaneously, the capacitor Cs is charged, the high voltage of the Vg point in the figure 1, which is the common point of the capacitor Cs and the thin film transistor T1, is kept until the refresh signal of the next frame is written, the Vg point voltage written with the refresh signal every time is the same, the gray scale is determined by the thin film transistor T1, and the longer the on-time of the thin film transistor T1 is, the longer the light emitting time of the light emitting diode is, the higher the gray scale is. Fig. 2 is a timing diagram of the light-emitting driving circuit of fig. 1, and fig. 2 includes a driving timing for displaying two frames of images on the display panel, the display time of the first frame of image is longer than that of the second frame of image, the forward voltage of the scanning signal line is 22V, the reverse voltage is-8V, the forward voltage of the data signal line is 12V, the reverse voltage is 0V, the voltage of the constant-voltage high-level signal line is 14V, and the voltage of the constant-voltage low-level signal line is 0V.
The refresh frequency of the current display panel is generally 60HZ, and the light-emitting driving circuit in fig. 1 can only perform 64 gray-scale display, that is, within one light-emitting period, the light-emitting time of one frame of image is divided into 64 parts, for example, some light-emitting diodes corresponding to the image display area emit light only within the 1 st part of time, other light-emitting diodes do not emit light, some light-emitting diodes corresponding to the image display area emit light … within the first to second parts of time, and so on, some light-emitting diodes corresponding to the image display area emit light within the 1 st to 63 rd parts of time, and some light-emitting diodes corresponding to the image display area do not emit light within the 1 st to 64 th parts of time, so that the 0 th to 64 th gray-scale display of the frame of image within the display area in the light-emitting period is realized. In order to realize a higher image level of the display screen, it is generally required that the display screen performs higher gray scale display, for example, 256 th gray scale, 512 th gray scale, 1024 th gray scale display. Since the time of one frame is fixed, it is difficult to achieve higher gray scale display such as 256 gray scale display by dividing the light emitting time, because the human visual system is not sensitive to fast bright and dark flashes and thus cannot distinguish gray scales. If the refresh frequency is increased and the time of each frame is shorter and shorter, the manner of dividing the light-emitting time can make it more difficult for the visual system to distinguish the gray scales. Therefore, it is difficult to divide the display into such a plurality of gray levels by differentiating the light emitting time, and it is also difficult to achieve fine control of the gray levels at a high refresh frequency of the display.
The embodiment of the invention provides a backlight circuit, which can enable a display screen to display higher-level gray scales, such as 128 gray scales, 256 gray scales, 512 gray scales, 1024 gray scales and the like.
Please refer to fig. 3. The backlight circuit comprises a plurality of data signal lines 310 for accessing scanning signals; a plurality of scan signal lines 320 for accessing data signals; a plurality of transmission control signal lines 330 for accessing transmission control signals; a plurality of light emitting cells 340 arranged in an array, each light emitting cell 340 including 2nA plurality of light emitting elements 342, n is 1 or more; and a plurality of light emitting driving circuits 350, each light emitting element 342 being connected to a light emitting driving circuit 350; as shown in fig. 3, each light-emitting driving circuit 350 is connected to one of the data signal lines 310, one of the scanning signal lines 320, and one of the emission control signal lines 330, and the light-emitting driving circuit 350 is configured to access a scanning signal and a data signal to control the light-emitting time of the light-emitting elements 342, so as to control the brightness gray scale of the light-emitting elements 342, and to access an emission control signal to control the enabling or disabling of each light-emitting element 342 in each light-emitting unit 340.
In one embodiment, as shown in fig. 4, the backlight circuit further includes at least one scan driving chip 360; at least one data driving chip 370; and at least one grayscale multiplier chip 380; the scan driving chip 360 is used for providing scan signals to the plurality of scan signal lines 320; the data driving chip 370 is used for providing pulse signals to the data signal lines 310 to control the brightness gray scale of the light emitting unit 340; the gray scale multiplication chip 380 is used for providing an emission control signal line 330 for providing an emission control signal to control the enabling or the shutting down of each of the light emitting driving circuits 350 in each of the light emitting units 340.
In one embodiment, the backlight circuit further includes a constant voltage high level signal line and a constant voltage low level signal line, and the specific circuit structure of each of the light emitting driving circuits 350 is described below by taking the light emitting elements 342 as light emitting diodes as an example. Unlike fig. 1, the light emitting driving circuit 350 of the embodiment of the invention employs three transistors, and the light emitting unit 340 is used to increase the gray scale level of the display panel.
Specifically, as shown in fig. 5 to 7, the light emission driving circuit 350 includes a first transistor T1, a second transistor T2, a third transistor T3, and a capacitor C1; the drain of the first transistor T1 is connected to the source of the third transistor T3, the gate is connected to the source of the second transistor T2, and the source is connected to the constant voltage low level signal line 410; the drain of the second transistor T2 is connected to the data signal line 310, the gate is connected to the scan signal line 320, and the source is connected to the constant voltage low level signal line 410 through the capacitor C1; the third transistor T3 has a drain connected to a constant high voltage signal line 390 via a light emitting diode, and a gate connected to an emission control (EM) signal line 330, wherein a cathode of the light emitting diode is connected to a drain of the third transistor T3, an anode of the light emitting diode is connected to the constant high voltage signal line 390, the first transistor T1 is used to supply current to the light emitting diode, the second transistor T2 is used to control a light emitting time of the light emitting diode in response to a scan signal and a data signal, the third transistor T3 is used to control whether the light emitting diode emits light in response to an emission control signal, and the capacitor C1 is used to charge when the scan signal and the digital signal are simultaneously high level to maintain a voltage at the gate of the first transistor T1.
Specifically, the first transistor T1, the second transistor T2, and the third transistor T3 are all thin film transistors. Each light emitting diode may be an inorganic light emitting diode, an organic light emitting diode, or an active matrix light emitting diode (AMLED for short), and so on. The light emitting units 340 may share a constant voltage high level signal line and a constant voltage low level signal line, and may uniformly control all the light emitting units 340, so that the light emitting diodes emit light more stably.
For each light emitting unit 340 of the light emitting elements 342 on two rows, the following wiring methods are possible. As shown in fig. 5, the light-emitting driving circuits 350 corresponding to each column of leds in the light-emitting unit 340 are connected to the same data signal line 310, and the light-emitting driving circuits 350 corresponding to each row of leds are connected to the same scanning signal line 320 and the same emission control signal line 330. As shown in fig. 6, the light-emitting driving circuits 350 corresponding to the respective light-emitting diodes in the light-emitting unit 340 are not shared but connected to one emission control signal line 330, respectively. In fig. 5, if the light-emitting unit is selected to emit light, two or four light-emitting diodes in the light-emitting unit may emit light. In fig. 6, if the light emitting unit is selected to emit light, one, two, three or four light emitting diodes in the light emitting unit may emit light.
As shown in fig. 7, the light emitting driving circuits 350 of the light emitting diodes of the light emitting unit 340 are connected to the same data signal line 310 and the same scanning signal line 320, and the light emitting driving circuits 350 are respectively connected to one emission control signal line 330. In other embodiments, each row of the light-emitting driving circuit 350 in fig. 7 may be connected to the same emission control signal line 330.
For each light emitting unit 340 of only one row of light emitting elements 342, the light emission driving circuit 350 should be connected to one emission control signal line 330, respectively, without sharing the emission control signal line 330.
Fig. 8 is a signal diagram showing operation timing of the light-emitting driving circuit 350 according to fig. 5, 6 or 7, in which the forward voltage of the scanning signal line 320 is 22V, the reverse voltage thereof is-8V, the forward voltage of the data signal line 310 is 12V, and the reverse voltage thereof is 0V. Fig. 8 includes driving timings at which the display panel displays two frame images, a display time of a first frame image is longer than that of a second frame image, EM denotes an emission control signal, Vg denotes a common point voltage of the capacitor C1 and the first transistor T1, and Ids denotes a turn-on current of the first transistor T1.
The number of the light emitting diodes in each light emitting unit 340 can be determined according to the gray scale level required by the display screen, when the gray scale level is required to be 128, each light emitting unit 340 comprises 2 light emitting diodes, when the gray scale level is required to be 256, each light emitting unit 340 comprises 4 light emitting diodes, when the gray scale level is required to be 512, each light emitting unit 340 comprises 8 light emitting diodes, and when the gray scale level is required to be 1024, each light emitting unit 340 comprises 16 light emitting diodes.
The layout of the leds in the light emitting units 340 is not unique, and for example, the light emitting units display to the 256 th gray scale, the light emitting time of each light emitting unit 340 is divided into 64 parts, each light emitting unit 340 includes 4 leds, which may be arranged in 1 × 4, 4 × 1, or 2 × 2, and the like, and is not limited herein, and when the light emitting units are arranged in 1 × 4, the light emitting driving circuit of each led is connected to an emission control signal line 330. Fig. 9 is a schematic diagram of 4 light emitting diodes arranged in a 2 × 2 manner in an embodiment, and the connection manner in fig. 7 is adopted, where the light emitting diodes at the first row and the first column are No. 1 light emitting diodes, the light emitting diodes at the first row and the second column are No. 2 light emitting diodes, the light emitting diodes at the first row and the first column are No. 3 light emitting diodes, and the light emitting diodes at the second row and the second column are No. 4 light emitting diodes. If the light emitting unit 340 is required to emit light, it may have one, two, three or four light emitting diodes emitting light under the control of the emission control signal line 330. Fig. 9 shows a light emitting layout of the light emitting unit 340 in the light emitting time of a certain frame of image, and the pattern filling indicates that the leds emit light, and in these 4 cases, the total light emitting time allocated in the light emitting unit 340 is the same, but the light emitting areas are different, the led No. 1 in fig. 9 a emits light, the leds No. 1 and 2 in fig. 9 b emit light, the leds No. 1 to 3 in fig. 9 c emit light, and the leds No. 1 to 4 in fig. 9 d emit light. Therefore, the light emitting unit 340 can realize 4 different luminances due to 4 choices of light emitting areas, and the light emitting time is divided into 64 gray scales for display, so that the gray scale display level of the display screen can be increased.
Therefore, in the backlight circuit of this embodiment, the light emitting time of each light emitting unit 340 is divided into 64 portions, each light emitting diode is separately provided with the light emitting driving circuit 350, the first transistor T1 is used for providing current to the light emitting diode, the second transistor T2 is connected to the data signal line 310 and the scanning signal line 320 for controlling the light emitting time of the light emitting diode, the light emitting time of each light emitting unit 340 is divided to realize 64 gray scales, so that 64 gray scales of the display panel can be realized, and each light emitting unit 340 includes 2 light emitting unitsnThe light emitting units 340 can select the size of the light emitting area under the control of the emission control signal, thereby further distinguishing the gray scale in space, and finally improving the display screen by combining the split light emitting time with the selection of the light emitting areaA gray scale level of (d).
In summary, in the backlight circuit of the embodiment of the invention, the light emitting duration of each light emitting unit 340 is controlled by the scan signal and the data signal, and the brightness gray scale of the light emitting element 342 is controlled in time, so that the gray scale division of the display screen can be realized in time, and each light emitting unit 340 comprises 2nThe light emitting unit 340 of the light emitting diode can select the size of the light emitting area under the control of the emission control signal, so that the gray scale can be further distinguished in space, and finally, the gray scale level of the display screen is improved by segmenting the light emitting time and combining the selection of the light emitting area.
The embodiment of the present invention further provides a liquid crystal display panel, which includes a liquid crystal cell and the backlight circuit described in any of the above embodiments, where the backlight circuit is disposed on the back surface of the liquid crystal cell and is used to illuminate the liquid crystal cell. Specifically, the refreshing frequency of the liquid crystal display screen is set to be 60HZ, the refreshing frequency enables a human vision system to distinguish gray scales, and the situation that the sensitivity of the human vision system to rapid bright and dark flicker is reduced due to the fact that the refreshing frequency is set to be too high is avoided.
In the liquid crystal display panel of the embodiment of the invention, the light emitting duration of each light emitting unit 340 is controlled by the scanning signal and the data signal, and the brightness gray scale of the light emitting element 342 is controlled in time, so that the gray scale division of the display panel can be realized in time, and each light emitting unit 340 comprises 2nThe light emitting unit 340 of the light emitting diode can select the size of the light emitting area under the control of the emission control signal, so that the gray scale can be further distinguished in space, and finally, the gray scale level of the display screen is improved by segmenting the light emitting time and combining the selection of the light emitting area. For example, the light emitting time of each display unit in the backlight circuit is divided into 64 parts, the light emitting time of each display unit is divided to realize 64 gray scales, so that 64 gray scale display of the display screen can be realized, if each light emitting unit 340 comprises 4 light emitting diodes, the total light emitting area is increased, the light emitting unit 340 can select the size of the light emitting area under the control of the emission control signal, so that gray scales can be further distinguished in space, and finally, the gray scale level is improved by dividing the light emitting time and combining the selection of the light emitting area.
An embodiment of the present invention further provides a backlight driving method for a backlight circuit, as shown in fig. 3, the backlight circuit includes:
a plurality of data signal lines 310 for receiving scan signals;
a plurality of scan signal lines 320 for accessing data signals;
a plurality of transmission control signal lines 330 for accessing transmission control signals;
a plurality of light emitting cells 340 arranged in an array, each light emitting cell 340 including 2nA plurality of light emitting elements 342, n is 1 or more; and
a plurality of light emitting driving circuits 350, each of the light emitting elements 342 being connected to the light emitting driving circuit 350;
each light-emitting driving circuit 350 is connected to one of the data signal lines 310, one of the scanning signal lines 320, and one of the emission control signal lines 330, and the light-emitting driving circuit 350 is configured to access a scanning signal and a data signal to control a light-emitting time of the light-emitting element 342, so as to control a brightness gray scale of the light-emitting element 342, and access an emission control signal to control enabling or disabling of each light-emitting element 342 in each light-emitting unit 340.
For the specific definition of the backlight circuit, reference is made to the foregoing embodiments, and details are not repeated here.
As shown in fig. 10, based on the backlight circuit, the backlight driving method in the embodiment of the present invention includes the following steps:
step 802: a data signal is supplied through the data signal line 310, a scan signal is supplied through the scan signal line 320, and an emission control signal is supplied through the emission control signal line 330;
step 804: the light emitting elements 342 required to emit light in each light emitting unit 340 are determined according to the emission control signal, the light emitting elements 342 in each light emitting unit 340 are controlled to be enabled or disabled, and the light emitting time of the light emitting elements 342 in each light emitting unit 340 is controlled according to the data signal and the scanning signal.
In the backlight driving method of the backlight circuit according to the embodiment of the invention, the light emitting duration of each light emitting unit 340 is controlled by the scan signal and the data signal, and the light emitting duration is controlled in timeThe brightness gray scale of the light elements 342, so that the gray scale division of the display screen can be realized in time, plus that each light emitting unit 340 comprises 2nThe light emitting unit 340 of the light emitting diode can select the size of the light emitting area under the control of the emission control signal, so that the gray scale can be further distinguished in space, and finally, the gray scale level of the display screen is improved by dividing the light emitting time and selecting the light emitting area.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A backlight circuit, comprising:
a plurality of data signal lines for accessing scanning signals;
a plurality of scanning signal lines for accessing data signals;
a plurality of emission control signal lines for accessing the emission control signals;
a plurality of light emitting cells arranged in an array, each light emitting cell comprising 2nA plurality of light emitting elements, n is 1 or more; and
the light-emitting drive circuits are connected with the light-emitting elements;
each light-emitting drive circuit is connected with one data signal line, one scanning signal line and one emission control signal line, and the light-emitting drive circuit is used for accessing scanning signals and data signals to control the light-emitting time of the light-emitting elements so as to control the brightness gray scale of the light-emitting elements and accessing emission control signals to control the enabling or closing of the light-emitting elements in each light-emitting unit.
2. The backlight circuit according to claim 1, wherein the backlight circuit further comprises a constant voltage high level signal line and a constant voltage low level signal line, and the light emitting element is a light emitting diode;
each of the light emission driving circuits includes a first transistor, a second transistor, a third transistor, and a capacitor; the drain electrode of the first transistor is connected with the source electrode of the third transistor, the grid electrode of the first transistor is connected with the source electrode of the second transistor, and the source electrode of the first transistor is connected with the constant-voltage low-level signal line; the drain electrode of the second transistor is connected with the data signal line, the grid electrode of the second transistor is connected with the scanning signal line, and the source electrode of the second transistor is connected with the constant-voltage low-level signal line through a capacitor; the drain electrode of the third transistor is connected with the constant voltage high level signal line through a light-emitting diode, the grid electrode of the third transistor is connected with the emission control signal line, the cathode electrode of the light-emitting diode is connected with the drain electrode of the third transistor, and the anode electrode of the light-emitting diode is connected with the constant voltage high level signal line; the first transistor is used for providing current for the light emitting diode, the second transistor is used for responding to a scanning signal and a data signal to control the light emitting time of the light emitting diode, the third transistor is used for responding to an emission control signal to control the light emitting or closing of the light emitting diode, and the capacitor is used for charging when the scanning signal and the digital signal are simultaneously high level so as to maintain the voltage of the grid electrode of the first transistor.
3. The backlight circuit according to claim 2, wherein each of the light emitting units shares a constant voltage high level signal line and a constant voltage low level signal line.
4. The backlight circuit of claim 2, wherein each light emitting unit comprises two or more rows of light emitting elements, the light emitting driving circuit corresponding to each row of light emitting diodes is connected to the same data signal line, and the light emitting driving circuit corresponding to each row of light emitting diodes is connected to the same scanning signal line and the same emission control signal line.
5. The backlight circuit according to claim 2, wherein the light-emitting driving circuit corresponding to each light-emitting diode in each light-emitting unit is connected to a same data signal line and a same scanning signal line, and the light-emitting driving circuit corresponding to each light-emitting diode is connected to a respective emission control signal line.
6. The backlight circuit according to claim 2, wherein the forward voltage of the scan signal line is 22V, the reverse voltage is-8V, the forward voltage of the data signal line is 12V, and the reverse voltage is 0V.
7. The backlight circuit according to any of claims 1-6, wherein each light-emitting unit comprises 4 light-emitting elements, and the light-emitting elements in each light-emitting unit are arranged in a 2 x 2 matrix.
8. A liquid crystal display panel comprising a liquid crystal cell and a backlight circuit according to any of claims 1 to 6, said backlight circuit being provided on the back side of said liquid crystal cell for illuminating said liquid crystal cell.
9. The lcd of claim 7, wherein the lcd panel has a refresh rate of 60 HZ.
10. A backlight driving method of a backlight circuit, the backlight circuit comprising:
a plurality of data signal lines for accessing scanning signals;
a plurality of scanning signal lines for accessing data signals;
a plurality of emission control signal lines for accessing the emission control signals;
a plurality of light emitting cells arranged in an array, each light emitting cell comprising 2nA plurality of light emitting elements, n is 1 or more; and
the light-emitting drive circuits are connected with the light-emitting elements;
each light-emitting drive circuit is connected with one data signal line, one scanning signal line and one emission control signal line, and is used for accessing scanning signals and data signals to control the light-emitting time of the light-emitting elements so as to control the brightness gray scale of the light-emitting elements and accessing emission control signals to control the enabling or closing of each light-emitting element in each light-emitting unit;
the backlight driving method includes the steps of:
providing a data signal through a data signal line, providing a scanning signal through a scanning signal line, and providing an emission control signal through an emission control signal line;
and determining the light-emitting element needing to emit light in each light-emitting unit according to the emission control signal, controlling the enabling or closing of the light-emitting element in each light-emitting unit, and controlling the light-emitting time of the light-emitting element in each light-emitting unit according to the data signal and the scanning signal.
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| CN201911300567.XA CN110992900A (en) | 2019-12-17 | 2019-12-17 | Liquid crystal display screen, backlight circuit and backlight driving method thereof |
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Application publication date: 20200410 |