EP0599621B1 - Steuervorrichtung für ein Anzeigegerät, die die Spannungseinstellung verbessert - Google Patents
Steuervorrichtung für ein Anzeigegerät, die die Spannungseinstellung verbessert Download PDFInfo
- Publication number
- EP0599621B1 EP0599621B1 EP19930309359 EP93309359A EP0599621B1 EP 0599621 B1 EP0599621 B1 EP 0599621B1 EP 19930309359 EP19930309359 EP 19930309359 EP 93309359 A EP93309359 A EP 93309359A EP 0599621 B1 EP0599621 B1 EP 0599621B1
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- EP
- European Patent Office
- Prior art keywords
- voltage
- circuit
- voltages
- gray
- driving circuit
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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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
- G09G3/2007—Display of intermediate tones
- G09G3/2011—Display of intermediate tones by amplitude modulation
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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
- 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
- G09G3/3685—Details of drivers for data electrodes
- G09G3/3688—Details of drivers for data electrodes suitable for active matrices only
-
- 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
- G09G3/3696—Generation of voltages supplied to electrode drivers
-
- 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
- G09G2310/0264—Details of driving circuits
- G09G2310/027—Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
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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
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
- G09G2320/0276—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
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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
- G09G3/2007—Display of intermediate tones
- G09G3/2014—Display of intermediate tones by modulation of the duration of a single pulse during which the logic level remains constant
Definitions
- the present invention relates to a driving circuit for a flat panel display apparatus, and more particularly relates to a driving circuit for a display apparatus which receives a digital image signal to produce a display image with gray scales in accordance with the received digital image signals.
- Figure 1 shows a data driver exemplifying a conventional driving circuit for driving a display apparatus which receives digital image data to produce a display image with gray scales in accordance with the received data.
- the digital image data consists of two bits (D 0 , D 1 ).
- This data driver supplies driving voltages to N pixels (where N is a positive integer) on a scanning line which has been selected by means of a scanning signal.
- FIG. 2 shows a circuit constituting part of the data driver of Figure 1 .
- This circuit which is denoted by the reference numeral 20 , supplies a driving voltage through a data line to the "n"th pixel (where n is an integer of 1 to N) of the above-mentioned N pixels provided along the single scanning line.
- the circuit 20 includes sampling (primary) flip-flops 21 each for receiving one bit of the digital image data (D 0 , D 1 ), holding (secondary) flip-flops 22 each also for receiving one bit, a decoder 23 and four analog switches 24 to 27 . To the analog switches 24 to 27 , signal voltages V 0 to V 3 are respectively supplied from four different voltage sources.
- D flip-flops or various other flip-flops can be used as the sampling flip-flops 21 .
- the circuit 20 shown in Figure 2 operates as follows. On receiving the leading edge of a sampling pulse T smpn corresponding to the "n"th pixel, the sampling flip-flops 21 obtain the digital image data (D 0 , D 1 ) and hold the thus obtained data therein. When such image data sampling for the 1st to Nth pixels on a single scanning line is completed (i.e., sampling corresponding to one horizontal period is completed), an output pulse OE is applied to the holding flip-flops 22 . On receiving the output pulse OE, the holding flip-flops 22 obtain the digital image data (D 0 , D 1 ) from the sampling flip-flops 21 , and transfer the thus obtained digital image data to the decoder 23 .
- the decoder 23 decodes each bit of the digital image data (D 0 , D 1 ), and turns on one of the analog switches 24 to 27 in accordance with the respective values of the thus decoded bits. As a result, one of the signal voltages V 0 to V 3 from the four different voltage sources, which corresponds to the thus turned-on analog switch 24, 25, 26 or 27 , is output from the circuit 20 .
- a conventional data driver such as described above requires 2 n different voltage sources (where n is the number of bits constituting digital image data).
- n is the number of bits constituting digital image data.
- the number of required voltage sources doubles when the digital image data is enlarged by one bit.
- Such voltage sources are connected through the analog switches of the data driver to a display apparatus, e.g., a liquid crystal panel, which provides a heavy load on the voltage sources.
- a display apparatus e.g., a liquid crystal panel
- each voltage source is required to have a sufficient performance to drive such a heavy load.
- the increase in the number of such high-performance voltage sources is a significant factor in the higher production cost of the entire driving circuit.
- high-performance voltage sources cannot readily be placed within the LSI circuit constituting the driving circuit, they must be located outside the LSI circuit. This means that signal voltages for driving the liquid crystal panel must be supplied from external voltage sources to the LSI circuit. As a result, with an increase in the number of voltage sources, the number of input terminals of the LSI circuit must be increased accordingly.
- Figure 3 shows a circuit 30 which constitutes part of a data driver exemplifying the above-described proposed driving circuit using the oscillating voltage driving method.
- Table 1 shows the relationship between voltages V 0 to V 7 applied to a pixel from the circuit 30 and gray-scale reference voltages V 0 , V 2 , V 5 and V 7 respectively supplied from four voltage sources.
- the four voltages V 1 , V 3 , V 4 and V 6 applied to the pixel from the circuit 30 are four interpolated voltages (V 0 +2V 2 )/3, (2V 2 +V 5 )/3, (V 2 +2V 5 )/3 and (2V 5 +V 7 )/3, respectively, which are obtained from the four gray-scale reference voltages V 0 , V 2 , V 5 and V 7 .
- the gray-scale reference voltages V 0 , V 2 , V 5 and V 7 and the interpolated voltages V 1 , V 3 , V 4 and V 6 produced therefrom are all used to generate gray scales. This means that, in this data driver, eight gray scales can be obtained from only four gray-scale reference voltages which are respectively supplied from the four voltage sources.
- the proposed driving circuit using the oscillating voltage driving method is advantageous in that the number of gray scales which can be obtained is greater than that of the voltage sources.
- This conventional driving circuit involves such problems as will be described below.
- Figure 4 shows the relationship between voltage applied to a pixel by the above-described circuit 30 and the resultant transmittance of the pixel.
- the problems to be solved by the invention will be described by taking the voltage V 0 as an example.
- the voltage V 0 is used to obtain the lowest transmittance, i.e., the highest gray scale (black).
- the transmittance gradually approaches 0% with an increase in the voltage.
- the absolute value of the voltage V 0 is increased to a practically possible level, the transmittance approaches 0%.
- the gray-scale reference voltage V 0 is used to obtain the interpolated voltage V 1 as shown in Table 1, so that it is extremely difficult to adjust the gray-scale reference voltage V 0 and the interpolated voltage V 1 separately.
- the voltage V 0 is determined in accordance with the voltage V 1 .
- the voltage V 1 is determined in accordance with the voltage V 0 .
- the voltage V 0 is used to produce only the interpolated voltage V 1 .
- the number of interpolated voltages to be obtained from the voltage V 0 increases. This makes it far more difficult to separately adjust the voltage V 0 and the interpolated voltages to be produced therefrom.
- this conventional driving circuit involves the following inconvenience: For example, even in the case where a slight increase in the voltage V 0 would further darken a black image (i.e., a highest-grey-scale image) to obtain higher contrast in the entire display image, it is impossible to actually increase the voltage V 0 without adversely affecting the other grey scales such as those obtained by interpolated voltages; even the slight increase in the voltage V 0 can deteriorate the characteristics of the grey scales of the entire display image. Therefore, a display apparatus using this conventional driving circuit cannot produce a high-contrast display image. This problem also arises in the case of the voltage V 7 which is used to obtain the highest transmittance, i.e., the lowest grey scale (white).
- EP-A-0 478 386 discloses a driving circuit for a display apparatus which outputs either a grey scale reference voltage or an interpolated voltage being between two grey-scale reference voltages.
- the lowest grey scale reference voltage is used to obtain the lowest grey scale, and is interpolated with the next lowest grey-scale reference voltage to obtain the lowest but one grey scale.
- the present invention provides a driving circuit for a display apparatus having pixels, the driving circuit applying, in use, a voltage to a selected pixel, the driving circuit comprising first voltage output means for generating at least an interpolated voltage on the basis of grey-scale reference voltages supplied to the voltage output means, the interpolated voltage being between two grey-scale reference voltages, and selectively applying the interpolated voltage or one of the grey-scale reference voltages to said pixel to obtain a desired grey scale display; characterised in that the driving circuit further comprises a second voltage output means for selectively supplying a first voltage higher than the highest of the grey-scale reference voltages or a second voltage lower than the lowest of the grey-scale reference voltages to the pixel to obtain the highest or lowest grey scale displays respectively.
- the voltage applied to said pixels by said second voltage output means is used to obtain a highest gray scale.
- the voltage applied to said pixels by said second voltage output means is used to obtain a lowest gray scale.
- the invention described herein makes possible the advantages of providing a driving circuit for a display apparatus, in which a voltage for the generation of the highest or lowest gray scale, or voltages for the generation of both the highest and lowest gray scales are provided separately from gray-scale reference voltages, so that the voltage(s) for the highest and/or lowest gray scale(s) can be adjusted separately from the gray-scale reference voltages, thereby allowing the display apparatus to produce a display image having the highest contrast possible for a liquid crystal panel.
- Figure 1 is a schematic diagram showing the circuit of a conventional data driver.
- Figure 2 is a schematic diagram showing a circuit constituting part of the conventional data driver of Figure 1 .
- Figure 3 is a schematic diagram showing a circuit constituting part of another conventional data driver.
- Figure 4 is a graph showing the relationship between voltage applied to a pixel and the resultant transmittance of the pixel.
- Figure 5 is a schematic diagram showing a circuit constituting part of a data driver exemplifying a driving circuit according to the invention.
- Figure 6 shows the waveform of a signal t which is input to a selective control circuit 53 shown in Figure 5 .
- Figure 7 is a schematic diagram showing a circuit constituting part of a data driver exemplifying another driving circuit according to the invention.
- Figure 8 is a graph showing the relationship between voltage applied to a pixel and the resultant transmittance of the pixel.
- a matrix-type liquid crystal display apparatus is herein used as a display apparatus to be driven by a driving circuit according to the invention. But it is understood that the driving circuit of the invention can also be applied to other types of display apparatus.
- Figure 5 shows the configuration of a circuit 50 which constitutes part of a data driver exemplifying a driving circuit according to the invention.
- the circuit 50 corresponds to the "n"th pixel of N pixels which are provided along each scanning line in a display apparatus (where N is a positive integer, and n is an integer of 1 to N).
- digital image data consists of three bits (D 0 , D 1 , D 2 ).
- the circuit 50 includes sampling (primary) flip-flops 51 and holding (secondary) flip-flops 52 both for receiving and holding the digital image data.
- the circuit 50 also includes a selective control circuit 53 , four analog switches 55 to 58 to which different gray-scale reference voltages are supplied, and an analog switch 54 to which a voltage different from the gray-scale reference voltages is supplied.
- the selective control circuit 53 turns on or off the analog switches 54 to 58 individually to control the on/off state thereof.
- the selective control circuit 53 receives a signal t.
- the output of the circuit 50 is connected to a data line (not shown), so that a voltage output from the circuit 50 is supplied through the data line to the "n"th pixel.
- gray-scale reference voltage is herein defined as a voltage used to obtain at least one interpolated voltage by the oscillating voltage driving method disclosed in the above-described Japanese Patent Application No. 4-129164.
- the sampling flip-flops 51 On receiving the leading edge of a sampling pulse T smpn corresponding to the "n"th pixel, the sampling flip-flops 51 obtain the respective bits of the digital image data (D 0 , D 1 , D 2 ), and hold the thus obtained data therein, thereby completing the sampling of the image data corresponding to the "n"th pixel.
- the data driver In the data driver, such image data sampling is performed for all the above-mentioned N pixels provided along a single scanning line (i.e., sampling corresponding to one horizontal period is performed).
- an output pulse OE is applied to the holding flip-flops 52 .
- the holding flip-flops 52 On receiving the output pulse OE, the holding flip-flops 52 obtain the digital image data (D 0 , D 1 , D 2 ) from the sampling flip-flops 51 , and also output the received digital image data to the selective control circuit 53 .
- the selective control circuit 53 is provided with input terminals d 0 , d 1 and d 2 , and output terminals S 0 ' , S 0 , S 2 , S 5 and S 7 .
- the three bits of the digital image data (D 0 , D 1 , D 2 ) are respectively input through the input terminals d 0 , d 1 and d 2 to the selective control circuit 53.
- the selective control circuit 53 outputs control signals respectively for turning on or off the analog switches 54 to 58 to control the on/off state thereof.
- Gray-scale reference voltages V 0 , V 2 , V 5 and V 7 of different voltage levels are supplied to the analog switches 55 to 58 , respectively.
- a voltage V 0 ' which is different from the gray-scale reference voltages is supplied to the analog switch 54 .
- the relationship among the levels of these voltages is: V 0 ' > V 0 > V 2 > V 5 > V 7 .
- Each of these voltages is output to the data line only when the corresponding analog switch 54, 55, 56, 57 or 58 is turned on.
- Table 2 is a logical table showing the relationship between the inputs and outputs of the selective control circuit 53 .
- the first section of Table 2 i.e., the first three columns from the left
- the second section of Table 2 i.e., the next five columns
- Each of the analog switches 54 to 58 is turned on when it receives a control signal having a value of 1 from the output terminal S 0 ', S 0 , S 2 , S 5 or S 7 connected thereto, and turned off when it receives a control signal having a value of 0 from the output terminal connected thereto.
- Each of the blanks in the second section of Table 2 indicates that the value of the control signal is 0.
- Each "t" indicates that the control signal has a value of 1 when the value of the signal t is 1, and that the control signal has a value of 0 when the value of the signal t is 0.
- each t ⁇ indicates that the control signal has a value of 0 when the value of the signal t is 1, and that the control signal has a value of 1 when the value of the signal t is 0.
- Figure 6 shows the waveform of the above-described signal t.
- the signal t is a pulse signal which periodically alternates between the values of 0 and 1 with a duty ratio of 1:2. Specifically, the ratio of the time for the signal t having a value of 0 to that for the signal t having a value of 1 is 1:2.
- the control signals output from the output terminals S 0 and S 2 have the values of the t ⁇ and of the signal t, respectively.
- the analog switch 56 connected to the output terminal S 2 is turned on, with the other analog switches off, thereby allowing the gray-scale reference voltage V 2 to be output from the circuit 50 to the data line.
- the value of the t ⁇ becomes 1, so that the analog switch 55 connected to the output terminal S 0 is turned on with the other analog switches off, thereby allowing the gray-scale reference voltage V 0 to be output from the circuit 50 to the data line. Since the value of the signal t periodically alternates between the values of 0 and 1 as described above, the voltage which is output from the circuit 50 to the data line becomes an oscillating voltage which oscillates between the gray-scale reference voltages V 0 and V 2 in the same cycle as that of the pulse signal t.
- the oscillating voltage thus applied through the data line to the pixel is an interpolated voltage of a level given by: (V 0 + 2V 2 )/3, which is between the voltage levels of the gray-scale reference voltages V 0 and V 2 .
- oscillating voltages which oscillate between the gray-scale reference voltages V 2 and V 5 , and between the gray-scale reference voltages V 5 and V 7 are output from the circuit 50 to the data line and accordingly applied to the pixel.
- These oscillating voltages applied to the pixel are also interpolated voltages the levels of which are between the voltage levels of V 2 and V 5 , and between the voltage levels of V 5 and V 7 , respectively. Therefore, since the gray-scale reference voltages V 0 , V 2 , V 5 and V 7 are all used to obtain interpolated voltages, they cannot be adjusted separately from the interpolated voltages.
- FIG. 7 shows the configuration of a circuit 70 which constitutes part of a data driver exemplifying another driving circuit according to the invention.
- the circuit 70 applies a voltage through a data line to the "n"th pixel of the N pixels provided along each scanning line in the display apparatus.
- the configuration of the circuit 70 is the same as that of the circuit 50 of Figure 5 , except that a selective control circuit 73 of the circuit 70 is provided with another output terminal S 7 ' connected to an analog switch 79 to which another voltage V 7 ' is supplied.
- the voltage V 7 ' is different from all the gray-scale reference voltages V 0 , V 2 , V 5 and V 7 , and also different from the voltage V 0 '.
- the relationship among the levels of these voltages is: V 0 ' > V 0 > V 2 > V 5 > V 7 > V 7 '.
- the detailed description of the other configuration of the circuit 70 is herein omitted.
- the voltage V 7 ' can be adjusted separately from the other voltages. Therefore, the lowest gray scale obtained by the voltage V 7 ' can be adjusted separately from the other gray scales. This will be described in detail below by reference to Table 3.
- Table 3 is a logic table showing the relationship between the inputs and outputs of the selective control circuit 73 .
- Table 3 in the case where the values of all the three bits respectively input to the input terminals d 2 , d 1 and d 0 of the selective control circuit 73 are 1, a control signal having a value of 1 is output from the output terminal S 7 ' of the selective control circuit 73 , so that the analog switch 79 connected thereto is turned on. The other analog switches 74 to 78 remain off. Accordingly, the circuit 70 outputs the voltage V 7 ' to the data line. The voltage V 7 ' is not used to obtain any oscillating voltage, so that it can be adjusted separately from the other voltages.
- Figure 8 shows the relationship between the voltage applied to the pixel by the above-described driving circuit of the invention including the circuit 70 of Figure 7 , and the resultant transmittance of the pixel.
- the voltage V 0 ' is made higher than the highest gray-scale reference voltage V 0
- the voltage V 7 ' is made lower than the lowest gray-scale reference voltage V 7 .
- the voltages V 0 ' and V 7 ' are used to obtain the highest and the lowest gray scales, respectively.
- the display apparatus using this driving circuit can produce a display image having the highest contrast possible for a liquid crystal panel.
- only the voltage V 0 ' for the generation of the highest gray scale, or both the voltages V 0 ' and V 7 ' respectively for the generation of the highest and lowest gray scales are provided so as to be adjusted separately from the other voltages.
- only the voltage V 7 ' for the generation of the lowest gray scale may be provided to be adjusted separately from the other voltages.
- a high-contrast display image can be obtained in the display apparatus.
- one or two additional voltages are supplied to the LSI circuit constituting the driving circuit (i.e., data driver), so that the number of the terminals of the LSI circuit and the number of the analog switches in the data driver are increased accordingly.
- the driving circuit i.e., data driver
- Such increase can never be significant.
- the conventional driving circuit using the oscillating voltage driving method requires nine voltage sources.
- a driving circuit of the invention using one additional voltage which can be adjusted independently for the generation of the highest or lowest gray scale requires only one more voltage source, i.e., ten voltage sources. Since the number of voltage sources is only increased from nine to ten, the number of input terminals of the LSI circuit is only increased from nine to ten, and the number of analog switches is increased by only one for each output terminal of the data driver. This indicates that the increase in the number of the terminals of the LSI circuit and in the number of analog switches due to the increase in the number of voltage sources is extremely small in the driving circuit of the invention.
- one or two voltages different from the gray-scale reference voltages are provided to be adjusted independently. Therefore, a voltage for the generation of the highest or lowest gray scale, or voltages for the generation of both the highest and lowest gray scales can be adjusted separately from the other voltages. This enables the generation of a display image having the highest contrast possible for a liquid crystal panel, while maintaining the advantage of the oscillating voltage driving method where the number of gray scales which can be obtained is greater than that of the voltage sources.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Liquid Crystal Display Device Control (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Claims (1)
- Steuerschaltung für eine Anzeigevorrichtung mit Pixeln, wobei diese Steuerschaltung im Gebrauch eine Spannung an ein ausgewähltes Pixel anlegt und sie eine erste Spannungsausgabeeinrichtung zum Erzeugen mindestens einer interpolierten Spannung auf Grundlage von von der Spannungsausgabeeinrichtung zugeführten Graustufen-Bezugsspannungen zu erzeugen, wobei diese interpolierte Spannung zwischen zwei Graustufen-Bezugsspannungen liegt, und sie die interpolierte Spannung oder eine der Graustufen-Bezugsspannungen selektiv an das Pixel anlegt, um eine gewünschte Graustufenanzeige zu erzielen;
dadurch gekennzeichnet, dass die Steuerschaltung ferner eine zweite Spannungsausgabeeinrichtung zum selektiven Liefern einer ersten Spannung, die höher als die höchste der Graustufen-Bezugsspannungen ist, oder einer zweiten Spannung, die niedriger als die niedrigste der Graustufen-Bezugsspannungen ist, an das Pixel aufweist, um die höchste bzw. niedrigste Graustufenanzeige zu erzielen.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP315421/92 | 1992-11-25 | ||
JP315422/92 | 1992-11-25 | ||
JP4315422A JP2806718B2 (ja) | 1992-11-25 | 1992-11-25 | 表示装置の駆動方法及び駆動回路 |
JP4315421A JP2849010B2 (ja) | 1992-11-25 | 1992-11-25 | 表示装置の駆動回路 |
Publications (2)
Publication Number | Publication Date |
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EP0599621A1 EP0599621A1 (de) | 1994-06-01 |
EP0599621B1 true EP0599621B1 (de) | 1997-09-03 |
Family
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Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
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EP19930309359 Expired - Lifetime EP0599621B1 (de) | 1992-11-25 | 1993-11-24 | Steuervorrichtung für ein Anzeigegerät, die die Spannungseinstellung verbessert |
EP19930309360 Expired - Lifetime EP0599622B1 (de) | 1992-11-25 | 1993-11-24 | Steuerschaltung zur Steuerung einer Anzeigeeinrichtung und Verfahren für dieselbe |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
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EP19930309360 Expired - Lifetime EP0599622B1 (de) | 1992-11-25 | 1993-11-24 | Steuerschaltung zur Steuerung einer Anzeigeeinrichtung und Verfahren für dieselbe |
Country Status (2)
Country | Link |
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EP (2) | EP0599621B1 (de) |
DE (2) | DE69313587T2 (de) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR0140041B1 (ko) * | 1993-02-09 | 1998-06-15 | 쯔지 하루오 | 표시 장치용 전압 발생 회로, 공통 전극 구동 회로, 신호선 구동 회로 및 계조 전압 발생 회로 |
KR0124975B1 (ko) * | 1994-06-07 | 1997-12-01 | 김광호 | 박막 트랜지스터형 액정표시장치의 전력 구동회로 |
US6057820A (en) * | 1996-10-21 | 2000-05-02 | Spatialight, Inc. | Apparatus and method for controlling contrast in a dot-matrix liquid crystal display |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2849740B2 (ja) * | 1986-03-17 | 1999-01-27 | セイコーインスツルメンツ株式会社 | 強誘電性液晶電気光学装置 |
EP0478386B1 (de) * | 1990-09-28 | 1995-12-13 | Sharp Kabushiki Kaisha | Steuerschaltung für ein Anzeigegerät |
-
1993
- 1993-11-24 EP EP19930309359 patent/EP0599621B1/de not_active Expired - Lifetime
- 1993-11-24 EP EP19930309360 patent/EP0599622B1/de not_active Expired - Lifetime
- 1993-11-24 DE DE1993613587 patent/DE69313587T2/de not_active Expired - Lifetime
- 1993-11-24 DE DE1993616852 patent/DE69316852T2/de not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
DE69313587T2 (de) | 1998-03-19 |
EP0599622B1 (de) | 1998-02-04 |
EP0599622A1 (de) | 1994-06-01 |
DE69313587D1 (de) | 1997-10-09 |
DE69316852D1 (de) | 1998-03-12 |
DE69316852T2 (de) | 1998-08-06 |
EP0599621A1 (de) | 1994-06-01 |
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