JPH11295699A - Matrix liquid crystal display device, correction data storage device therefor and correction data forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of display non-uniformity caused by the error of production inside a liquid crystal(LC) cell in the production process of this LC cell to a minimum. SOLUTION: Concerning this matrix liquid crystal display device, a ratio between the gradient of a first linear approximate expression expressing the target luminance of an LC cell 10 with the gradation level of an external input image signal as an independent variable and the gradient of a second linear approximate expression expressing the real luminance of the LC cell with the gradation level of output to the LC cell as an independent variable and the ratio of the gradient in the second linear approximate expression to the difference of respective pieces in the first and second linear approximate expressions are respectively stored in a correction data storage circuit 130 for each of plural pixels of the LC cell as first and second correction data. The microcomputer of a control circuit 20 multiplies the first correction data by the gradation level of the external input image signal and adds the second correction data to this multiplied value. Based on this operation, a signal electrode driving circuit 60 drives the LC cell 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a matrix type liquid crystal display device, a correction data storage device thereof, and a correction data forming method.

[0002]

2. Description of the Related Art Heretofore, in this type of matrix type liquid crystal display device, there is a liquid crystal cell using an antiferroelectric liquid crystal sealed between both electrode substrates.

[0003]

In the manufacturing process of the above-mentioned liquid crystal cell, variations in the film formation layers of each electrode substrate and variations in the cell gap often occur in the liquid crystal cell.
In such a case, the optical response characteristics to the applied voltage of the antiferroelectric liquid crystal in each pixel of the liquid crystal cell vary.

For this reason, even if the same color and the same gradation are displayed on the display surface of the liquid crystal cell, the brightness (ie, brightness) and the chromaticity (ie, hue) of the display surface of the liquid crystal cell become uneven. Occurs. As a result, there arises a problem that the image quality of a general display image is deteriorated as well as the same color and the same gradation display.

As disclosed in Japanese Patent Application Laid-Open No. 7-28023 and Japanese Patent Application Laid-Open No. 7-64520, however, waveform distortion of a driving signal of a driving circuit for driving a liquid crystal cell based on an image signal and pixel distortion are disclosed. A method of correcting an error in the waveform of each drive signal can be considered. However, in such a method, although the video based on the video signal is displayed after correcting the drive signal of the drive circuit, the optical response characteristics of the liquid crystal in each pixel cannot be corrected, so that the display of the liquid crystal cell is not performed. There is almost no effect of reducing unevenness.

[0006] In order to cope with the above, the present invention minimizes the occurrence of display unevenness due to variations caused by manufacturing errors in the liquid crystal cell during the manufacturing process of the liquid crystal cell. It is an object of the present invention to provide a matrix type liquid crystal display device as described above, a correction data storage device thereof, and a correction data forming method.

[0007]

In order to solve the above problems, according to the first aspect of the present invention, a liquid crystal, a plurality of scanning electrodes (Y1 to Yn) and a plurality of signal electrodes (X1 to Xm) are used. A liquid crystal cell (10) formed with a plurality of matrix-shaped pixels, and an external input image signal is corrected for each pixel so that an actual luminance based on a variation occurring during the manufacturing process in the liquid crystal cell matches a target luminance. Correction means (300 to 320, 300A to 320A, 300B
To 320B) and scan electrode drive control means (30, 5) for driving a plurality of scan electrodes while scanning based on the synchronization signal.
0, 330, 330A, 330B) and signal electrode drive control means (40, 60,...) Which output the correction results of the correction means as image data to a plurality of signal electrodes in synchronization with scanning by the scan electrode drive control means. 330, 330A, 3
30B), and a matrix-type liquid crystal display device in which a plurality of pixels perform a matrix display in accordance with both control operations of the scan electrode drive control means and the signal electrode drive control means is provided.

Accordingly, the correction means corrects the external input image signal for each pixel so that the actual luminance matches the target luminance. Therefore, if a matrix display is performed by the liquid crystal cell under such correction, even if there is a variation in the liquid crystal cell during the manufacturing process, the display is maintained without being affected by the variation. it can. Claim 2
And 3, the liquid crystal, the plurality of scanning electrodes (Y1 to Yn), and the plurality of signal electrodes (X1 to X
m), a liquid crystal cell (10) formed by forming a plurality of matrix-shaped pixels, a gradient of a first linear approximation expressing target luminance of the liquid crystal cell as a gradation level of an external input image signal as an independent variable, and a liquid crystal cell. Second linear approximation to the ratio between the actual luminance and the gradient of the second linear approximation that represents the output gradation level to the liquid crystal cell as an independent variable, and the difference between the intercepts of the first and second linear approximations The ratio of the gradient in the equation is set as the first and second correction data, the correction data storage means (130) stored for each of the plurality of pixels, and the gray level of the external input image signal as the first correction data. Multiplication means (310, 310A, 310B) for multiplying the correction data, and addition means (32) for adding the second correction data to the multiplied value by the multiplication means
0, 320A, 320B), scanning electrode drive control means (30, 50, 330, 330A, 330B) for driving a plurality of scan electrodes while scanning based on a synchronization signal, and synchronization with scanning by the scan electrode drive control means. Signal electrode drive control means (40, 60, 330, 3) for outputting the addition result of the addition means to a plurality of signal electrodes as image data.
30A, 330B), and a matrix type liquid crystal display device in which a plurality of pixels perform a matrix display according to both control operations of the scan electrode drive control means and the signal electrode drive control means is provided.

Thus, the first correction data stored in the correction data storage means is multiplied by the gradation level of the external input image signal, and the multiplied value is multiplied by the second correction data stored in the correction data storage means.
Even when the correction data is added, the same operation and effect as the first aspect can be achieved. Here, claim 3
According to the invention described in (1), the correction data storage means stores the first and second correction data for each of R, G, and B. The multiplying unit performs the multiplication for each of R, G, and B, and the adding unit performs the addition for each of R, G, and B.

According to this, the same operation and effect as in the second aspect of the invention can be achieved even when color display is performed by the liquid crystal cell. According to the fourth and fifth aspects of the present invention, a liquid crystal cell (10) having a plurality of matrix pixels is provided.
Of the first linear approximation formula representing the target luminance of the external input image signal as an independent variable and the second linear approximation formula representing the actual luminance of the liquid crystal cell as the output variable to the liquid crystal cell as an independent variable. And the ratio of the gradient of the second linear approximation to the difference between the intercepts of the first and second linear approximations, respectively. In order to suppress display unevenness of a liquid crystal cell based on the correction data, a correction data storage device for a matrix type liquid crystal display device is stored as first and second correction data for each of a plurality of pixels.

This makes it possible to provide a correction data storage device suitable for use in the first and second aspects of the present invention. Here, according to the invention described in claim 5, the first and second correction data are correction data for each of R, G, and B.
For this reason, it is possible to provide correction data suitable for the invention according to the third aspect even in color display by the liquid crystal cell.

According to the present invention, the brightness of the liquid crystal cell (10) is measured, and the display unevenness of the liquid crystal cell due to the variation in the liquid crystal cell during the manufacturing process is suppressed. As described above, there is provided a correction data forming method for a matrix type liquid crystal display device which forms correction data for each pixel based on the measured luminance and the external input image signal.

This makes it possible to form correction data suitable for use in the third aspect of the present invention. According to the seventh aspect of the invention, the luminance of the liquid crystal cell (10) is measured, and the target luminance of each pixel of the liquid crystal cell is linearly approximated in relation to the input gradation level of the external input image signal. It is formed as a first linear approximation formula, and the measured luminance is linearly approximated for each pixel in relation to the output gradation level to the liquid crystal cell, and each is formed as a second linear approximation formula. A third linear approximation is formed for each pixel based on the first and second linear approximations in relation to the tone level, and the coefficient of the input gradation level, which is the gradient of the third linear approximation, and the third There is provided a correction data forming method for a matrix type liquid crystal display device in which a term which is an intercept of a linear approximation is formed as first and second correction data for each pixel.

According to this, the same operation and effect as the invention described in claim 6 can be achieved. . According to the present invention, the luminance and chromaticity of the liquid crystal cell (10) are measured, and the target luminance of each pixel of the liquid crystal cell is set to R in relation to the input gradation level of the external input image signal. , G, and B are linearly approximated to form a first linear approximation formula, and the measured luminance is linearly approximated for each pixel and for each of R, G, and B in relation to the output gradation level to the liquid crystal cell. A third straight line is formed for each pixel and for each of R, G, and B based on the first and second straight line approximations in relation to the input gray level. The coefficients of the input tone level, which are the gradients of the third linear approximation, and the terms, which are the intercepts of the third linear approximation, respectively, are formed as approximation formulas.
A correction data forming method for a matrix type liquid crystal display device formed for each of G and B is provided.

[0015] With this configuration, substantially the same operation and effect as those of the invention described in claim 7 can be achieved in color display by the liquid crystal cell.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall circuit configuration of a matrix type liquid crystal display device according to the present invention. As shown in FIGS. 1 and 2, the liquid crystal display device includes a liquid crystal panel 10. The liquid crystal panel 10 encloses an antiferroelectric liquid crystal 10c between both electrode substrates 10a and 10b. Polarizing plates 10d and 10e are attached to the outer surfaces of both electrode substrates 10a and 10b.

The electrode substrate 10a is a transparent glass substrate 11
On the inner surface of the glass substrate 11, m color filter layers 12 (made of R, G, B), m transparent conductive films 13, and alignment films 14 are sequentially formed. . On the other hand, the electrode substrate 10b has a transparent glass substrate 15, and on the inner surface of the glass substrate 15, an n-row transparent conductive film 16 and an alignment film 17 are sequentially formed.

Here, the m transparent conductive films 13 and the n transparent conductive films 16 are formed together with the antiferroelectric liquid crystal 10c as shown in FIG.
M × n pixels G11, G12,.
.. Are arranged crossing each other to form Gmn. The m transparent conductive films 13 correspond to the m signal electrodes X1 to Xm shown in FIG. 1, while the n transparent conductive films 16 correspond to the n scan electrodes Y1 shown in FIG. To Yn.

The two polarizing plates 10d and 10e are attached so that their optical axes are set at the positions of crossed Nicols. Thereby, the antiferroelectric liquid crystal 10c is extinguished in its antiferroelectric state. In addition, both electrode substrates 10
The interval between a and 10b is maintained uniformly at, for example, 2 μm by a large number of spacers (not shown). Examples of the antiferroelectric liquid crystal 10c include, for example, those disclosed in
4- (1-trifluoromethylheptoxycarbonylphenyl) -4 'as described in JP 9746
-Octyloxycarbonylphenyl-4-carboxylate. As this kind of antiferroelectric liquid crystal, a mixed liquid crystal obtained by mixing a plurality of these antiferroelectric liquid crystals or a mixed liquid crystal containing at least one kind of antiferroelectric liquid crystal may be employed.

The liquid crystal display device has a control circuit 20, both power supply circuits 30, 40, and a scan electrode drive circuit 5 connected between the power supply circuit 30 and the scan electrodes Y1 to Yn.
0, and a signal electrode drive circuit 60 connected between the power supply circuit 40 and the signal electrodes X1 to Xm. As shown in FIG. 4, the control circuit 20 includes an image data signal processing circuit 21, a frame memory 22, a microcomputer 23, and a line memory 24.

The image data signal processing circuit 21 synchronizes the image data signal from the external circuit with the synchronizing signal (vertical synchronizing signal VSYC and horizontal synchronizing signal HSYC) from the external circuit by R, G and B for each signal by signal processing. Convert to digital image data. The frame memory 22 stores digital image data from the image data signal processing circuit 21 for each of R, G, and B. The microcomputer 23 executes the control program according to the flowchart of FIG. And
The microcomputer 23 receives the synchronizing signal during its execution, forms a timing signal for driving scanning by the scan electrode driving circuit 50, and
0, and corrects data stored in the frame memory 22 based on correction data from a correction data storage circuit described later, and stores the image correction data in the line memory 24. The line memory 24 outputs the stored image correction data to the signal electrode drive circuit 60.

The scan electrode drive circuit 50 selects a plurality of voltages from the power supply circuit 30 based on a timing signal from the microcomputer 23 of the control circuit 20, and selects a plurality of voltages corresponding to the respective states of erase, select, and hold. Are sequentially applied to the scan electrodes Y1 to Yn, and the voltage polarity is switched to positive or negative every time the selection period is performed in order to drive the scan electrodes Y1 to Yn with AC.

The signal electrode drive circuit 60 reads out the stored image correction data from the line memory 24 of the control circuit 20 one line at a time, and as an image data signal in accordance with a plurality of output voltages from the power supply circuit 40, X1
To Xm. The surface luminance meter 110 is
The distribution of the luminance L and the (x, y) chromaticity of the display surface is measured over all the pixels.

In this embodiment, the surface luminance meter 110 is
A CA-1000 type surface luminance meter manufactured by Minolta Co., Ltd. is used. The measurement resolution of the surface luminance meter 110 is 180 on the signal electrode side (direction parallel to the scanning electrode) × 150 on the scanning side (direction parallel to the signal electrode). In other words, this resolution corresponds to every 7 × 7 pixels among all the pixels of the liquid crystal cell 10. Therefore, it is possible to measure the distribution of the luminance L and the (x, y) chromaticity for each 7.times.7 pixel. The luminance and (x, y) chromaticity of the pixel at the i-th row and the j-th column of the liquid crystal cell 10 with respect to the image data signal are represented by L _ij and (x _ij , y _ij ).
Expressed as

In the present embodiment, the liquid crystal display device is
It has 56 gradation levels (8-bit gradation). Therefore, when measuring with the surface luminance meter 110,
As the image data signal, a gray display (, R,
(G and B have the same gray level) gray level m = 0, 3
1, 63, 95, 127, 159, 191, 223, 2
55 types are adopted.

The correction data forming circuit 120 is composed of a microcomputer.
0 executes the correction program according to the flowcharts shown in FIGS. During the execution, the correction data forming circuit 120 performs processing for forming correction data based on the measurement output of the surface luminance meter 110 as follows, and stores the correction data in the correction data storage circuit 130. Remember.

In the correction data storage circuit 130, in step 200 of FIG.
Is approximated by a straight line.

[0028]

## EQU1 ## R _ij (M _Rij ) = P _Rij × M _Rij + Q _Rij where M _Rij is the gradation level of R of the pixel in the i-th row and the j-th column of the input image signal. R _ij (M _Rij ) is R
Is the target luminance at the gradation level M _Rij . Next, in step 210, the actual luminance r _ij (m
_rij ) is obtained based on the output of the surface luminance meter 110 under the condition of m _rij = 0.

Specifically, based on the output of the surface luminance meter 110, that is, the luminance L _ij and the (x _ij , y _ij ) chromaticity,
By converting into the following expression, the actual luminance r _ij (m _rij ) becomes
It is obtained under the condition of m _rij = 0. Where m _rij is R
Represents the input gradation level to the liquid crystal cell 10 (that is, the output gradation level of the signal electrode driving circuit 60).

[0030]

## EQU2 ## r _ij (m _rij ) = 0.41844X _ij −0.1
5866Y _ij -0.08283Z _ij where X _ij = (x _ij / y _ij ) × L _ij , Y _ij = L _ij , and Z _ij = ｛(1-x _ij) -Y
_ij ) / y _ij ｝ × L _ij . Note that these values and Equation 2
Is converted according to the specifications of the surface luminance meter 110.

When the processing in step 210 is completed, a determination of NO is made in step 220. Thereafter, the processing in both steps 210 and 220 is similarly repeated for the remaining gradation levels among the above nine gradation levels. Then, in step 230, the actual luminance characteristic of R is linearly approximated by the following equation (3) using the least square method.

[0032]

R _ij (m _rij ) = P _rij × m _rij + Q _rij Next, at step 240, r _ij (m _rij ) = R
_In order to realize _ij (M _Rij ), the gradation level m _rij is calculated by the following equation (4) from both equations (1) and (3).

[0033]

(Equation 4) This is an equation for correcting the actual gradation level in R to the target gradation level.

[0034] In order to perform the correction by equation of this number 4, by the equation of the following Equation 5 and Equation 6, the correction data P _Rij when the R ^* and Q _Rij ^* is calculated in step 240.

[0035]

## _EQU5 ## P _Rij ^* = P _Rij / P _rij

[0036]

[Equation 6] Q_Rij ^*= (Q_Rij−Q_rij) / P_rij Thereafter, in step 250, the determination is NO.
After that, the processing of steps 210 to 240
It is done sequentially for each element. And in step 250
If the determination is YES, each pair of
Correction data P _Rij ^*And Q_Rij ^*Goes to step 260
And stored in the correction data storage circuit 130.

After the above processing, the correction control program is executed based on the flowchart of FIG. In step 200A of FIG. 6, the target luminance characteristic of G is linearly approximated by the following equation (7).

[0038]

G _ij (M _Gij ) = P _Gij × M _Gij + Q _Gij Here, M _Gij is the gray level of the pixel at the i-th row and the j-th column of the input image signal. G _ij (M _Gij ) is G
_Is the target luminance at the gray level M _Gij . Next, in Step 210A, the actual luminance g of the pixel G at the i-th row and the j-th column with respect to each input image signal data is calculated.
_ij (m _gij ) is obtained based on the output of the surface luminance meter 110 under m _gij = 0.

Specifically, based on the output of the surface luminance meter 110, that is, the luminance L _ij and the (x _ij , y _ij ) chromaticity,
By converting into the following expression, the actual luminance g _ij (m _gij ) becomes
It is obtained under the condition of m _gij = 0.

[0040]

G _ij (m _gij ) = − 0.09117 X _ij +0.
25242Y _ij + 0.01570Z _{ij When} the process in step 210A ends, a determination of NO is made in step 220A.

Thereafter, the processing in both steps 210A and 220A is similarly repeated for the remaining gradation levels among the above nine gradation levels. Then, step 230
In A, the actual luminance characteristic of G is linearly approximated by the following equation (9) using the least square method.

[0042]

G _ij (m _gij ) = P _gij × m _gij + Q _gij Next, in step 240A, r _ij (m _gij ) =
In order to realize R _ij (m _Gij ), a gradation level m _gij is calculated from both equations ( ₇ ) and ( ₉ ) by the following equation (10).

[0043]

(Equation 10) This is an equation for correcting the actual gray level in G to the target gray level.

In order to perform the correction by the equation (10),
The respective correction data P _Gij ^* and Q _Gij ^* for G are calculated in step 240A by the following equations 11 and 12.

[0045]

P _Gij ^* = P _Gij / P _gij

[0046]

Q _Gij ^* = (Q _Gij −Q _gij ) / P _gij Then, in step 250A, it is determined to be NO. Thereafter, the processing of steps 210A to 240A is sequentially performed for each of the remaining pixels. And step 25
If the determination at 0A is YES, each pair of correction data P _Gij ^* and Q _Gij ^* for each of all pixels is stored in the correction data storage circuit 130 at step 260A.

After the above processing, the correction control program is executed based on the flowchart of FIG. In step 200B of FIG. 7, the target luminance characteristic of B is linearly approximated by the following equation (13).

[0048]

## _EQU13 ## where B _ij (M _Bij ) = P _Bij × M _Bij + Q _Bij where M _Bij is the gray level of the pixel B at the i-th row and the j-th column of the input image signal. B _ij (M _Bij ) is B
Is the target luminance at the gradation level M _Bij . Next, in step 210B, the actual luminance b of the pixel B in the i-th row and the j-th column with respect to each input image signal data
_ij (m _bij ) is obtained based on the output of the surface luminance meter 110 under m _bij = 0.

Specifically, based on the output of the surface luminance meter 110, that is, the luminance L _ij and the (x _ij , y _ij ) chromaticity,
4, the actual luminance b _ij (m _bij )
Is obtained under the condition m _{bi j} = 0.

[0050]

## EQU14 ## b _ij (m _bij ) = 0.9092X _ij +0.
When the processing in 00255Y _ij + 0.17858Z _ij step 210B is completed, the determination of NO is made at step 220B.

Thereafter, the processing in both steps 210B and 220B is similarly repeated for the remaining gradation levels among the above nine gradation levels. Then, step 230
In B, the actual luminance characteristic of B is linearly approximated by the following equation (15) using the least square method.

[0052]

B _ij (m _bij ) = P _bij × m _bij + Q _bij Next, at step 240B, B _ij (m _bij ) =
To realize R _ij (M _Bij), the gradation level m _{bi j} from both the numerical formula 13 and the number 15 by the formula for a number 16 is calculated.

[0053]

(Equation 16) This is an equation for correcting the actual gray level in B to the target gray level.

In order to perform the correction by the equation (16),
The respective correction data P _Bij ^* and Q _Bij ^{* for B} are calculated in step 240B by the following equations 17 and 18.

[0055]

## _EQU17 ## P _Bij ^* = P _Bij / P _bij

[0056]

## _EQU18 ## Q _Bij ^* = (Q _Bij -Q _bij ) / P _bij Then, in step 250B, it is determined to be NO. Thereafter, the processing of steps 210B to 240B is sequentially performed for each of the remaining pixels. And step 25
If the determination at 0B is YES, each pair of correction data P _Bij ^* and Q _Bij ^* for each of all pixels is stored in the correction data storage circuit 130 at step 260B.

In this embodiment, since the surface luminance meter 110 and the correction data forming circuit 120 are required during the manufacturing process of the liquid crystal cell 10, they are independent components from the liquid crystal display device. Therefore, the liquid crystal display device is configured by components other than the surface luminance meter 110 and the correction data forming circuit 120 in FIG. Therefore, the storage of each correction data from the correction data storage circuit 130 by the correction data storage circuit 130 is completed at the end of the manufacturing process.

The target luminance according to each of the above equations 1, 7, and 13 may be set so as to suppress display unevenness due to variations in the liquid crystal cell 10, or may be set to a desirable value. It may be. In the embodiment configured as described above, when the image data signal and the synchronization signal are input to the control circuit 20, the image data signal processing circuit 21 of the control circuit 20 converts the image data signal in synchronization with the synchronization signal. The image data is converted into digital image data for each of R, G, and B by signal processing, and
To memorize.

Then, the microcomputer 23 reads the digital image data for R in the frame memory 22 in step 300 under the execution of the control program according to the flowchart of FIG.
Set to _Rij . Then, in step 310,
The correction data _QRij ^* from the correction data storage circuit 130 is multiplied by the gradation level _MRij .

Thereafter, in step 320, the correction data _QRij ^* from the correction data storage circuit 130 is added to the multiplication value _QRij ^* _MRIij . As a result, the gradation level m _rij based on Expression 4 is calculated. After this calculation, in step 330, a timing signal based on the synchronization signal is output to the scan electrode driving circuit 50, and the calculated gradation level m _rij is output to the signal electrode driving circuit 60.
Is output to

Thereafter, in step 300A, the digital image data for G in the frame memory 22 is read and set as the gradation level M _Gij . Next, in step 310A, the correction data Q _Rij from the correction data storage circuit 130 ^* is multiplied by the gray level M _Gij.
Thereafter, in step 320A, the correction data Q _Gij ^* from the correction data storage circuit 130 is multiplied by the multiplication value Q _Gij ^* ×
It is added to M _Gij .

As a result, the gradation level m _gij is calculated based on the equation (10). After this calculation, in step 330A, a timing signal based on the synchronization signal is output to the scan electrode drive circuit 50, and the calculated gradation level m _gij is output to the signal electrode drive circuit 60.
Thereafter, in step 300B, the digital image data of B in the frame memory 22 is read and set to the gradation level M _Bij .

[0063] Next, in step 310B, the correction data Q _Rij from the correction data storage circuit 130 ^* is multiplied by the gray level M _Gij. Then, step 320B
, The correction data Q _Bij ^* from the correction data storage circuit 130 is added to the multiplication value Q _Bij ^* × M _Bij . As a result, the gradation level m _bij is calculated based on the equation (16).

After this calculation, in step 330B,
The timing signal based on the synchronization signal is supplied to the scan electrode driving circuit 5.
At the same time, the calculated gradation level m _bij is output to the signal electrode drive circuit 60. After this output, a determination of NO is made in step 340. Thereafter, the processing of steps 300 to 330B is performed for each of the remaining pixels. The determination in step 340 is YE
In S, the processing of the control program for one screen is terminated.

As described above, when the output from the control circuit 20 to the scan electrode drive circuit 50 and the signal electrode drive circuit 60 is made for one screen, the scan electrode drive circuit 50 scans the scan electrode based on the timing signal from the control circuit 20. The driving of Y1 to Yn is controlled. On the other hand, the signal electrode drive circuit 60 outputs one line of the output of all gradation levels from the control circuit 20 to the signal electrodes X1 to Xm.

As a result, the liquid crystal cell 10 performs display based on the image signal. In this case, each gradation level output from the control circuit 20 to the signal electrode driving circuit 60 is
As described above, since the value is corrected based on the correction data stored in the correction data storage circuit 130, the liquid crystal cell 1
Even if there is a variation in the manufacturing process within 0, a display without display unevenness is obtained without being affected by the variation.
Can be done by

In implementing the present invention, the surface luminance meter 1
Instead of 10, a photodiode may be provided corresponding to each pixel. Also by measuring the luminance of the liquid crystal cell 10, substantially the same operation and effect as described in the above embodiment can be easily achieved. In implementing the present invention, the liquid crystal cell is not limited to the color display using R, G, and B, and the same operation and effects as those of the above embodiment can be achieved even for a monochrome display.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of a matrix type liquid crystal display device according to the present invention.

FIG. 2 is a cross-sectional view of the liquid crystal panel of FIG.

FIG. 3 is a schematic illustration of a pixel in the liquid crystal panel of FIG. 1;

FIG. 4 is a detailed circuit diagram of the control circuit of FIG. 1;

FIG. 5 is a part of a flowchart showing an operation of the correction data forming circuit of FIG. 1;

FIG. 6 is a part of a flowchart showing the operation of the correction data forming circuit of FIG. 1;

FIG. 7 is a part of a flowchart showing an operation of the correction data forming circuit of FIG. 1;

8 is a flowchart showing the operation of the microcomputer of FIG.

[Explanation of symbols]

Reference Signs List 10: liquid crystal cell, 20: control circuit, 23: microcomputer, 30, 40: power supply circuit, 50: scan electrode drive circuit, 60: signal electrode drive circuit, 110: surface luminance meter, 120: correction data formation circuit, 130 ... Correction data storage circuit.

Claims (8)

[Claims] A liquid crystal, a plurality of scanning electrodes (Y1 to Y1)
n) and a liquid crystal cell (10) in which a plurality of matrix-shaped pixels are formed by a plurality of signal electrodes (X1 to Xm).
Correction means (300 to 32) for correcting an external input image signal for each pixel so that the actual luminance based on the variation occurring during the manufacturing process in the liquid crystal cell matches the target luminance.
0, 300A to 320A, 300B to 320B)
Scan electrode drive control means (30, 50, 330, 3) for driving the plurality of scan electrodes while scanning based on a synchronization signal.
30A, 330B) and signal electrode drive control means (40, 6) for outputting the correction result of the correction means as image data to the plurality of signal electrodes in synchronization with the scanning by the scan electrode drive control means.
0, 330, 330A, and 330B), wherein the plurality of pixels perform a matrix display in accordance with both control operations of the scan electrode drive control means and the signal electrode drive control means. 2. A liquid crystal, a plurality of scanning electrodes (Y1 to Y1).
n) and a liquid crystal cell (10) in which a plurality of matrix-shaped pixels are formed by a plurality of signal electrodes (X1 to Xm).
The gradient of a first linear approximation that expresses the target luminance of the liquid crystal cell as a gradation level of an external input image signal as an independent variable, and the actual luminance of the liquid crystal cell is the output gradation level to the liquid crystal cell. And the ratio of the slope of the second straight-line approximation to the difference between the intercepts of the first and second straight-line approximations, respectively, (2) correction data storage means (130) stored for each of the plurality of pixels as correction data, and multiplication means (310, multiplying the gradation level of the external input image signal by the first correction data). 310A, 310B)
Adding means (320, 320A, 320B) for adding the second correction data to the multiplied value by the multiplying means; and scan electrode drive control means (30) for driving the plurality of scan electrodes while scanning based on a synchronization signal. , 50, 330, 3
30A, 330B) and signal electrode drive control means (40, 6) for outputting the addition result of the addition means as image data to the plurality of signal electrodes in synchronization with scanning by the scan electrode drive control means.
0, 330, 330A, and 330B), wherein the plurality of pixels perform a matrix display in accordance with both control operations of the scan electrode drive control means and the signal electrode drive control means. 3. The correction data storage means stores the first and second correction data for each of R, G, and B, and the multiplication means performs the multiplication for each of R, G, and B. 3. The matrix type liquid crystal display device according to claim 2, wherein the adding means performs the addition for each of R, G, and B. 4. The target luminance of a liquid crystal cell having a plurality of pixels in a matrix is represented by a gradient of a first linear approximation formula expressing a gradation level of an external input image signal as an independent variable and an actual luminance of the liquid crystal cell. A ratio between a gradient of a second linear approximation expression representing an output gradation level to the liquid crystal cell as an independent variable;
And the ratio of the gradient of the second linear approximation formula to the difference between the intercepts of the first and second linear approximation formulas is determined based on the variation that occurs in the liquid crystal cell during its manufacturing process. In order to suppress display unevenness, the first and second
A correction data storage device for a matrix type liquid crystal display device, wherein the correction data is stored for each of the plurality of pixels as correction data. 5. The first and second correction data are R,
5. The correction data for each of G and B.
3. A correction data storage device for a matrix type liquid crystal display device according to item 1. 6. The luminance of a liquid crystal cell (10) is measured, and the measured luminance and an external input image signal are applied to the measured luminance and an external input image signal so as to suppress display unevenness of the liquid crystal cell based on a variation generated in a manufacturing process in the liquid crystal cell. A correction data forming method for a matrix-type liquid crystal display device that forms correction data for each pixel based on the correction data. 7. A luminance of the liquid crystal cell (10) is measured, and a target luminance of each pixel of the liquid crystal cell is linearly approximated in relation to an input gradation level of an external input image signal to form respective first linear approximations. The measured luminance is linearly approximated for each pixel in relation to the output gradation level to the liquid crystal cell, and each is formed as a second linear approximation, and the output gradation level is determined in relation to the input gradation level. Based on the first and second linear approximations, a third linear approximation is formed for each pixel, and the input gradation level coefficient, which is the gradient of the third linear approximation, and the third linear approximation. A correction data forming method for a matrix type liquid crystal display device, wherein a term which is an intercept is formed as first and second correction data for each pixel. 8. A luminance and a chromaticity of the liquid crystal cell (10) are measured, and a target luminance of each pixel of the liquid crystal cell is set to a straight line for each of R, G, and B in relation to an input gradation level of an external input image signal. Approximate and respectively form a first linear approximation formula, and the measured luminance is linearly approximated for each pixel and for each of R, G, and B in relation to the output gradation level to the liquid crystal cell, and each of them is defined as a second linear approximation formula. Forming the output gradation level as a third linear approximation for each pixel and for each of R, G, and B based on the first and second linear approximations in relation to the input gray level. The coefficient of the input gradation level, which is the gradient of the third linear approximation, and the term, which is the intercept of the third linear approximation, are used as first and second correction data for each pixel and for R, G, and B. Matrix type liquid crystal display device Correction data forming method of.