JP2005352444A - Liquid crystal display device, color management circuit, and display control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a color management of the whole screen is performed which corrects, in real time, the mutual affections caused by the primary colors in each of the pixels and the inter-pixel affections without using any complicated correction circuits and which includes prevention of cross-talk over the whole screen. <P>SOLUTION: A pixel signal of a predetermined level m to be inputted to a pixel electrode is corrected such that the display brightness obtained by the pixel signal is approximately constant independently of the level of pixel signals to be inputted to adjacent pixel electrodes. Pixel signals of a local color, an adjacent color and a second adjacent color, which is a color adjacent to that adjacent color, are used for a calculation to obtain a signal that is to present the local color. That is, a pixel signal to be inputted to a noticed pixel electrode is corrected by use of the pixel signal to be inputted to the noticed pixel electrode, a pixel signal to be inputted to an adjacent pixel electrode that is adjacent to the noticed pixel electrode in a predetermined direction, and a pixel signal to be inputted to a next adjacent pixel electrode that is adjacent to the foregoing adjacent pixel electrode in the predetermined direction. For example, in a case of obtaining a signal (G<SB>n</SB>)<SB>out</SB>, a signal of a local color (G<SB>n</SB>)<SB>in</SB>, a signal of an adjacent color (B<SB>n</SB>)<SB>in</SB>, and a signal of a next adjacent color (R<SB>n+1</SB>)<SB>in</SB>are used for the calculation using conversion formula 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, a color management circuit for the liquid crystal display device, and a display control method for the liquid crystal display device.

  At present, the spread of liquid crystal display (LCD) is remarkable and has become indispensable as a display device. Along with this, the demand for higher image quality is increasing, and standardization of color management for managing color information is being promoted mainly by the International Electrotechnical Commission (IEC) and the International Color Consortium (ICC).

  There are various means for improving the image quality of the LCD, and the ICC defines a 3 × 3 color conversion matrix method, which is one of them, as a display color correction algorithm. This 3 × 3 color conversion matrix system is the following system for solving the problem that the color balance of the LCD is lost and accurate color display cannot be performed.

In an LCD color model, arbitrary digital signal values CV _r , _g , _b (a value of a certain pixel) and tristimulus values (X, Y, Z) can be expressed by the following relationship. Accordingly, digital signal values (CV _r , CV _g , CV _b ) whose color development on the LCD is tristimulus values (X, Y, Z) can be obtained by calculation.

ｋ（Ｍ）で表されるマトリクスは、任意の色の三刺激値が各原色の三刺激値の和に等しいという加法則と、各原色の三刺激値が任意のデジタル信号値ＣＶに対して比例するという比例則とが成り立つ仮定の下で決められている。ｋ（Ｍ）の各係数値は、入力値と出力値の誤差から最小二乗法によって求められたり、人間の色覚による評価によって最適化して求められたりしている。

The matrix represented by k (M) has an addition rule that the tristimulus values of any primary color are equal to the sum of the tristimulus values of each primary color, and the tristimulus values of each primary color are for any digital signal value CV. It is determined under the assumption that the proportionality rule of proportionality holds. Each coefficient value of k (M) is obtained by the least square method from the error between the input value and the output value, or is obtained by optimization by evaluation based on human color vision.

FIG. 10 is a conceptual diagram of correction by the 3 × 3 color conversion matrix method according to the prior art, in which P _n is the own pixel, P _{n + 1} is an adjacent pixel, and R _n is a red sub-pixel in the own pixel P _n . , G _n are green sub-pixels in the own pixel P _n , B _n is a blue sub-pixel in the own pixel P _n , R _{n + 1} is a red sub-pixel in the adjacent pixel P _{n + 1} , and G _{n + 1} is adjacent A green sub-pixel in the pixel P _{n + 1} , B _{n + 1} is a blue sub-pixel in the adjacent pixel P _{n + 1} , and 50 is a conversion equation for correction. Here, the sub-pixel refers to each of R, G, and B picture elements, and is usually used to display one of the R, G, and B colors. In addition, one sub-pixel is a group of three RGB picture elements. Pixels are formed.

The correction of the 3 × 3 color conversion matrix method according to the prior art is intended for a color (a color expressed by three subpixels) displayed by a certain pixel (P _n or the like). Therefore, an input signal used for the correction is It is limited to signals within the same pixel ( _Pn etc.). For example, for the target pixel P _n, and the matrix calculation subpixels of the input target pixel in _{P n (R n, G n} , B n) the signal _in the conversion formula 50, (R _n, G _n , B _n ) _out is output as a correction signal.

FIG. 11 is a diagram conceptually showing a process in which an observer sees on an LCD through a PC when a tristimulus value is set as an initial value. In the figure, 51 is a PC (personal computer), 52 is an LCD. It is. Tristimulus values (X, Y, Z) ₁ set as initial values based on the above-mentioned 3 × 3 color conversion matrix calculation are converted into digital signals (CVr, CVb, CVg) by an input device such as PC 51, Input to the LCD 52. On the LCD 52, the input (CVr, CVb, CVg) is displayed as (R, G, B), and the observer obtains (R, G, B) as the tristimulus value (X, Y, Z) _2. . Here, (X, Y, Z) ₂ obtained by the observer is ideally the initial tristimulus values (X, Y, Z) set based on the above-mentioned 3 × 3 color conversion matrix calculation. It should be the same as ₁ .

  However, in an actual LCD, there is a mutual influence between the primary colors. One example is crosstalk. Crosstalk will be described by taking a VA (Vertical Alignment) type LCD as an example.

  FIG. 12 is a schematic diagram for explaining a cross-sectional structure of a VA type LCD. In the figure, 61 and 66 are glass substrates, 62 is a counter electrode, 63a and 63b (hereinafter 63) are pixel capacities, and 64a. 64b, 64c (hereinafter 64) are picture element electrodes, 65a, 65b, 65c are TFTs, 67a, 67b, 67c (hereinafter 67) are stray capacitances, and 68a, 68b, 68c are source lines. . The pixel electrode 64 is supported by an insulator (not shown), and the actual liquid crystal is sandwiched between the counter electrode 62 and the pixel electrode 64 and is driven by an electric field by the pixel capacitor 63. The picture element electrodes 64a, 64b, and 64c correspond to, for example, R, G, and B picture elements, respectively.

  Here, in the LCD, when the gate line (not shown) drives the TFT, the voltage of the source line is energized to the pixel electrode through the TFT, and the voltage is held in the pixel capacitor 63 so that the liquid crystal molecules are stored. It is a mechanism to drive and obtain a display screen.

  Here, as shown in the figure, a stray capacitance 67 is generated between the pixel electrode 64 and the source line on the adjacent pixel side. Such a stray capacitance is unavoidably generated because the pixel electrode 64 and the source line 68 are arranged so as to partially overlap each other vertically. For this reason, the state of the source line of the adjacent picture element affects the picture element electrode of the self picture element.

For example, 64a, 64b, the pixel R _n of 64c each pixel P _n, G _n, if assumed to be B _n, R _n is affected by source line 68a which drives the G _n through the stray capacitance 67a. G _n is affected by the source line 68b that drives B _n through the stray capacitance 67b. As described above, unexpected mutual coupling between the R, G, and B channels occurs due to electrical factors such as capacitive coupling generated between the electrode and the source line in the structure of the LCD. In other words, electrical crosstalk. This crosstalk occurs in a specific direction as described above. In other words, in the above example, the color component of the right picture element affects the color component of the left picture element. The direction of influence depends on the arrangement of electrodes and TFTs.

  FIG. 13 illustrates the spectral characteristics of a general color filter. As shown in FIG. 13, the transmittance of the color filter overlaps the primary colors and affects the color purity of the display color. In addition to the wavelength dependency of the light transmittance, it is also induced by optical factors such as leakage light from the polarizing plate. In other words, optical crosstalk.

As one of the conventional correction methods for reducing crosstalk, a crosstalk noise is used by using a look-up table (hereinafter abbreviated as LUT) having a two-dimensional or three-dimensional structure to correct color characteristics peculiar to liquid crystal. A liquid crystal display device that improves color reproducibility by reducing the above has been proposed (see, for example, Patent Document 1). There has also been proposed a plasma addressed display device that prevents changes in luminance, chromaticity, and saturation due to crosstalk and faithfully reproduces luminance and color (for example, see Patent Document 2). ).
JP 2002-41000 A JP 2000-321559 A

Crosstalk occurs due to the various problems described above, and as shown in FIG. 4, although the input level of the self picture element does not change, the display luminance displayed by the influence of the digital signal value CV of the peripheral picture element is high. Due to the change, an error occurs in the display color of the LCD. In such an LCD, the addition law and the proportional law do not hold, and the nonlinearity of the electrical characteristics of the digital signal value CV with respect to chromaticity cannot be expressed by a power of a single constant. Therefore, an appropriate correction value cannot be obtained with the conventional matrix determined under the above-mentioned law. For this purpose, the tristimulus values (X, Y, Z) ₁ set as initial values and the tristimulus values (X, Y, Z) obtained by the observer from the output (R, G, B) of the LCD via an input device such as a PC are used. , Y, Z) ₂ does not match (see FIG. 11).

  In addition, the optimization of the matrix is evaluated based on the measurement value of the display color and the human sense as described above, and is determined by repeatedly feeding it back. The evaluation criteria are unstable and very troublesome. There are problems such as this. At this time, if the sense of the human eye is used as a criterion for evaluation, it is difficult to reduce the display color error over the entire color gamut so that some can be corrected well but others cannot.

Furthermore, although each dot corresponding to each RGB can be physically defined on the liquid crystal panel, the concept of a pixel composed of three RGB is a logical concept. Jump over and exist. For example, a bond between the blue sub-pixel B _n of the own pixel P _n in FIG. 10 and the red sub-pixel R _{n + 1} of the adjacent pixel P _{n + 1.}

Actually, in the general 3 × 3 color conversion matrix method which is one of the conventional correction methods and in the liquid crystal display device described in Patent Document 1, as described with reference to FIG. only are corrected using, for example, the correction value of the blue sub-pixel B _n of the own pixel P _n is calculated using the values of R _n and G _n is a sub-pixel of the target pixel. For this reason, correction for the display color of one pixel is possible, but correction of the influence of peripheral input signals on the display color, such as crosstalk that occurs between the primary colors that jumped over the pixels as described above. Has the problem of not being able to. Further, when a plurality of LUTs are used like this correction circuit, there is a problem that the scale of hardware is increased.

  Furthermore, in the plasma addressed display device described in Patent Document 2, correction is performed using the signals of the picture elements adjacent to the target picture element in consideration of the influence of adjacent picture elements. As a condition for canceling the talk component, an arbitrary picture element is assumed to have a correlation with a picture element of the same color adjacent to one pixel. Therefore, if the difference between the pixel to which the pixel of interest belongs and its neighboring pixels is large, that is, if the signal difference between the pixel of interest and the same color pixel in the neighboring pixel is large, an error (the size of the correction) Error). In addition, when nonlinear processing such as that performed in this correction is performed, the calculation becomes very complicated, and problems such as an increase in circuit scale and delay in processing speed are likely to occur.

  As described above, in the conventional technology, regardless of the signal level of the adjacent picture element, the influence of the signal of the adjacent picture element on the display luminance of the self picture element is corrected, and the adjacent pixel is not caught by the pixel boundary. It is very difficult to correct the influence of the self-picture element on the display luminance of the picture element, and the picture element signal cannot be corrected so as to prevent electrical and optical crosstalk on the entire screen. Further, the conventional technique requires a nonlinear and very complicated correction circuit and a large amount of LUT, and has problems such as an increase in hardware scale and a delay in processing speed.

  The present invention has been made in view of the above-described circumstances, and does not require a complicated correction circuit, and has a simple configuration, the mutual influence of each primary color in the pixel including crosstalk on the entire screen, and the pixel boundary. It is an object of the present invention to provide a liquid crystal display device, a color management circuit for the liquid crystal display device, and a display control method for the liquid crystal display device that can correct the influence between pixels exceeding the above in real time.

  Another object of the present invention is to provide a method for deriving a correction coefficient matrix that can be used for the above-described correction.

  The present invention is constituted by the following technical means in order to solve the above-described problems.

  The first technical means is a liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells, and includes a correction means for correcting a pixel signal input to each pixel electrode, and the correction means includes: The display luminance by the halftone level m pixel signal input to a certain pixel electrode is the pixel signal level input to the adjacent pixel electrode adjacent to the pixel electrode in a predetermined direction, and the adjacent pixel The pixel signal input to the pixel electrode is corrected so as to be substantially constant regardless of the level of the pixel signal input to the adjacent pixel electrode adjacent to the electrode in the predetermined direction. And

According to a second technical means, the pixel electrode is composed of electrodes representing primary colors of red, green and blue, and the correcting means is white, red, and white based on a pixel signal of a halftone level m in each primary color. When the display brightness of green and blue is W _m , R _m , G _m , and B _m , the pixel signal input to the pixel electrode is corrected so that W _m ≈R _m + G _m + B _m is satisfied. It is characterized by doing.

  According to a third technical means, the correction means includes a pixel signal input to the target pixel electrode, and a pixel signal input to an adjacent pixel electrode adjacent to the target pixel electrode in a predetermined direction. Generating a correction signal for the pixel signal input to the pixel electrode of interest from the pixel signal input to the adjacent contact electrode adjacent to the adjacent pixel electrode in the predetermined direction. And

  According to a fourth technical means, the correction means performs 1 × 3 color conversion using each pixel signal input to each of the target pixel electrode, the adjacent pixel electrode, and the adjacent pixel electrode. By performing a matrix operation, a correction signal for the pixel signal input to the pixel electrode of interest is generated.

  A fifth technical means is a color management circuit of a liquid crystal display device having a picture element electrode corresponding to each of the liquid crystal cells, and includes a correction means for correcting a picture element signal inputted to each picture element electrode, The display unit is configured such that the display luminance by the pixel signal of the halftone level m input to a certain pixel electrode is input to an adjacent pixel electrode adjacent to the pixel electrode in a predetermined direction, and The pixel signal input to the pixel electrode is corrected so as to be substantially constant regardless of the level of the pixel signal input to the adjacent pixel electrode adjacent in the predetermined direction of the adjacent pixel electrode. It is characterized by doing.

  A sixth technical means is a display control method for a liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells, and when correcting a pixel signal input to each pixel electrode, a certain pixel electrode The display luminance by the pixel signal of the halftone level m input to the pixel signal level input to the adjacent pixel electrode adjacent in the predetermined direction of the pixel electrode and the predetermined of the adjacent pixel electrode The pixel signal input to the pixel electrode is corrected so as to be substantially constant regardless of the level of the pixel signal input to the adjacent pixel electrode adjacent in the direction.

  According to the present invention, the influence of each primary color (each picture element) within a pixel, including crosstalk on the entire screen, and the influence between pixels beyond the pixel boundary, including crosstalk with respect to the entire screen, with a simple configuration without requiring a complicated correction circuit. Can be corrected in real time.

  In the liquid crystal display device and the color management circuit thereof according to the present invention, this influence is corrected in view of the fact that the display color of the pixel of the LCD having the pixel electrode corresponding to each of the liquid crystal cells is affected by various surrounding effects. Therefore, correction means for correcting the pixel signal input to the pixel electrode corresponding to each of the liquid crystal cells in the LCD without being bound by the pixel boundary is introduced. This correction means is a means for generating a correction signal from which the influence of adjacent picture elements is removed from the pixel signal input to the picture element electrode corresponding to each liquid crystal cell in the LCD, and is also called a correction signal generation means. .

  In the present invention, the following correction means I and / or correction means II are introduced in order to correct the influence of adjacent picture elements.

  The corrector I corrects the picture so that the display luminance of a picture element signal of a predetermined level m inputted to a certain picture element electrode becomes substantially constant regardless of the picture element signal level inputted to the neighboring picture element electrode. This is a means for correcting the pixel signal input to the element electrode. That is, the picture element signal corrected by the correction means I is output as being substantially constant regardless of the signal of the adjacent picture element at least near the predetermined level m. Therefore, the correction means I may be any correction that takes into account at least the input pixel signal to the adjacent pixel electrode. The correcting means I is configured so that the display brightness of a pixel signal of a predetermined level m input to a certain pixel electrode is substantially constant regardless of the level of the pixel signal level input to the adjacent pixel electrode. It is preferable to correct the pixel signal input to each pixel electrode with a correction coefficient calculated based on the actually measured luminance value at level m.

  The correcting means II includes a pixel signal input to the target pixel electrode, a pixel signal input to an adjacent pixel electrode adjacent to the target pixel electrode in a predetermined direction, and the adjacent pixel electrode On the other hand, it is a means for generating a correction signal for the pixel signal input to the pixel electrode of interest from the pixel signal input to the adjacent contact electrode adjacent in the same predetermined direction. That is, when correcting the pixel signal to the target pixel electrode, the correction unit II considers not only the adjacent pixel electrode but also the pixel signal to the adjacent pixel electrode.

  Further, the present invention can be realized as a liquid crystal display device provided with the correction means as described above, or a color management circuit provided with the correction means, or a liquid crystal display device provided with this circuit or an external of the liquid crystal display device. It may be realized as a device. Hereinafter, only the color management circuit having this correction means and the liquid crystal display device including this circuit will be described, but the following description can be applied to other cases. Furthermore, the present invention also has a form as a display control method in the liquid crystal display device, and this method controls display on the display panel by the correction processing in the correction means described above, and the description below is also diverted. it can.

  Further, in describing the correction means I described above, in addition to the correction means I taking into account the input pixel signal to the adjacent picture element electrode, actually, the input picture element to the adjacent picture element electrode is used. Since the signal is also influenced by the input pixel signal to the adjacent pixel electrode (the adjacent pixel electrode of the pixel electrode of interest), an embodiment that takes this into consideration is illustrated. Since this embodiment can be realized by adopting, for example, the correction unit II described above, first, various embodiments related to the correction unit II will be described first, and in the calculation, the correction coefficient matrix is calculated. The description will focus on an embodiment (an embodiment in which the correction means I and II are used in combination) that realizes that “the display luminance by the pixel signal of the predetermined level m is substantially constant” in the correction means I. However, the present invention can be realized not only by the correction means alone, but also by the correction means I alone, which will be described later, and in this case, the following description can be used.

FIG. 1 is a diagram for conceptually explaining correction in a color management circuit according to an embodiment of the present invention. In FIG. 1, P _n is an own pixel, P _{n + 1} is an adjacent pixel, and R _n is an own pixel. red subpixels in P _n, G _n are green sub-pixels in its own pixel P _n, B _n subpixel of the blue in the own pixel P _n, R _{n + 1} is the red color of the adjacent pixels P _{n + 1} sub-pixel , G _{n + 1} is a green sub-pixel in the adjacent pixel P _{n + 1} , B _{n + 1} is a blue sub-pixel in the adjacent pixel P _{n + 1} , 1 is a correction conversion formula for the sub-pixel R _n , and 2 is a sub-pixel A conversion equation for correction for the pixel G _n , 1 is a conversion equation for correction for the sub-pixel B _n . In the conversion formulas 1, 2, and 3, R, G, B, (R) _in , (G) _in , (B) _in are input signals, (R) _out , (G) _out , (B) “ _out” indicates an output signal after the matrix calculation (a pixel signal to be input to each pixel electrode).

The color management circuit according to the present invention is a circuit that is incorporated in a liquid crystal display device in which a display area is formed of a liquid crystal cell or an external device connected to the liquid crystal display device, and does not depend on each peripheral device to be used. This is hardware for obtaining consistent color reproduction (some of which may be configured by software) and may be mounted on a system LSI. This color management circuit inputs, for example, image data (R, G, B) _in expressed in three colors of red, green, and blue, corrects the image data, and each liquid crystal cell (each liquid crystal in the LCD). Output to the cell corresponding to each pixel electrode).

  In the color management circuit according to the embodiment of the present invention, the correction signal generation means (correction means II described above) uses the input signal value as the value of the input color signal, the adjacent color picture element signal, and the adjacent ones. The signal of the color to be displayed is obtained by using the pixel signal of the touching color for calculation. This correction signal generation means includes a pixel signal of a target pixel electrode (self-colored pixel signal) that is a target pixel electrode, and an adjacent picture that is a pixel electrode adjacent to the target pixel electrode in a predetermined direction. A pixel signal input to a pixel electrode and a pixel signal input to a neighboring contact electrode that is also adjacent to the adjacent pixel electrode in the predetermined direction are input to the target pixel electrode. A correction signal for the pixel signal is generated.

  In this way, since the signals used for the correction processing are signals of adjacent colors and adjacent colors, the influence of jumping over the boundary between pixels can be corrected, and color management of the entire screen is possible. Also, the correction signal is calculated from the signal value of the adjacent picture element that affects the own pixel, and the signal of the adjacent picture element can be treated as a value that takes into account the influence of the adjacent picture element. It becomes possible to perform correction | amendment with respect more accurately.

Further, the correction signal generating means performs a 1 × 3 color conversion matrix operation using each pixel signal input to each of the target pixel electrode, the adjacent pixel electrode, and the adjacent pixel electrode, thereby performing the target pixel element. It is preferable to generate a correction signal for the pixel signal input to the electrode. For example, when the signal (Rn) _out is obtained, the self-color signal (Rn) _in , the adjacent color signal (G _n ) _in , and the adjacent color signal (B _n ) _in are used. Calculate by Similarly, when obtaining the signal (G _n ) _out , the self-color signal (G _n ) _in , the adjacent color signal (B _n ) _in , and the adjacent color signal (R _{n + 1} ) _in are used. Thus, the calculation is performed according to the conversion formula 2. When obtaining the signal (B _n ) _out , the self-color signal (B _n ) _in , the adjacent color signal (R _{n + 1} ) _in , and the adjacent color signal (G _{n + 1} ) _in are used. The calculation is performed according to the conversion formula 3. The calculation coefficients of the 1 × 3 color conversion matrix calculation shown in the conversion formulas 1, 2, and 3 are (a, b, c), (d, e, f), (g, h, i) in this example. Yes. In this way, when the pixel electrode of interest is an electrode that expresses red, an electrode that expresses green, or an electrode that expresses blue, 1 × 3 colors It is preferable to vary the calculation coefficient of the conversion matrix calculation.

  In this way, by assigning individual values to the matrix calculation calculation coefficients for each primary color, it is possible to cope with the case where the luminance that varies due to the influence of adjacent picture elements differs for each primary color, and more accurate display Brightness can be obtained.

  Further, the calculation example shown here is a preferred example in which the predetermined direction is determined in consideration of the influence direction of crosstalk. In the LCD having the structure as shown in FIG. The direction opposite to the direction toward the source line arranged for supplying the pixel signal to the electrode is preferably determined as the predetermined direction. That is, as shown in FIG. 1, the predetermined direction is the direction of the adjacent picture element on the side on which the target picture element is affected by the crosstalk, and the adjacent picture element is the picture element in which the target picture element affects the crosstalk. It is. As a result, the influence on the luminance of the self-picture element received from the signal of the adjacent picture element for each picture element can be captured, and an accurate correction value can be obtained. Further, the pixel of interest is continuously calculated while being sequentially shifted in the direction in which a signal is input to the display device, and is processed in real time without impairing the drawing speed of the display device.

FIG. 2 is a block diagram showing a circuit configuration example of a color management circuit according to another embodiment of the present invention. In FIG. 2, 10 is a color management circuit, 11 is a pixel acquisition circuit, 12 is a matrix coefficient storage memory, 13 _R , 13 _B and 13 _G are product-sum operation circuits, 21 is a synchronization signal generation circuit, 22 is a timing control circuit (TC), 23 is a source driver, 24 is a gate driver, and 25 is a TFT (Thin Film Transistor) -LCD. .

3 is a diagram showing details of the product-sum operation circuit and the LCD in the color management circuit of FIG. 2, FIG. 3A shows the product-sum operation circuit, and FIG. 3B shows a part of the liquid crystal of the TFT-LCD. Each cell is illustrated. In the figure, 13 is a product-sum operation circuit, 14 is a coefficient selector, 15 _R , 15 _B and 15 _G are multipliers for R (R ′) signal, G (G ′) signal and B signal, respectively. Is an adder.

In another embodiment of the present invention illustrated in FIGS. 2 and 3, the correction signal generating means includes a pixel acquisition circuit (hereinafter referred to as an adjacent pixel acquisition circuit) 11, a coefficient storage memory 12, a first product-sum operation. It is assumed that a circuit 13 _R , a second product-sum operation circuit 13 _G , and a third product-sum operation circuit 13 _B are provided.

The coefficient storage memory 12 is a memory for storing calculation coefficients of 3 × 3 color conversion matrix calculation. The adjacent picture element acquisition circuit 11 is a circuit that sequentially acquires picture element signals input to the picture element electrodes. The first product-sum operation circuit 13 _R , the second product-sum operation circuit 13 _G , and the third product-sum operation circuit 13 _B are circuits that perform a product-sum operation, and receive correction signals for R, G, and B, respectively. It will be exemplified as one for calculating.

The first product-sum operation circuit 13 _R outputs a pixel signal of interest, which is an input signal to the pixel of interest electrode 25a among the pixel signals acquired by the adjacent pixel acquisition circuit 11, and a pixel pixel 25b. An adjacent picture element signal that is an input signal and an adjacent picture element signal that is an input signal to the adjacent picture element electrode 25c are input, and the respective picture element values are stored in the coefficient storage memory 12. Multiply by the operation coefficient M (n, 1) in the first row and add and output as a correction signal for the pixel signal of interest. Similarly, the second product-sum operation circuit 13 _G corresponds to the pixel electrode corresponding to the adjacent pixel electrode 25 b in the first product-sum operation circuit 13 _R among the pixel signals acquired by the adjacent pixel acquisition circuit 11. , A target pixel signal that is an input signal to the target pixel electrode 25b, an adjacent pixel signal that is an input signal to the adjacent pixel electrode 25c of the target pixel electrode 25b, and Next, adjacent pixel element signals that are input signals to adjacent pixel electrode electrodes (not shown) of the target pixel electrode 25b are input, and the respective pixel values are stored in the coefficient storage memory 12. Multiply and add the operation coefficients M (n, 2) in the second row, and output as a correction signal for the target pixel signal for the target pixel electrode 25b. Further, the third product-sum operation circuit 13 _B selects a pixel electrode corresponding to the adjacent pixel electrode 25 c in the second product-sum operation circuit 13 _G out of the pixel signals acquired by the adjacent pixel acquisition circuit 11. In the case of the target pixel electrode, the target pixel signal that is an input signal to the target pixel electrode 25c and the adjacent picture element that is an input signal to an adjacent pixel electrode (not shown) of the target pixel electrode 25c A signal and an adjacent pixel signal that is an input signal to an adjacent pixel electrode (not shown) of the pixel electrode 25c of interest are input to the coefficient storage memory 12 for each pixel value. The stored operation coefficient M (n, 3) in the third row is multiplied and added, and the result is output as a correction signal for the target pixel signal for the target pixel electrode 25c.

In the example shown in FIGS. 2 and 3, the color management circuit 10 includes the picture element acquisition circuit 11, the matrix coefficient storage memory 12, and the product-sum operation circuits 13 _R , 13 _G , and 13 _B as described above. As shown in FIG. 3A, the circuit 13 includes a coefficient selector 14 for selecting a coefficient to be multiplied by a multiplier from matrix coefficients in the matrix coefficient storage memory 12, and an R (R ′) signal multiplier 15R, A G (G ′) signal multiplier 15 _G , a B signal multiplier 15 _B, and an adder 16 summing the outputs of the multipliers 15 _R , 15 _G , and 15 _B are provided.

  Since these circuits are simple circuits that do not require a large amount of LUTs and non-linear complex calculations, the scale of the hardware can be small. Further, since the liquid crystal display panel itself does not need to be improved, the cost can be reduced. Furthermore, since the hardware is small, the processing speed is high and no delay occurs with respect to the input signal.

This liquid crystal display device generates a timing control circuit (TC) 22 for inputting the outputs of the product-sum operation circuits 13 _R , 13 _B , and 13 _{G in} the color management circuit 10 and a synchronization signal used for control in the TC 22. The synchronizing signal generating circuit 21, the source driver 23, the gate driver 24, and the TFT-LCD 25 are configured. Here, the outputs of the product-sum operation circuits 13 _R , 13 _B and 13 _G input to the TC 22 are controlled in timing to control the source driver 23 and the gate driver 24, and each pixel electrode in the TFT-LCD 25 is controlled. Control the drive.

As shown in FIG. 3B, on the active matrix substrate of the TFT-LCD 25, a plurality of pixel electrodes 25a, 25b, 25c, etc. (hereinafter referred to as 25 ') are formed in a matrix. The pixel electrodes 25 'are connected to TFTs 28a, 28b, 28c and the like (hereinafter referred to as 28) which are switching elements. The gate electrode of the TFT 28 is connected to gate wirings (gate lines) 27 ₁ and 27 ₂ (hereinafter referred to as 27) for supplying scanning signals, and the TFT 30 is driven and controlled by the gate signal input to the gate electrode. Is done.

  Further, source wirings (source lines) 26a, 26b, 26c and the like (hereinafter referred to as 26) for supplying a display signal (data signal) are connected to the source electrode of the TFT 30, and when the TFT 30 is driven, the display signal is displayed. Is input to the pixel electrode 25 ′ through the TFT 30. The gate lines 27 and the source lines 26 are provided so as to pass through the periphery of the pixel electrodes 25 ′ arranged in a matrix and to be orthogonal to each other. Further, the drain electrode of the TFT 30 is connected to the pixel electrode 25 '.

  Next, in the color management circuit according to each of the above-described embodiments, a 3 × 3 color conversion matrix (corresponding to a 1 × 3 color conversion matrix for each picture element) is determined together with a preferable correction signal generation process. A method will be described. In the matrix determination method described here, first, the influence of the color to be originally displayed and the adjacent color on the own color is measured by paying attention to the display luminance, and converted into a numerical value as a level difference. Then, a 3 × 3 color conversion matrix is obtained by simple calculation based on this value.

<Color conversion (correction signal generation)>
First, color conversion will be described again. In this embodiment, in order to correct the mutual influence of each primary color and the influence between pixels, and to enable color management of the entire screen, the input value is independent of the pixel boundary, and the own color For the conversion, the input levels of the adjacent color and the adjacent color that are influencing the crosstalk are used for the conversion. In the case of a pixel at the screen end, the input level of each picture element of an adjacent pixel may be handled as 0.

For example, when receiving the influence of crosstalk from the right direction, the input signal of its own pixel is (R ₁ , G ₁ , B ₁ ) _in and the input signal of the right pixel is (R ₂ , G ₂ , B ₂ ) _in. When an arbitrary matrix is A (M), output values (R ₁ , G ₁ , B ₁ ) _out after correction by A (M) are obtained by the following calculation. Output values of R ₁ may be calculated using the input values _{(R 1, G 1, B} 1) in. G ₁ uses R ₂ of the adjacent pixel and calculates the input value as (R ₂ , G ₁ , B ₁ ) _in . Similarly, in B ₁ , an output value is obtained by using (R ₂ , G ₂ , B ₁ ) _in for calculation. Next to B ₁ , the output of the adjacent picture element R ₂ is obtained.

このように、各絵素にクロストークの影響を及ぼしている右方向へ常にスライドさせながら演算に使用する入力値を設定する（図１を参照）。すなわち、補正信号生成手段は、着目画素電極をソース信号の流れる方向へ順番にずらし、補正信号を生成するとよい。逆に、左から影響を受ける場合は左へスライドさせるとよい。この色変換は、加減算及び掛け算のみの簡単で小規模な演算によって補正後の信号を得ることが可能である。

In this way, the input value used for the calculation is set while always sliding in the right direction which has an influence of crosstalk on each picture element (see FIG. 1). That is, the correction signal generation unit may generate the correction signal by sequentially shifting the pixel electrode of interest in the direction in which the source signal flows. Conversely, if you are affected from the left, slide it to the left. In this color conversion, it is possible to obtain a corrected signal by a simple and small-scale calculation including only addition and subtraction and multiplication.

<Determination of matrix A (M)>
[Calculation of correction coefficient]
4 is a graph showing the influence (before correction) of the input level of the adjacent color B on the display luminance with respect to the input level of G, and FIG. 5 shows an enlarged view and a linear approximation in the vicinity of the reference level of FIG. FIG. 6 is a graph showing the amount of change (difference) from the reference level of the own color G with respect to the input level of the adjacent color B. FIG. Here, although 256 gradations are exemplified, the present invention is not limited to this.

  In order to determine the correction coefficient necessary for calculating the matrix calculation coefficient, the input level of the target own color and the input level of the adjacent color as a reference are arbitrarily set. FIG. 4 shows the measurement of luminance characteristics of a certain LCD, and shows the influence of the display luminance with respect to the input level of the primary color on the input level of adjacent picture elements. In FIG. 4, the line for measuring the display luminance when the input level of G is 0 to 255 in a state where B is 0 is L_B0, and similarly, the line of G when B is 64, 128, 192, 255 L_B64, 128, 192, and 255 represent lines for measuring display luminance when the input level is 0 to 255 levels, respectively. In the setting of this example, the luminance difference is maximum at the input level 136, the input level 136 having the maximum luminance difference is set as the target level, that is, the predetermined input level m, and the input level of the adjacent color is The case of 0 is used as a reference.

In FIG. 5, the slope of the linear approximation indicates a change in display luminance with respect to a change in one level in the input signal of the own color. In this example, the slope of the approximate straight line is 1.3547 (cd / (cm ² · level)), and the intercept is −117.47 (cd / cm ² ). From this value, the amount of change relative to the display luminance reference due to the change in adjacent picture elements is converted into a level and plotted. This is shown in FIG. That is, the slope (0.0579) in FIG. 6 represents the influence on the display brightness of the own color, which is caused by a change in one level in the input signal of the adjacent color. This value is used as a correction coefficient for the primary color G, and is set for each primary color by the same method.

[Calculation of matrix calculation coefficients]
FIG. 7 is a conceptual diagram of the correction by the correction coefficient and the error after the correction. FIG. 8 is a conceptual diagram of the correction by the adjacent and adjacent calculation coefficients.

The output after correcting the influence of the adjacent color by the correction coefficient is not an appropriate correction for the output of the adjacent color after correction. The output level error due to the correction of the adjacent color is corrected by the adjacent color calculation coefficient. If the self color was R, Ng correction coefficient correction factors a R _out R _out2, R Nr, the G at the time of the R _out R _out1, G _out when the G _in, the correction coefficient B Nb Then, it can be expressed as follows.

R _out1 = (aR _in −NrG _in )
R _out2 = (aR _in −NrG _out )
The correction error that occurs during output is as follows.

_{R out1 -R out2 = (aR in} -NrG in) - (aR in -NrG out)
= Nr (G _out -G _in )
Since G _out = (eG _in −NgB),
_{R out1 -R out2 = Nr {(} eG in -NgB in) -G in}
= Nr (e-1) G _in -NrNgB _in
Therefore, an expression for correcting this error after correcting the influence of the adjacent color with the adjacent color calculation coefficient is given by the following expression.

R _out = R _out1 − (R _out1 −R _out2 )
_{= AR in -NrG in - {Nr} (e-1) G in -NrNgB in}
= AR _in -NreG _in + NrNgB _in
Similarly, G and B are given by the following equations.

G _out = NgNbR _in −eG _in + NgiB _in
B _out = NbaRin−NrNbG _in + iB _in
From the above, the adjacent calculation coefficients are b = Nre, f = Ngi, and g = Nba, and the adjacent calculation coefficients are c = NrNg, d = NgNb, and h = NrNb.

The display color shall not be achromatic. Therefore, when R _in = G _in = B _in , it is necessary that R _out = G _out = B _out . The conditions that satisfy this are as follows, where K is an arbitrary real number.

a + b + c = K
d + e + f = K
g + h + i = K
In particular, when K = 1, R _in = R _out , G _in = G _out , and B _in = B _out are satisfied, and white (255, 255, 255) luminance (example of 256 gradations) is stored. it can.

  As described above, nine values of the 3 × 3 color conversion matrix are determined by designating the target level (predetermined level m) in the input picture element signal and obtaining three correction coefficients from the display luminance measurement result. This color conversion matrix can be applied regardless of whether the proportionality law or the addition law is established.

Further, when correction is not performed, each primary color is affected by adjacent picture elements. For example, in the case of R, display luminance R _m ′ when the adjacent picture element G is displayed at an arbitrary input level m. And the display brightness (display brightness when the input level of G is 0) R _m in the state of being displayed independently did not match. For this reason, the white luminance W _m when all the primary colors are displayed at the input level m and the total value of the luminances R _m , G _m , and B _m when each primary color is displayed alone are: Did not match. That is, in the case of R, R _m ′ ≠ R _m , in the case of G, G _m ′ ≠ G _m , and in the case of B, B _m ′ ≠ B _m , so that W _m ≠ R _m + G _m + B _m .

However, since the correction according to the present invention as described above can cancel the influence of the adjacent picture element on the self picture element, the display brightness R _m ′ of the picture element R when the adjacent picture element G is displayed is displayed. When the picture element R is displayed alone (the input level of the adjacent picture element G is 0), the display brightness R _m is substantially equal. This also holds true for G and B. Therefore, the following equation is established by the correction according to the present invention.

R _m ′ ≈R _m
G _m ′ ≒ G _m
B _m ′ ≒ B _m
Therefore, at any input level m, each primary color can always obtain a constant display luminance regardless of the value of the input level of the adjacent picture element, so that the following equation can be satisfied. Become.

W _m ≈R _m ′ + G _m ′ + B _m ′ ≈R _m + G _m + B _m
FIG. 9 is a diagram illustrating the influence (after correction) of the display luminance on the input levels due to the input levels of adjacent colors. FIG. 9 shows a graph after correction when K = 1, but the luminance difference due to the influence of the peripheral pixel signal existing near the target (input level 136) is dispersed to the color gamut other than the target. I understand that

  According to such a method, when the input signal of the self-picture element is near the predetermined level m, the influence from the peripheral picture elements is corrected, and the self-picture element regardless of the input level of the adjacent picture elements. The luminance displayed by the picture element can be made constant. Further, the display brightness of achromatic colors such as white, gray, and black for the predetermined level m can be matched with the total display brightness of each primary color for the predetermined level m, and the achromatic color due to the change of the display brightness of the primary color Therefore, it is possible to display with a certain chromaticity.

  In addition, the correction coefficient is set based on the measured value of the display brightness at the target level m without being caught under the conditions of addition law or proportional law, so that any color gamut displayed on any monitor can be corrected. It is. Here, by setting an arbitrary color gamut to a region where human vision is sharp (near halftone), the display color error is dispersed in a region where human visual sensitivity is low and influence on monitor visual performance is small. Is possible. In addition, by setting an arbitrary color gamut to a region where the display luminance error due to the influence of adjacent picture elements is the maximum value, the error that is unevenly distributed in a specific color gamut is averaged over all color gamuts. And the maximum error can be reduced.

  Note that if the region where the human vision is sharp and the region where the display luminance error due to the influence from adjacent picture elements does not coincide with the maximum value, the input picture of the predetermined level m is adjusted by adjusting the correction strength. It is possible to correct the display color error over the entire color gamut while maintaining the display luminance of the raw signal substantially constant (suppressing the error within a predetermined range), and to improve the display characteristics as a total. it can.

  Furthermore, the matrix can derive all nine arithmetic coefficients by simple calculation using correction coefficients, so it does not require complicated processing such as evaluation relying on human color vision and fine adjustment by feedback, and in a short time. Therefore, after the display panel is completed, an arbitrary matrix can be given to the coefficient storage memory 12 in FIG. 2 in a short time, and the characteristics of each LCD can be dealt with.

  The present invention is not limited to an LCD that performs three primary color displays as in the above-described embodiment. For example, in the case of displaying six primary colors, a 6 × 3 matrix is set. By setting the matrix structure according to the number of primary colors, the same applies to an LCD using a single color and a large number of primary colors. Can be corrected.

  As described above, in the embodiment of the present invention, a liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells, comprising correction means for correcting a pixel signal input to each pixel electrode, The correction means is configured so that the display luminance by a pixel signal of a predetermined level m input to a certain pixel electrode is substantially constant regardless of the pixel signal level input to the adjacent pixel electrode. This corrects the pixel signal input to the pixel electrode.

  According to this, since correction of the input signal of the self picture element is performed so as to remove the influence of the adjacent picture element on at least the self picture element in the vicinity of the predetermined level m, a predetermined level m is determined and a simple process corresponding to the level is performed. It is possible to maintain the luminance displayed by the own picture element at a desired level with a very simple configuration and processing that only requires calculation, regardless of fluctuations in the input signal level of adjacent picture elements.

In addition, the picture element electrodes are composed of electrodes expressing the primary colors of red, green, and blue, and the correction means displays white, red, green, and blue display luminances based on picture element signals of a predetermined level m in the respective primary colors. Is a pixel signal input to the pixel electrode so as to satisfy W _m ≈R _m + G _m + B _m , where W _m , R _m , G _m and B _m respectively.

  According to this, in addition to the above-described effects, it is possible to prevent achromatic coloring caused by the change in luminance of each primary color when displaying the three primary colors, and display with substantially constant chromaticity. Become.

  Further, the predetermined level m may be near a luminance value with high human visibility.

  According to this, in addition to the above-described effects, it is possible to disperse the error to a region where the human visual sensitivity is dull and the influence on the monitor performance is small, and the visual characteristics of the monitor can be improved.

  Further, the predetermined level m may be near a luminance value at which the influence from the adjacent pixels is maximized.

  According to this, in addition to the above-described effects, errors that are unevenly distributed in a specific color gamut can be averaged over all the color gamuts, and the display characteristics of the monitor can be improved.

  Further, the correction means includes a pixel signal input to the target pixel electrode, a pixel signal input to an adjacent pixel electrode adjacent to the target pixel electrode in a predetermined direction, and the adjacent pixel element. A correction signal for the pixel signal input to the pixel electrode of interest is generated from the pixel signal input to the adjacent contact electrode adjacent to the electrode in the predetermined direction.

  According to this, in addition to the above-described effects, it is possible to calculate a correction value based on adjacent picture elements that affect the target picture element (self picture element) without being bound by the pixel boundary. Furthermore, by treating the input signals of adjacent picture elements as values that take into account the influence of adjacent picture elements, it is possible to more accurately correct the self picture elements.

  Further, the correction means performs a 1 × 3 color conversion matrix calculation using each pixel signal input to each of the target pixel electrode, the adjacent pixel electrode, and the adjacent pixel electrode. Thus, a correction signal for the pixel signal input to the pixel electrode of interest is generated.

  According to this, in addition to the above-described effects, an LUT or complicated calculation is not required, and the influence of the adjacent pixel signal on the target pixel (self-picture element) is calculated and displayed with a simple circuit configuration. The brightness can be corrected.

  Further, the 1 × 3 color conversion matrix calculation is performed for each of the case where the pixel electrode of interest is an electrode expressing red, an electrode expressing green, and an electrode expressing blue. The calculation coefficient of is different.

  According to this, in addition to the above-described effects, it is possible to provide a correction value suitable for each primary color having a different display luminance value.

  The liquid crystal display device includes a pixel electrode corresponding to each of the liquid crystal cells, and includes a correcting unit that corrects a pixel signal input to each pixel electrode. An input pixel signal, a pixel signal input to an adjacent pixel electrode adjacent to the target pixel electrode in a predetermined direction, and an adjacent pixel electrode adjacent to the adjacent pixel electrode in the predetermined direction A correction signal for the pixel signal input to the pixel electrode of interest is generated from the pixel signal input to the contact electrode.

  According to this, it is possible to calculate the correction value based on the neighboring picture element that affects the target picture element (self picture element) without being bound by the pixel boundary. Furthermore, by treating the input signals of adjacent picture elements as values that take into account the influence of adjacent picture elements, it is possible to more accurately correct the self picture elements.

  Further, the correction means performs a 1 × 3 color conversion matrix calculation using each pixel signal input to each of the target pixel electrode, the adjacent pixel electrode, and the adjacent pixel electrode. Thus, a correction signal for the pixel signal input to the pixel electrode of interest is generated.

  According to this, in addition to the above-described effects, an LUT or complicated calculation is not required, and the influence of the adjacent pixel signal on the target pixel (self-picture element) is calculated and displayed with a simple circuit configuration. The brightness can be corrected.

  Further, the 1 × 3 color conversion matrix calculation is performed for each of the case where the pixel electrode of interest is an electrode expressing red, an electrode expressing green, and an electrode expressing blue. The calculation coefficient of is different.

  According to this, in addition to the above-described effects, it is possible to provide a correction value suitable for each primary color having a different display luminance value.

  In addition, the correction unit stores a coefficient storage memory that stores calculation coefficients of 3 × 3 color conversion matrix calculation, a pixel element acquisition circuit that sequentially acquires a pixel signal input to each pixel electrode, and the pixel acquisition Of the pixel signals acquired by the circuit, the target pixel signal input to the target pixel electrode, the adjacent pixel signal input to the adjacent pixel electrode, and the adjacent pixel electrode The adjacent pixel element signals are input, multiplied by the operation coefficient of the first row stored in the coefficient storage memory and added to each pixel signal, and output as a correction signal for the target pixel signal. Of the pixel signals acquired by the first product-sum operation circuit and the pixel acquisition circuit, the pixel electrode corresponding to the adjacent pixel electrode in the first product-sum operation circuit is set as the pixel electrode of interest. Signal pixel signal input to the pixel electrode of interest and the pixel electrode of interest An adjacent pixel signal input to an adjacent pixel electrode and an adjacent pixel signal input to an adjacent pixel electrode of the target pixel electrode are input, and the coefficient is stored in each pixel signal. Obtained by a second product-sum operation circuit that multiplies and adds the operation coefficient of the second row stored in the memory and outputs the result as a correction signal of the target pixel signal for the target pixel electrode, and the pixel acquisition circuit Of the pixel signals, when the pixel electrode corresponding to the adjacent pixel electrode in the second product-sum operation circuit is the pixel electrode of interest, the pixel signal of interest input to the pixel electrode of interest The adjacent pixel signal input to the adjacent pixel electrode of the target pixel electrode and the adjacent pixel signal input to the adjacent pixel electrode of the target pixel electrode are input, Multiply the pixel signal by the operation coefficient in the third row stored in the coefficient storage memory, and add And a third product-sum operation circuit that outputs a correction signal for the pixel signal of interest for the pixel electrode.

  According to this, in addition to the above-mentioned effects, it is possible to correct the target pixel (self-picture element) with a very small circuit configuration, and realize reduction of hardware and cost and improvement of processing speed. Is possible.

  Further, the predetermined direction is a direction from the target pixel electrode toward an adjacent pixel electrode that has a crosstalk effect on the target pixel electrode.

  According to this, in addition to the above-described effects, an accurate correction value can be given to the influence of crosstalk generated due to the structure of the display panel.

  Further, the correction means may shift the target pixel electrode in the direction in which the source signal flows in order to generate a correction signal.

  According to this, in addition to the above-described effects, correction values can be continuously calculated while sequentially shifting the pixel of interest (self-picture element) one by one in the direction in which a signal is input to the display device.

  Further, the calculation coefficient of the conversion matrix calculation is derived by calculating a correction coefficient obtained by converting a change in display luminance due to the target pixel signal caused by a change in one level of the adjacent pixel signal into a level using a predetermined conversion formula. It is what is done.

  According to this, in addition to the above-described effects, the calculation coefficient can be obtained without performing complicated measurement or calculation. Further, since the correction coefficient can be derived from the actually measured luminance value of the display panel, a value suitable for each display panel can be given.

  Further, a color management circuit of a liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells, comprising correction means for correcting a pixel signal input to each pixel electrode, the correction means being The display luminance by the pixel signal of the predetermined level m input to the pixel electrode is input to the pixel electrode so that it is substantially constant regardless of the pixel signal level input to the adjacent pixel electrode. The pixel signal is corrected.

  According to this, since the correction to the input signal of the self-picture element is performed so as to remove the influence of the self-picture element on at least the self-picture element near the predetermined level m, regardless of the fluctuation of the input signal level of the adjacent picture element, The luminance displayed by the self picture element can be maintained at a desired level.

  Further, a color management circuit in a liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells, comprising a correction means for correcting a pixel signal input to each pixel electrode, the correction means comprising: A pixel signal input to the target pixel electrode, a pixel signal input to an adjacent pixel electrode adjacent to the target pixel electrode in a predetermined direction, and the predetermined direction with respect to the adjacent pixel electrode The correction signal for the pixel signal input to the pixel electrode of interest is generated from the pixel signal input to the adjacent contact electrode adjacent to the pixel electrode.

  According to this, it is possible to calculate the correction value based on the neighboring picture element that affects the target picture element (self picture element) without being bound by the pixel boundary. Furthermore, by treating the input signals of adjacent picture elements as values that take into account the influence of adjacent picture elements, it is possible to more accurately correct the self picture elements.

  Also, there is provided a display control method for a liquid crystal display device having a pixel electrode corresponding to each liquid crystal cell, and when a pixel signal input to each pixel electrode is corrected, a predetermined input to a certain pixel electrode is performed. The pixel signal input to the pixel electrode is corrected so that the display luminance of the pixel signal of level m is substantially constant regardless of the pixel signal level input to the adjacent pixel electrode. Is.

  According to this, since the correction to the input signal of the self-picture element is performed so as to remove the influence of the self-picture element on at least the self-picture element near the predetermined level m, regardless of the fluctuation of the input signal level of the adjacent picture element, The luminance displayed by the self picture element can be maintained at a desired level.

Further, for the pixel signals input to the pixel electrodes representing the primary colors of red, green, and blue, the display luminances of white, red, green, and blue based on the pixel signals of a predetermined level m in the respective primary colors are respectively expressed as W. _{When m 1} , R _m , G _m , and B _m , the pixel signal input to the pixel electrode is corrected so that W _m ≈R _m + G _m + B _m is satisfied.

  According to this, in addition to the above-described effects, it is possible to prevent achromatic coloring caused by the change in luminance of each primary color when displaying the three primary colors, and display with substantially constant chromaticity. Become.

  In addition, when correcting the pixel signal input to each pixel electrode, the pixel signal input to the target pixel electrode and the adjacent pixel electrode adjacent to the target pixel electrode in a predetermined direction. Correction for the pixel signal input to the pixel electrode of interest from the input pixel signal and the pixel signal input to the adjacent contact electrode adjacent to the adjacent pixel electrode in the predetermined direction. A signal is generated.

  According to this, in addition to the above-described effects, it is possible to calculate a correction value based on adjacent picture elements that affect the target picture element (self picture element) without being bound by the pixel boundary. Furthermore, by treating the input signals of adjacent picture elements as values that take into account the influence of adjacent picture elements, it is possible to more accurately correct the self picture elements.

  In addition, by performing a 1 × 3 color conversion matrix operation using each pixel signal input to each of the target pixel electrode, the adjacent pixel electrode, and the adjacent pixel electrode, the target picture A correction signal for a pixel signal input to the element electrode is generated.

  According to this, in addition to the above-described effects, an LUT or complicated calculation is not required, and the influence of the adjacent pixel signal on the target pixel (self-picture element) is calculated and displayed with a simple circuit configuration. The brightness can be corrected.

  Furthermore, there is provided a display control method for a liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells, and when the pixel signal input to each pixel electrode is corrected, the picture input to the pixel electrode of interest is corrected. An elementary signal, a pixel signal input to an adjacent pixel electrode adjacent to the target pixel electrode in a predetermined direction, and an input to an adjacent electrode adjacent to the adjacent pixel electrode in the predetermined direction The correction signal for the pixel signal input to the pixel electrode of interest is generated from the generated pixel signal.

  According to this, it is possible to calculate the correction value based on the neighboring picture element that affects the target picture element (self picture element) without being bound by the pixel boundary. Furthermore, by treating the input signals of adjacent picture elements as values that take into account the influence of adjacent picture elements, it is possible to more accurately correct the self picture elements.

  As described above in detail, according to the present invention, a complex circuit configuration is not required, and the mutual influence of each primary color in a pixel is corrected by real-time processing. Correction can be performed, and color management of the entire screen including prevention of crosstalk with respect to the entire screen can be performed. In addition, according to the present invention, it is possible to provide a method for deriving a correction coefficient matrix that can be used for the above-described correction, and it is possible to provide a calculation coefficient of an arbitrary matrix calculation in a short time to each completed display panel. It becomes possible.

It is a figure for demonstrating conceptually the correction | amendment in the color management circuit which concerns on one Embodiment of this invention. It is a block diagram which shows the circuit structural example of the color management circuit which concerns on other embodiment of this invention. FIG. 3 is a diagram illustrating details of a product-sum operation circuit and an LCD in the color management circuit of FIG. 2. It is a graph which shows the influence (before correction | amendment) by the level of the adjacent color on the display brightness with respect to an input level. FIG. 5 is a graph showing an enlarged view and linear approximation in the vicinity of the reference level in FIG. 4. It is a graph which shows the variation | change_quantity (difference) from the level used as the reference | standard of the own color with respect to the input level of an adjacent color. It is a conceptual diagram of the correction | amendment by an adjacent calculation coefficient, and the error after correction | amendment. It is a conceptual diagram of the correction | amendment by the adjacent calculation coefficient. It is a figure which shows the influence (after correction | amendment) by the input level of the adjacent color of the display brightness with respect to each input level. It is a conceptual diagram of the correction | amendment by a 3x3 color conversion matrix system by a prior art. It is the figure which showed notionally the process in which an observer sees with LCD via PC, when setting a tristimulus value as an initial value. It is the schematic for demonstrating the cross-section of VA type | mold LCD. It is the figure which showed the spectral characteristic of the general color filter.

Explanation of symbols

1,2,3 correction conversion equation 10 ... color management circuit 11 ... picture element acquisition circuit 12 ... matrix coefficient storage memory _{13,13 R, 13 B, 13 G} ... product-sum operation circuit 14 ... coefficient selector 15 _R, 15 _B , 15 _G ... Multiplier 16... Adder 21... Sync signal generator 22. Timing control circuit 23... Source driver 24.
25a, 25b, 25c, 25 '... picture element electrode 26, 26a, 26b, 26c ... source lines 27, 27 _1, 27 ₂ ... gate lines 28, 28a, 28b, 28c ... TFT
29 ... Counter electrode side glass plate 30 ... Counter electrode 31a, 31b ... Pixel capacity 32a, 32b, 32c ... Pixel electrode 33a, 33b, 33c ... TFT
34 ... Glass plates 35a, 35b, 35c ... Additional capacitance 36a, 36b, 36c ... Source line _Pn ... Own pixel _{Pn + 1} ... Adjacent pixel R ... Red subpixel G ... Green subpixel B ... Blue subpixel

Claims (6)

A liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells,
Compensating means for correcting the pixel signal input to each pixel electrode,
The correction means includes a pixel signal level at which a display luminance by a halftone level m pixel signal input to a certain pixel electrode is input to an adjacent pixel electrode adjacent to the pixel electrode in a predetermined direction, and The pixel signal input to the pixel electrode is substantially constant regardless of the pixel signal level input to the adjacent pixel electrode adjacent to the adjacent pixel electrode in the predetermined direction. A liquid crystal display device characterized by correcting. The pixel electrode is composed of electrodes representing primary colors of red, green and blue,
The correction means has W _m ≈R _m + G, where W _m , R _m , G _m , and B _m are the display luminances of white, red, green, and blue, respectively, based on a pixel signal of a halftone level m in each primary color. to meet _m + B _m, the liquid crystal display device according to claim 1, wherein the correcting the pixel signal input to the picture element electrode.   The correcting means includes a pixel signal input to the target pixel electrode, a pixel signal input to an adjacent pixel electrode adjacent to the target pixel electrode in a predetermined direction, and the adjacent pixel electrode The correction signal for the pixel signal input to the pixel electrode of interest is generated from the pixel signal input to the adjacent contact electrode adjacent in the predetermined direction. The liquid crystal display device according to any one of the above.   The correction means performs a 1 × 3 color conversion matrix operation using each pixel signal input to each of the target pixel electrode, the adjacent pixel electrode, and the adjacent pixel electrode, The liquid crystal display device according to claim 3, wherein a correction signal for a pixel signal input to the pixel electrode of interest is generated. A color management circuit of a liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells,
Compensating means for correcting the pixel signal input to each pixel electrode,
The correction means includes a pixel signal level at which a display luminance by a halftone level m pixel signal input to a certain pixel electrode is input to an adjacent pixel electrode adjacent to the pixel electrode in a predetermined direction, and The pixel signal input to the pixel electrode is substantially constant regardless of the pixel signal level input to the adjacent pixel electrode adjacent to the adjacent pixel electrode in the predetermined direction. A color management circuit characterized by correction. A display control method of a liquid crystal display device having a pixel electrode corresponding to each of the liquid crystal cells,
When correcting the pixel signal input to each pixel electrode, the display luminance by the halftone level m pixel signal input to a certain pixel electrode is adjacent to the predetermined pixel pixel in the predetermined direction. Regardless of the pixel signal level input to the electrode and the pixel signal level input to the adjacent pixel electrode adjacent to the adjacent pixel electrode in the predetermined direction, the level is substantially constant. A display control method for correcting a pixel signal input to a pixel electrode.

Images