JP2003280614A - Color sequential display type liquid crystal display device and driving method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize both a color breakage reduction and power consumption reduction of a color sequential display type liquid crystal display device. <P>SOLUTION: The color sequential display type liquid crystal display device is equipped with an arithmetic means which extracts achromatic color components from a stored video signal at respective pixels and extracts yellow, magenta, and cyan components from the video signal after the achromatic color components are subtracted and a six-time speed driving means which displays pictures of six colors R, G, B, Y, M, and C in six subfields obtained by dividing a one-frame period. In the driving method of this liquid crystal display device, luminance allocation of R, G, and B light sources in respective subfields of Y, M, and C and luminance allocation of the extracted achromatic color components to the respective subfields are properly carried out. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color display device. In particular, the present invention relates to a technique suitable for achieving both color breakup that occurs when displaying a moving image and a color rainbow phenomenon that occurs when the line of sight is greatly deviated and low power consumption in a color display device of a color sequential display system.

[0002]

2. Description of the Related Art Color images are displayed by displaying red (R), green (G), and blue (B) images, and in conjunction with them, illuminating light sources corresponding to the respective colors from the rear in an arbitrary order. The method is called the color sequential display method. This method is also called a field sequential color method, and has recently attracted attention as a display method that does not require a color filter and is easy to achieve high definition. However, as a problem peculiar to the color-sequential display method, since an image in which two or more colors of R, G, and B are mixed is expressed by a combination of R, G, and B primary color subfields, the image is moved. When the line of sight of the observer follows this, there is a problem of color breakup in that the time lag of the R, G, B emission timings is perceived as a spatial lag. Also, regardless of whether it is a still image or a moving image, when the line of sight is diverted from the screen, a so-called color rainbow phenomenon occurs in which colors are recognized over the entire screen, which gives viewers an unpleasant feeling. To solve these problems, JP-A-8-10
In Japanese Patent No. 1672 and Japanese Patent Laid-Open No. 9-90916, an achromatic color signal calculated from R, G, and B signals is generated, and four of red, green, blue, and white (W) are displayed in four subfields. A color break prevention measure is disclosed (FIG. 8). Here, the subfield is one frame period which is a minimum unit required to display one image, and R, G, B, R,
The individual time widths divided into G, B, and W are shown. Further, Japanese Patent Laid-Open No. 9-90916 also discloses a method of using an intermediate color instead of W. In addition, JP-A-8-24
In Japanese Patent No. 8381, as shown in FIG. 9, the number of subfields is 3, and the light emission order of the subfields is set in units of 3 frames as R → B → G, G → R → B, and B → G → R. Discloses a method of avoiding color breakup.

[0003]

[Problems to be Solved by the Invention]
The method of Japanese Patent No. 2 has a remarkable effect on a completely achromatic portion. However, it is not so effective for neutral color areas. The method using the intermediate color disclosed in Japanese Patent Laid-Open No. 9-90916 is expected to be effective not only for the achromatic portion but also for the intermediate portion.
However, in Japanese Patent Laid-Open No. 9-90916, only a conceptual description is made regarding the use of intermediate colors, which is technically insufficient. In these methods, if the luminance ratio of the achromatic color component or the intermediate color component is set to be high, the color breakage prevention effect is also enhanced. However, when these methods are applied to a liquid crystal display device, the amount of light actually extracted in the R, G, B subfields becomes small, even though the R, G, B backlights are turned on. That is, the transmittance of the pixel becomes low. Therefore, the luminance component that is not effectively used increases. As a result, there are problems that power consumption increases, environmental load increases, and it is difficult to apply to a display device driven by a built-in battery. JP-A-8-101672 and JP-A-9-90916.
In the publication, a technical explanation is given with the use of a monochrome CRT and a liquid crystal shutter as a color filter in mind, and no description is found regarding the problem of power consumption when applied to a liquid crystal display device. .

Further, in the method disclosed in Japanese Unexamined Patent Publication No. 8-248381, the 3-frame period is longer than the time during which the image remains in the eyes of the observer, so the effect of reducing color breakup cannot be actually obtained.

Further, in order to obtain a high-speed response suitable for the color sequential display system, it is considered that the OCB (Optically Compensated Bend) mode in which the nematic liquid crystal is used in the bend alignment state is the most preferable. However, the bend alignment has a critical voltage Vc necessary to maintain it, and if a voltage lower than Vc is continuously applied to the bend alignment pixel, the liquid crystal shifts to the splay alignment state, and an image cannot be displayed. 1 to prevent spray transfer
A method of applying the bend orientation maintaining signal separately from the video signal for each frame or for each subfield is usually used. This method is called CR (cyclic resetting) drive. However, in order to prevent color breakup, if one frame is divided into four subfields and further six subfields and CR driving is performed, the time aperture ratio of the liquid crystal is reduced, which causes a problem that the luminance is reduced. .

[0006]

In order to overcome the above-mentioned problems, a color sequence display type liquid crystal display device of the present invention is
A color sequential display system including a light source of three primary colors of G and B, a plurality of pixels, a light source control means, a video signal input means, a video signal storage means, a calculation means, and a 6 × speed drive means. Liquid crystal display device. Here, a light emitting diode or the like can be used as the light source of the three primary colors of R, G, and B. The pixel has a thin film transistor array and its source, a source that controls a gate voltage, a gate driver, and the like, and a transmittance control unit that controls the transmittance of light independently of other pixels, and is arranged in a matrix in front of the light source. Has been done. Further, the light source control means controls the light source in synchronization with the transmittance control means. The storage means can store one screen of digitized video signal. Further, the calculating means extracts an achromatic color component in each pixel from the stored video signal, and further extracts Y, M and C components from the video signal obtained by subtracting the achromatic color component from the original video signal. To do. Then, the 6 × speed driving means has R, G, B, yellow (Y), and 6 subfields each of which is formed by dividing one frame period into six, respectively.
Images of 6 colors of magenta (M) and cyan (C) are displayed. In this liquid crystal display device, the use of the intermediate colors of Y, M, and C allows the achromatic component to be appropriately distributed to each subfield, whereby the color rainbow phenomenon can be significantly suppressed, which is preferable.

Further, for this display device, a predetermined ratio of the luminance of the extracted achromatic component is assigned to each of the Y, M and C subfields, and the rest is assigned to the R, G and B subfields. It is preferable that a distribution unit is added because this predetermined ratio can be set in consideration of the balance between the color rainbow phenomenon and power consumption.

Further, if a means for setting the light emission order of the subfields in units of two frame periods is added to this display device, color breakup can be reduced by an appropriate driving method. preferable.

Next, as a method of driving the above liquid crystal display device, one frame period is divided into 6 subfields of R, G, B, Y, M and C, and the luminance distribution of the relative luminance of the light source is made. , In the R subfield (R, G, B) = (1, 0,
0), in the G subfield (R, G, B) = (0, 1,
0), in the B subfield (R, G, B) = (0, 0,
1), in the Y subfield (R, G, B) = (0.5, 0.
5, 0), in the M subfield (R, G, B) = (0.5, 0,
0.5), in the C subfield (R, G, B) = (0, 0.
5, 0.5) is preferable because the increase in power consumption can be suppressed even if the intermediate color subfield is used. In addition, the inventors have found that even if the luminance of the intermediate color subfield is set to 50%, the deterioration of the display performance related to the color rainbow phenomenon can be suppressed to an allowable limit as compared with the case of setting the luminance to 100%. Confirmed by evaluation.

Further, as shown below, it is preferable to extract an achromatic color component and an intermediate color component from the video signal and distribute the luminance to each subfield. First, an achromatic color component is extracted from each of the stored video signals in each pixel. Then, the Y, M, and C components are extracted from the video signal obtained by subtracting the achromatic component from the original video signal. Next, Y, M, C
2/9 of the luminance of the extracted achromatic color component is assigned to each subfield of, and each subfield of R, G, B is
Allocate 1/9. Further, the luminances of the extracted Y, M, and C components are assigned to the Y, M, and C subfields, respectively, and the achromatic component and the Y, M, and C components are assigned to the R, G, and B subfields, respectively. R of the video signal from which
The luminances of the G and B components are assigned respectively. By this driving method, color breakup can be reduced while suppressing the color rainbow phenomenon.

Further, it is preferable to set the light emission order of the subfields in units of two frame periods. That is, the k-th subfield of the first frame and the second subfield
The color mixture with the k-th subfield of the frame is R,
The emission order includes all the G and B three primary colors. This allows
Color breaks are significantly suppressed. However, k is an arbitrary integer of 1 or more and 6 or less.

Further, it is preferable to set the light emitting order of the sub-fields in one frame period. That is, the color mixture of an arbitrary subfield and the next subfield has a light emission order that includes all the three primary colors of R, G, and B. As a result, the color rainbow phenomenon and color breakage can be suppressed more significantly.

Further, with respect to the problem that the time aperture ratio of the liquid crystal is lowered and the luminance is lowered due to the CR driving,
In the above driving method using the intermediate color in 6 sub-fields, it is possible to avoid applying a voltage lower than Vc to the pixels in 6 consecutive sub-fields, thereby maintaining the bend alignment. This method is preferable because it is possible to prevent the time aperture ratio from decreasing, and thus to prevent the brightness from decreasing or the power consumption from increasing. This is the same when R, G, B, and W are used in 4 subfields.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1) In Embodiment 1, a color sequential display type liquid crystal display device of the present invention will be described. FIG. 1 shows a schematic diagram thereof. A video signal is input from the video signal input terminal 1. The storage unit 2 can store one screen. Then, the calculation means 3 reads the video signal of each pixel from the storage means 2 and extracts the achromatic color component. Then, the extracted achromatic color component and the video signal from which the achromatic color component has been removed from the original video signal are stored again in the storage means 2. The calculation means 3 extracts the yellow (Y), magenta (M), and cyan (C) components for each pixel from the video signal from which the achromatic color component has been removed. The extracted Y, M, C components and the video signal from which the achromatic color components and the Y, M, C components have been removed are stored in the storage means 2 again. Extracted achromatic component, Y,
The M, C components and the finally left R, G, B components are passed to the 6 × speed driving means 4. Here, the 6 × speed driving is a driving method in which one frame is normally driven at 60 Hz, while one frame is divided into 6 subfields and driven at 360 Hz. The 6 × speed driving unit 4 outputs a control signal to the source driver 6 and the gate driver 7 according to the received video signal, and the source driver 6 and the gate driver 7
Drive the pixel 8 at 6 × speed. 6x speed drive means 4
Also outputs a backlight control signal to the backlight control means 5. The backlight control unit 5 controls the backlight 9 based on the received control signal of the backlight, and the backlight 9 emits R, G, B, Y, M, and C in each subfield. In this display device, the achromatic component is assigned with priority over the Y, M, and C subfields over the R, G, and B subfields. Therefore, the achromatic component is displayed using all 6 subfields. According to a subjective evaluation made by the inventors, if the achromatic color components are evenly distributed in the six subfields, the color rainbow phenomenon becomes less visible. as a result,
In the liquid crystal display device of the color sequential display system according to the present embodiment, the color rainbow phenomenon is remarkably suppressed, as compared with the liquid crystal display device of the normal triple-speed color sequential display system using only the R, G, and B primary colors. preferable.

Further, as shown in FIG. 2, when a luminance distribution means 21 capable of setting the distribution of the luminance of the achromatic color component to each subfield is added, the achromatic color components of the Y, M and C subfields are added. The color rainbow phenomenon can be reduced by adjusting the distribution, which is preferable.

Further, as shown in FIG. 3, by adding a light emission sequence control means 31 for setting the light emission sequence of subfields in units of two frames, driving for preventing color breakup described in the second embodiment. It is particularly preferred because it makes the method feasible.

The color sequential display system has at least one
It is necessary to divide the frame into three, and it is desirable to have a high-speed response in which the response is complete even in 1/3 of one frame period of 60 Hz. Therefore, the OCB mode liquid crystal using the nematic phase liquid crystal in the bend alignment is suitable. For example, it is preferable to use a normally white type pixel and to use an OCB liquid crystal, an alignment film, a cell gap, etc., which has a response from black display to white display of 2.2 ms or less at room temperature. In the OCB mode, the modulation factor is determined by the Δnd product and the phase compensation plate, so Δnd is preferably set to 0.5 μm or more and 1.0 μm or less. Where Δn is the liquid crystal wavelength of 589 nm
Is the anisotropy of refractive index at room temperature with respect to light, and d is the cell gap. According to the study by the inventors, it is particularly preferable that the liquid crystal used at this time has a bulk viscosity of 60 mPa · s or less at room temperature from the viewpoint of high-speed response. Further, if the applied voltage during black display of the pixel is too low, the reverse transition is likely to occur in the splay alignment state, and if it is too high, the load applied to the drive circuit increases, so that it is preferably 4.5 V or more and 7.5 V or less. Furthermore, it is preferable to use a cyano-containing liquid crystal as a liquid crystal having a bulk viscosity of 60 mPa · s or less even if Δn is high. In order to achieve both low viscosity and reliability, the cyano content is 5% or more and 20% or more. % Or less is particularly preferable.

(Embodiment 2) In this embodiment, a driving method of a color sequential display type liquid crystal display device of the present invention will be described.

The maximum brightness of Y, M, and C is a color mixture in the maximum brightness of any two colors of R, G, and B.
In the M and C subfields, in the R subfield, (R, G, B) = (1, 0,
0), in the G subfield (R, G, B) = (0, 1,
0), in the B subfield (R, G, B) = (0, 0,
1), in the Y subfield (R, G, B) = (1, 1,
0), in the M subfield (R, G, B) = (1, 0,
1), in the C subfield, (R, G, B) = (0, 1,
It is natural to set 1). However, in this case, in order to display Y with the highest brightness, only 1 is required in the Y subfield.
Since it is 00%, the luminances of the R, G, and B subfields are not effectively utilized at all, even though the light source emits light. Therefore, power consumption increases.

Therefore, in the present invention, the intermediate color Y,
The sum of the R, G, and B luminances in the M and C subfields is set to be equal to the luminance in the primary color subfields. That is, in the R subfield, (R, G, B) = (1, 0,
0), in the G subfield (R, G, B) = (0, 1,
0), in the B subfield (R, G, B) = (0, 0,
1), in the Y subfield (R, G, B) = (0.5, 0.
5, 0), in the M subfield (R, G, B) = (0.5, 0,
0.5), in the C subfield (R, G, B) = (0, 0.
5, 0.5). FIG. 4 shows an example of the backlight luminance ratios of R, G, and B in the six subfields and the light emitting order of the subfields in the driving method according to the present embodiment.

As a result, for example, in order to display Y of the highest luminance, only 50% luminance is obtained in the Y subfield, so the remaining 50% luminance is distributed to the R and G primary color subfields. The need arises. Therefore, simply, when Y is displayed, a color rainbow phenomenon and color breakup are considered to occur. However, in actuality, according to the subjective evaluation by the inventors, it was confirmed that the color rainbow phenomenon of the intermediate colors of Y, M, and C is sufficiently within the allowable limit even if 50% of the luminance is distributed to the primary color subfields. Has been done. By thus distributing 50% luminance to the primary color subfields, the luminance of R, G, and B is used 50% when displaying Y, M, and C, so that power consumption is reduced. Therefore, the driving method of the present embodiment can suppress the color rainbow phenomenon and reduce power consumption.

Next, the order of light emission will be described. As shown in FIG. 4, the emission order is such that an arbitrary subfield is mixed with one of the subfeeds on both sides of the arbitrary subfield and includes all the three primary colors of R, G, and B. For example, B of SF2 is SF
By mixing R and G of 1, the three primary colors are available. When the three primary colors are aligned by mixing the colors of the adjacent subfields in this way, it becomes an achromatic color, so that it is less noticeable even if a color rainbow phenomenon and color breakage occur, which is preferable.

Next, a method of allocating luminance to each subfield of the stored video signal will be described. The distribution method is shown in FIG. First, the achromatic component is extracted from each pixel. Then, the Y, M, and C components are extracted from the residual component obtained by subtracting the achromatic component from the original video signal. Then Y,
2/9 of the luminance of the extracted achromatic component is assigned to each of the M and C subfields, and 1/9 is assigned to each of the R, G, and B subfields. Further, the luminances of the extracted Y, M, and C components are assigned to the Y, M, and C subfields, respectively, and the achromatic component and the Y, M, and C components are assigned to the R, G, and B subfields, respectively. The respective luminances of the R, G, and B components of the video signal from which is subtracted are assigned. This allocation method is preferable because the brightness is efficiently distributed to each subfield, the power consumption is reduced, and the color rainbow phenomenon can be suppressed. In FIG. 5, the primary color subfield is described as having one type (R in this case) finally, but the luminance of the Y, M, and C subfields is 50.
Since% is the maximum, the number of primary color subfields is not always one.

FIG. 6 shows the order of light emission in which the achromatic color component is distributed and the two-frame period of the subfield is a unit. This is a driving method of a color sequential display type liquid crystal display device (FIG. 3) to which a light emission order control means is added, and it will be explained that color breakage can be avoided by this. First, as shown in FIG. 5, the distribution method of the achromatic color components is as follows.
It is 2/9 for the C intermediate color subfield and 1/9 for each of the R, G, B primary color subfields. As a result, SF1 and S
The mixed colors of F2, SF3 and SF4, and SF5 and SF6 are all completely achromatic. Further, as shown in FIGS. 6a and 6b, SF1 and SF2 in frame 1 and frame 2,
When SF3 and SF4 and SF5 and SF6 are replaced with each other, it can be seen that, as shown in the color mixing result shown in FIG. 6c, the colors are mixed in each subframe of the two-frame period and completely achromatic in all of SF1 to SF6. As a result, as shown in FIG. 7a, even if an achromatic object moves on the screen and the line of sight follows it, the achromatic object is always achromatic in two frame periods. Not detected. It should be noted that FIG. 7b shows the result of integration of the luminance considering the movement of the line of sight. In the conventional example, the method of aligning the three primary colors of R, G, and B using three frame periods did not substantially function to reduce the color breakup. However, the present invention is completely achromatic in two frame periods. Therefore, the effect of preventing color breakup has made remarkable progress and has reached a practical level sufficiently.

In FIG. 4 and FIG. 6, the light emission order in units of two frames of the sub-field is shown in the frame 1
In the above description, the case of Y → B → M → G → C → R and the corresponding frame B → Y → G → M → R → C are described. This is because, according to the studies made by the inventors, it is effective to use a color in which color breakup is not easily visually recognized at the beginning and the end of one frame. According to the inventors' examination, Y and C
It has been found that the color breakage of is hard to be visually recognized. In addition, Y->B->M-> G as the light emission sequence in units of two frames.
It has been confirmed that an effect equivalent to that of the light emission order of FIGS. 4 and 6 can be obtained by setting → R → C and B → Y → G → M → C → R. However, the present invention is not limited to these. That is, R, G, and B3 colors are prepared by mixing the colors of adjacent subfields, and R, G, and B3 are mixed by mixing the colors of the subfields of frame 1 and frame 2.
If the primary colors are uniform and the emission order satisfies these conditions, the emission orders shown in FIGS. 4 and 6 are not necessarily required.

In this embodiment, regarding the luminance distribution of the backlight in the subfields, (R, G, B) = (1, 0,
0), in the G subfield (R, G, B) = (0, 1,
0), in the B subfield (R, G, B) = (0, 0,
1), in the Y subfield (R, G, B) = (0.5, 0.
5, 0), in the M subfield (R, G, B) = (0.5, 0,
0.5), in the C subfield (R, G, B) = (0, 0.
5, 0.5), but the luminance distribution in the intermediate color sub-field does not need to be exactly 50%, but rather is adjusted appropriately near 50% according to the gamma characteristic of the liquid crystal display device. Preferably.

(Embodiment 3) This embodiment particularly
The present invention relates to a driving method of a color sequential display type liquid crystal display device using OCB mode liquid crystal in a liquid crystal cell. Even if the following four R, G, B, and W subfields are used as input signals up to a voltage range below the critical voltage Vc required to maintain the bend orientation, the same as when CR driving is performed. Explain that the bend orientation can be maintained. Figure 8
As shown in a, in the W subfield, R,
R with the same brightness as the brightness in the G, B3 primary color subfields,
All G and B are made to emit light. As shown in FIG. 8b, during Y display with the highest brightness, the transmittance of the liquid crystal becomes highest in the R and G subfields. At this time, the voltage applied to the pixel is set to 0V. Since Vc is usually 2 to 3 V, if 0 V is continuously applied, the bend alignment is changed to the splay alignment, and normal display cannot be performed. However, as can be seen from FIG. 8B, in Y display, since the B and W subfields have a transmittance of 0, the black level voltage is applied to the pixels in these subfields. Therefore, in practice, C
As in the case of performing the R drive, the spray transition does not occur. This is the same when displaying M and C with the highest brightness. Further, as shown in FIG. 8c, during W display with the highest brightness, the liquid crystal transmittance becomes maximum only in the W subfield, and the applied voltage becomes 0V. However, in the R, G, and B subfields, since the black level voltage is applied, the spray transition does not occur as in the case of the CR driving. When the inventors proceeded with the above consideration in detail,
In the color sequential display method using four subfields of R, G, B, and W, a voltage of Vc or less is never applied to the pixel continuously for four subfields, and CR for maintaining the bend alignment is maintained. We found that driving was not necessary. Therefore, the bend alignment can be maintained without separately applying the video signal and the bend alignment maintaining signal in the subfield. As a result, the time aperture ratio of the pixel is improved, and the gate,
It is preferable because the source driver is not required to operate at high speed.

In the driving of the R, G, B and W4 subfields, the order of light emission in which color breakage is least noticeable is as follows.
The inventors have confirmed that the sequence is repeated in the order of B → R → G → W shown in FIG.

Even in the driving method using the 6 subfields described in the second embodiment, the bend orientation is maintained without the CR driving as in the case of the present embodiment. This is because a voltage lower than Vc is never applied to the pixel for 6 consecutive subfields.

[0031]

As described above, the inventors have newly devised a liquid crystal display device of a 6-subfield color sequential display system using an intermediate color and a driving method thereof. Thereby, the color rainbow phenomenon can be remarkably suppressed, and the color breakup in the intermediate color portion can be remarkably suppressed. In addition, regarding the problem that power consumption increases due to the use of intermediate colors, the luminance of the primary color subfield is
By making the total luminance of the intermediate color sub-fields equal, appropriately distributing the achromatic component to each sub-field, and maintaining the bend alignment state without applying CR drive to improve the time aperture ratio, A driving method that can effectively suppress the color rainbow phenomenon and color breakup while effectively utilizing the brightness of the light was shown. As a result, the color sequential display method can be applied to a liquid crystal display device driven by a built-in battery while maintaining high image quality.

In conclusion, according to the present invention, it is possible to obtain a liquid crystal display device which is free from color breakup even in the color sequential display system, and consumes less power than the conventional example, which is friendly to the global environment and space environment.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a liquid crystal display device in which an achromatic component luminance distribution unit is added to the liquid crystal display device of FIG.

FIG. 3 is a schematic view of a liquid crystal display device in which a light emission sequence control unit in units of two frames of a subfield is added to the liquid crystal display device of FIG.

4A and 4B are views for explaining a light emitting order of subfields and luminance distribution of R, G, and B backlights in each subfield in a driving method of a liquid crystal display device according to a second embodiment.

5A and 5B are views for explaining a luminance distribution method for each subfield of a video signal in a driving method of a liquid crystal display device according to a second embodiment.

6A and 6B are views for explaining a light emission sequence in units of two frames of subfields and a luminance distribution to each subfield of an achromatic component in a method for driving a liquid crystal display device according to a second embodiment.

FIG. 7 is a diagram for explaining that color breakup can be suppressed by the emission order of subfields in FIG. 6 and the luminance distribution of achromatic components.

8A and 8B are diagrams showing backlight luminance distribution of each subfield and relative liquid crystal transmittances during yellow and white display in a method for driving a liquid crystal display device according to a third embodiment.

FIG. 9 is a diagram showing that color breakup in an achromatic portion is reduced by a conventional color sequential display method using four subfields of B → G → W → R.

FIG. 10 shows a conventional example in which the light emission order in three sub-fields is R → B → G and G → R → in units of three frame periods.
A diagram showing that color breakup in an achromatic portion is reduced by the color sequential display method in which B, B → G → R are set.

[Explanation of symbols]

1: Video input terminal 2: video signal storage means 21: Brightness distribution means 3: Computing means 31: Light emission order control means 4: 6 speed drive means 5: Backlight control means 6: Source driver 7: Gate driver 8: Pixel 9: Backlight

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 G09G 3/20 641R 3/34 3/34 J (72) Inventor Shigeki Hirohata Kadoma City, Osaka Prefecture Daiji Kadoma 1006 Matsushita Electric Industrial Co., Ltd. F term (reference) 2H088 HA28 JA04 MA20 2H093 NA65 NC34 NC42 ND17 ND39 5C006 AA14 AA22 AF44 AF69 BA15 BB15 BB29 EA01 FA29 FA47 GA03 5C080 AA10 BB05 CC03 DDEEDD28 EE021919

Claims (18)

[Claims] 1. A light source having three primary colors of red (R), green (G), and blue (B), and a transmittance control means for controlling the transmittance of light independently of other pixels. A color composed of a plurality of pixels arranged in a matrix on the front surface of the substrate, a light source control means for controlling the light emission of the light source, a means for inputting a video signal, and a storage means capable of storing the video signal for one screen. A sequential display type liquid crystal display device, wherein an achromatic color component is extracted from each pixel from the video signal stored in the storage means, and the achromatic color component is subtracted from the video signal to obtain a yellow color from the video signal. Six sub-frames are formed by dividing one frame period into six by operating the calculation means for extracting the (Y), magenta (M), and cyan (C) components, and the transmittance control means and the light source control means in synchronization. R in each field , G, B, Y, M, C, and a 6 × speed driving means for displaying images of 6 colors, and a liquid crystal display device of a color sequential display system. 2. A brightness distribution means for distributing the brightness to each subfield is added.
In the liquid crystal display device of the color sequential display system described in (3) above, the distribution method by the brightness distribution unit first allocates a predetermined ratio of the brightness of the achromatic color component to each of the Y, M, and C subfields. Next, the rest of the luminance of the achromatic component is assigned to the R, G, and B subfields, respectively, and the luminance of the Y, M, and C components is assigned to the Y, M, and C subfields, respectively. Allocation, and finally, R, of the video signal from which the achromatic component and Y, M, C components are subtracted,
2. The color sequential display type liquid crystal display device according to claim 1, wherein the method is a luminance distribution method in which G and B components are assigned to the R, G, and B subfields. 3. The liquid crystal display device of the color sequential display system according to claim 1, further comprising a light emission sequence control means for setting the light emission sequence of the subfields in units of two frame periods. 4. The OCB liquid crystal mode in which the pixel displays an image in a bend alignment state and a normally white type, and a response time from black display to white display at room temperature is 2.
The color sequential display type liquid crystal display device according to claim 1, wherein the liquid crystal display device has a period of 2 ms or less. 5. The product Δnd of the refractive index anisotropy Δn and the cell gap d at room temperature for light having a wavelength of 589 nm of the liquid crystal.
Is 0.5 μm or more and 1.0 μm or less. 5. The color sequential display type liquid crystal display device according to claim 1, wherein . 6. The bulk viscosity of the liquid crystal at room temperature is 60 m.
It is below Pa * s, The claim 4 or 5 characterized by the above-mentioned.
The liquid crystal display device of the color sequential display method described in. 7. The applied voltage during black display of the pixel is 4.5.
7. The color sequential display type liquid crystal display device according to claim 4, wherein the liquid crystal display device has a voltage of V or more and 7.5 V or less. 8. The color-sequential display type liquid crystal display device according to claim 4, wherein the liquid crystal is a cyano-containing liquid crystal. 9. The color sequential display type liquid crystal display device according to claim 8, wherein the cyano content is 5% or more and 20% or less. 10. A light source for the three primary colors of red (R), green (G), and blue (B), and a transmittance control unit for controlling the transmittance of light independently of other pixels. A plurality of pixels arranged in a matrix on the front surface of the, a light source control means for controlling the light emission of the light source, a means for inputting a video signal, and a storage means capable of storing the video signal for one screen, An achromatic color component is extracted from each of the pixels from the video signal stored in the storage unit, and a video signal obtained by subtracting the achromatic color component from the video signal is yellow (Y), magenta (M), cyan ( C) The arithmetic means for extracting the component, the transmittance control means and the light source control means are operated in synchronism with each other so that one frame period is divided into six subfields R, G, B, respectively.
A method for driving a liquid crystal display device of a color sequential display system, which comprises a 6 × speed driving means for displaying images of 6 colors of Y, M and C, wherein the luminance distribution of the relative luminance of the light source in each subfield is as described above. In the R subfield, (R, G, B) = (1, 0,
0), in the G subfield (R, G, B) = (0, 1,
0), in the B subfield (R, G, B) = (0, 0,
1), in the Y subfield (R, G, B) = (0.5, 0.
5, 0), in the M subfield (R, G, B) = (0.5, 0,
0.5), in the C subfield (R, G, B) = (0, 0.
5, 0.5), and a driving method of a liquid crystal display device of a color sequential display system. 11. An achromatic color component is extracted from each of the pixels from the video signal stored in the storage means, and Y, M, and C components are extracted from the video signal in which the achromatic color component is subtracted from the video signal. First, 2/9 of the luminance of the achromatic color component is assigned to each of the Y, M, and C subfields, and then the luminance of the achromatic color component of each of the R, G, and B subfields is assigned. 1/9 is assigned, the brightness of the Y, M, and C components is assigned to each of the Y, M, and C subfields, and finally, the achromatic color is assigned to each of the R, G, and B subfields. 11. The method of driving a liquid crystal display device of a color sequential display system according to claim 10, wherein the luminance of the R, G, B components of the video signal from which the components and the Y, M, C components are subtracted is assigned. 12. The subfield has a unit of two frame periods, and the light emitting order is such that the kth subfield of the first frame and the kth subfield of the second frame are mixed in colors R, G, and 12. The driving method of a liquid crystal display device according to claim 10, wherein the emission order includes all of the B3 primary colors. However, k is 1
Any integer not less than 6 and not more than 6. 13. The light emitting order of the sub-fields in one frame period is configured such that the color mixture of an arbitrary sub-field and the preceding or next sub-field is a light-emitting order including all three primary colors of R, G and B. The method for driving a liquid crystal display device according to claim 10, wherein the method is used. 14. The subfield has a unit of two frame periods, and the light emitting order is Y → B → M → G → C →.
14. The method of driving a liquid crystal display device according to claim 13, wherein R, B, Y, G, M, R, and C are repeated in this order. 15. The subfield has a unit of two frame periods, and the light emission order is Y → B → M → G → R →.
14. The method for driving a liquid crystal display device according to claim 13, wherein C, B, Y, G, M, C, and R are repeated in this order. 16. The critical voltage required to maintain the bend alignment is Vc, and by maintaining the bend alignment state by avoiding continuously applying a voltage less than Vc to the pixel for 6 subfields, The method for driving a liquid crystal display device according to claim 9, wherein an image is displayed. 17. A light source for the three primary colors of red (R), green (G), and blue (B), and a transmittance control means for controlling the transmittance of light independently of other pixels. A color composed of a plurality of pixels arranged in a matrix on the front surface of the substrate, a light source control means for controlling the light emission of the light source, a means for inputting a video signal, and a storage means capable of storing the video signal for one screen. A sequential display type liquid crystal display device, in which an arithmetic means for extracting an achromatic color component in each pixel from the video signal stored in the storage means, the transmittance control means and the light source control means are synchronized with each other. By operating
Displaying four color images of R, G, B, and white (W) in four subfields in which the frame period is divided into four 4
A method for driving a liquid crystal display device of a color sequential display system comprising a double speed driving means, wherein the luminance distribution of the relative luminance of the light source in each subfield is (R, G , B) = (1, 0,
0), in the G subfield (R, G, B) = (0, 1,
0), in the B subfield (R, G, B) = (0, 0,
1), the subfield of W is configured such that (R, G, B) = (1, 1, 1), the critical voltage required to maintain the bend alignment is Vc, and A method for driving a liquid crystal display device, wherein an image is displayed by avoiding continuously applying a voltage lower than Vc for four subfields and maintaining a bend alignment state. 18. The subfield emission sequence is B → R.
18. The method for driving a liquid crystal display device according to claim 17, wherein the order of → G → W is repeated.