JP2006293095A - Liquid crystal display device and display method of liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, when a white frame is inserted in order to solve the problem of a color breakup in a field sequential color system, resulting in gamma collapse and abnormal display. <P>SOLUTION: In the liquid crystal display device making display in the field sequential color system, a signal processing section 10 determines a white gradation in the case of forming one frame by field sequentially changing over four fields; red, green, blue and white from the gradations of inputted red (R), green (G), and blue (b), determines each luminance from the inputted red, green, blue, and white gradations, determines each luminance of the red, green, and blue in the case of forming the one frame by field sequentially changing over four fields based on the white luminance, and determines the gradations for each luminance of the determined red, green, and blue as the respective gradations of the red, green, and blue in the case of forming the one frame by field sequentially changing over the four fields. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device and a display method thereof. For example, the present invention relates to a field sequential color liquid crystal display device using OCB mode liquid crystal and a display method thereof.

  Liquid crystal display devices include those for small and portable applications such as mobile phones and PDAs, in addition to desktop PC monitors and TV display applications. Up to now, reflective monochrome liquid crystal has been often used for portable displays, but colorization has been progressing due to the widespread use of mobile phones. In addition, from the conventional STN type LCD, recently, an active matrix type using a TFT capable of displaying images with higher image quality has been widely used.

  In general, a color filter is used for color display in a liquid crystal display device. The color filter is a substrate on which a plurality of types of resins having characteristics of allowing selective wavelengths to pass are formed.

  Recently, image quality similar to that of personal computers has been demanded for portable applications, and field sequential color liquid crystal display devices have been developed.

  The field sequential color method is a method of sequentially displaying images of three colors (R, G, B) with one pixel without attaching a color filter to each pixel, and has a higher transmittance than the liquid crystal of the conventional driving method. In addition, there are advantages such as higher resolution.

  FIG. 7 is a diagram showing an example of display data writing timing and LED light emission timing when one frame is displayed by the field sequential color method. In this case, high-speed color switching is realized using a backlight using RGB three-color LED light sources.

  FIG. 7A shows data write timing and data hold timing. FIGS. 7B, 7C, and 7D show the light emission timings of the red (R) LED, the green (G) LED, and the blue (B) LED, respectively. 7B to 7D, the LOW period indicates the timing when the LED does not emit light, and the HIGH period indicates the timing when the LED emits light.

  The R order shown in FIG. 7A indicates the timing at which red (R) gradation data is written to the liquid crystal, and the HOLD subsequent thereto indicates the timing at which the red data written to the liquid crystal is held. ing. Similarly, G sequential indicates the timing at which green (G) gradation data is written in the liquid crystal, and HOLD subsequent thereto indicates the timing at which the green data written in the liquid crystal is held. Similarly, B sequential indicates the timing when blue (B) gradation data is written in the liquid crystal, and HOLD subsequent thereto indicates the timing when the blue data written in the liquid crystal is held.

  As shown in FIG. 7, red is emitted by causing a red LED to emit light at the timing when data of red gradation is written and held. Similarly, when the green gradation data is written and held, the green LED is caused to emit light to display green, and when the blue gradation data is written and held, the blue LED is turned on. Blue is displayed by emitting light.

  In this way, by controlling the liquid crystal state according to the gradation for each color of red, green, and blue, and turning on the backlight while switching between red, green, and blue in time, images of red, green, and blue are displayed. Full color display can be obtained by sequentially displaying and mixing temporally. In one frame period (16.6 ms), the red, green, and blue backlights are switched and turned on to display an image of one frame.

  Since the frame frequency is usually 60 Hz, the color switching frequency in the field sequential color system is 180 Hz, which is three times that. Accordingly, since the liquid crystal panel is required to have high-speed response, for example, OCB mode liquid crystal is used.

  However, in the field sequential color system, when there is a scene that moves rapidly, or when the human line of sight moves rapidly (saccade), the position shift of the residual colors of the R, G, and B signals on the retina is colored. This causes the problem of color breakup.

  As a measure against the color breakup, various methods that devise a driving method have been proposed (for example, see Patent Document 1).

  FIGS. 8B and 8C show on / off drive timings of two liquid crystal cells of the liquid crystal shutter optical system in the display panel disclosed in Patent Document 1, and FIG. 8A shows these timings. It is a figure which shows the order of the image of each color of B (blue), G (green), R (red), and W (white) selected within one frame by the liquid crystal cell.

  This display device is configured to display a color image by forming one frame by a field sequential method using at least one or more fields in addition to the three primary colors of RGB. One frame is formed of R, G, B3 primary color fields and, for example, white or an intermediate color field (W) of three primary colors.

  Light from the fluorescent screen passes through the liquid crystal cell A and the liquid crystal cell B, and is irradiated onto the display surface for display. Depending on the combination of the on / off states of the liquid crystal cell A and the liquid crystal cell B, only light of any color selected from B, G, R, and W is transmitted.

  When the liquid crystal cell A is off and the liquid crystal cell B is on, only the B light is transmitted. When the liquid crystal cell A is on, only the G light is transmitted when the liquid crystal cell B is off. The liquid crystal cell A is off. When the liquid crystal cell B is off, only R light is transmitted. When both the liquid crystal cell A and the liquid crystal cell B are on, all RGB light is transmitted.

  B, G, R, W are lit in each signal of B, G, R, W, and the liquid crystal cell A and the liquid crystal cell B are switched on / off in accordance with the timing of each color, so that B, G, R, W within one frame Switch to display.

  With such a configuration, the display time of each field is shortened, and a portion obtained by adding the color signals of the previous field caused by the time shift is displayed whitish. Further, the color signals B and R that are slightly added before and after are very inconspicuous colors. Therefore, it is possible to display with almost no color breakup.

  Also, a liquid crystal display device has been proposed that improves the problem of color breakup by inserting a white frame in a field sequential color system using OCB mode liquid crystal (see, for example, Patent Document 2).

  FIG. 9 is a block diagram showing the configuration of the liquid crystal display device of Patent Document 2.

  This liquid crystal display device is a field sequential color liquid crystal display device, and includes an OCB mode liquid crystal display panel 116 in which a phase compensation plate is disposed in front of a bend alignment liquid crystal. An LED backlight 117 composed of LED elements of R (red), G (green), and B (blue) colors is provided, and color display is enabled by mixing these colors over time.

  A signal processing unit 110 that divides the input video signal into the three primary colors of RGB is provided. Further, a source driver 113 that drives the liquid crystal display panel 116 and a liquid crystal control unit 111 that controls the gate driver 114 are provided. Moreover, the LED control part 12 which controls the LED driver 115 which drives the LED backlight 117 is provided.

  The signal processing unit 110 generates RGB three primary color data from the input video signal and generates white (W) data to be inserted between the three primary color fields. These R, G, B, and W data are sequentially written on the liquid crystal display panel 116 during one field. By switching the light emission of the LED backlight 117 to R, G, B, and three colors simultaneously in accordance with the timing of writing each of these colors on the liquid crystal display panel 116, R, G, B, W between one field is switched. Are displayed sequentially.

Thus, the problem of color breakup is improved by inserting and displaying W (white) between one field.
JP-A-9-90916 JP 2003-241165 A

  However, in the conventional method of inserting a white frame, the gamma is lost, so that it cannot be displayed normally.

  In other words, simply inserting a white frame results in a whitish image. In addition, since gradation and brightness are not linearly related, the gamma characteristic after inserting a white frame differs from the gamma characteristic of the original video data only by controlling by gradation. Cannot be displayed in a gamma.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problems, and to provide a liquid crystal display device and a display method thereof that can improve the color breakup phenomenon in the field sequential color system and display images with normal gamma.

In order to solve the above-described problem, the first aspect of the present invention provides:
A liquid crystal panel, a light source that irradiates the liquid crystal panel, a signal processing unit that creates display data from input video data, and a color of the light source are sequentially switched, and the liquid crystal panel transmits or A liquid crystal display device including a driving means for controlling the reflection state, and performing color display with additive color mixture over time,
The signal processing unit
From the input red, green, and blue gradations, the four gradations of red, green, blue, and white are switched in the field order to determine the white gradation when forming one frame.
Respective luminances are obtained from the inputted red, green, and blue gradations and the white gradation,
Based on the brightness of white, determine the brightness of each of red, green, and blue when the four fields are switched in frame order to form one frame;
The gradations corresponding to the determined luminances of red, green, and blue are the gradations of red, green, and blue in the case where one frame is formed by switching the four fields in the frame order. A liquid crystal display device.

The second aspect of the present invention
The signal processing unit
It has a conversion table that shows the correspondence between gradation and brightness,
Based on the conversion table, obtain the respective luminance from the input red, green, blue gradation and white gradation,
Based on the conversion table, each gradation of red, green, and blue in the case where one frame is formed by switching the four fields in the field order from the determined luminances of red, green, and blue 1 is a liquid crystal display device according to the first aspect of the present invention.

The third aspect of the present invention
The signal processing unit
The minimum gradation among the input red, green, and blue gradations is set as a white gradation,
Find the brightness of red, green and blue in the white component,
A value obtained by subtracting the respective luminances of red, green, and blue in the white component from the luminances corresponding to the input red, green, and blue gradations, and switching the four fields in a frame sequential manner. It is the liquid crystal display device according to the first aspect of the present invention, which has respective luminances of red, green, and blue when one frame is formed.

The fourth aspect of the present invention is
In the liquid crystal display device according to the first aspect of the present invention, the driving means inserts a black field between the respective color fields.

The fifth aspect of the present invention provides
In the liquid crystal display device according to the first aspect of the present invention, the light source is a red, green, or blue LED element.

The sixth aspect of the present invention provides
A liquid crystal panel, a light source that irradiates the liquid crystal panel, a signal processing unit that creates display data from input video data, and a color of the light source are switched sequentially in time, and the transmission or transmission of the liquid crystal panel is synchronized with it. A display method for a liquid crystal display device, which includes a driving means for controlling a reflection state and performs color display with additive color mixture over time,
By the signal processing unit,
From the input red, green, and blue gradations, the four gradations of red, green, blue, and white are switched in the field order to determine the white gradation when forming one frame.
Respective luminances are obtained from the inputted red, green, and blue gradations and the white gradation,
Based on the brightness of white, determine the brightness of each of red, green, and blue when the four fields are switched in frame order to form one frame;
The gradations corresponding to the determined luminances of red, green, and blue are the gradations of red, green, and blue in the case where one frame is formed by switching the four fields in the frame order. A display method of a liquid crystal display device.

  According to the present invention, it is possible to provide a liquid crystal display device and a display method thereof that can improve the color breakup phenomenon in the field sequential color system and display images with normal gamma.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a liquid crystal display device according to Embodiment 1 of the present invention. The liquid crystal display device according to the first embodiment is a field sequential color liquid crystal display device using OCB mode liquid crystal.

  The liquid crystal display device according to the first embodiment includes a liquid crystal display panel 16 using OCB mode liquid crystal and an LED backlight 17 having RGB three-color light sources.

  And the signal processing part 10 which converts the input data of a video signal into data without a color breakup is provided. Further, a source driver 13 for driving the liquid crystal display panel 16 and a liquid crystal control unit 11 for controlling the gate driver 14 are provided. Moreover, the LED control part 12 which controls the LED driver 15 which drives the LED backlight 17 is provided.

  The liquid crystal display panel 16 is an example of the liquid crystal panel of the present invention. A combination of the liquid crystal control unit 11, the LED control unit 12, the source driver 13, the gate driver 14, and the LED driver 15 corresponds to an example of the driving unit of the present invention.

  In addition, a gradation-luminance conversion table 18 indicating correspondence between gradation and luminance is provided for reference by the signal processing unit 10.

  The graph of FIG. 2 shows an example of the relationship between gradation and luminance in the OCB liquid crystal. Although the relationship between gradation and luminance differs depending on the characteristics of the liquid crystal and the like, in any liquid crystal, the gradation and luminance are not in a linear relationship. The gradation-luminance conversion table 18 is a table associating gradations with luminances. By using the gradation-luminance conversion table 18, conversion from gradations to luminance values and conversion from luminance values to gradations are performed. Can be done.

  Next, the operation of the liquid crystal display device according to the first embodiment will be described.

  In the liquid crystal display device according to the first embodiment, display red (R), green (G), blue (B), and white (W) data are created from input video signals, and these data are sequentially generated. By switching and displaying, one frame is displayed with additive color mixing over time.

  First, a method of creating red, green, blue, and white data for display in the signal processing unit 10 will be described.

  FIG. 3 is a block diagram showing a method of creating red data for display from an input video signal.

  First, the white gradation (W gradation) is selected from the red gradation (R gradation), the green gradation (G gradation), and the blue gradation (B gradation) of the input video signal. decide. Here, the W gradation is the same gradation as the minimum gradation among the R gradation, the G gradation, and the B gradation.

  Next, the red gradation in the white component having the gradation determined above is obtained, and the red gradation in the white component is referred to the gradation-luminance conversion table 18 from the red gradation in the white component. Luminance (R luminance in W component) is obtained. At the same time, with reference to the gradation-luminance conversion table 18, the luminance (R luminance) corresponding to the R gradation of the input video signal is obtained.

  The gradation corresponding to the luminance value obtained by subtracting the R luminance in the W component from the R luminance calculated above (R luminance-R luminance in the W component) is obtained with reference to the gradation-luminance conversion table 18. The gradation value is defined as a display red gradation (R-Wr gradation).

  Similarly, a green gradation (G-Wg gradation) and a blue gradation (B-Wb gradation) for display are determined. That is, a luminance value (G luminance-G in W component) obtained by subtracting the green luminance (G luminance in W component) in the white component from the luminance (G luminance) corresponding to the G gradation of the input video signal. The gradation corresponding to (luminance) is G-Wg gradation, and from the luminance (B luminance) corresponding to the B gradation of the input video signal, the blue luminance in the white component (B luminance in the W component) is changed. A gradation corresponding to the reduced luminance value (B luminance-B luminance in the W component) is defined as a B-Wb gradation.

  Next, a display method of the liquid crystal display device according to the first embodiment will be described.

  FIG. 4 shows display data writing timing and LED light emission timing when the liquid crystal display device of the first embodiment displays one frame.

  FIG. 4A shows data writing timing and holding timing. FIGS. 4B, 4C, and 4D show the light emission timings of the red (R) LED, the green (G) LED, and the blue (B) LED, respectively. 4B to 4D, the LOW period indicates the timing when the LED does not emit light, and the HIGH period indicates the timing when the LED emits light.

  R-Wr shown in FIG. 4A indicates the timing at which red (R) gradation data for display is written in the liquid crystal, and the subsequent HOLD holds the red data written in the liquid crystal. The following black indicates the timing for inputting black gradation data. Similarly, G-Wg indicates the timing at which display green (G) grayscale data is written to the liquid crystal, and the subsequent HOLD indicates the timing at which the green data written to the liquid crystal is held. Subsequent black indicates the timing at which black gradation data is input. Similarly, B-Wb indicates the timing at which display blue (B) grayscale data is written in the liquid crystal, and the subsequent HOLD indicates the timing at which the blue data written in the liquid crystal is held. The following black indicates the timing of entering black gradation data. Similarly, W indicates the timing at which white (W) gradation data is written to the liquid crystal, and the subsequent HOLD indicates the timing at which the white data written on the liquid crystal is retained, followed by black. Indicates the timing of each black gradation data.

  As shown in FIG. 4, red is emitted by causing a red LED to emit light at the timing of writing red gradation data. Similarly, the green LED is caused to emit light at the timing of writing the green gradation data, and the blue LED is caused to emit light at the timing of writing the blue gradation data. Similarly, white is displayed by simultaneously emitting red, green and blue LEDs at the timing of writing white gradation data.

  Within a period of one frame (16.6 ms), the LED backlight 17 is made to emit red LED only, green LED only, blue LED only, red, green and blue LEDs simultaneously, To display red, green, blue, and white in order.

  As shown in FIG. 4, in the liquid crystal display device according to the first embodiment, black gradation data is written in the liquid crystal and the black field is inserted between the red, green, blue, and white fields. ing.

  This is to prevent color mixing when switching between red, green, blue, and white colors for display, and the reason will be described below.

  Here, a case will be described as an example in which three colors of red, green, and blue are displayed in frame sequential order without inserting a white field. The same applies to the case where a white field for improving the phenomenon of color breakup is inserted.

  FIG. 5 shows a case where a black field is not inserted between each color field, and FIG. 6 shows a display data when one frame is displayed when a black field is inserted between each color field. It is the figure which showed writing timing and LED light emission timing.

  FIG. 5A shows data writing timing and holding timing. FIGS. 5B, 5C, and 5D show light emission timings of the red (R) LED, the green (G) LED, and the blue (B) LED, respectively. 5B to 5D, the LOW period indicates the timing when the LED does not emit light, and the HIGH period indicates the timing when the LED emits light.

  FIG. 5E shows the liquid crystal response timing of each line of the liquid crystal panel. Here, the response timing of the liquid crystal in the first line and the response timing of the liquid crystal in the final line are shown. The voltage of the liquid crystal response varies depending on the gradation, but in one frame shown in FIG. 5, the gradation of red is the largest, and the gradation is decreased in the order of blue and green.

  FIG. 6A shows the data writing timing and holding timing when a black field is written between each color field. FIG. 6B, FIG. 6C, and FIG. 6D show the emission timings of the red (R) LED, the green (G) LED, and the blue (B) LED, respectively. The light emission timing is the same as in FIGS.

  FIG. 6E shows the liquid crystal response timing of each line of the liquid crystal panel. Here, the gray levels of red, green, and blue in the frame shown in FIG. 6 are the same as those in the case of FIG.

  Usually, in the liquid crystal display device, data is written for each line in order from the liquid crystal of the first line to the liquid crystal of the last line. Therefore, the writing timing to the liquid crystal is slightly shifted for each line. FIGS. 5E and 6E show only the liquid crystal response timings of the first line and the last line, but the response timings of the lines between these lines are also sequentially shifted. Among them, the difference in liquid crystal response timing between the first line and the last line is the largest. In the field sequential color system, since the color switching interval is short, the field sequential color system is easily affected by the deviation of the writing timing to the liquid crystal.

  In the case of FIG. 5 in which the black field is not inserted, the liquid crystal response of the first line is fast and there is no problem, but the liquid crystal response of the last line is delayed and a timing shift occurs to cause a color mixing problem. .

  For example, looking at the red display, the liquid crystal holding period for the red gradation is completed during the period when the red LED is emitting light for the first line, but the red LED is emitting light for the last line. The liquid crystal holding period with respect to the red gradation continues even after the period during which the current period is exceeded. Since the green LED emits light while the liquid crystal holding period for the red gradation of the final line continues, green is displayed with the red gradation on the final line.

  In the period when the green LED emits light and during the period when the blue LED emits light, a timing shift occurs in the same manner. In the final line, blue is displayed with green gradation, and blue gradation is displayed. Red will be displayed.

  On the other hand, as shown in FIG. 6, if the black gradation is written during the writing of each color, the holding period of each color can be shortened.

  For example, looking at the red display, the liquid crystal response is delayed for the last line, causing a timing shift, but because the black gradation retention period is shortened by writing black, the green LED The holding period of the red gradation does not continue until the light emission period. Therefore, green is not displayed with a red gradation, and the problem of color mixing does not occur. By inserting black between the other colors, the problem of color mixing does not occur between the other colors as well.

  In the first embodiment, the white gradation (W gradation) is set to the same gradation as the smallest gradation among the R gradation, the G gradation, and the B gradation. The predetermined gradation determined from the R gradation, the G gradation, and the B gradation may be smaller than the minimum gradation among the gradations, for example, the R gradation, the G gradation, and the B gradation. Even in this case, the display data creation method described in the first embodiment can be applied.

  Further, since the correlation between the gradation and the luminance varies depending on the temperature, the gradation-luminance conversion table 18 is provided with a plurality of different tables indicating the relationship between the gradation and the luminance for each temperature, and the signal processing. The unit 10 may perform gradation-to-luminance conversion and luminance-to-gradation conversion using the gradation-luminance conversion table 18 corresponding to the temperature of the liquid crystal display panel 16 at that time. . By doing so, it is possible to always display with normal gamma without being affected by ambient temperature change.

  In the first embodiment, the gradation-to-luminance conversion and the luminance-to-gradient conversion are obtained using the gradation-luminance conversion table 18, but without using such a table. You may make it calculate using the function which shows the correlation of a gradation and a brightness | luminance.

  Further, in addition to displaying white (W) mixed between the three primary color fields of R, G, and B, the problem of color breakup can be improved by displaying the three primary colors mixed with the three primary colors. be able to. That is, in the first embodiment, an example in which W is mixed and displayed between the three primary color fields has been described, but instead of W, cyan (Y), magenta (M), yellow (which are intermediate colors of the three primary colors) Y) may be mixed and displayed. Further, instead of mixing W, even if a combination of a plurality of colors of W and intermediate colors is displayed by mixing the three primary colors, the problem of color breakup can be improved. That is, the problem of color breakup can be improved by displaying one frame with a combination of colors such as RGBY, RGBM, RGBC, RGBYMC, RGBWYMC,.

  As described above, even when the intermediate colors of the three primary colors or the combination of the intermediate colors of W and the three primary colors are mixed and displayed, the present invention is applied to determine the gradation of the color to be mixed and convert it into luminance once. By determining the luminance of each color and converting them into gradations and displaying them, it is possible to display with normal gamma.

  For example, when Y, which is an intermediate color between R and G, is mixed, the smaller gradation of the original R and G gradations is set as the Y gradation, and the R in the Y component is determined from the original R luminance value. The R gradation to be displayed is determined from the value obtained by subtracting the luminance value of G, and the G gradation to be displayed is determined from the value obtained by subtracting the G luminance value in the Y component from the original G luminance value. These gradations may be used as they are and switched to RGBY for display.

  As described above, in the liquid crystal display device and the display method thereof according to the present invention, the gray level of white is determined from the gray levels of red, green, and blue, and the gray level of each color is converted into luminance, respectively. Since the luminance of each color is obtained and the gradation of each color for display is determined from the obtained luminance of each color, it is possible to improve color breakup and display with normal gamma. As shown in FIG. 2, since the gradation and the luminance are not in a linear relationship, normal gamma display data can be obtained by converting the luminance into the luminance once and obtaining the luminance of each color.

  Further, in the liquid crystal display device and the display method thereof according to the present invention, a black field is inserted between red, green, blue, and white colors, so that normal display can be performed without mixing colors.

  The liquid crystal display device and the display method thereof according to the present invention can improve the color breakup phenomenon in the field sequential color system and display with normal gamma, so that the liquid crystal display device of the field sequential color system using OCB mode liquid crystal can be used. Useful.

1 is a block diagram illustrating a configuration of a liquid crystal display device according to a first embodiment of the present invention. The figure which shows an example of the relationship between the gradation and brightness | luminance in OCB liquid crystal FIG. 2 is a block diagram illustrating a method for creating red, green, blue, and white data for display in the liquid crystal display device according to the first embodiment of the present invention. The figure which shows the display data write timing and LED light emission timing at the time of displaying 1 frame of the liquid crystal display device of Embodiment 1 of this invention. The figure which shows the display data write timing and LED light emission timing at the time of displaying one frame when not inserting a black field between the fields of each color The figure which shows the display data write timing and LED light emission timing at the time of displaying one frame at the time of inserting a black field between the fields of each color The figure which shows the display data write timing and LED light emission timing at the time of displaying 1 frame by the conventional field sequential color system The figure which shows the order of the image of each B, G, R, and W color selected within the 1 frame by the on / off drive of the liquid crystal cell of the liquid-crystal shutter optical system of the conventional method for measures against color breakage, and this liquid crystal cell A block diagram showing the configuration of a field sequential color liquid crystal display device using a conventional OCB mode liquid crystal

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Signal processing part 11 Liquid crystal control part 12 LED control part 13 Source driver 14 Gate driver 15 LED driver 16 Liquid crystal display panel 17 LED backlight 18 Tone-brightness conversion table

Claims (6)

A liquid crystal panel, a light source that irradiates the liquid crystal panel, a signal processing unit that creates display data from input video data, and a color of the light source are sequentially switched, and the liquid crystal panel transmits or A liquid crystal display device including a driving means for controlling the reflection state, and performing color display with additive color mixture over time,
The signal processing unit
From the input red, green, and blue gradations, the four gradations of red, green, blue, and white are switched in the field order to determine the white gradation when forming one frame.
Respective luminances are obtained from the inputted red, green, and blue gradations and the white gradation,
Based on the brightness of white, determine the brightness of each of red, green, and blue when the four fields are switched in frame order to form one frame;
The gradations corresponding to the determined luminances of red, green, and blue are the gradations of red, green, and blue in the case where one frame is formed by switching the four fields in the frame order. Liquid crystal display device. The signal processing unit
It has a conversion table that shows the correspondence between gradation and brightness,
Based on the conversion table, obtain the respective luminance from the input red, green, blue gradation and white gradation,
Based on the conversion table, each gradation of red, green, and blue in the case where one frame is formed by switching the four fields in the field sequence from the determined luminances of red, green, and blue The liquid crystal display device according to claim 1, wherein: The signal processing unit
The minimum gradation among the input gradations of red, green, and blue is set as a white gradation,
Find the brightness of red, green and blue in the white component,
A value obtained by subtracting each luminance of red, green, and blue in the white component from each luminance corresponding to the input red, green, and blue gradations, and switching the four fields in a frame sequential manner. The liquid crystal display device according to claim 1, wherein each of the luminances of red, green, and blue when forming one frame is used.   The liquid crystal display device according to claim 1, wherein the driving unit inserts a black field between each of the color fields.   The liquid crystal display device according to claim 1, wherein the light source is a red, green, or blue LED element. A liquid crystal panel, a light source that irradiates the liquid crystal panel, a signal processing unit that creates display data from input video data, and a color of the light source are switched sequentially in time, and the transmission or transmission of the liquid crystal panel is synchronized with it. A display method for a liquid crystal display device, which includes a driving means for controlling a reflection state and performs color display with additive color mixture over time,
By the signal processing unit,
From the input red, green, and blue gradations, the four gradations of red, green, blue, and white are switched in the field order to determine the white gradation when forming one frame.
Respective luminances are obtained from the inputted red, green, and blue gradations and the white gradation,
Based on the brightness of white, determine the brightness of each of red, green, and blue when the four fields are switched in frame order to form one frame;
The gradations corresponding to the determined luminances of red, green, and blue are the gradations of red, green, and blue in the case where one frame is formed by switching the four fields in the frame order. And display method of liquid crystal display device.

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