JPH09127479A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of full-color display with a simple constitution. SOLUTION: One display dot consists of two adjacent picture elements in a double refraction control type liquid crystal display element 1 which has the display color changed in the range of a low applied voltage and has the gradation changed in achromatic color in the range of a high applied voltage. A driving circuit 2 converts picture data to color data and gradation data and applies a voltage corresponding to color data to one of two adjacent picture elements of the double refraction control type liquid crystal display element 1 and applies a voltage corresponding to gradation data to the other. The display color and the display gradation of two adjacent picture elements are visually synthesized to recognize a color gradation picture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device capable of full color display, and more particularly to a liquid crystal display device which displays a full color image using a birefringence control type liquid crystal display element.

[0002]

2. Description of the Related Art As a color liquid crystal display device capable of displaying a color image, a birefringence control type, a preoic type, a color filter type and the like are known. Among these, birefringence control (ECB: electrically controlled birefringenc)
The e) type liquid crystal display element changes the molecular alignment of the liquid crystal by applying an electric field to the liquid crystal to change the birefringence effect of the liquid crystal layer, and the birefringence effect is transmitted through the pair of polarizing plates. A desired color is displayed by changing the spectral distribution of light. This birefringence control type liquid crystal display element has a problem that it is difficult to perform gradation display and multicolor display because the display color and gradation (brightness) simultaneously change with applied voltage.

[0003]

As a method for solving this problem, a method of forming a liquid crystal display element by stacking a birefringence control type liquid crystal display element and a black-and-white TN liquid crystal display element in two stages can be considered. That is, by controlling the intensity of light (colored light) that has passed through the birefringent pixel by the black-and-white TN liquid crystal display element, it is considered that multi-gradation display is possible for each color. According to this method, a full color display liquid crystal display device can be realized. However, such a liquid crystal display element has a problem in that its structure is complicated and the cost is doubled.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal display device capable of full-color display with a simple structure.

[0005]

In order to achieve the above object, a liquid crystal display device according to a first aspect of the present invention includes a first substrate on which a first electrode is arranged, and a first substrate. The second substrate is arranged on the opposite side and faces the first substrate.
A second substrate on which the electrode is arranged, a liquid crystal arranged between the first and second substrates, and a polarizing plate arranged outside at least one of the first substrate and the second substrate. Have
Each pixel is formed by a portion where the first electrode and the second electrode face each other and a liquid crystal therebetween, and a plurality of chromatic colors are formed according to a first applied voltage in a predetermined range applied to the liquid crystal. And a birefringence control type liquid crystal display element for displaying an achromatic color according to a second applied voltage in a voltage range different from the first applied voltage range, and a color and gradation of each pixel are designated. Image data output means for outputting image data, and image data output from the image data output means are converted into color data and gradation data, and one of two adjacent pixels of the birefringence control type liquid crystal display element. A voltage corresponding to the color data is applied between the first electrode and the second electrode of the pixel, and the grayscale data is applied between the first electrode and the second electrode of the other pixel of the two adjacent pixels. Drive means for applying a corresponding voltage, and the adjacent two Wherein the by the visual synthesis of display of pixels displaying the color and gradation indicated by the image data.

According to the liquid crystal display device having the above structure, in one pixel, the first voltage is applied to the liquid crystal to display a color. Further, in the other pixel, a second voltage is applied to the liquid crystal, and gradation display is performed. The display of one pixel and the display of the other pixel are visually combined to perform color gradation display.

Further, in a liquid crystal display device according to a second aspect of the present invention, a first substrate on which a first electrode is arranged and a first substrate are arranged so as to face the first substrate, and the first substrate is arranged. A second substrate having a second electrode disposed on a surface facing the substrate, liquid crystal disposed between the first substrate and the second substrate, and the first substrate and the second substrate. A polarizing plate disposed outside at least one of the first electrode and the second electrode.
Each pixel is formed by a portion facing the electrode of and the liquid crystal therebetween, and one of a plurality of chromatic colors is displayed according to a first applied voltage in a predetermined range applied to the liquid crystal, and the first pixel is displayed. A birefringence control type liquid crystal display element for displaying an achromatic color according to a second applied voltage in a voltage range different from the applied voltage range, and an image data output means for outputting image data designating a color and a gradation of each pixel. And converting the image data output from the image data output means into color data and gradation data, and connecting between the first electrode and the second electrode of each pixel of the birefringence control type liquid crystal display device. In one frame, a driving means for alternately applying a voltage corresponding to color data and a voltage corresponding to gradation data is provided, and the display color and the display gradation of each pixel in a plurality of frames are visually combined. The feature is that color gradation display is performed.

According to the liquid crystal display device having the above structure, in a certain frame, the first voltage is applied to the liquid crystal of each pixel to display a color. Also, in the other frame, the second
Is applied to display gradation. The display of a plurality of frames is visually combined and color gradation display is performed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration of the liquid crystal display device according to the embodiment, and FIG. 2 is a sectional view showing the configuration of the birefringence control type liquid crystal display element.

As shown in FIG. 1, the liquid crystal display device comprises a birefringence control type liquid crystal display element 1 and a drive circuit 2. The birefringence control type liquid crystal display element 1 includes a pair of transparent substrates 11 and 12 and a pair of transparent substrates 1 as shown in FIG.
A liquid crystal 13 sealed by a sealing material SC between 1 and 12,
Two phase plates 21 and 22 arranged outside the substrate 12
And a pair of transparent substrates 11, 12 and two phase plates 21,
It is composed of a pair of polarizing plates 23 and 24 which are arranged so as to sandwich 22 and a reflecting plate 25 which is arranged outside the polarizing plate 23.

The pair of transparent substrates 11 and 12 are made of glass, transparent resin or the like. On the lower transparent substrate (TFT substrate) 11, as shown in FIG. 1, TFTs 14 and pixel electrodes 15 are arranged in a matrix.

As shown in FIG. 1, the gate electrode of each TFT 14 is connected to the gate line GL arranged in the row direction, and the drain electrode is arranged in the data line D arranged in the column direction.
It is connected to L and the source electrode is connected to each pixel electrode 15.

Each gate line GL is connected to the row driver 31 via the terminal portion T1. Each data line DL is connected to the column driver 32 via the terminal portion T2.

On each TFT 14 and pixel electrode 15,
An alignment film 16 is arranged on the entire surface. As shown in FIG. 3D, the surface of the alignment film 16 is subjected to an alignment treatment such as rubbing in a direction 16a at a lower right angle of 45 ° with respect to a horizontal direction H parallel to the lower side of the substrate 11. .

On the other hand, the upper transparent substrate (counter substrate) 12 is provided with a counter electrode 17 facing each pixel electrode 15. A common voltage is applied to the counter electrode 17. An alignment film 18 is formed on the entire surface of the counter electrode 17.
Is arranged. The orientation film 18 is subjected to an orientation treatment such as rubbing in a direction 18a shown in FIG. 3D (90 ° counterclockwise to the orientation direction 16a of the orientation treatment of the orientation film 16). .

The liquid crystal 13 is composed of a nematic liquid crystal to which a chiral material is added, and the TFT substrate 11 to the counter substrate 12 are subjected to the alignment treatment applied to the alignment films 16 and 18.
It is oriented by twisting 90 ° toward.

The reflector 25 has a surface 25a shown in FIG.
Hairline treatment is applied in the direction of. Phase plate 21
3C, the axis (stretching axis) 21a having the largest refractive index on the plane is arranged so as to intersect the horizontal direction H at 113 °. The phase plate 22 is shown in FIG.
As shown in (B), the axis (stretching axis) 22a having the largest refractive index on the plane is arranged so as to intersect the horizontal direction H at 20 °. The transmission axis 23a of the polarizing plate 23 is
As shown in FIG. 3 (E), it intersects the horizontal direction H at 90 °. The transmission axis 24a of the polarizing plate 24 is shown in FIG.
As shown in FIG.

On the other hand, the drive circuit 2 is, as shown in FIG.
CPU 41, program memory 42, image memory (display memory) 43, display control circuit 44, first conversion table 45, second conversion table 46, D / A
(Digital-analog) converter 47A, D / A (digital-analog) converter 47B, row driver 31,
And a column driver 32.

The CPU 41 controls the entire system according to a predetermined program. Program memory 4
Reference numeral 2 stores an operation program of the CPU 41, for example, an image creation program. The image memory 43 is a CPU
The digital image data is written under the control of 41. The display control circuit 44 sequentially reads the digital image data stored in the image memory 43 under the control of the CPU 41, and outputs RGB color data of 2 bits (total 6 bits) DC.
And 3-bit gradation data DG and color data DC
Is supplied to the first conversion table 45, and the gradation data DG is supplied to the second conversion table 46.

The first conversion table 45 converts 6-bit color data DC into 4-bit digital voltage data Dc 'and supplies it to a D / A (digital-analog) converter 47A. The D / A converter 47A converts the digital voltage data DC ′ into an analog color signal and supplies it to the column driver 32. The second conversion table 46 converts the 3-bit gradation data DG into 5-bit digital voltage data DG 'and supplies it to the D / A converter 47B. D / A converter 4
7B converts the digital voltage data DG 'into an analog gradation signal and supplies it to the column driver 32.

The column driver 32 sequentially samples the analog color signal and the analog grayscale signal for one scanning line, supplies the sampled analog color signal to the odd-numbered data lines DL, and outputs the analog grayscale signal to the even-numbered column data. Supply to line DL. The row driver 31 is the CPU 4
According to control No. 1, a gate signal (scanning signal) is supplied to each gate line GL.

In the liquid crystal display device having such a structure,
As shown in FIG. 4, one dot (minimum dot for displaying an image) of the birefringence control type liquid crystal display element 1 is composed of two pixels (first pixel and second pixel) adjacent to each other. .

When a driving voltage is applied between the pixel electrode 15 of the first pixel or the second pixel and the counter electrode 17, the relationship between the applied voltage and the reflectance and display color shown in FIG. 5 is obtained. As the applied voltage is increased, the reflectance changes accordingly, and the display color also changes from red → green → blue → black → white. FIG. 6 shows a CIE (x, y) chromaticity diagram in this case. As can be seen from FIG. 6, the purity of each display color is excellent.

In the characteristic of FIG. 5, the hue changes in a range of a certain voltage value (2.4 V) or less, and in the range exceeding this voltage value, only the achromatic brightness changes. Therefore, the color can be designated by applying an arbitrary voltage in the range of 2.4 V or less to the first pixel. Also,
By applying an arbitrary voltage in the range exceeding 2.4 V to the second pixel, the gradation can be designated. Each pixel is so small that it cannot be visually identified. Therefore, the first
The display of the pixel and the second pixel is visually combined to recognize colors having different gradations, and color gradation display can be performed.

For example, as shown in FIG. 7A, in order to display "bright red", "red" is displayed in the first pixel,
"White" is displayed on the second pixel. By displaying in this way, "bright red" can be displayed. FIG.
As shown in (B), in order to display "a little bright red", "red" is displayed on the first pixel and "bright gray" is displayed on the second pixel. As shown in FIG. 7C, in order to display “a little dark red”, “red” is displayed in the first pixel,
"Dark gray" is displayed on the second pixel. As shown in FIG. 7D, in order to display "dark red", "red" is displayed in the first pixel.
Is displayed, and “black” is displayed on the second pixel.

Next, the operation in which the first pixel and the second pixel perform color display and gradation display respectively will be described. First, in the drive circuit 2 shown in FIG. 1, the CPU 41 processes a program stored in the program memory 42, and appropriately writes digital image data defining an image to be displayed in the image memory 43. The digital image data written in the image memory 43 by the CPU 41 is the display control circuit 4
4 is read. The display control circuit 44 converts the color data DC of each 2 bits of RGB (total 6 bits) from the read digital image data into the first conversion table 45.
The 3-bit gradation data DG to the second conversion table 4
6, respectively.

The first conversion table 45 converts the 6-bit color data DC into 4-bit digital voltage data DC 'according to the conversion table of FIG. The second conversion table 46 converts the 3-bit gradation data DG into 5-bit digital voltage data DG 'according to the conversion table of FIG.

For example, in the conversion table of FIG.
“000001” indicating “dark blue”, “000010” indicating “dark blue”, “000011” indicating “light blue”
Each of the data is converted into digital voltage data of "1001". In the conversion table of FIG. 9, the data of “000” indicating “dark gradation” is “01”.
The digital voltage data "101" and the data "111" indicating "bright gradation" are converted into the digital voltage data "10100", respectively.

The first conversion table 45 converts the converted 4-bit digital voltage data DC 'into a D / A converter 47.
A. The D / A converter 47A converts the digital voltage data DC 'into an analog color signal and supplies it to the column driver 32. Also, the second conversion table 46 is
The 5-bit digital voltage data DG 'is supplied to the D / A converter 47B. The D / A converter 47B converts this digital voltage data DG 'into an analog gradation signal and supplies it to the column driver 32.

The column driver 32 sequentially samples the analog color signal and the analog gradation signal for one scanning line and supplies a voltage corresponding to the sampled analog color signal to the odd-numbered column data lines DL to generate the analog gradation signal. A corresponding voltage is supplied to the data lines DL in even columns. The TFT 14 is turned on at the timing when the scanning signal (gate signal) is supplied from the row driver 31, and the voltages corresponding to the analog color signal and the analog gradation signal applied to the data line DL are pixel electrodes in odd and even columns, respectively. Applied to. That is, it is applied to the first pixel and the second pixel, respectively.

According to the applied voltage, the first pixel displays a corresponding color and the second pixel displays an achromatic gradation.
The display of the first pixel and the second pixel adjacent to each other is visually combined by the viewer, and a color image having gradation is recognized.

(Second Embodiment) In the first embodiment, the column driver 32 drives the first pixel and the second pixel respectively, but the first pixel and the second pixel are separately driven. You may drive with. FIG. 10 shows the structure of a birefringence control type liquid crystal display device of this structure.

The data lines DL in the odd columns have terminal portions T.
A digital driver 33 is connected via 2.
The digital driver 33 includes a first conversion table 45
Are connected and digital voltage data DC 'is supplied. On the other hand, the even-numbered data lines DL have terminal portions T3.
The analog driver 34 is connected via. A D / A converter 47 is connected to the analog driver 34,
An analog gradation signal is supplied.

The digital driver 33 samples the digital voltage data DC 'for one scanning line, converts it into an analog color signal by the D / A converter built therein, and outputs a voltage corresponding to the analog color signal. It is supplied to the odd-numbered data lines DL. The analog driver 34 is
Sampling the analog gradation signal for one scanning line,
A voltage corresponding to the sampled analog gradation signal is supplied to the data lines DL in even columns.

When the scanning signal is supplied from the row driver 31, the TFT 14 is turned on, and the voltage according to the analog color signal and the analog gradation signal is applied to the first pixel and the second pixel corresponding to the TFT 14 via the turned-on TFT 14, respectively. Is applied. Depending on the applied voltage, the first pixel displays a corresponding color. The second pixel displays an achromatic gradation.

The display of the first pixel and the display of the second pixel are combined visually by the viewer to recognize a color image having gradation.

In the above configuration, the digital driver 3
3 supplies only the voltage corresponding to the analog color signal to the data line DL. Therefore, the power supply voltage of the digital driver 33 can be suppressed to the maximum voltage (3.75 V) for displaying colors, and the power consumption can be suppressed to a low level. Further, the data DC 'supplied to the digital driver 33 is a digital signal, and the variation of the designated color due to the signal rounding in the case of an analog signal does not occur. Therefore, the color as set can be displayed on the first pixel, and color unevenness can be prevented.

The present invention is not limited to the above embodiment, but various modifications and applications are possible. For example, in the above embodiment, one dot is composed of two pixels, but it is not limited to two and may be composed of a plurality of pixels of three or more. For example, one dot may be configured by one pixel that displays a color and a plurality of pixels that display a gradation. Further, one dot may be composed of a plurality of pixels that display a color and one pixel that displays a gradation, or a plurality of pixels that display a color and a plurality of pixels that display a gradation.

In the above-described embodiment, the color display is performed by the first pixel and the gradation display is performed by the second pixel. However, separate display is performed for the first pixel and the second pixel. Instead of displaying them, the color display and the gradation display may be performed respectively in two consecutive frames.

The circuit configuration in this case is substantially the same as that of FIG. In this case, for example, in odd frames,
The first conversion table 45 and the D / A converter 47A operate, the column driver 32 sequentially samples the analog grayscale signal from the D / A converter 47A, and outputs all the voltages corresponding to the corresponding sample data. Data line DL. In the even frame, the second conversion table 46 and the D / A converter 47B operate, the column driver 32 sequentially samples the analog gradation signals from the D / A converter 47A, and the corresponding sample data. Corresponding voltage is supplied to all the data lines DL.

With this configuration, the chromatic image displayed in the odd-numbered frame and the achromatic gradation image displayed in the even-numbered frame are synthesized visually by the viewer.
A color gradation image is recognized.

It is also possible to realize the same configuration with the circuit configuration shown in FIG. However, in this case, the digital driver 33 and the analog driver 34 are connected to all the data lines DL, respectively. Therefore, the output end of the digital driver 33 and the output end of the analog driver 34 are connected via the data line DL. In the odd-numbered frame, the first conversion table 45 and the digital driver 33 operate to supply the voltage according to the gradation signal to all the corresponding data lines DL. At this time, the output end of the analog driver 34 is set to the open state. Also,
In the even-numbered frame, the second conversion table 46 and the D / A converter 47 operate to supply the voltage according to the analog gradation signal to all the corresponding data lines DL. At this time, the output end of the digital driver 33 is set to the open state.

With such a structure, the chromatic image displayed in the odd-numbered frame and the achromatic gradation image displayed in the even-numbered frame are visually combined by the viewer to recognize the color gradation image. To be done.

When an arbitrary image is displayed by combining the display images of a plurality of frames, it is desirable to set the effective frame frequency to 30 Hz or higher in order to prevent flicker.

The color displayed by each dot of the liquid crystal display element 1 is not limited to the three primary colors. By combining an arbitrary color that can be displayed on the chromaticity diagram shown in FIG. 5 and an achromatic color gradation display, gradation display of an arbitrary color can be realized.

In the above embodiment, the present invention is applied to the birefringence control type liquid crystal display element using the TFT as the active element, but the present invention is also applied to the birefringence control type liquid crystal display element using the MIM as the active element. Applicable. Further, it is also applicable to a passive matrix type birefringence control type liquid crystal display element which does not use an active element.

In the above embodiment, the polarizing plate 2
The positions of the transmission axes of 3 and 24 and the stretching axes of the phase plates 21 and 22 may be appropriately changed. Further, the polarizing plates 23 and 24 and the phase plates 21 and 22 may be appropriately omitted. Further, although the present invention is applied to the reflection type birefringence control type liquid crystal display element in the above-mentioned embodiment, the present invention is also applicable to the transmission type birefringence control type liquid crystal display element.

[0048]

As described above, according to the present invention, it is possible to provide a liquid crystal display device capable of full-color display with a simple structure.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing a configuration of a birefringence control type liquid crystal display element according to the first embodiment.

FIG. 3A is a diagram showing a direction of a transmission axis of an upper polarizing plate. (B) is a figure which shows the direction of the extending | stretching axis | shaft of an upper phase plate. (C) is a figure which shows the direction of the extending | stretching axis | shaft of a lower phase plate. (D) is a figure which shows the orientation process direction of an orientation film.
(E) is a figure which shows the direction of the transmission axis of a lower polarizing plate.
(F) is a figure which shows the direction of the hairline of a reflector.

FIG. 4 is a diagram showing a configuration of one dot of a birefringence control type liquid crystal display element.

FIG. 5 is a diagram showing a relationship among an applied voltage, a reflectance and a display color.

FIG. 6 is a chromaticity diagram of a display color of a birefringence control type liquid crystal display element.

FIG. 7 is a diagram showing an example of display colors and display gradations for one dot.

FIG. 8 is a diagram showing an example of a first conversion table.

FIG. 9 is a diagram showing an example of a second conversion table.

FIG. 10 is a block diagram showing a configuration of a liquid crystal display device according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Birefringence control type liquid crystal display element, 2 ... Drive circuit, 11
... TFT substrate, 12 ... Counter substrate, 13 ... Liquid crystal, 14 ...
..TFT, 15 ... Pixel electrode, 16 ... Alignment film, 17 ...
Counter electrode, 18 ... Alignment film, 21 ... Phase plate, 22 ... Phase plate, 23 ... Polarizer, 24 ... Polarizer, 25 ... Reflector, 31 ... Row Driver, 32 ... Column driver, 33 ...
Digital driver, 34 ... Analog driver, 41.
.... CPU, 42 ... Program memory, 43 ... Image memory, 44 ... Display control circuit, 45 ... First conversion table, 46 ... Second conversion table, 47, 47A, 47
B ... D / A converter, DC ... color data, DG ... gradation data, GL ... gate line, DL ... data line, T1
・ T2 ・ T3 ・ ・ ・ Terminal part, SC ・ ・ ・ Seal material

Claims (5)

[Claims] 1. A first substrate on which a first electrode is arranged, and a first substrate which is arranged so as to face the first substrate and a second electrode is arranged on a surface which faces the first substrate. A second substrate, a liquid crystal disposed between the first substrate and the second substrate, and a polarizing plate disposed outside at least one of the first substrate and the second substrate, Each pixel is formed by a portion where the first electrode and the second electrode face each other and a liquid crystal therebetween, and a plurality of chromatic colors are formed according to a first applied voltage in a predetermined range applied to the liquid crystal. And a birefringence control type liquid crystal display element for displaying an achromatic color according to a second applied voltage in a voltage range different from the first applied voltage range, and specifying a color and gradation of each pixel. Image data output means for outputting image data; and the image data output from the image data output means as color data. The data corresponding to the color data is applied to the first electrode and the second electrode of one of the two adjacent pixels of the birefringence control type liquid crystal display element by applying a voltage corresponding to the color data. Drive means for applying a voltage corresponding to the grayscale data between the first electrode and the second electrode of the other pixel of the two pixels, and the display of the two adjacent pixels is visually recognized. A liquid crystal display device, which displays a color and gradation indicated by the image data by combining. 2. A first substrate on which a first electrode is arranged, and a first substrate which is arranged so as to face the first substrate and has a second electrode arranged on a surface which faces the first substrate. A second substrate, a liquid crystal arranged between the first substrate and the second substrate, and a polarizing plate arranged outside at least one of the first substrate and the second substrate. The first electrode and the second electrode
Each pixel is formed by a portion facing the electrode of and the liquid crystal therebetween, and one of a plurality of chromatic colors is displayed according to a first applied voltage in a predetermined range applied to the liquid crystal, and the first pixel is displayed. A birefringence control type liquid crystal display element for displaying an achromatic color according to a second applied voltage in a voltage range different from the applied voltage range, and an image data output means for outputting image data designating a color and a gradation of each pixel. And converting the image data output from the image data output means into color data and gradation data, and continuously connecting between the first electrode and the second electrode of each pixel of the birefringence control type liquid crystal display element. Drive means for alternately applying a voltage corresponding to the color data and a voltage corresponding to the gradation data in the two frames.
A liquid crystal display device comprising: a color gradation display by visually combining display colors and display gradations of each pixel in a plurality of frames. 3. The driving means supplies a voltage corresponding to the color data with a digital driver and a voltage corresponding to the gradation data with an analog driver between the first electrode and the second electrode. The method according to claim 1 or 2, wherein
3. The liquid crystal display device according to 1. 4. One of a plurality of chromatic colors is displayed according to a first applied voltage in a predetermined range, and an achromatic color is displayed according to a second applied voltage in a voltage range different from the first applied voltage range. A birefringence control type liquid crystal display element in which a plurality of pixels for displaying are arranged in a matrix, image data output means for outputting image data designating color and gradation of each pixel, and output from the image data output means The converted image data is converted into color data and gradation data, and a voltage corresponding to the color data is applied to one of the two adjacent pixels of the birefringence control type liquid crystal display element, and the two adjacent pixels are On the other hand, a driving means for applying a voltage corresponding to the grayscale data, and a liquid crystal display device. 5. One of a plurality of chromatic colors is displayed according to a first applied voltage within a predetermined range, and an achromatic color is displayed according to a second applied voltage within a voltage range different from the first applied voltage range. A birefringence control type liquid crystal display element in which a plurality of pixels for displaying are arranged in a matrix, image data output means for outputting image data designating color and gradation of each pixel, and output from the image data output means The converted image data is converted into color data and gradation data, and two frames which are continuous between the first electrode and the second electrode of each pixel of the birefringence control type liquid crystal display element correspond to the color data. A liquid crystal display device comprising: a driving unit that alternately applies a voltage and a voltage corresponding to gradation data.