JPH1010532A - Color liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color liquid crystal display device by which bright color display is obtained and whose display color is hardly fluctuated by temperature. SOLUTION: This device is provided with 1st and 2nd liquid crystal cells 10A and 10B where liquid crystal molecules are twisted to be oriented, three polarizing plates 21, 22 and 23, and one phase difference plate 24. The respective liquid crystal cells and the respective polarizing plates are alternately laminated and arranged and the plate 24 is arranged between the liquid crystal cell 10B and the intermediate polarizing plate 22 so that its lagging axis may be obliquely deviated from the transmission axis of the polarizing plate 22. The transmission of light is controlled by either liquid crystal cell 10A and the surface-side and intermediate polarizing plates 21 and 22, so that the transmitted light is made elliptically polarized light where each wavelength light has a different polarized state by the double refraction effect of the plate 24, and made incident on the other polarizing plate 23 through the other liquid crystal cell 10B so as to obtain colored light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color liquid crystal display device for obtaining a colored display without using a color filter.

[0002]

2. Description of the Related Art As a color liquid crystal display device capable of obtaining a colored display, a device for coloring light using a color filter is generally used. However, since this color liquid crystal display device uses a color filter to color light, it has a problem that the light transmittance is low and the display is dark.

[0003] This is due to the absorption of light by a color filter. The color filter absorbs not only light of a wavelength outside the wavelength band corresponding to the color but also light of the wavelength band at a considerably high absorption rate. Therefore, the colored light that has passed through the color filter becomes light whose light intensity is significantly reduced as compared with the light in the wavelength band before the light enters the color filter, and the display becomes dark.

There are two types of liquid crystal display devices: a transmissive type that displays by using light from the backlight, and a reflective type that displays by using external light (natural light, indoor illumination light, etc.). However, if the above color liquid crystal display device is of a reflection type, light that enters from the front side, is reflected by the reflection plate on the back side, and exits to the front side passes through the color filter twice and doubles the light intensity. Because of the reduction, the display becomes extremely dark and can hardly be used as a display device.

On the other hand, conventionally, as a color liquid crystal display device for obtaining a colored display without using a color filter, EC
A B-type (birefringence effect type) liquid crystal display device is known.
This ECB type liquid crystal display device comprises a liquid crystal cell having a liquid crystal layer provided between a pair of substrates, and polarizing plates disposed on the front side and the back side, respectively. In, the linearly polarized light transmitted through one of the polarizers is converted into elliptically polarized light in which each wavelength light has a different polarization state due to the birefringence effect of the liquid crystal in the process of transmitting through the liquid crystal cell. Light incident on the other polarizing plate and transmitted through the other polarizing plate becomes colored light having a color corresponding to the ratio of the light intensities of the respective wavelength lights constituting the light.

That is, the ECB type liquid crystal display device obtains a colored display without using a color filter by utilizing the birefringence effect of the liquid crystal and the polarizing action of the polarizing plate. Since there is no absorption, the light transmittance can be increased.

For this reason, the ECB type liquid crystal display device can be used as a reflection type display device by disposing a reflection plate on the back surface side. Even in this case, a sufficiently bright color display can be obtained. .

In addition, in the ECB type liquid crystal display device, the birefringence of the liquid crystal changes depending on the alignment state of the liquid crystal molecules according to the voltage applied between the electrodes of the two substrates of the liquid crystal cell, and the other polarizing plate accordingly changes. Since the polarization state of each wavelength light incident on the liquid crystal changes, the color of the colored light can be changed by controlling the voltage applied to the liquid crystal cell.

[0009]

However, the conventional ECB type liquid crystal display device has a problem that the display color fluctuates depending on the temperature because the change in the birefringence of the liquid crystal due to the temperature affects the display color. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color liquid crystal display device which can obtain a bright color display by coloring light without using a color filter, and in which the display color does not easily change with temperature. It is.

[0011]

A color liquid crystal display device according to the present invention comprises two liquid crystal cells each having a liquid crystal layer in which liquid crystal molecules are twist-aligned between a pair of substrates having electrodes formed on the inner surface, and three liquid crystal cells. And one retardation plate, wherein the two liquid crystal cells and the three polarizing plates are alternately stacked and arranged, and one surface of any one of the liquid crystal cells and its surface Wherein the retardation plate is interposed between adjacent polarizing plates, and the optical axes of the retardation plate and the adjacent polarizing plate are obliquely shifted from each other.

This color liquid crystal display device comprises one liquid crystal cell of two liquid crystal cells and two polarizing plates sandwiching the one liquid crystal cell of the three polarizing plates. A transmission control system for controlling the transmission of light is formed, and one of the polarizing plates of the transmission controlling system, the other liquid crystal cell, the other polarizing plate, and one surface of the other liquid crystal cell and the other liquid crystal cell. A coloring system for obtaining colored light by a retardation plate interposed between a polarizing plate adjacent to the surface and a colored plate, wherein the transmission of light is controlled by the transmission control system and the transmitted light is controlled. Color display is performed by coloring with the coloring system.

The coloring effect of light by the coloring system will be described by taking as an example a case where light is incident from the side where the retardation plate is disposed. In this coloring system, the light is disposed on the retardation plate and the incident side thereof. Since the respective optical axes of the polarizing plate and the respective optical axes are obliquely shifted, light that has passed through the polarizing plate and becomes linearly polarized light and incident on the phase difference plate has a birefringence effect of the phase difference plate, thereby causing each of the visible light bands. The light of each wavelength becomes elliptically polarized light having a different polarization state, and the light passes through the liquid crystal cell, enters the opposite polarizing plate, and is transmitted through the polarizing plate (along the transmission axis of the polarizing plate). Of the polarized light component) becomes light of a color corresponding to the ratio of the light intensities of the respective wavelength lights constituting the light.

The color of the colored light varies depending on the alignment state of the liquid crystal molecules of the liquid crystal cell. When the liquid crystal molecules are in the initial twist alignment state, the light transmitted through the retardation plate (the light of each wavelength is polarized). The elliptically polarized light in different states) is rotated and incident on the opposite polarizer, and when the liquid crystal molecules rise and align almost perpendicularly to the substrate surface by applying a voltage, they pass through the retardation plate. Since the light is incident on the opposite polarizer without being rotated, the transmitted light is colored differently when the liquid crystal molecules are in the initial twist alignment state and when they are almost vertically aligned.

Since the color liquid crystal display device includes the above-described coloring system and transmission control system, the transmission control system controls the transmission of light and the transmitted light is colored by the coloring system. Multiple colors can be displayed.

Therefore, according to the color liquid crystal display device of the present invention, a bright color display can be obtained by coloring light without using a color filter, and the birefringence of the retardation plate varies with temperature. The liquid crystal cell only has to perform the function of rotating incident light or transmitting it without rotating it. Therefore, birefringence of liquid crystal depending on temperature as in the conventional ECB type liquid crystal display device is sufficient. Since the change in sex does not affect the display color, the display color hardly fluctuates depending on the temperature.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the color liquid crystal display device of the present invention, each of the three polarizing plates may be an uncolored polarizing plate, in which case, in addition to the plurality of colors obtained by the coloring system, By absorbing light by the transmission control system, it is possible to display black which cannot be obtained by the conventional ECB type liquid crystal display device.

[0018] One of the three polarizing plates may be a colored polarizing plate. In this case, one of the liquid crystal cells and two polarizing plates sandwiched between the two liquid crystal cells may be used. A transmission control system constituted by: a transmission control system, one polarizing plate, the other liquid crystal cell, another one polarizing plate, and one surface of the other liquid crystal cell and a polarizing plate adjacent to the surface. And a coloring system constituted by a retardation plate interposed therebetween, and the transmission control system is positioned on the light incident side, and the polarizing plate on the incidence side of the transmission control system is colored by a colored polarizing plate. It is preferred that

With this configuration, of the light incident on the colored polarizing plate, light in the wavelength range corresponding to the color of the polarizing plate is in the state of circularly polarized light containing polarized components in all directions. The light passes through the colored polarizer and enters the transmission control system, and light in the other wavelength range becomes linearly polarized light along the transmission axis of the colored polarizer and enters the transmission control system. When the light is absorbed, the polarized light along the transmission axis of the exit-side polarizing plate of the transmission control system out of the light incident in the state of the circularly polarized light (light in the wavelength range corresponding to the color of the colored polarizing plate). The component light exits the transmission control system and enters the coloring system. At this time, since the light entering the coloring system is light colored in the color of the colored polarizing plate, the color does not change even if the light passes through the coloring system.

Therefore, if the transmission control system is positioned on the light incident side and laminated as described above, and if the polarizing plate on the incident side of the transmission control system is a colored polarizing plate, a plurality of the polarizing systems obtained by the coloring system can be obtained. In addition to the above color, by setting the transmission control system to absorb light, another color corresponding to the color of the colored polarizing plate can be displayed.

Further, in the color liquid crystal display device of the present invention, if a reflection plate is disposed on the back surface of the laminated body of the liquid crystal cell and the polarizing plate, the color liquid crystal display device can be used as a reflection type display device for displaying by using external light. Can be.

[0022]

1 and 2 show an embodiment of the present invention. FIG. 1 is a sectional view of a color liquid crystal display device. The color liquid crystal display device of this embodiment is of a reflection type that displays by using external light such as natural light or indoor illumination light.
And two second liquid crystal cells 10A, 10B, three polarizing plates 21, 22, 23, and one retardation plate 24,
The two liquid crystal cells 10A, 10B and the three polarizing plates 21, 22, 23 are alternately stacked and arranged, and the back side (the lower side in FIG. 1) of the two liquid crystal cells 10A, 10B. Liquid crystal cell 10B arranged in
The phase difference plate 24 is interposed between the front surface of the liquid crystal panel and the polarizing plate 22 adjacent to the surface, and the back surface of the laminate of the liquid crystal cells 10A, 10B, the polarizing plates 21, 22, 23, and the phase difference plate 24 And a reflection plate 25 is disposed in the first position.

The first and second liquid crystal cells 10A, 10B
Are transparent electrodes 1 made of an ITO film or the like on the inner surface.
A liquid crystal layer 18 in which liquid crystal molecules are twist-oriented is provided between a pair of front and back transparent film substrates 11 and 12 on which alignment films 15 and 16 are formed. The substrates 11 and 12 are frame-shaped sealing materials 17.
And the liquid crystal 18 is connected to both substrates 11 and 12.
It is sealed in a region surrounded by the sealing material 17 between the two.

The liquid crystal cells 10A, 10B
Is a segment type, and each liquid crystal cell 10A,
The transparent electrode 13 formed on the front substrate 11 of 10B is a common electrode, and the transparent electrode 14 formed on the rear substrate 12 is a plurality of segment electrodes. The segment electrodes 14 are formed in the same pattern in both the liquid crystal cells 10A and 10B. Have been.

The liquid crystal 18 is a nematic liquid crystal to which a chiral agent is added.
The orientation direction of the molecules of the B liquid crystal 18 in the vicinity of the substrates 11 and 12 is regulated by the orientation films 15 and 16.
In a state where the substrates are inclined at a slight pretilt angle with respect to the surfaces 1 and 12, the substrates 11 and 12 are twist-oriented at a predetermined twist angle.

The first and second liquid crystal cells 10A, 10B
And the twist angles of the liquid crystal molecules are substantially the same, and the value of Δnd (the product of the refractive index anisotropy Δn of the liquid crystal 18 and the thickness d of the liquid crystal layer) of both liquid crystal cells 10A and 10B is set to be substantially the same. Have been. The value of Δnd is about 476 nm
Alternatively, it is preferable to select about 1065 nm.

In this embodiment, the twist angles of the liquid crystal molecules of each of the liquid crystal cells 10A and 10B are set to 90 degrees.
°, and the three polarizing plates 21, 22, 23
Are all ordinary non-colored polarizing plates, and these polarizing plates 21, 22, 23 and the retardation plate 24 are each connected to an optical axis (a transmission axis for a polarizing plate and a slow axis for a retardation plate). Are oriented in the following directions.

That is, in this embodiment, the transmission axis of the front polarizing plate 21 disposed on the surface of the first liquid crystal cell 10A, which is the front liquid crystal cell, is set to the front polarizing plate 21 of the first liquid crystal cell 10A. The direction along the alignment direction of the liquid crystal molecules in the vicinity of the adjacent front side substrate 11 is set to
The transmission axis of the intermediate polarizer 22 disposed between the first and second liquid crystal cells 10A and 10B is set in a direction along the alignment direction of the liquid crystal molecules in the vicinity of the back substrate 12 adjacent to the intermediate polarizer 22 of the first liquid crystal cell 10A. The slow axis of the phase difference plate 24 disposed between the intermediate polarizer 22 and the second liquid crystal cell 10B is obliquely shifted by about 45 ° with respect to the transmission axis of the intermediate polarizer 22. The orientation direction of the liquid crystal molecules in the vicinity of the front substrate 11 adjacent to the phase difference plate 24 of the second liquid crystal cell 10B is inclined at a shift angle of about 45 ° with respect to the direction of the slow axis of the phase difference plate 24. And the transmission axis of the back side polarizing plate 23 disposed on the back side of the second liquid crystal cell 10B is shifted to the back side polarizing plate 23 of the second liquid crystal cell 10B.
The direction is set substantially perpendicular to the orientation direction of the liquid crystal molecules in the vicinity of the back substrate 12 adjacent to.

FIG. 2 shows the liquid crystal molecule orientation directions near the two substrates of each of the liquid crystal cells 10A and 10B of the color liquid crystal display device, the transmission axes of the polarizing plates 21, 22 and 23, and the slow axis of the phase difference plate 24. FIG. 3 is a view of the direction of the liquid crystal display as viewed from the front side of the liquid crystal display device.

As shown in FIG. 2, in each of the first and second liquid crystal cells 10A and 10B, the front substrate 11 is provided.
Is approximately 47 ° counterclockwise when viewed from the front side with respect to the horizontal axis S of the screen of the display device.
, The orientation direction 12a of the liquid crystal molecules in the vicinity of the back substrate 12 is about 47 ° clockwise with respect to the horizontal axis S when viewed from the front side.
The molecules of the liquid crystal 18 of A and 10B are moved from the back substrate 12 to the front substrate 11 as indicated by the dashed arrows in the twist direction.
, A twist orientation of about 86 ° in a clockwise direction as viewed from the surface side.

On the other hand, the three polarizing plates 21, 22, 23
Of the front polarizer 21 on the surface of the first liquid crystal cell 10A
Is arranged with its transmission axis 21a oriented counterclockwise about 50 ° with respect to the horizontal axis S from the front side, so that the transmission axis 21a of the front-side polarizing plate 21 is
In the vicinity of the front substrate 11 of the liquid crystal cell 10A.

The intermediate polarizing plate 22 between the liquid crystal cells 10A and 10B is arranged so that its transmission axis 22a is oriented approximately 130 ° counterclockwise with respect to the horizontal axis S when viewed from the front side. Therefore, the transmission axis 22 of the intermediate polarizing plate 22
a is in a direction along the alignment direction 12a of the liquid crystal molecules in the vicinity of the back substrate 12 of the first liquid crystal cell 10A.

Further, the retardation plate 24 between the intermediate polarizer 22 and the second liquid crystal cell 10B has its slow axis 24a oriented in a direction substantially parallel to the horizontal axis S (the shift angle with respect to the horizontal axis S is substantially zero). 0 ° direction) and therefore
The slow axis 24a of the retardation plate 24 is
About 5 counterclockwise with respect to the transmission axis 22a of FIG.
It is inclined at an angle of 0 °, and is inclined at an angle of about 47 ° clockwise as viewed from the front side with respect to the orientation direction 11a of the liquid crystal molecules in the vicinity of the front substrate 11 of the second liquid crystal cell 10B.

The rear polarizing plate 23 on the rear surface of the second liquid crystal cell 10B is arranged with its transmission axis 23a oriented approximately 45 ° counterclockwise with respect to the horizontal axis S when viewed from the front side. Therefore, the transmission axis 23 of the rear polarizing plate 23
a is in a direction substantially orthogonal to the alignment direction 12a of the liquid crystal molecules in the vicinity of the back substrate 12 of the second liquid crystal cell 10B.

This color liquid crystal display device comprises a first liquid crystal cell 10A disposed on the front side of the two liquid crystal cells 10A and 10B, and a first liquid crystal cell 10A of the three polarizing plates 21, 22 and 23. A transmission control system for controlling transmission of light is constituted by the front-side polarizing plate 21 and the intermediate polarizing plate 22 interposed between the liquid crystal cells 10A, and the intermediate polarizing plate, which is one of the transmission controlling systems, 22, the second liquid crystal cell 10B, and a back-side polarizing plate 23, which is another polarizing plate.
And a phase difference plate 24 interposed between the surface of the second liquid crystal cell 10B and the intermediate polarizer 22 adjacent to the surface.
And a coloring system for obtaining colored light, wherein the transmission of light is controlled by the transmission control system, and the transmitted light is colored by the coloring system to perform color display.

First, control of light transmission by the transmission control system will be described.
The external light (white light) incident on the front polarizing plate 21 from the front side of the liquid crystal display element is transmitted through the transmission axis 21 of the front polarizing plate 21.
The light becomes linearly polarized light along a and enters the first liquid crystal cell 10A.

When the first liquid crystal cell 10A is in the OFF state, that is, when the liquid crystal molecules are in the initial twisted state in which the liquid crystal molecules are most inclined with respect to the substrates 11 and 12, the light passes through the front side polarizing plate 21. And the first liquid crystal cell 10
A (linearly polarized light) incident on A is rotated and the intermediate polarizer 2
In this case, the first liquid crystal cell 10A
Is transmitted through the intermediate polarizing plate 22 and enters the next coloring system.

When an ON voltage is applied between the electrodes 13 and 14 of the two substrates 11 and 12 of the first liquid crystal cell 10A, the ON voltage is high enough to cause the liquid crystal molecules to sufficiently rise. Rises almost vertically with respect to
As described above, when the first liquid crystal cell 10A is turned on, that is, when the liquid crystal molecules are aligned in a substantially vertical rising direction, the first liquid crystal cell 1A is transmitted through the front side polarizing plate 21 and is turned on.
Since the light (linearly polarized light) incident on the first liquid crystal cell 10A is transmitted without being rotated and is incident on the intermediate polarizer 22, the light transmitted through the first liquid crystal cell 10A is transmitted by the intermediate polarizer 22A.
Is absorbed by.

Next, the coloring effect of light by the coloring system will be described. In this embodiment, the retardation plate 24 is disposed between the intermediate polarizing plate 22 and the second liquid crystal cell 10B. The light transmitted through the transmission control system enters the coloring system from the side where the retardation plate 24 is disposed.

In this coloring system, the retardation plate 2
4 and the transmission axis 22a of the intermediate polarizing plate 22 disposed on the incident side thereof are obliquely shifted, so that the light passes through the intermediate polarizing plate 22 to become linearly polarized light and is incident on the phase difference plate 24. Is converted into elliptically polarized light in which each wavelength light in the visible light band has a different polarization state due to the birefringence effect of the phase difference plate 24, and the light passes through the second liquid crystal cell 10B and is on the opposite side. Incident on the back-side polarizing plate 23 and transmitted through the back-side polarizing plate 23 (the transmission axis 23 of the back-side polarizing plate 23).
The light of the polarized light component along a) becomes light of a color corresponding to the ratio of the light intensity of each wavelength light constituting the light.

The color of the colored light depends on the color of the second liquid crystal cell 1.
When the liquid crystal molecules are in the initial twisted alignment state in which the liquid crystal molecules are most inclined with respect to the surfaces of the substrates 11 and 12, when the liquid crystal molecules are in the initial twisted alignment state, the light transmitted through the retardation plate 24 (each wavelength light is polarized). The elliptically polarized light having different states) is rotated and incident on the back-side polarizing plate 23, and when the liquid crystal molecules rise and align substantially perpendicularly to the surfaces of the substrates 11 and 12 by application of a voltage, the phase difference plate 24 Is incident on the rear polarizing plate 23 without being rotated.

Therefore, the second liquid crystal cell 10B is
When the liquid crystal molecules are in the FF state, that is, when the liquid crystal molecules are in the initial twist alignment state, and when the second liquid crystal cell 10B
When the liquid crystal molecules are in the FF state, that is, when the liquid crystal molecules rise almost vertically, the polarization state of the light incident on the rear polarizing plate 23 is different.
The light transmitted through is colored differently.

Since the color liquid crystal display device has the above-mentioned coloring system and transmission control system, the transmission control system controls the transmission of light and the transmitted light is colored by the coloring system. Multiple colors can be displayed.

In this embodiment, the display is of a reflection type in which display is performed by using external light such as natural light or indoor illumination light, and light colored by the above-described coloring system, that is, light transmitted through the back-side polarizing plate 23. Then, the light is reflected by the reflection plate 25 disposed on the back surface of the back-side polarizing plate 23 and is emitted to the front surface side of the liquid crystal display device.

The color of the colored light obtained by the coloring system is determined by the retardation value of the retardation plate 24 and the transmission axis 22a of the intermediate polarizing plate 22 disposed on the incident side of the retardation plate 24. Angle of the plate 24 with respect to the slow axis 24a, the orientation direction of the liquid crystal molecules in the vicinity of the two substrates 11 and 12 of the second liquid crystal cell 10B, and
And the direction of the transmission axis 23a.

For example, when the retardation plate 24 has a retardation value of 620 nm, the second liquid crystal cell 10
B, the orientation directions 11a and 12a of the liquid crystal molecules in the vicinity of the substrates 11 and 12, the directions of the transmission axes 22a and 23a of the intermediate polarizer 22 and the rear polarizer 23, and the slow axis 24a of the retarder 24. Is set as shown in FIG. 2, orange colored light is obtained when the second liquid crystal cell 10B is in the OFF state.
Blue colored light is obtained when OB is in the ON state.

In this embodiment, since the three polarizing plates 21, 22, and 23 are all uncolored polarizing plates, a plurality of colors obtained by the coloring system, for example, the orange and blue colors are obtained. In addition, by absorbing light by the transmission control system, it is possible to display black which cannot be obtained by the conventional ECB type liquid crystal display device.

The change of the display color due to ON / OFF of each of the liquid crystal cells 10A and 10B in this color liquid crystal display device is summarized as follows. 1st cell OFF, 2nd cell OFF ... orange 1st cell OFF, 2nd cell ON ... blue 1st cell ON, 2nd cell OFF ... black 1st cell ON, 2nd cell ON ... black Therefore, the above color liquid crystal display According to the device, orange as a display color when the first and second liquid crystal cells 10A and 10B are both in the OFF state is set as a background, and the lighting color in the background is selected from two types of blue and black. Thus, a display with variations can be realized.

The above-mentioned color liquid crystal display device has a first liquid crystal cell 10A, 10B.
Liquid crystal cell 10A, and the three polarizing plates 21, 22, 2
3, the transmission of light is controlled by the front-side polarizing plate 21 and the intermediate polarizing plate 22 which are arranged with the first liquid crystal cell 10A interposed therebetween, and the intermediate polarized light which is one of the polarizing plates of this transmission control system. Plate 22, a second liquid crystal cell 10B, a backside polarizing plate 23 as another polarizing plate, and a surface of the second liquid crystal cell 10B and the intermediate polarizing plate 2 adjacent to the surface.
Since the transmitted light is colored by the phase difference plate 24 interposed between the light emitting device 2 and the color display, a color display can be obtained by coloring the light without using a color filter. The birefringence of the retardation plate 24 hardly changes even when the temperature changes, and the liquid crystal cell 1
Since 0A and 10B only have to function to rotate incident light or transmit without rotating the incident light, a change in the birefringence of the liquid crystal due to temperature affects the display color as in a conventional ECB type liquid crystal display device. Therefore, the display color hardly fluctuates depending on the temperature.

The background color and the lighting color of the color liquid crystal display device can be arbitrarily selected by using retardation plates having different retardation values. For example, the second liquid crystal cell 10B Both substrates 11, 1
2, the orientation directions 11a and 12a of the liquid crystal molecules near
And the directions of the transmission axes 22a and 23a of the intermediate polarizer 22 and the rear polarizer 23, and the slow axis 2 of the retarder 24.
When the direction of 4a is set as shown in FIG. 2, the relationship between the value of the retardation Re of the phase difference plate 24, the background color, and the lighting color is as follows.

When Re = 510 nm Background color: green, lighting color: red (purple), black When Re = 510 nm Background color: yellow, lighting color: purple, black When Re = 1400 nm Background color: pink, lighting Color: green, black In the above embodiment, the first and second liquid crystal cells 10A,
The 10B segment electrodes 14 are formed in the same pattern, but the second liquid crystal cell 10B is a colored liquid crystal cell.
Each segment electrode 14 may be further divided into a plurality of electrodes. In this case, one lighting pattern can be displayed by being classified into the two lighting colors.

Further, in the above embodiment, the transmission control system and the coloring system are laminated with the transmission control system positioned on the light incident side (front side). In this case, the retardation plate 24 is disposed between the front polarizing plate 21 and the first liquid crystal cell 10A, and a coloring system is constituted by these and the intermediate polarizing plate. , The intermediate polarizer 22, the second liquid crystal cell 10B, and the back polarizer 2
3 to form a transmission control system. In this case, first, incident light is colored by the coloring system, and transmission of the light is controlled by the transmission control system.

In the above embodiment, three polarizing plates 2 were used.
Each of the polarizers 1, 22, and 23 is an uncolored polarizer, but one of the three polarizers 21, 22, and 23 may be a colored polarizer colored in a predetermined color. In this case, a transmission control system including one liquid crystal cell 10A and two polarizing plates 21 and 22 sandwiching the liquid crystal cell 10A, and one polarizing plate 22 and the other polarizing plate 22 of the transmission control system. The liquid crystal cell 10B, another one polarizing plate 23, and one surface of the other liquid crystal cell 10B and the polarizing plate 22 adjacent to the surface.
And a coloring system constituted by the phase difference plate 24 interposed between the transmission control system and the transmission control system as in the above-described embodiment. It is preferable that the front-side polarizing plate 21, which is the polarizing plate on the side, is a colored polarizing plate.

With such a configuration, of the light incident on the colored polarizing plate (front side polarizing plate) 21, the light in the wavelength range corresponding to the color of the polarizing plate 21 is a circle containing polarized components in all directions. The polarized light passes through the colored polarizing plate 21 and enters the transmission control system while being in a polarized state, and light in the other wavelength region becomes linearly polarized light along the transmission axis 21a of the colored polarizing plate 21 and enters the transmission control system. Therefore, when the transmission control system is set in a state of absorbing light, the incident light (colored polarizing plate 2) remains circularly polarized.
The light of the polarization component along the transmission axis 22a of the transmission-side polarization plate 22 of the transmission control system out of the light of the wavelength range corresponding to the one color) exits the transmission control system and enters the coloring system. At this time, since the light entering the coloring system is light colored in the color of the colored polarizing plate 21, even if this light passes through the coloring system, the color does not change.

Therefore, when the transmission control system is positioned on the light incident side and laminated as described above, and the polarizing plate 21 on the incident side of the transmission control system is a colored polarizing plate, the transmission system can be obtained by the coloring system. By setting the transmission control system to absorb light in addition to the plurality of colors, another color corresponding to the color of the colored polarizing plate 21 can be displayed.

In this case, it is desirable to use, as the colored polarizing plate 21, a polarizing plate having a color different from a plurality of colors obtained by the coloring system. That is, for example,
The retardation R of the retardation plate 24 constituting the coloring system
When the value of e is 620 nm, and the colors obtained by the coloring system are the orange background color and the blue lighting color, another lighting is performed by using a red or green polarizing plate as the colored polarizing plate 21. It is desirable that the color, that is, the lighting color obtained by the colored polarizing plate 21 be red or green.

Further, in the above embodiment, each liquid crystal cell 10
Although the segment type is used for A, 10B and 10C, these liquid crystal cells may be of the dot matrix type, and the present invention is not limited to the reflection type, but the light from the backlight may be used. It is needless to say that the present invention can also be applied to a transmission type liquid crystal display device that performs display by utilizing the above.

[0058]

The color liquid crystal display device of the present invention comprises two liquid crystal cells each having a liquid crystal layer in which liquid crystal molecules are twist-aligned between a pair of substrates having electrodes formed on the inner surface, and three polarizing plates. A retardation plate, wherein the two liquid crystal cells and the three polarizing plates are alternately laminated and arranged, and one of the liquid crystal cells and a polarized light adjacent to the surface. Wherein the optical axis of the phase difference plate and the optical axis of the polarizing plate adjacent thereto are obliquely shifted from each other, and one of the liquid crystal cells of the two liquid crystal cells The transmission of light is controlled by a cell and two polarizing plates disposed between the one liquid crystal cell of the three polarizing plates, and each wavelength light is controlled by a birefringence effect of the retardation plate. Creates elliptically polarized light with different polarization states, Is applied to another polarizing plate through the other liquid crystal cell to obtain colored light, so that light can be colored without using a color filter to obtain a bright color display. The display color does not easily change depending on the temperature.

In the color liquid crystal display device of the present invention,
If all of the three polarizing plates are uncolored polarizing plates,
In addition to the plurality of colors obtained by the coloring system, by absorbing light by the transmission control system, the conventional ECB
It is possible to display black, which cannot be obtained with the liquid crystal display device.

One of the three polarizing plates may be a colored polarizing plate. In this case, one of the liquid crystal cells and two polarizing plates sandwiching the liquid crystal cell sandwich the liquid crystal cell. A transmission control system to be constructed, and one of a polarizing plate, another liquid crystal cell, another one polarizing plate, and one surface of the other liquid crystal cell and a polarizing plate adjacent to the surface of the other liquid crystal cell of the transmission control system. A coloring system constituted by a phase difference plate interposed therebetween,
While laminating the transmission control system on the light incident side and stacking, if the polarizing plate on the incident side of the transmission control system is a colored polarizing plate, in addition to the plurality of colors obtained by the coloring system,
By setting the transmission control system in a state of absorbing light,
Another color corresponding to the color of the colored polarizing plate can be displayed.

Further, in the color liquid crystal display device of the present invention, if a reflection plate is arranged on the back surface of the laminated body of the liquid crystal cell and the polarizing plate, the color liquid crystal display device can be used as a reflection type display device for displaying using external light. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of a color liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a liquid crystal molecule alignment direction and a transmission axis direction of each polarizing plate in the vicinity of both substrates of each liquid crystal cell of the color liquid crystal display device.

[Explanation of symbols]

 10A, 10B: Liquid crystal cell 11a: Orientation direction of liquid crystal molecules near the front substrate 12a: Orientation direction of liquid crystal molecules near the back substrate 21, 22, 23 ... Polarizers 21a, 22a, 23a ... Transmission axis 24 ... Phase difference Plate 24a: Slow axis 25: Reflector

Claims (4)

[Claims] 1. A liquid crystal cell comprising a liquid crystal layer in which liquid crystal molecules are twist-aligned between a pair of substrates having electrodes formed on an inner surface thereof, three polarizing plates, and one retardation plate. Prepared,
The two liquid crystal cells and the three polarizing plates are alternately stacked and arranged, and the retardation plate is interposed between one surface of one of the liquid crystal cells and a polarizing plate adjacent to the surface. Wherein the optical axes of the phase difference plate and the polarizing plate adjacent thereto are obliquely shifted from each other. 2. A color liquid crystal display device according to claim 1, wherein each of said three polarizing plates is a non-colored polarizing plate. 3. The color liquid crystal display device according to claim 1, wherein one of the three polarizing plates is a colored polarizing plate. 4. A reflection plate is provided on the back surface of a laminate of a liquid crystal cell, a polarizing plate and a retardation plate.
3. The color liquid crystal display device according to any one of 3.