JPH08328001A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE: To embody a multicolor display which is bright and is extremely colorful by coloring light without using color filters and displaying white and black which are the fundamental of display and three primary colors of red, green and blue. CONSTITUTION: This color liquid crystal display device has a liquid crystal cell 10 formed by twist-orienting liquid crystal molecules 90 deg., polarizing plates 21, 22, a reflection plate 20 and phase difference plates 23, 24. The Δnd of the liquid crystal cell 10, the retardation of the phase difference plates 23, 24, the transmission axis of the polarizing plates 21, 22 and the direction of the delay phase axes of the phase difference plates 23, 24 are so set that the colors of exit light change to red, green, blue, black and white according to impressed voltage. The transmission axis of the one polarizing plate 21 with respect to the orientation direction of the liquid crystal molecules near the one substrate 11 of the liquid crystal cell 10 is set in the direction of 110 to 130 deg. in a direction reverse from the twist direction of the liquid crystal molecules. The transmission axis of the other polarizing plate 22 is set in a direction of 127 to 140 deg. in a direction reverse from the twist direction of the liquid crystal molecules.

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 providing a colored display, one that colors light using a color filter is generally used.

However, this color liquid crystal display device has a problem that the light transmittance is low and therefore the display is dark because it uses a color filter to color light.

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

There are two types of liquid crystal display devices, a transmissive type which uses the light from its backlight for display, and a reflective type which uses external light such as natural light or room illumination light to place that light on the back side. There is a reflection type that reflects the light on a plate for display, but when the color liquid crystal display device is a reflection type, the light that enters from the front surface side, is reflected by the reflection plate on the back surface side, and goes out to the front surface side is colored. Since the light intensity is doubly reduced by passing through the filter twice, the display becomes extremely dark, making it almost useless as a display device.

Moreover, in the above color liquid crystal display device, since the display color of each pixel is determined by the color of the color filter corresponding to that pixel, in order to display many colors,
For example, it is necessary to obtain a desired display color by controlling the light transmission of each pixel by forming a set of three pixels corresponding to the color filters of the three primary colors of red, green and blue. The intensity of light is significantly weakened and the display color is dark.

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.

In this ECB type liquid crystal display device, a liquid crystal cell sandwiching a liquid crystal between a pair of substrates is sandwiched, and a polarizing plate is arranged on each of the front surface side and the back surface side of the liquid crystal cell. In the device, the linearly polarized light that has passed through one of the polarizing plates and is incident becomes elliptically polarized light with each polarization state having different polarization states due to the birefringence effect of the liquid crystal layer in the process of passing through the liquid crystal cell. The light is incident on the other polarizing plate and the light transmitted through the other polarizing plate becomes colored light having a color corresponding to the ratio of the light intensities of the respective wavelength light components of the light.

That is, the ECB type liquid crystal display device is
Light is colored by utilizing the birefringence effect of the liquid crystal layer of the liquid crystal cell and the polarization effect of the pair of polarizing plates without using a color filter. Therefore, there is no absorption of light by the color filter. It is possible to obtain a bright color display by increasing the transmittance.

Moreover, in the ECB type liquid crystal display device, the birefringence of the liquid crystal layer changes depending on the alignment state of the liquid crystal molecules according to the voltage applied between the electrodes of both substrates of the liquid crystal cell, and the birefringence of the other liquid crystal layer changes accordingly. Since the polarization state of each wavelength light entering the polarizing plate changes, the color of the colored light can be changed by controlling the voltage applied to the liquid crystal cell, and therefore, the same pixel displays multiple colors. be able to.

[0011]

However, in the conventional ECB type liquid crystal display device, white and black which are the basics of display cannot be obtained, and red, green and blue which are the three primary colors of light can be displayed. Therefore, it is impossible to display full-color or multi-color with rich colors called multi-color.

According to the present invention, light can be colored without using a color filter, and a plurality of colors can be displayed by the same pixel. Moreover, white, black, red, and
It is an object of the present invention to provide a color liquid crystal display device capable of displaying three primary colors of green and blue to realize a clear and rich multicolor display.

[0013]

According to the present invention, a liquid crystal is sandwiched between a pair of substrates on which electrodes are formed, and molecules of the liquid crystal are twisted by about 90 ° from one substrate side to the other substrate side. A liquid crystal cell that is twist-aligned in a predetermined direction at an angle, a pair of polarizing plates that sandwich the liquid crystal cell, and one of the polarizing plates and the liquid crystal cell are laminated to each other. And the retardation value of each of the two retardation plates, the product of the refractive index anisotropy Δn of the liquid crystal of the liquid crystal cell and the liquid crystal layer thickness d, and the retardation value of each of the two retardation plates. And the direction of the transmission axis or the absorption axis of each of the pair of polarizing plates and the direction of the slow axis or the fast axis of each of the two retardation plates when the incident light is white light. The color of the emitted light depends on the voltage applied between the electrodes on both substrates of the liquid crystal cell. Depending on the, at least red, green,
The basic configuration is to change to blue, black, and white, and when the alignment direction of liquid crystal molecules near one substrate of the liquid crystal cell is 0 °, the pair of One of the polarizing plates has a transmission axis or an absorption axis of 110 ° to 130 ° in a direction opposite to the liquid crystal molecule twist direction of the liquid crystal cell, and the other polarizing plate has a transmission axis or an absorption axis of the twist direction. 127 ° -14 in the opposite direction
It is characterized by being in the direction of 0 °.

The first retardation plate of the two retardation plates has its slow axis oriented in the direction of 60 ° to 70 ° in the direction opposite to the twist direction of liquid crystal molecules with respect to the direction of 0 °. Place and
The second retardation plate is preferably arranged such that its slow axis is in the direction of 150 ° to 165 ° in the direction opposite to the twist direction with respect to the direction of 0 °.

Further, according to the present invention, in the above basic structure, the value of Δnd of the liquid crystal cell is 800 nm to 1100 n.
m, the retardation value of the first retardation plate of the two retardation plates is 350 nm to 610 nm, and the retardation value of the second retardation plate is 400 nm to 650 nm.

Here, the value of Δnd of the liquid crystal cell is 92.
0 nm to 1050 nm, the retardation value of the first retardation plate is 570 nm ± 2.5 nm to 590 nm ± 2.5
nm, the retardation value of the second retardation plate is 585n
m ± 2.5 nm to 605 nm ± 2.5 nm is desirable, and the retardation value of the first retardation plate is 575 nm ± 2.5 nm to 585 nm ± 2.5.
nm range, the retardation value of the second retardation plate is 5
The range of 85 nm ± 2.5 nm to 605 nm ± 2.5 nm is more desirable.

Further, according to the present invention, in the above basic structure, the retardation value of the first retardation plate of the two retardation plates is 350 nm to 610 nm, and the retardation value of the second retardation plate is 400 nm. .About.650 nm, the slow axis or fast axis of the first retardation plate in the direction of 60.degree. To 70.degree. In the direction opposite to the liquid crystal molecule twist direction with respect to the direction of 0.degree. The slow axis or the fast axis of the retardation plate is 150 ° to 1 in the direction opposite to the twist direction.
It is characterized in that the direction is 65 °.

Furthermore, according to the present invention, in the above basic structure, the retardation value of the first retardation plate of the two retardation plates is 350 nm to 610 nm, and the retardation value of the second retardation plate is the same. 400 nm to 650 nm, and with respect to the 0 ° direction, the transmission axis or the absorption axis of one of the pair of polarizing plates is 110 ° to 130 ° in the direction opposite to the liquid crystal molecule twist direction. The transmission axis or absorption axis of the other polarizing plate is in the direction of 127 ° to 140 ° in the direction opposite to the twist direction, and the slow axis or the fast axis of the first retardation plate is in the direction opposite to the twist direction. In the direction of ° to 70 °, and the slow axis or the fast axis of the second retardation plate in the direction opposite to the twist direction to 150 ° to 1
It is characterized in that the direction is 65 °.

One of the polarizing plates has a transmission axis of 113 ° ± in the direction opposite to the liquid crystal molecule twist direction with respect to the direction of 0 °.
The polarizing plate is arranged in the direction of 1 ° to 119 ° ± 1 °, and the other polarizing plate has a transmission axis of 127 ° ± 1 ° to 137 ° ± 1 in a direction opposite to the twist direction with respect to the direction of 0 °. The first retardation plate has a slow axis of 61 ° ± 1 ° to 67 ° ± 1 ° in the direction opposite to the liquid crystal molecule twist direction with respect to the direction of 0 °. The second retardation plate has a slow axis of 156 ° ± 1 ° to a direction opposite to the twist direction with respect to the 0 ° direction.
It is desirable to dispose in the direction of 60 ° ± 1 °, and further, the angle of the transmission axis of one polarizing plate with respect to the direction of 0 ° is 115 ° ± 1 ° to 117 °, and the transmission of the other polarizing plate. The angle of the axis is 129 ° ± 1 ° to 135 ° ± 1 °,
More preferably, the angle of the slow axis of the first retardation plate with respect to the 0 ° direction is 62 ° ± 0.5 ° to 66 ° ± 0.5 °. The value of Δnd of the liquid crystal cell is 800 nm
The range of 1100 nm is preferred.

Further, according to the present invention, in addition to the above basic structure, in a reflective type color liquid crystal display device in which a reflecting plate is arranged on the back side of the other polarizing plate, the value of Δnd of the liquid crystal cell is 9
20 nm to 1050 nm, the first of the two retardation plates
The retardation value of the retardation plate of 350 nm to 610
nm, the retardation value of the second retardation plate is 400 n
m to 650 nm, and the transmission axis or absorption axis of the polarizing plate on the side where the retardation plate is arranged is 110 ° to 1 in the direction opposite to the liquid crystal molecule twist direction with respect to the 0 ° direction.
The direction of 30 °, the transmission axis or the absorption axis of the other polarizing plate is set in the direction of 130 ° to 140 ° in the direction opposite to the twist direction, and the slow axis or the fast axis of the first retardation plate is set in the twist direction. And 60 ° to 70 ° in the opposite direction, and the slow axis or the fast axis of the second retardation plate is in the opposite direction to the twist direction of 150 ° to 165 °.

According to the present invention, in the above two retardation plates, the retardation plate having the smaller retardation value is adjacent to the polarizing plate, and the retardation plate having the larger retardation value is adjacent to the liquid crystal cell. It is characterized by being arranged.

The color liquid crystal display device according to the present invention colors light by utilizing the birefringence action of the liquid crystal layer of the liquid crystal cell and the retardation plate and the polarization action of the pair of polarizing plates.
In this color liquid crystal display device, linearly polarized light that has passed through one of the polarizing plates and is incident is caused by the birefringence action of each retardation plate and the birefringence action of the liquid crystal layer in the process of passing through the two retardation plates and the liquid crystal cell. The polarization state can be changed, and each wavelength light becomes elliptically polarized light with different polarization state, enters the other polarizing plate, and the light transmitted through this polarizing plate is the wavelength light that composes the light. The colored light has a color corresponding to the ratio of the light intensities.

The birefringence effect of the liquid crystal layer of the liquid crystal cell is changed by the change of the alignment state of the liquid crystal molecules according to the voltage applied to the liquid crystal layer, and the light incident on the other polarizing plate is accordingly changed. Since the polarization state of the liquid crystal changes, the coloration of the light changes according to the ratio of the light intensity of each wavelength light transmitted through this polarizing plate, and the display color of the color liquid crystal display device is changed between the electrodes of both substrates of the liquid crystal cell. Depending on the applied voltage, at least red, green, blue, black, and white are changed.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
A case of applying to a reflective color liquid crystal display device that utilizes external light (natural light, indoor illumination light, etc.) and reflects light incident from the front surface side by a reflection plate arranged on the rear surface side for display will be described with reference to the drawings. To do. 1 and 2 show an embodiment in which the present invention is applied to a reflective color liquid crystal display device, and FIG. 1 is a sectional view of the color liquid crystal display device.

This color liquid crystal display device includes a liquid crystal cell 10
And a front-side polarizing plate 21 and a back-side polarizing plate 22 which are arranged on the front surface side and the back surface side of the liquid crystal cell 10, respectively.
The reflection plate 20 arranged on the back side of the back side polarizing plate 22.
And two retardation films 23 and 24 which are laminated and arranged between the front side polarizing plate 21 and the liquid crystal cell 10. The reflection plate 20 is an omnidirectional reflection plate in which a metal film such as silver or aluminum is deposited on the surface of a base sheet made of a resin film or the like.

The liquid crystal cell 10 has transparent electrodes 13 and 14 formed of an ITO film or the like, on which alignment films 15 and 16 are formed.
A pair of transparent substrates (for example, glass substrates) 11 on which
A nematic liquid crystal 18 is sandwiched between 12 and molecules of the nematic liquid crystal are twisted between the substrates 11 and 12, and the substrates 11 and 12 are bonded to each other via a frame-shaped sealing material 17. Is sealed in a region surrounded by the sealing material 17 between the two substrates 11 and 12.

The liquid crystal cell 10 is of an active matrix type in which a TFT (thin film transistor) is an active element, and the electrode 1 formed on the substrate 11 on the back side thereof.
3 is a plurality of pixel electrodes arranged in rows and columns,
The electrode 14 formed on the substrate 12 on the front surface side is a single film-shaped counter electrode facing all of the pixel electrodes 13.

Although not shown in FIG. 1, the substrate 11 on which the pixel electrodes 13 are formed has a plurality of TFTs connected to each pixel electrode 13 and a gate wiring for supplying a gate signal to each row TFT. And data wiring for supplying a data signal to the TFTs in each column.

The alignment films 15 and 16 provided on both the substrates 11 and 12 are horizontal alignment films made of polyimide or the like, and the alignment films 15 and 16 are each subjected to an alignment treatment (rubbing treatment) in a predetermined direction. Therefore, the molecules of the liquid crystal 18 are regulated by the alignment films 15 and 16 in the alignment direction on both substrates 11 and 12 (on the alignment films 15 and 16), and a slight pretilt angle with respect to the surfaces of the alignment films 15 and 16. Tilted at about 9 ° from one substrate side to the other substrate side.
It is twist-oriented in a predetermined direction with a twist angle of 0 °.

In this color liquid crystal display device, the value of the product Δnd of the refractive index anisotropy Δn of the liquid crystal 18 of the liquid crystal cell 10 and the liquid crystal layer thickness d, and the two retardation plates 23,
The respective retardation values Re1 and Re2 of 24, the directions of the transmission axis or the absorption axis of the pair of front and back polarizing plates 21 and 22, and the slow axis or the fast axis of each of the two retardation plates 23 and 24. The direction of the light emitted from the liquid crystal cell 10 when the incident light is white light is
It is set such that at least red, green, blue, black, and white are changed according to the voltage applied between the electrodes 13 and 14 of the.

In this color liquid crystal display device, the value of Δnd of the liquid crystal cell 10 is 800 nm to 1100 nm, and the front polarizing plate 2 of the two retardation plates 23 and 24 is used.
Retardation Re of the first retardation film 23 adjacent to 1
The value of 1 is 350 nm to 610 nm, and the value of the retardation Re2 of the second retardation plate 24 adjacent to the liquid crystal cell 10 is 400 nm to 650 nm.

FIG. 2 shows the alignment state of the liquid crystal molecules of the liquid crystal cell 10, the polarizing plates 21 and 22 and the retardation plates 23 and 24.
Is a view of the optical axis (transmission axis or absorption axis in the polarizing plate, slow axis or fast axis in the retardation plate) viewed from the surface side of the liquid crystal display device. The rear side polarizing plates 21 and 22 have their transmission axes 21a and 22
a is arranged in the following direction, and two phase difference plates 2
3, 24 are arranged with their slow axes 23a, 24a oriented as follows.

As shown in FIG. 2, the alignment directions 11a and 12a of liquid crystal molecules (rubbing directions of the alignment films 15 and 16) near both substrates 11 and 12 of the liquid crystal cell 10 are substantially orthogonal to each other, and Is clockwise when viewed from the front side from the back side substrate 11 side to the front side substrate 12 side, as indicated by the dashed arrow in the twist direction (clockwise in the figure).
And is twist-oriented at a twist angle of approximately 90 °.

When the orientation direction 11a of the liquid crystal molecules near the rear substrate 11 of the liquid crystal cell 10 is set to 0 °, the transmission axis 21a of the front side polarizing plate 21 is opposite to the twist direction of the liquid crystal molecules ( Counterclockwise in the diagram)
The transmission axis 22a of the back side polarizing plate 22 is in the direction shifted by 1.
Is in a direction deviated from the twist direction by a predetermined angle θ2.

Of the two phase difference plates 23 and 24,
First retardation plate (retardation plate adjacent to front-side polarizing plate 21)
The slow axis 23a of 23 is in a direction deviated by a predetermined angle ψ1 in the direction opposite to the twist direction of the liquid crystal molecules with respect to the direction of 0 °, and the second retardation plate (the retardation plate adjacent to the liquid crystal cell 10). ) 24, the slow axis 24a is in a direction deviated from the 0 ° direction by a predetermined angle ψ 2 in the direction opposite to the twist direction.

The respective polarizing plates 21, 2 with respect to the direction of 0 ° described above.
The deviation angles θ1 and θ2 of the two transmission axes 21a and 22a and the deviation angles ψ1 and ψ2 of the slow axes 23a and 24a of the respective phase difference plates 23 and 24 are θ1 = 110 ° to 130 ° and θ2 = 127 ° to 140 °. ψ1 = 60 ° to 70 ° ψ2 = 150 ° to 165 °.

This color liquid crystal display device utilizes external light and reflects light incident from the front surface side on the rear surface side.
This liquid crystal display device reflects the light at 0, and the electrodes 13 and 14 of both substrates 11 and 12 of the liquid crystal cell 10 are displayed.
A display is driven by applying a voltage between them.

In this color liquid crystal display device, incident light from the surface side thereof passes through the front side polarizing plate 21 to become linearly polarized light, and the light sequentially passes through the two retardation plates 23 and 24 and the liquid crystal cell 10. The light that has passed through and entered the back side polarizing plate 22 is reflected by the reflection plate 20, and the back side polarizing plate 22, the liquid crystal cell 10, the two phase difference plates 24 and 23, and the front side. The light is sequentially transmitted through the polarizing plate 21 and emitted to the front surface side.

Then, in a non-selected state (a state in which the liquid crystal molecules are in the initial twist alignment state) in which a voltage for rising and aligning the liquid crystal molecules is not applied between the electrodes 13 and 14 of the liquid crystal cell 10, the front side polarizing plate 21 is set. In the process in which the linearly polarized light that is transmitted and incident passes through the two retardation plates 23 and 24 and the liquid crystal cell 10, the polarization state is changed by the birefringence action of each of the retardation plates 23 and 24 and the liquid crystal layer of the liquid crystal cell 10. Each wavelength light becomes elliptically polarized light having a different polarization state, enters the back side polarizing plate 22, and the light transmitted through the back side polarizing plate 22 is the light of each wavelength light forming the light. Colored light having a color corresponding to the intensity ratio is obtained, and the light is reflected by the reflection plate 20 and emitted to the front surface side.

The colored light reflected by the reflecting plate 20 is birefringent in a path opposite to that at the time of incidence by the liquid crystal layer of the liquid crystal cell 10 and the phase difference plates 23 and 24 in the process of exiting to the surface side. In response, the light having the same wavelength component as the colored light is emitted from the front surface side polarizing plate 21. For this reason,
The light transmitted through the front-side polarizing plate 21 and emitted is colored light which is almost the same as the light reflected by the reflection plate 20.

When a voltage is applied between the electrodes 13 and 14 of the liquid crystal cell 10, the liquid crystal molecules are vertically aligned while maintaining the twist alignment state, and the birefringence action of the liquid crystal layer is changed by the change of the alignment state of the liquid crystal molecules. To do. The birefringence effect of the liquid crystal layer becomes smaller as the rising angle of the liquid crystal molecules becomes larger.

When the birefringence action of the liquid crystal layer of the liquid crystal cell 10 changes, the retardation plates 23 and 2 are accordingly changed.
4 and the liquid crystal cell 10 and incident on the back-side polarizing plate 22 changes its polarization state.
The coloring of the light changes according to the ratio of the light intensity of each wavelength light passing through the light, and the light is reflected by the reflection plate 20 and emitted to the front surface side of the liquid crystal display device.

As described above, the color of the emitted light of this color liquid crystal display device, that is, the display color, changes depending on the voltage applied to the liquid crystal cell 10. The colors that can be displayed by one pixel of this color liquid crystal display device are all of the three primary colors of light, red, green, and blue, black that is a nearly achromatic dark display, and white that is a nearly achromatic bright display. These display colors are obtained in the order of red → green → blue → black → white as the applied voltage to the liquid crystal cell 10 is increased.

Therefore, according to the color liquid crystal display device, light can be colored to obtain a bright color display without using a color filter, and a plurality of colors can be displayed by the same pixel. Moreover, by displaying white and black, which are the basics of display, and the three primary colors of red, green, and blue, it is possible to realize a clear and rich multicolor color display.

The display color is the color of one pixel. However, in the color liquid crystal display device, in addition to the display colors of the individual pixels, they are combined by combining the display colors of a plurality of adjacent pixels. It is also possible to express colors.

Moreover, in the conventional ECB type liquid crystal display device, it is necessary to use a liquid crystal cell having a large value of Δnd in order to display a plurality of colors, but in the above color liquid crystal display device, two phase difference plates are used. Since the light is colored by utilizing the birefringence effect between the liquid crystal layers 23 and 24 and the liquid crystal layer of the liquid crystal cell 10, the value of Δnd of the liquid crystal cell 10 is 800 as described above.
nm to 1100 nm may be relatively small.

The fact that the value of Δnd of the liquid crystal cell 10 may be small means that one or both of the refractive index anisotropy Δn of the liquid crystal 18 and the liquid crystal layer thickness d can be made small, and the liquid crystal layer thickness d. Is smaller, the strength of the electric field applied to the liquid crystal layer is higher, and the viscosity of the liquid crystal having smaller Δn is low, so that the response becomes faster and the threshold voltage also lowers. Therefore, the color liquid crystal display device can display a plurality of colors with a lower applied voltage than the conventional ECB type liquid crystal display device.

Further, the retardations Re1 and Re2 of the retardation plates 23 and 24 are the same as Re1 in the first retardation plate 23.
= 350 nm to 610 nm, Re in the second retardation plate 24
Since 2 = 400 nm to 650 nm, which is relatively large, a large birefringence effect can be obtained by these phase difference plates 23 and 24, so that many colors can be displayed and the color purity can be improved.

[0049]

EXAMPLES Specific examples of the present invention will be described below. Each of the following examples is directed to the reflective color liquid crystal display device having the configuration shown in FIG.

[First Embodiment] FIG. 3 shows a first embodiment of the present invention, in which the alignment state of the liquid crystal molecules of the liquid crystal cell 10 and the optical axes of the polarizing plates 21 and 22 and the phase difference plates 23 and 24. FIG. 6 is a view of the front side and back side polarizing plates 21 and 22 with their transmission axes 21a and 22a oriented as follows in this embodiment, as viewed from the front side of the liquid crystal display device. The retardation plates 23 and 24 are arranged with their slow axes 23a and 24a oriented as follows.

The alignment state of the liquid crystal molecules of the liquid crystal cell 10 is the same as that shown in FIG. Twisted at the twist angle.

In this embodiment, as shown in FIG. 3, the transmission axis 21a of the front side polarizing plate 21 is set in the direction of 0 °, that is, in the liquid crystal molecule orientation direction 11a in the vicinity of the back side substrate 11 of the liquid crystal cell 10. The liquid crystal molecule of the liquid crystal cell 10 is set in a direction of about 117 ° in the opposite direction to the twist direction, and the transmission axis 22a of the back side polarizing plate 22 is set to about 13 in the direction opposite to the twist direction.
The direction is 5 °.

Of the two phase difference plates 23 and 24,
The slow axis 23a of the first retardation plate 23 adjacent to the front-side polarizing plate 21 is in the direction of about 65 ° in the direction opposite to the twist direction with respect to the direction of 0 ° and is adjacent to the liquid crystal cell 10. The slow axis 24a of the second retardation plate 24 is substantially 158 ° in the direction opposite to the twist direction with respect to the 0 ° direction.

Further, the liquid crystal cell 10 is designed so that the value of Δnd becomes about 1040 nm.
The retardation plate 23 has a retardation Re1 of about 585 nm, and the second retardation plate 24 has a retardation Re2 of about 610 nm.

Further, in this embodiment, as the front side polarizing plate 21, a polarizing plate having a low degree of polarization with respect to light (blue component light) in the short wavelength region of the visible light region is used.
For 2, a polarizing plate with a normal degree of polarization is used. The average polarization degree of the front side polarizing plate 21 with respect to light in the visible light region is about 94%, and the average polarization degree of the back side polarizing plate 22 is about 99%.
Is.

As described above, in the color liquid crystal display device of this embodiment, as the applied voltage to the liquid crystal cell 10 is increased, the order of red → green → blue → black → white is increased. Therefore, it is possible to realize a vivid and colorful multi-color display.

In this color liquid crystal display device, the value of Δnd of the liquid crystal cell 10 may be relatively small, about 1040 nm, and therefore one or both of the refractive index anisotropy Δn of the liquid crystal 18 and the liquid crystal layer thickness d may be small. Therefore, it is possible to obtain a display of a plurality of colors with a lower applied voltage than that of the conventional ECB type liquid crystal display device.
The retardations Re1 and Re2 of 24 are relatively large, that is, Re1 = about 585 nm in the first retardation plate 23 and Re2 = about 610 nm in the second retardation plate 24. By virtue of the effect, many colors can be displayed and the color purity can be improved.

Further, in this embodiment, a polarizing plate having a low degree of polarization for light in the short wavelength region of the visible light region is used as the front side polarizing plate 21 on which the incident light to the liquid crystal display device first enters. Therefore, it is possible to increase the incident amount of the light in the short wavelength range, that is, the light of the blue component, and display blue, which is difficult to be displayed as a display color, in a bright and clear color.

Further, in the above color liquid crystal display device, since the two retardation plates 23 and 24 are arranged on the surface side of the liquid crystal cell 10, the viewing angle dependency of the light emission rate is determined by the retardation plate 2.
3,24, and therefore,
It is possible to widen the viewing angle at which the displayed image can be viewed brightly and with good contrast.

[Second Embodiment] FIG. 4 shows a second embodiment of the present invention, in which the alignment state of the liquid crystal molecules of the liquid crystal cell 10 and the optical axes of the respective polarizing plates 21 and 22 and the phase difference plates 23 and 24. FIG. 6 is a view of the front side and back side polarizing plates 21 and 22 with their transmission axes 21a and 22a oriented as follows in this embodiment, as viewed from the front side of the liquid crystal display device. The retardation plates 23 and 24 are arranged with their slow axes 23a and 24a oriented as follows.

The alignment state of the liquid crystal molecules of the liquid crystal cell 10 is the same as that shown in FIG. 2, and the liquid crystal molecules are oriented from the back side substrate 11 to the front side substrate 12 in an approximately 90 ° clockwise direction when viewed from the front side. Twisted at the twist angle.

In this embodiment, as shown in FIG. 4, the transmission axis 21a of the front-side polarizing plate 21 is set in the direction of 0 °, that is, in the liquid crystal molecule orientation direction 11a in the vicinity of the rear substrate 11 of the liquid crystal cell 10. The liquid crystal molecule of the liquid crystal cell 10 is set in a direction of about 115 ° in the opposite direction to the twist direction, and the transmission axis 22a of the back side polarizing plate 22 is set to about 1 in the direction opposite to the twist direction.
The direction is 35 °.

Of the two phase difference plates 23 and 24,
The slow axis 23a of the first retardation plate 23 adjacent to the front-side polarizing plate 21 is in the direction of about 64 ° in the direction opposite to the twist direction with respect to the direction of 0 ° and is adjacent to the liquid crystal cell 10. The slow axis 24a of the second retardation plate 24 is substantially 151 ° in the direction opposite to the twist direction with respect to the 0 ° direction.

In this embodiment, the value of Δnd of the liquid crystal cell 10 is set to about 920 nm, the first retardation plate 23 has a retardation value of 375 nm, and the second retardation plate 24 is used. In addition, a retardation value of about 430 nm is used.

Also in this example, the front polarizing plate 2 is also used.
1. Light in the short wavelength range of visible light (light of blue component)
A polarizing plate having a low degree of polarization is used for the back side polarizing plate 22.

Also in the color liquid crystal display device of this embodiment, as the display color thereof increases, as the applied voltage to the liquid crystal cell 10 increases, the order of red → green → blue → black → white is obtained. Therefore, it is possible to realize a vivid and colorful multi-color display.

Since the color liquid crystal display device has a relatively small Δnd value of about 920 nm in the liquid crystal cell 10, it is possible to obtain a display of a plurality of colors with a lower applied voltage than the conventional ECB type liquid crystal display device. And the retardation values Re1 and Re2 of the retardation films 23 and 24 are
Re1 = about 375 nm for the first retardation plate 23 and Re2 = about 430 nm for the second retardation plate 24, which are relatively large. Therefore, a large birefringence effect is obtained by these retardation plates 23, 24, and many colors are obtained. Can be displayed and the color purity can be improved.

Furthermore, since a polarizing plate having a low degree of polarization for light in the short wavelength region of the visible light region is used as the front polarizing plate 21, it is possible to display blue, which is difficult to be displayed as a bright color, in a bright and clear color. In addition, since the two retardation films 23 and 24 are disposed on the front surface side of the liquid crystal cell 10, the viewing angle can be widened.

In the above first and second embodiments,
Transmission axes 21a, 22 of front and back side polarizing plates 21, 22
The direction of a and the slow axis 23 of the two phase difference plates 23 and 24
Although the directions of a and 24a are set as shown in FIG. 3 or FIG. 4, the directions of the transmission axes 21a and 22a of the polarizing plates 21 and 22 may be the directions of the absorption axis, and the retardation plate 2
The direction of the slow axes 23a and 24a of 3, 24 may be the direction of the fast axis.

Further, in the first and second embodiments,
The two retardation plates 23 and 24 are arranged such that the retardation plate having the smaller retardation value is adjacent to the front polarizing plate 21 and the retardation plate having the larger retardation value is adjacent to the liquid crystal cell 10. However, conversely, even if the retardation plate having the larger retardation value is arranged adjacent to the front-side polarizing plate 21 and the retardation plate having the smaller retardation value is arranged adjacent to the liquid crystal cell 10. Good.

[Third Embodiment] FIG. 5 shows a third embodiment of the present invention, in which the alignment state of the liquid crystal molecules of the liquid crystal cell 10 and the optical axes of the respective polarizing plates 21 and 22 and the retardation films 23 and 24. Is a view of the direction of the liquid crystal display device from the front side, and in this embodiment, the retardation plate having the larger retardation value of the two retardation plates 23 and 24 is adjacent to the front side polarizing plate 21. The retardation plate having the smaller retardation value is adjacent to the liquid crystal cell 10, and the front and back polarizing plates 21 and 22 are arranged so that their transmission axes 21a and 22a are oriented as follows. The first retardation plate 23 adjacent to the polarizing plate 21 is arranged so that the fast axis 23b thereof has the following orientation, and the second retardation plate 24 adjacent to the liquid crystal cell 10 is provided with its slow axis. 24a is arranged so that .

The alignment state of the liquid crystal molecules of the liquid crystal cell 10 is the same as that shown in FIG. 2, and the liquid crystal molecules are oriented from the back side substrate 11 to the front side substrate 12 in an angle of 90 ° clockwise when viewed from the front side. Twisted at the twist angle.

In this embodiment, as shown in FIG. 5, the transmission axis 21a of the front-side polarizing plate 21 is set in the direction of 0 °, that is, in the liquid crystal molecule alignment direction 11a in the vicinity of the rear substrate 11 of the liquid crystal cell 10. The liquid crystal molecule of the liquid crystal cell 10 is set in a direction of about 127 ° in the opposite direction to the twist direction, and the transmission axis 22a of the back side polarizing plate 22 is set to about 13 in the direction opposite to the twist direction.
The direction is 8 °.

On the other hand, of the two retardation plates 23 and 24,
The first retardation plate 23 adjacent to the front-side polarizing plate 21 is arranged with its fast axis 23a directed in the direction of approximately 62 ° opposite to the twist direction with respect to the direction of 0 ° described above. The slow axis 23a of the first retardation plate 23 is approximately 152 ° in the direction opposite to the twist direction with respect to the direction of 0 ° as shown by the chain line in FIG.

The second retardation plate 24 adjacent to the liquid crystal cell 10 is arranged so that its slow axis 24a is oriented in a direction of approximately 72 ° opposite to the twist direction with respect to the direction of 0 °. Has been done.

In this embodiment, the value of Δnd of the liquid crystal cell 10 is set to about 920 nm, the first retardation plate 23 has a retardation value of 630 nm, and the second retardation plate 24 is used. In addition, a retardation value of about 585 nm is used. In this embodiment, both the front-side polarizing plate 21 and the back-side polarizing plate 22 are ordinary polarizing plates having an average polarization degree of about 99% with respect to light in the visible light range.

Also in the color liquid crystal display device of this embodiment, as the display color thereof increases as the voltage applied to the liquid crystal cell 10 increases, the order of red → green → blue → black → white is increased. Therefore, it is possible to realize a vivid and colorful multi-color display.

In this color liquid crystal display device, since the value of Δnd of the liquid crystal cell 10 is relatively small at about 920 nm, a plurality of colors can be displayed with a lower applied voltage than the conventional ECB type liquid crystal display device. And the phase difference plate 2
The retardations Re1 and Re2 of 3, 24 are Re1 = about 630 nm in the first retardation plate 23, and the second retardation plate 2
4 has a relatively large Re2 of about 585 nm, a large birefringence effect can be obtained by these phase difference plates 23 and 24, so that many colors can be displayed and the color purity of the liquid crystal cell 10 can be improved. Two retarders 2 on the front side
Since 3 and 24 are arranged, the viewing angle can be widened.

Further, when the retardation plate 23 having the larger retardation value out of the two retardation plates 23 and 24 is adjacent to the front side polarizing plate 21 as in this embodiment, the front side polarizing plate 21. Even if the polarizing plate has a normal polarization degree, a relatively bright blue color is displayed.

In the color liquid crystal display device, the Δnd value of the liquid crystal cell 10 and the retardation values Re1 and Re2 of the respective phase differences 23 and 24 and the optical values of the pair of front and back polarizing plates 21 and 22 and the phase difference plates 23 and 24 are set. The direction of the axis is not limited to the first to third embodiments,
The value of Δnd of the liquid crystal cell 10 is 800 nm to 1100 n.
m, more preferably 920 nm to 1050 nm,
The first phase difference plate 23 of the two phase difference plates 23 and 24
Retardation Re1 of 350 nm to 610 n
m, the value of the retardation Re2 of the second retardation plate 24 is set to 400 nm to 650 nm, and the substrate on the side opposite to the side where the retardation plates 23 and 24 of the liquid crystal cell 10 are arranged (in the above embodiment, When the alignment direction 11a of the liquid crystal molecules near the rear substrate 11 is set to 0 °, the phase difference plates 23, 2 of the pair of polarizing plates 21, 22 are arranged.
Polarizing plate on the side where 4 is arranged (front-side polarizing plate in the above example)
21 has a transmission axis 21a or an absorption axis in the direction opposite to the liquid crystal molecule twist direction of the liquid crystal cell 10 in the direction of 110 ° to 130 °, and the other polarizing plate 22 has a transmission axis 22a or the absorption axis in the opposite direction to the twist direction. It is in the direction of 127 ° to 140 ° (desirably 130 ° to 140 °), and the slow axis 23a or the fast axis 23b of the first retardation plate 23 is 60 ° to 70 ° in the direction opposite to the twist direction. If the slow axis 24a or the fast axis of the second retardation plate 24 is in the direction of 150 ° to 165 ° in the direction opposite to the twist direction,
By displaying white and black, which are the basics of display, and the three primary colors of red, green, and blue, it is possible to realize a vivid and colorful multicolor display.

[Other Embodiments] Next, other embodiments of the present invention will be described. This embodiment is intended for the reflective color liquid crystal display device having the configuration shown in FIGS. 1 and 2, in which liquid crystal molecules of the liquid crystal cell 10 are transferred from the back side substrate 11 to the front side as shown in FIG. The twist orientation is made at a twist angle of approximately 90 ° clockwise when viewed from the front surface side toward the substrate 12, and the value of Δnd of the liquid crystal cell 10 and the retardation Re1 of each of the two retardation plates 23 and 24.
The value of Re2, the directions of the transmission axes 21a and 22a of the pair of polarizing plates 21 and 22, and the two retardation plates 2 described above.
The directions of the slow axes 23a and 24a of 3 and 24 are set as follows.

That is, in this embodiment, the liquid crystal cell 10
Value of 800 nm to 1100 nm, preferably 920 nm to 1050 nm, and the value of retardation Re1 of the first retardation film 23 adjacent to the front polarizing plate 21 of the two retardation films is 570 nm ± 2. .5
nm to 590 nm ± 2.5 nm, and the liquid crystal cell 1
Retardation Re of the second retardation plate 24 adjacent to 0
The value of 2 is 585 nm ± 2.5 nm to 605 nm ± 2.5
in the range of 0 nm, that is, the deviation angles θ1 and θ2 of the transmission axes 21a and 22a of the polarizing plates 21 and 22 with respect to the liquid crystal molecule alignment direction 11a in the vicinity of the back surface side substrate 11 of the liquid crystal cell 10, and the phase differences. The shift angles ψ1 and ψ2 of the slow axes 23a and 24a of the plates 23 and 24 are θ1 = 113 ° ± 1 ° to 119 ° ± 1 ° θ2 = 127 ° ± 1 ° to 137 ° ± 1 ° ψ1 = 61 ° ± 1 ° to 67 ° ± 1 ° ψ2 = 156 ° ± 1 ° to 160 ° ± 1 °.

That is, in this embodiment, the transmission axis 21a of the front polarizing plate 21 is 113 ° ± 1 ° in the direction opposite to the liquid crystal molecule twist direction of the liquid crystal cell 10 with respect to the direction of 0 °.
To 119 ° ± 1 °, and the transmission axis 22a of the back side polarizing plate 22 is set to 127 ° in the direction opposite to the twist direction.
Within the range of ± 1 ° to 137 ° ± 1 °,
Of the two retardation plates 23 and 24, the slow axis 23a of the first retardation plate 23 adjacent to the front-side polarizing plate 21 is set to 61 ° ± 1 ° to 67 ° ± 1 in the direction opposite to the twist direction. The second retardation plate 2 adjacent to the liquid crystal cell 10 in the direction of the range of °
4 the slow axis 24a in the opposite direction to the twist direction.
The direction is in the range of 6 ° ± 1 ° to 160 ° ± 1 °.

Also in the color liquid crystal display device of this embodiment, as the display color thereof increases, as the applied voltage to the liquid crystal cell 10 increases, the order of red → green → blue → black → white is obtained. Therefore, it is possible to realize a vivid and colorful multi-color display.

FIG. 6 is an a ^* -b ^* chromaticity diagram showing a change in display color of the color liquid crystal display device. Here, .DELTA.nd of the liquid crystal cell 10 and retardations Re1 and Re2 of the retardation films 23 and 24 are shown. And the angles (deviation angles with respect to the 0 ° direction) ψ1 and ψ2 of the slow axes 23a and 24a, and the angles (deviation angles with respect to the 0 ° direction) θ1 and θ2 of the transmission axes 21 and 22 of the respective polarizing plates 21 and 22. 3 shows the color changes of the three types of prototype devices LCD1, LCD2, and LCD3 in which the above range is set.

In these prototype devices LCD1, LCD2 and LCD3, the values of Δnd, Re1, Re2, ψ1 and ψ2 are Δnd = 990 nm Re1 = 580 nm Re2 = 595 nm ψ1 = 64 ° ψ2 = 158 °, and One or both of the angles θ1 and θ2 of the transmission axes 21 and 22 of the polarizing plates 21 and 22 are different. For the prototype device LCD1, θ1 = 113 ° θ2 = 133 ° For the prototype device LCD2, θ1 = 115 ° θ2 = The 129 ° prototype LCD3 has θ1 = 115 ° and θ2 = 135 °.

As shown in FIG. 6, the prototype devices LCD1, LCD2,
In LCD3, the display color in the initial state in which no voltage is applied between electrodes 13 and 14 of liquid crystal cell 10 is a color close to purple (P) in LCD1 and LCD2, and almost red in LCD3. LCD1, LCD2, and LCD3 are also electrodes 1 of the liquid crystal cell 10.
As the voltage applied between 3 and 14 is increased, the display colors are red, green, and blue with high color purity, black that is almost achromatic dark display, and almost achromatic bright display. It changes to white.

This change in display color is caused by the above-mentioned prototype device LCD1,
Not only LCD2 and LCD3, but also Δnd, Re1, Re2, ψ1
, .Psi.2, .theta.1, .theta.2 are set in the above-mentioned range, the same applies to other liquid crystal display devices.

In the color liquid crystal display device of this embodiment, as described above, the value of Δnd of the liquid crystal cell 10 is 80.
Since the refractive index anisotropy Δn of the liquid crystal 18 and / or the liquid crystal layer thickness d can be made small, it can be relatively small, such as 0 nm to 1100 nm. Color display can be obtained, and the retardations Re1 and Re2 of the retardation films 23 and 24 are Re1 = 570 nm ± 2.5 n
m ~ 590nm ± 2.5nm, Re2 = 585nm ±
Since it is relatively large at 2.5 nm to 605 nm ± 2.5 nm, a large birefringence effect can be obtained by these phase difference plates 23 and 24, so that many colors can be displayed and the color purity can be improved.

Further, in this embodiment, since the two retardation plates 23 and 24 are arranged on the surface side of the liquid crystal cell 10,
The viewing angle dependence of the light emission rate can be reduced by the phase difference plates 23 and 24, and therefore, the viewing angle at which the displayed image can be viewed brightly and with good contrast can be widened.

In the color liquid crystal display device of this embodiment, the front and back side polarizing plates 21 and 22 may be polarizing plates having a normal polarization degree, but the front side polarizing plate to which the incident light to the liquid crystal display device first enters. If a polarizing plate having a low degree of polarization with respect to light in the short wavelength region (blue component light) of the visible light region is used for the plate 21, the incident amount of the blue component light is increased and it is difficult to output a blue color as a display color. Can be displayed in bright and vivid colors.

Next, a more preferable structure of the color liquid crystal display device will be described. Δnd of the liquid crystal cell 10 in the color liquid crystal display device is 920 nm as described above.
The range of 1050 nm is preferable, and the angles θ1 and θ2 of the front and back polarizing plates 21 and 22 are preferably in the following ranges.

The following [Table 1] shows Δnd of the liquid crystal cell 10.
Is 990 nm, the retardation Re1 of the first retardation plate 23 is 580 nm, the retardation Re2 of the second retardation plate 24 is 595 nm, and the slow axis of the first retardation plate 23 is 0 °. Regarding the color liquid crystal display device in which the angle ψ 1 is set to 64 ° and the slow axis angle ψ 2 of the second retardation plate 24 is set to 158 °, the transmission axis angles θ 1 of the front side and back side polarizing plates 21 and 22 with respect to the 0 ° direction, θ2
Where θ1 = 113 ° to 119 ° and θ2 = 127 ° to 13
The results obtained by examining the light emission rate and the contrast by changing the range of 7 ° are shown. Here, the emission rate is the ratio of the emitted light amount to the incident light amount when white is displayed, and the contrast is the ratio of brightness between black display and white display.

[0094]

[Table 1]

In this [Table 1], θ1 = 113 °,
The one having θ2 = 133 ° corresponds to the LCD1 in the chromaticity diagram shown in FIG. 6, and the one having θ1 = 115 ° and θ1 = 129 ° corresponds to the LCD2 in the chromaticity diagram, and θ1 = 115 °, θ1 = 135 °
Corresponds to LCD3 in the chromaticity diagram.

FIG. 7 shows the front and back side polarizing plates 21,
22 is a diagram showing the relationship between the transmission axis angles θ 1 and θ 2 of 22 and the emission rate, and FIG. 8 is the transmission axis angles θ 1 and θ of the polarizing plates 21 and 22.
FIG. 2 is a diagram showing the relationship between 2 and contrast.
As described above, the values of nd, Re1, Re2, ψ1, and ψ2 are Δnd = 990 nm, Re1 = 580 nm, and Re2.
= 595 nm, ψ1 = 64 °, ψ2 = 158 °, the transmission axis angle θ1 of the front-side polarizing plate 21 is set to 113 °, 115 °, and 117 °. Transmission axis angle θ2 of 127 ° ~
The results of examining the emission rate and the contrast by changing the range of 137 ° are shown.

As shown in [Table 1] and FIGS. 7 and 8,
The above color liquid crystal display device includes front and back polarizing plates 2
The transmission axis angles θ 1 and θ 2 of 1 and 22 are θ 1 = 113 °
119 °, θ2 = 127 ° to 137 °,
The emission rate is 16.5% or more and the contrast is 4.3 or more, and the display characteristics sufficiently satisfied as a reflective color liquid crystal display device are shown.

Above all, the front and back polarizing plates 21, 2
The transmission axis angles θ1 and θ2 of 2 are θ1 = 115 ° to 117
Most of those having a range of 20 ° and θ2 = 129 ° to 135 ° have an emission rate of about 20% or more (θ1 = 115 °, θ
2 = 135 °, 19.9%), contrast is 4.5 or more (where θ1 = 117 °, θ2 = 129 °)
In the case of 4.3), which shows better display characteristics.

FIG. 9 shows the front and back polarizing plates 21 and 22.
The results of evaluation of the display characteristics of the transmission axis angles θ1 and θ2 of the above are shown in consideration of the hue of the display in addition to the above-mentioned emission rate and contrast.

As shown in FIG. 9, in the above-mentioned color liquid crystal display device, better display characteristics, that is, red, green, which has a higher emission rate and a higher contrast and a higher color purity,
Polarizing plate 2 that can display blue and more achromatic black and white
The transmission axis angles θ 1 and θ 2 of 1 and 22 are in the range of θ 1 = 115 ° to 117 ° and θ 2 = 129 ° to 135 °, as shown by enclosing the range with a broken line in the figure, and have the best display characteristics. The transmission axis angles .theta.1 and .theta.2 at which .theta. Are obtained are .theta.1 = 115.degree.

The transmission axis angles θ1 and θ2 of the polarizing plates 21 and 22 do not substantially change the display characteristics even if they change in the range of ± 1 °, so that there is an allowable range of ± 1 °. Therefore, the transmission axis angle θ1 that provides better display characteristics
, Θ2 is θ1 = 115 ° ± 1 ° to 117 ° ± 1 °,
θ2 = 129 ° ± 1 ° to 135 ° ± 1 °, the transmission axis angles θ1 and θ2 that give the best display characteristics are θ1
= 115 ° ± 1 °, θ2 = 129 ° to 135 ° ± 1 °.

Further, FIG. 10 shows the front and back polarizing plates 2
The transmission axis angles θ1 and θ2 of 1 and 22 are in a range (θ1 = 115 ° to 117 °, θ2 =) where better display characteristics can be obtained.
129 ° to 135 °), the evaluation results of the display tint are shown.

In the evaluation of this color tone, the best one is θ1 = 115 ° and θ2 = 135 °, and the front and back polarizing plates 21 and 22 are
The transmission axis angles θ1 and θ2 are θ1 = 115 ° ± 1 ° and θ2
= 135 ° ± 1 ° (± 1 ° is an allowable range), red, green, and blue with the highest color purity and black and white with the most achromatic colors can be obtained.

Next, the first and second retardation plates 23, 2
Attention is paid to the values of the retardations Re1 and Re2 of No. 4 and the values of the angles ψ1 and ψ2 of the slow axes 23a and 24a. First, looking at the relationship between the slow axis angles ψ 1 and ψ 2 of the phase difference plates 23 and 24 and the display color, FIG. 11 shows Δnd of the liquid crystal cell 10.
Of 945 nm, the retardation Re1 of the first retardation plate 23 is 580 nm, the retardation Re2 of the second retardation plate 24 is 595 nm, and the transmission axis angles of the front and back polarizing plates 21 and 22 are θ1, θ2
Is the best angle (θ1 = 115 °, θ2 = 13
5 °), and the slow axis angle ψ1 of the phase difference plates 23 and 24
, Ψ2 in the above range ψ1 = 61 ° ± 1 ° to 67 ° ± 1 ° = 60 ° to 68 ° ψ2 = 156 ° ± 1 ° to 160 ° ± 1 ° = 157 ° to 161 ° Changes in the display color of a ^* −
b ^{* is a} chromaticity diagram, in which the combination of the slow axis angles ψ1 and ψ2 of the retardation plates 23 and 24 is (1) ψ1 = 63 °, ψ2 = 156 ° (2) ψ1 = 63 °, 4 shows the display color changes of the four types of color liquid crystal display devices selected as ψ2 = 160 ° (3) ψ1 = 68 °, ψ2 = 158 ° (4) ψ1 = 68 °, ψ2 = 160 °.

As shown in FIG. 11, in the color liquid crystal display device, ψ1 is 61 ° even if the slow axis angles ψ1 and ψ2 of the first and second retardation plates 23 and 24 and the combination thereof are changed. ± 1 ° ~ 67 ° ± 1 °, ψ2 is 156 ° ± 1 ° ~
If it is in the range of 160 ° ± 1 °, the display color changes only in a slight range of about 2.5 on the a ^* -b ^* chromaticity diagram.
Almost the same display color can be obtained.

Although only the color change in the red region is shown in FIG. 11, the change in the display color from the initial state of the color liquid crystal display device is shown in FIG. 6 as the prototype device LCD3 (Δnd =
990nm, Re1 = 580nm, Re2 = 595n
m, ψ1 = 64 °, ψ2 = 158 °, θ1 = 115 °,
θ2 = 135 °).

FIG. 12 is a ^* -b ^* chromaticity diagram showing the relationship between the slow axis angles .psi.1 and .psi.2 of the retardation plates 23 and 24 and the white display color in the color liquid crystal display device, and FIG. Slow axis angles ψ1 and ψ2 of the phase difference plates 23 and 24 and the emission rate (the ratio of the emitted light amount to the incident light amount when white is displayed)
FIG. 3 is a diagram showing the relationship between the contrast and contrast (ratio of brightness between black display and white display).

As shown in FIGS. 12 and 13, the color liquid crystal display device includes the first and second retardation films 23,
Even if the slow axis angles ψ1 and ψ2 of 24 and the combination thereof are changed, ψ1 is 61 ° ± 1 ° to 67 ° ± 1 °, and ψ2 is 15 °.
Within the range of 6 ° ± 1 ° to 160 ° ± 1 °, it is possible to obtain a white display of sufficiently satisfactory purity, and an emission rate and contrast.

Here, regarding white display, the white display color of the color liquid crystal display device in which the slow axis angles ψ 1 and ψ 2 of the phase difference plates 23 and 24 are within the above range is as shown in FIG. The values of ^* are concentrated in the vicinity of 0, but the value of b ^* varies depending on the slow axis angles ψ1 and ψ2 of the retardation plates 23 and 24 and the combination thereof.

The white display becomes achromatic as the value of b ^* becomes closer to 0, and becomes more yellow (Y) as the value of b ^* becomes larger. From the viewpoint of (4), it is desirable that the slow axis angles ψ1 and ψ2 of the retardation plates 23 and 24 and the combination thereof be such that the value of b ^* becomes closer to zero.

On the other hand, in terms of the emission rate and the contrast, the emission rate and the contrast are different from each other.
The slow axis angles ψ 1 and ψ 2 and their combinations are shown in FIG.
In, the closer to the upper right, the higher the height.

Therefore, it is more preferable to select the slow axis angles ψ 1 and ψ 2 of the retardation plates 23 and 24 and the combination thereof so that the white purity is high and a high emission rate and contrast can be obtained.

In FIG. 17, the slow axis angles ψ 1 and ψ 2 of the phase difference plates 23 and 24 are ψ 1 = 61 ° to 67 ° and ψ 2 = 15.
The results of evaluating the white purity, the emission rate, and the contrast by changing the range of 6 ° to 159 ° are shown.

As shown in FIG. 17, in the color liquid crystal display device, the slow axis angles ψ 1 and ψ 2 of the phase difference plates 23 and 24 are set.
, Ψ1 = 61 ° ± 1 ° to 67 ° ± 1 °, ψ2 = 156
If the display range is ± 1 ° to 159 ° ± 1 ° (± 1 ° is a permissible range in which the display characteristics do not substantially change), then the display characteristics are sufficiently satisfactory. The retardation plate 23 having the slow axis angle ψ1 in the range of 62 ° to 66 ° shows the display characteristics in which the white purity, the emission rate, and the contrast are better evaluated. When the slow axis angle ψ1 of the plate 23 is 64 ° and the slow axis angle ψ2 of the second retardation plate 24 is 158 °, the best display characteristics are exhibited.

The slow axis angle ψ 1 of the first retardation plate 23 showing a better display characteristic has an allowable range of ± 0.5 °. Therefore, the first retardation plate showing a better display characteristic has a tolerable range. The slow axis angle ψ1 of the retardation plate 23 is 62 ° ± 0.5 ° to 6 °
The range may be 6 ° ± 0.5 °.

Further, since the slow axis angles ψ 1 and ψ 2 of the phase difference plates 23 and 24 exhibiting the best display characteristics do not change substantially within ± 1 °, the display characteristics do not change ± 1. °
Therefore, the slow axis angles ψ 1 and ψ 2 of the phase difference plates 23 and 24 exhibiting the best display characteristics are
1 = 64 ° ± 1 ° and ψ2 = 158 ° ± 1 °.

Next, the first and second retardation plates 23, 2
Looking at the relationship between the retardations Re1 and Re2 of No. 4 and the display color, FIG. 14 shows that the value of Δnd of the liquid crystal cell 10 is 945.
nm, and the transmission axis angles θ 1 and θ 2 of the front and back polarizing plates 21 and 22 and the first and second retardation plates 23 and 24.
And the slow axis angles ψ 1 and ψ 2 of
1 = 115 °, θ2 = 135 °, ψ1 = 64 °, ψ2 =
158 °) and the retardation values Re1 and Re2 of the respective retardation films 23 and 24 are in the above-mentioned range Re1 = 570 nm ± 2.5 nm to 590 nm ± 2.5 nm = 567.5 nm to 592.5 nm Re2 = 585 nm ± 2 .5 nm to 605 nm ± 2.5 nm = 582.5 nm to 607.5 nm showing a change in display color of the color liquid crystal display device a ^* −
b ^{* is a} chromaticity diagram, where the combination of the retardations Re1 and Re2 of the retardation films 23 and 24 is (1) Re1 = 575 nm, Re2 = 590 nm (2) Re1 = 575 nm, Re2 = 600 nm (3) Re1 = 580 nm, Re2 = 595 nm (4) Re1 = 585 nm, Re2 = 590 nm (5) Re1 = 585 nm, and Re2 = 600 nm.

As shown in FIG. 14, in the color liquid crystal display device, Re1 is 567.5 nm to 592 even if the retardations Re1 and Re2 of the first and second retardation plates 23 and 24 and the combination thereof are changed. 0.5 nm, Re2
Is in the range of 582.5 nm to 607.5 nm, almost the same display color can be obtained by changing the display color in a slight range of about 1.5 on the a ^* -b ^* chromaticity diagram.

Although only the color change in the red region is shown in FIG. 14, the change in the display color from the initial state of the color liquid crystal display device is shown in FIG. 6 as the prototype device LCD3 (Δnd =
990nm, Re1 = 580nm, Re2 = 595n
m, ψ1 = 64 °, ψ2 = 158 °, θ1 = 115 °,
θ2 = 135 °).

Further, FIG. 15 shows the retardations Re1 and R of the retardation films 23 and 24 in the color liquid crystal display device.
The a ^* -b ^* chromaticity diagram showing the relationship between the value of e2 and the white display color. FIG. 16 shows the retardation Re of the phase difference plates 23 and 24.
FIG. 3 is a diagram showing the relationship between the values of 1, Re2, the emission rate (the ratio of the emitted light amount to the incident light amount when white is displayed), and the contrast (the ratio of the brightness of black display and white display).

As shown in FIGS. 15 and 16, the color liquid crystal display device includes the first and second retardation films 23,
Even if the retardations Re1 and Re2 of 24 and the combination thereof are changed, Re1 is 567.5 nm to 592.5 n.
When m and Re2 are in the range of 582.5 nm to 607.5 nm, it is possible to obtain a white display of sufficiently satisfactory purity, an emission rate and a contrast.

Now, regarding the white display, the white display color of the color liquid crystal display device in which the retardation values Re1 and Re2 of the retardation films 23 and 24 are within the above range is a ^* as shown in FIG. Values are concentrated near 0, but b
The value of ^* is the retardation Re1 of the phase difference plates 23 and 24.
, Re2 and combinations thereof.

The white display becomes achromatic as the value of b ^* becomes closer to 0, and becomes more yellow (Y) as the value of b ^* becomes larger. From the viewpoint of (1), it is desirable that the retardations Re1 and Re2 of the retardation plates 23 and 24 and the combination thereof be such that the value of b ^* becomes closer to zero.

On the other hand, in terms of the emission rate and the contrast, the emission rate and the contrast are determined by the phase difference plates 23 and 24.
Retardations Re1 and Re2 and the combination thereof are closer to the diagonally upper right direction in FIG.

Therefore, it is more desirable to select the retardations Re1 and Re2 of the retardation plates 23 and 24 and the combination thereof so that the white purity is high and a high emission rate and contrast can be obtained.

FIG. 18 shows the retardations Re1 and Re2 of the respective retardation films 23 and 24 as Re1 = 570nn to 59.
The results of evaluating the white purity, the emission rate, and the contrast by changing the range of 0 nm and Re2 = 585 nm to 605 nm are shown.

As shown in FIG. 18, in the color liquid crystal display device, the retardation Re1 of each retardation plate 23, 24 is
, Re2 is Re1 570 nm ± 2.5 nm to 590
nm ± 2.5 nm, Re2 = 585 nm ± 2.5 nm
If it is 605 nm ± 2.5 nm (± 2.5 nm is an allowable range), sufficiently satisfactory display characteristics are shown.

Among them, the first polarizing plate adjacent to the front polarizing plate 21
Retardation Re1 of the retardation plate 23 of 575 nm
Most of those in the range of 585 nm exhibit better display characteristics in evaluation of white purity, emission rate and contrast, and in particular, the retardation Re1 of the first retardation plate 23 is in the range of 575 nm to 585 nm, Retardation R of the second retardation plate 24 adjacent to the liquid crystal cell 10.
All of e2 having a range of 590 nm to 600 nm show display characteristics with better evaluation of white purity, emission rate and contrast.

Further, when the retardation Re1 of the first retardation plate 23 is 575 nm and the retardation Re2 of the second retardation plate 24 is in the range of 590 nm to 600 nm, the best display characteristics are exhibited.

Here, the retardations Re1 and Re2 of the retardation films 23 and 24 exhibiting better display characteristics are ±
Since the substantial display characteristics do not change even if the change is in the range of 2.5 nm, there is an allowable range of ± 2.5 nm, and therefore, the retardation Re1 showing better display characteristics,
The value of Re2 is Re1 = 575 nm ± 2.5 nm to 58
5nm ± 2, 5nm, Re2 = 590nm ± 2.5nm
The value of the retardations Re1 and Re2 showing the best display characteristics is R
e1 = 575 nm ± 2.5 nm, Re2 = 590 nm ±
It may be 2.5 nm to 600 nm ± 2.5 nm.

As shown in FIG. 18, Re1 = 580n
m, Re2 = 600 nm and Re1 = 575n
m, Re2 = 605 nm also shows the best display characteristics, but here, considering the allowable range of the retardation, the values of the retardations Re1 and Re2 at which the best display characteristics are obtained are Re1 = 575 nm. ± 2.5
nm, Re2 = 590 nm ± 2.5 nm to 600 nm ±
It was set to 2.5 nm.

The front and back polarizing plates 21 and 22 described above
Transmission axis angles θ1, θ2 of the first and second retardation plates 2
3, 24 slow axis angles ψ 1, ψ 2, these retarder 2
Comprehensively judging from the display characteristics based on the retardations Re1 and Re2 of 3, 24, in the color liquid crystal display device of this embodiment, the alignment direction 11a of the liquid crystal molecules in the vicinity of the back side substrate 11 of the liquid crystal cell 10 is 0 °. And when
The transmission axis 21a of the front-side polarizing plate 21 is in the opposite direction of the liquid crystal molecule twist direction of the liquid crystal cell 10 from θ1 = 115 ° ± 1 ° to 11 °.
In the direction of 7 ° ± 1 °, the transmission axis 22a of the back side polarizing plate 22 is θ2 = 129 ° ± 1 ° to 13 in the direction opposite to the twist direction.
The slow axis 23a of the first retardation plate 23 adjacent to the front side polarizing plate 21 in the direction of 5 ° ± 1 ° is ψ 1 = 62 ° ± 0.5 ° to 66 ° in the direction opposite to the twist direction. ± 0.5
The second retardation plate 24 adjacent to the liquid crystal cell 10 in the direction of
Of the slow axis 24a of ψ2 = 1 in the direction opposite to the twist direction.
It is in the direction of 56 ° ± 1 ° to 165 ° ± 1 °, and the value of the retardation Re1 of the first retardation plate 23 is 5
75 nm ± 2.5 nm to 585 nm ± 2.5 nm, and the value of the retardation Re2 of the second retardation plate 24 is 58.
It is more desirable that the structure is in the range of 5 nm ± 2.5 nm to 605 nm ± 2.5 nm.

Here, the front and back polarizing plates 21, 22 are
A more desirable value of the transmission axis angles θ1 and θ2 of is θ1 = 1
15 ° ± 1 ° to 117 ° ± 1 °, θ2 = 129 ° ± 1 °
To 135 ° ± 1 °, and the transmission axis angle θ 1,
By setting θ2 to such a value, it is possible to obtain a display of red, green, and blue, which has a higher emission rate, a higher contrast, and a higher color purity, and black and white, which are more achromatic. The angles θ 1 and θ 2 are θ 1 = 115 ° ± 1 °, θ 2 = 13
When the angle is 5 ° ± 1 °, it is possible to obtain a display excellent in color tone.

Further, the first and second retardation plates 23, 2
A more desirable value of the slow axis angles ψ 1 and ψ 2 of 4 is ψ 1 =
64 ° ± 1 ° ψ2 = 158 ° ± 1 °, these phase difference plates 2
3,24 more desirable retardation Re1, Re2
The values of Re1 = 575 nm ± 2.2 nm, Re2 = 5
90 nm ± 2.2 nm to 600 nm ± 2.2 nm, and the slow axis angles ψ1, ψ2 and retardation R
By setting e1 and Re2 to such values, it is possible to obtain the display characteristics with the highest evaluation in which the purity of white, the emission rate and the contrast are comprehensively evaluated.

In each of the embodiments described above, the phase difference plate 2
3 and 24 are arranged between the liquid crystal cell 10 and the front-side polarizing plate 21 which also serves as a light incident surface and a display surface (display observation surface), but the phase difference plates 23 and 24 are opposite to each other. It may be arranged between the polarizing plate (back side polarizing plate) 22 and the liquid crystal cell 10.

Further, the color liquid crystal display device of each of the above embodiments is of a reflection type in which the reflection plate 20 is arranged on the back surface side, but the present invention does not include a reflection plate and the light from the backlight is not provided. The present invention can also be applied to a transmission type color liquid crystal display device that uses and displays.

In the case of this transmission type color liquid crystal display device,
The retardation plate is preferably arranged between the polarizing plate on the light emitting surface (display surface) side and the liquid crystal cell, but may be arranged between the polarizing plate on the light incident surface side and the liquid crystal cell.

Furthermore, in each of the above embodiments, the liquid crystal cell 10 is used.
Although an active matrix type in which a plurality of TFTs are arranged is used as the liquid crystal cell 10, the liquid crystal cell 10 may be an active matrix type provided with an MIM type element having a diode characteristic, or a simple matrix type. It may be a segment type.

[0139]

According to the color liquid crystal display device of the present invention, light is colored without using a color filter, and
Displaying multiple colors with the same pixel, and increasing the contrast, white, black, and red, which are the basics of display,
By displaying the three primary colors of green and blue, it is possible to realize a clear and rich multicolor display.

[Brief description of 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 view of the alignment state of liquid crystal molecules of the liquid crystal cell and the orientations of the optical axes of each polarizing plate and the retardation plate as viewed from the surface side of the liquid crystal display device.

FIG. 3 is a diagram showing an alignment state of liquid crystal molecules of a liquid crystal cell and a direction of optical axes of respective polarizing plates and a retardation plate as seen from a surface side of a liquid crystal display device showing a first embodiment of the present invention.

FIG. 4 is a diagram showing an alignment state of liquid crystal molecules of a liquid crystal cell and a direction of an optical axis of each polarizing plate and a retardation plate as seen from a surface side of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing an alignment state of liquid crystal molecules of a liquid crystal cell and a direction of an optical axis of each polarizing plate and a retardation plate as seen from a surface side of a liquid crystal display device showing a third embodiment of the present invention.

FIG. 6 is an a ^* -b ^* chromaticity diagram showing a change in display color in a color liquid crystal display device according to another embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a transmission axis angle and an emission rate of each polarizing plate in the color liquid crystal display device of the same example.

FIG. 8 is a view showing a relationship between a transmission axis angle of each polarizing plate and contrast in the color liquid crystal display device of the same example.

FIG. 9 is a diagram in which the display characteristics depending on the transmission axis angle of each polarizing plate in the color liquid crystal display device of the same example are evaluated in consideration of the hue of display in addition to the emission rate and contrast.

FIG. 10 is a diagram in which the hue of display is evaluated in the color liquid crystal display device of the example in which the transmission axis angle of each polarizing plate is in a range in which better display characteristics can be obtained.

FIG. 11 is an a ^* -b ^* chromaticity diagram showing a change in display color when the slow axis angle of each retardation plate is within a predetermined range in the color liquid crystal display device of the example.

FIG. 12 is a diagram showing a relationship between a slow axis angle of each retardation plate and a white display color in the color liquid crystal display device of the example ^.
-B ^* Chromaticity diagram.

FIG. 13 is a diagram showing a relationship between a slow axis angle of each retardation plate, an emission rate and a contrast in the color liquid crystal display device of the example.

FIG. 14 is an a ^* -b ^* chromaticity diagram showing a change in display color when the retardation value of each retardation plate is within a predetermined range in the color liquid crystal display device of the same example.

FIG. 15 is an a ^* -b ^* chromaticity diagram showing the relationship between the retardation value of each retardation plate and the white display color in the color liquid crystal display device of the example.

FIG. 16 is a diagram showing the relationship between the retardation value of each retardation plate and the emission rate and contrast in the color liquid crystal display device of the same example.

FIG. 17 is a diagram for evaluating the white purity, the emission rate and the contrast depending on the slow axis angle of each retardation plate in the color liquid crystal display device of the example.

FIG. 18 is a diagram for evaluating the white purity, the emission rate, and the contrast according to the retardation value of each retardation plate in the color liquid crystal display device of the same example.

[Explanation of symbols]

 10 ... Liquid crystal cell 11a ... Alignment direction of liquid crystal molecules near the back side substrate 12a ... Alignment direction of liquid crystal molecules near the front side substrate 20 ... Reflectors 21, 22 ... Polarizing plates 21a, 22a ... Transmission axes 23, 24 ... Phase difference Plates 23a, 24a ... Slow axis 23b ... Fast axis

Claims (12)

[Claims] 1. A liquid crystal is sandwiched between a pair of substrates on which electrodes are formed, and molecules of the liquid crystal are twist-aligned in a predetermined direction at a twist angle of about 90 ° from one substrate side to the other substrate side. Liquid crystal cell, a pair of polarizing plates arranged to sandwich the liquid crystal cell, and two retardation plates laminated to each other between any one of the polarizing plates and the liquid crystal cell. And a value of a product Δnd of a refractive index anisotropy Δn of liquid crystal of the liquid crystal cell and a liquid crystal layer thickness d, a value of retardation of each of the two retardation plates, and a value of the pair of polarizing plates. The direction of the transmission axis or the absorption axis and the direction of the slow axis or the fast axis of each of the two retardation plates are such that the color of the emitted light when the incident light is white light is the liquid crystal. Depending on the voltage applied between the electrodes of both substrates of the cell, at least red, , Blue, black, and white, and when the alignment direction of liquid crystal molecules near one substrate of the liquid crystal cell is 0 °, one of the pair of polarizing plates is The transmission axis or the absorption axis of one of the polarizing plates is 110 ° to 1 in the direction opposite to the twist direction of the liquid crystal molecules of the liquid crystal cell.
A color liquid crystal display device, wherein the direction of 30 ° and the transmission axis or absorption axis of the other polarizing plate are in the direction of 127 ° to 140 ° in the direction opposite to the twist direction. 2. The first retardation plate of the two retardation plates has its slow axis oriented in the direction of 60 ° to 70 ° opposite to the liquid crystal molecule twist direction with respect to the direction of 0 °. Placed
The second retardation plate is arranged such that its slow axis is oriented in a direction of 150 ° to 165 ° in a direction opposite to the twist direction with respect to the direction of 0 °. The described color liquid crystal display device. 3. A liquid crystal is sandwiched between a pair of substrates on which electrodes are formed, and molecules of the liquid crystal are twist-aligned in a predetermined direction at a twist angle of approximately 90 ° from one substrate side to the other substrate side. Liquid crystal cell, a pair of polarizing plates arranged to sandwich the liquid crystal cell, and two retardation plates laminated to each other between any one of the polarizing plates and the liquid crystal cell. And a value of a product Δnd of a refractive index anisotropy Δn of liquid crystal of the liquid crystal cell and a liquid crystal layer thickness d, a value of retardation of each of the two retardation plates, and a value of the pair of polarizing plates. The direction of the transmission axis or the absorption axis and the direction of the slow axis or the fast axis of each of the two retardation plates are such that the color of the emitted light when the incident light is white light is the liquid crystal. Depending on the voltage applied between the electrodes of both substrates of the cell, at least red, , Blue, black, are set to change to white, and the value of Δnd of the liquid crystal cell 800nm~110
0 nm, the retardation value of the first retardation plate of the two retardation plates is 350 nm to 610 nm, and the retardation value of the second retardation plate is 400 nm to 650 nm. apparatus. 4. The value of Δnd of the liquid crystal cell is 920 nm to 10
50 nm, the retardation value of the first retardation plate is 570 nm ± 2.5 nm to 590 nm ± 2.5 nm,
The retardation value of the second retardation plate is 585 nm ±
The color liquid crystal display device according to claim 3, wherein the color liquid crystal display device has a thickness of 2.5 nm to 605 nm ± 2.5 nm. 5. The retardation value of the first retardation plate is 5
It is in the range of 75 nm ± 2.5 nm to 585 nm ± 2.5 nm, and the retardation value of the second retardation plate is 590.
The color liquid crystal display device according to claim 4, wherein the color liquid crystal display device has a range of nm ± 2.5 nm to 600 nm ± 2.5 nm. 6. A liquid crystal is sandwiched between a pair of substrates on which electrodes are formed, and molecules of the liquid crystal are twist-aligned in a predetermined direction at a twist angle of approximately 90 ° from one substrate side to the other substrate side. Liquid crystal cell, a pair of polarizing plates arranged to sandwich the liquid crystal cell, and two retardation plates laminated to each other between any one of the polarizing plates and the liquid crystal cell. And a value of a product Δnd of a refractive index anisotropy Δn of liquid crystal of the liquid crystal cell and a liquid crystal layer thickness d, a value of retardation of each of the two retardation plates, and a value of the pair of polarizing plates. The direction of the transmission axis or the absorption axis and the direction of the slow axis or the fast axis of each of the two retardation plates are such that the color of the emitted light when the incident light is white light is the liquid crystal. Depending on the voltage applied between the electrodes of both substrates of the cell, at least red, , Blue, black, and white, and the retardation value of the first retardation plate of the two retardation plates is 350 nm to 610 nm. Retardation value is 400 nm to 650 nm
Further, when the alignment direction of the liquid crystal molecules near one substrate of the liquid crystal cell is set to 0 °, the slow axis or the fast axis of the first retardation plate is the liquid crystal molecule of the liquid crystal cell. The direction of 60 ° to 70 ° in the direction opposite to the twist direction, and the slow axis or the fast axis of the second retardation plate is 1 in the direction opposite to the twist direction.
A color liquid crystal display device, which is in the direction of 50 ° to 165 °. 7. A liquid crystal is sandwiched between a pair of substrates on which electrodes are formed, and molecules of the liquid crystal are twist-aligned in a predetermined direction at a twist angle of approximately 90 ° from one substrate side to the other substrate side. Liquid crystal cell, a pair of polarizing plates arranged to sandwich the liquid crystal cell, and two retardation plates laminated to each other between any one of the polarizing plates and the liquid crystal cell. And a value of a product Δnd of a refractive index anisotropy Δn of liquid crystal of the liquid crystal cell and a liquid crystal layer thickness d, a value of retardation of each of the two retardation plates, and a value of the pair of polarizing plates. The direction of the transmission axis or the absorption axis and the direction of the slow axis or the fast axis of each of the two retardation plates are such that the color of the emitted light when the incident light is white light is the liquid crystal. Depending on the voltage applied between the electrodes of both substrates of the cell, at least red, , Blue, black, and white, and the retardation value of the first retardation plate of the two retardation plates is 350 nm to 610 nm. Retardation value is 400 nm to 650 nm
In addition, when the alignment direction of the liquid crystal molecules near one substrate of the liquid crystal cell is set to 0 °, the transmission axis or the absorption axis of one of the pair of polarizing plates is the liquid crystal cell. Liquid crystal molecules of 110 ° to 130 ° in the direction opposite to the twist direction
Direction, the transmission axis or the absorption axis of the other polarizing plate is in the direction of 127 ° to 140 ° in the direction opposite to the twist direction, and the slow axis or the fast axis of the first retardation plate is opposite to the twist direction. Direction of 60 ° to 70 °, and the slow axis or the fast axis of the second retardation plate is 1 in the direction opposite to the twist direction.
A color liquid crystal display device, which is in the direction of 50 ° to 165 °. 8. One polarizing plate has a transmission axis of 113 ° ± 1 ° in a direction opposite to the twist direction of liquid crystal molecules with respect to the direction of 0 °.
The other polarizing plate is arranged so that its transmission axis is 127 ° ± 1 ° to 137 ° ± 1 ° in a direction opposite to the twist direction with respect to the 0 ° direction. The first retardation plate has a slow axis of 61 ° ± 1 ° to 67 ° in a direction opposite to the liquid crystal molecule twist direction with respect to the 0 ° direction.
The second retardation plate is arranged in the direction of ± 1 °, and has a slow axis of 156 ° ± 1 ° to 160 ° ± 1 ° in a direction opposite to the twist direction with respect to the direction of 0 °. The color liquid crystal display device according to claim 6, wherein the color liquid crystal display device is arranged in a direction. 9. The angle of the transmission axis of one polarizing plate with respect to the direction of 0 ° is 115 ° ± 1 ° to 117 °, and the angle of the transmission axis of the other polarizing plate is 129 ° ± 1 ° to 135 ° ± 1 °. And
9. The color liquid crystal display according to claim 8, wherein the angle of the slow axis of the first retardation plate with respect to the 0 ° direction is 62 ° ± 0.5 ° to 66 ° ± 0.5 °. apparatus. 10. A liquid crystal cell having a Δnd value of 800 nm to 1
The range is 100 nm, and the range is 6 to 9.
7. The color liquid crystal display device according to any one of 1. 11. A liquid crystal is sandwiched between a pair of substrates on which electrodes are formed, and molecules of the liquid crystal are twist-aligned in a predetermined direction at a twist angle of about 90 ° from one substrate side to the other substrate side. Liquid crystal cell, a pair of polarizing plates arranged to sandwich the liquid crystal cell, and two retardation plates laminated to each other between any one of the polarizing plates and the liquid crystal cell. And a reflection plate arranged on the back surface side of the other polarizing plate, wherein the product Δnd of the refractive index anisotropy Δn of the liquid crystal of the liquid crystal cell and the liquid crystal layer thickness d is 920 nm to 1050 nm, The retardation value of the first retardation plate of the retardation plate is set to 350 nm to 610 nm, the retardation value of the second retardation plate is set to 400 nm to 650 nm, and the retardation of the liquid crystal cell is set. Arranged the board When the alignment direction of the liquid crystal molecules near the substrate on the side opposite to is the direction of 0 °, the transmission axis or absorption axis of the polarizing plate of the pair of polarizing plates on which the retardation plate is arranged is the liquid crystal. The liquid crystal molecule twist direction of the cell is 110 ° to 130 ° in the opposite direction, and the transmission axis or the absorption axis of the other polarizing plate is in the direction of 130 ° to 140 ° in the opposite direction to the twist direction. The slow axis or the fast axis of the retardation plate is in the direction of 60 ° to 70 ° in the opposite direction to the twist direction, and the slow axis or the fast axis of the second retardation plate is 150 in the opposite direction to the twist direction. ° ~ 16
A color liquid crystal display device characterized by being in a direction of 5 °. 12. The two retardation plates are arranged such that the retardation plate with the smaller retardation value is adjacent to the polarizing plate and the retardation plate with the larger retardation value is adjacent to the liquid crystal cell. Claims 3, 4, 5, characterized in that
6. The color liquid crystal display device according to any one of 6, 7, and 9.