JPH086012A - Color liquid crystal display - Google Patents

Abstract

PURPOSE:To provide the color liquid crystal display device which can obtain a bright color display by coloring light without using any color filter and display plural colors by one pixel. CONSTITUTION:This color liquid crystal display device is equipped with a liquid crystal cell 20 wherein liquid crystal molecules are twisted and oriented, a top surface side polarizing plate 31 which is arranged on the top surface side of the liquid crystal cell 20, a reverse surface side polarizing plate 32 which is arranged on the reverse side of the liquid crystal cell 20, and a phase difference plate 33 which is arranged between the top surface side polarizing plate 31 and liquid crystal cell 20; and the liquid crystal molecule twist angle of the liquid crystal cell 20 is set to 120+ or -20 deg. and the axis of transmission of the reverse surface side polarizing plate 32 is deviated obliquely to the orientation direction of liquid crystal molecules on the surface of the reverse surface side substrate 22 of the liquid crystal cell 20.

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.

[0002]

2. Description of the Related Art As a liquid crystal display device, there is a color liquid crystal display device which can obtain a colored display. As the color liquid crystal display device, a TN (twisted nematic) system has been conventionally used, and a color filter is used for coloring transmitted light.

FIG. 16 is a sectional view of a conventional color liquid crystal display device. In this color liquid crystal display device, a liquid crystal cell 1 having a color filter and a pair of front and back polarized lights arranged with the liquid crystal cell 1 in between. It consists of plates 11 and 12.

The liquid crystal cell 1 is one in which a liquid crystal LC is sandwiched between a pair of transparent substrates (for example, glass substrates) 2 and 3 on which transparent electrodes 4 and 5 are formed and on which alignment films 6 and 7 are provided. The pair of substrates 2 and 3 are joined together with a frame-shaped sealing material 9 with their electrode formation surfaces facing each other.
The liquid crystal LC is sealed in a region surrounded by the sealing material 9 between the substrates 2 and 3.

The liquid crystal LC is a nematic liquid crystal having a positive dielectric anisotropy, and its molecules are aligned in the orientation directions on the respective substrates 2 and 3 by the orientation films 6 and 7 provided on the substrates 2 and 3. It is regulated and twist-oriented between the two substrates 2 and 3 at a twist angle of approximately 90 °.

The liquid crystal cell 1 is, for example, an active matrix type liquid crystal cell in which thin film transistors are used as active elements, and the transparent electrode 4 formed on one substrate 2 is a single film counter electrode and the other substrate 3 is formed on the other substrate 3. Formed transparent electrode 5
Are a plurality of pixel electrodes arranged in a matrix.

Although not shown in FIG. 16, the thin film transistors (active elements) are arranged on the substrate 3 on which the pixel electrodes 5 are formed so as to correspond to the pixel electrodes 5, respectively. A gate line for supplying a gate signal and a data line for supplying a data signal are wired, and the pixel electrodes 5 are connected to the corresponding thin film transistors.

Any one of the substrates of the liquid crystal cell 1,
For example, the pixel electrode 4 is formed on the substrate 3 on which the pixel electrode 5 is formed.
A plurality of color filters, for example, three color filters 8R, 8G, and 8 of red, green, and blue.
B are alternately arranged.

In the liquid crystal cell shown in FIG. 16, the color filters 8R, 8G and 8B are provided on the pixel electrode 5. However, in this type of liquid crystal cell, electrodes are provided on the color filter. Some are.

FIG. 17 shows a liquid crystal molecule alignment direction of the liquid crystal cell 1 and a pair of polarizing plates 1 in the color liquid crystal display device.
FIG. 2 is a plan view showing the transmission axes 1 and 12, and 2 in FIG.
a is a liquid crystal molecule orientation direction on the front surface side substrate (upper side substrate in FIG. 16) of the liquid crystal cell 1, 3a is the liquid crystal cell 1
3 shows the orientation direction of liquid crystal molecules on the three surfaces of the back-side substrate (lower substrate in FIG. 16).

As shown in FIG. 17, the liquid crystal molecule orientation direction 2a on the front surface side substrate 2 surface of the liquid crystal cell 1 is approximately 90 ° with respect to the liquid crystal molecule orientation direction 3a on the back surface side substrate 3 surface.
The molecules of the liquid crystal LC are misaligned, and are twisted clockwise at a twist angle of approximately 90 ° when viewed from the surface side.

Further, in FIG. 17, reference numeral 11a denotes a transmission axis of the front surface side polarizing plate 11 arranged on the front surface side of the liquid crystal cell 1, and 1a.
Reference numeral 2a denotes a back side polarizing plate 1 arranged on the back side of the liquid crystal cell 1.
2 shows the transmission axis, and the front-side polarizing plate 11 is arranged such that the transmission axis 11a is substantially orthogonal or substantially parallel (orthogonal in the figure) to the liquid crystal molecule orientation direction 2a on the front-side substrate 2 surface of the liquid crystal cell 1. The rear surface side polarizing plate 12 is arranged such that its transmission axis 12a is substantially parallel to the transmission axis 11a of the front surface side polarizing plate 11.

On the other hand, in FIG. 16, reference numeral 13 denotes a light source arranged on the back surface side of the color liquid crystal display device. The light source 13 and a light guide plate 14 facing substantially the entire back surface of the back surface side polarizing plate 12. The light source lamp 15 is arranged so as to face one end surface of the light guide plate 14.

The light guide plate 14 is a transparent plate made of acrylic resin or the like and a reflective film 14a made of an aluminum vapor deposition film or the like formed on the entire back surface thereof. The light enters from one end surface thereof, is guided through the light guide plate 14, and exits from the entire front surface toward the back surface side polarizing plate 12.

The above-mentioned color liquid crystal display device is driven for display by applying a voltage between the electrodes 4 and 5 of both substrates 2 and 3 of the liquid crystal cell 1, and the light from the light source 13 is a back side polarizing plate. The polarized light of 12 forms linearly polarized light and enters the liquid crystal cell 1.

When the light incident on the liquid crystal cell 1 passes through the color filters 8R, 8G and 8B, it absorbs light having a wavelength other than the wavelength band corresponding to the color, and the color filters 8R, 8G, The light becomes a light colored in 8B and is emitted to the surface side of the liquid crystal cell 1.

Then, when the ON voltage is not applied between the electrodes 4 and 5 of the liquid crystal cell 1, that is, when the liquid crystal molecules are in the initial twist alignment state, the linearly polarized light incident on the liquid crystal cell 1 is of the liquid crystal layer. Since the liquid crystal cell 1 is rotated by about 90 ° due to the birefringence effect and is emitted from the liquid crystal cell 1, the emitted light is absorbed by the front surface side polarizing plate 11, and the display is in a dark (black) state.

When an on-voltage is applied between the electrodes 4 and 5 of the liquid crystal cell 1, the liquid crystal molecules rise and align almost vertically to the surfaces of the substrates 2 and 3, and the birefringence effect of the liquid crystal layer is apparently almost zero. At this time, the linearly polarized light that has entered the liquid crystal cell 1 exits the liquid crystal cell 1 in that polarization state, and this light passes through the front surface side polarization plate 11 and exits to the front surface side of the liquid crystal display device. , Pixels of colors colored by the color filters 8R, 8G, and 8B are displayed.

[0019]

However, since the above-mentioned conventional color liquid crystal display device colors the transmitted light by using the color filter, it has a problem that the light transmittance is low and therefore the display is dark. .

This is due to the absorption of light by the color filter. Since the color filter also absorbs light in the wavelength range corresponding to the color with a considerably high absorption rate, the colored light passing through the color filter is The light has a significantly reduced amount of light as compared with the light in the wavelength range before entering the color filter, and the display becomes dark.

The color liquid crystal display device shown in FIG. 17 is of a transmissive type in which the light source 13 is arranged on the back surface side of the color liquid crystal display device. If the reflection type device is arranged, the light that enters from the front surface side, is reflected by the reflection plate on the back surface, and goes out to the front surface side passes twice through the color filter, and the light amount is double reduced.
The display becomes so dark that it becomes almost unusable as a display device.

Moreover, in the above-mentioned conventional color liquid crystal display device, since the display color is determined by the color of the color filter, one pixel cannot display a plurality of colors.

The present invention can obtain bright color display by coloring light without using a color filter, and
It is an object of the present invention to provide a color liquid crystal display device capable of displaying a plurality of colors with one pixel.

[0024]

[Means for Solving the Problems]

[First Invention] The present invention is intended for a transmissive color liquid crystal display device in which light is incident from the rear surface side for display, and a liquid crystal cell in which liquid crystal molecules are twist-aligned.
A front-side polarizing plate disposed on the front side of the liquid crystal cell, a back-side polarizing plate disposed on the back side of the liquid crystal cell, and a phase difference disposed between the front-side polarizing plate and the liquid crystal cell. And a liquid crystal molecule twist angle of the liquid crystal cell of 120 ± 20 °, and a transmission axis of the back surface side polarizing plate with respect to a liquid crystal molecule alignment direction on a back surface side substrate surface of the liquid crystal cell. It is characterized by being slanted.

In the present invention, the deviation angle between the transmission axis of the back side polarizing plate and the liquid crystal molecule orientation direction on the back side substrate surface of the liquid crystal cell is 30 ± 10 °, and the slow axis of the retardation plate is , With respect to the alignment direction of the liquid crystal molecules on the front surface side substrate surface of the liquid crystal cell, it is displaced by 15 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front surface side, and the transmission axis of the front surface side polarizing plate is set to the back surface side. The transmission axis of the polarizing plate is made substantially orthogonal to the retardation plate and the retardation of the retardation plate is set to 910.
± 20 nm, Δnd value of liquid crystal cell is 600 ± 60 nm
Is desirable.

[Second Invention] The present invention is intended for a transmission type color liquid crystal display device for displaying light by making light incident from the back side thereof, and a liquid crystal cell in which liquid crystal molecules are twist-aligned. A front surface side polarizing plate arranged on the front surface side of the liquid crystal cell, a rear surface side polarizing plate arranged on the rear surface side of the liquid crystal cell, and a phase difference arranged between the rear surface side polarizing plate and the liquid crystal cell. A plate, the liquid crystal molecule twist angle of the liquid crystal cell is 120 ± 20 °, and the slow axis of the retardation plate is slanted with respect to the transmission axis of the back surface polarizing plate. And

In the present invention, the shift angle between the slow axis of the retardation plate and the transmission axis of the back side polarizing plate is set to about 45 °, and the slow axis of the retardation plate is set to the back surface of the liquid crystal cell. The liquid crystal molecule alignment direction on the side substrate surface is shifted by 75 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front surface side, and the transmission axis of the front surface side polarizing plate is set to the transmission axis of the back surface side polarizing plate. It is desirable that the retardation plates are made substantially orthogonal to each other, the retardation of the retardation plate is 910 ± 20 nm, and the Δnd value of the liquid crystal cell is 600 ± 60 nm.

[Third Invention] The present invention is intended for a reflection type color liquid crystal display device in which light incident from the front surface side is reflected on the back surface side for display, and liquid crystal molecules are twist-aligned. A liquid crystal cell, a front surface side polarizing plate arranged on the front surface side of the liquid crystal cell, a back surface side polarizing plate arranged on the back surface side of the liquid crystal cell, and between the front surface side polarizing plate and the liquid crystal cell. A retardation plate disposed on the back side of the back-side polarizing plate; and a liquid crystal molecule twist angle of 120 ± 20 ° of the liquid crystal cell, and a retardation plate of the retardation plate. The phase axis is slanted with respect to the transmission axis of the front-side polarizing plate.

In the present invention, the shift angle between the slow axis of the retardation plate and the transmission axis of the front-side polarizing plate is approximately 45 °, and the slow axis of the retardation plate is the surface of the liquid crystal cell. The alignment axis of the liquid crystal molecules on the side substrate surface is displaced by 15 ± 10 ° in the direction opposite to the twist direction of the liquid crystal molecules viewed from the front surface side, and the transmission axis of the back side polarizing plate is set to the transmission axis of the front side polarizing plate. It is desirable that the retardation plates are made substantially orthogonal to each other, the retardation of the retardation plate is 910 ± 20 nm, and the Δnd value of the liquid crystal cell is 600 ± 60 nm.

[Fourth Invention] The present invention is intended for a reflective type color liquid crystal display device in which light incident from the front surface side is reflected on the back surface side for display, and liquid crystal molecules are twist-aligned. A liquid crystal cell, a front side polarizing plate disposed on the front side of the liquid crystal cell, a back side polarizing plate disposed on the back side of the liquid crystal cell, and between the back side polarizing plate and the liquid crystal cell. A retardation plate disposed on the back side of the back side polarizing plate; and a liquid crystal molecule twist angle of the liquid crystal cell of 120 ± 20 °. It is characterized in that the transmission axis is slanted with respect to the alignment direction of the liquid crystal molecules on the surface side substrate surface of the liquid crystal cell.

In the present invention, the deviation angle between the transmission axis of the polarizing plate on the surface side and the alignment direction of liquid crystal molecules on the surface of the substrate on the surface side of the liquid crystal cell is 30 ± 10 °, and the slow axis of the retardation plate is , With respect to the liquid crystal molecule alignment direction on the back surface side substrate surface of the liquid crystal cell, it is displaced by 75 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front surface side, and the transmission axis of the back surface side polarizing plate is The transmission axis of the polarizing plate is made substantially orthogonal to the retardation plate and the retardation of the retardation plate is set to 910.
± 20 nm, Δnd value of liquid crystal cell is 600 ± 60 nm
Is desirable.

[Fifth Invention] The present invention has a reflective display function of displaying light reflected from the front surface side by reflecting it on the rear surface side, and a transmissive display function of displaying light by making light incident from the rear surface side. The present invention is directed to a reflective / transmissive color liquid crystal display device having a liquid crystal cell in which liquid crystal molecules are twist-aligned, a surface side polarizing plate disposed on the surface side of the liquid crystal cell, and the liquid crystal cell. A rear surface side polarizing plate disposed on the back surface side, a phase difference plate disposed between the front surface side polarizing plate and the liquid crystal cell, and a half mirror disposed on the back side of the rear surface side polarizing plate. In addition, the liquid crystal molecule twist angle of the liquid crystal cell is set to 120 ± 20 °, and the slow axis of the retardation plate is slanted with respect to the transmission axis of the front surface side polarizing plate to form a back surface side polarizing plate. Align the transmission axis to the backside substrate surface of the liquid crystal cell. It is characterized in that it is slanted with respect to the liquid crystal molecule alignment direction.

In the present invention, the deviation angle between the slow axis of the retardation plate and the transmission axis of the front side polarizing plate is approximately 45 °, the transmission axis of the back side polarizing plate and the liquid crystal on the back side substrate surface of the liquid crystal cell. The deviation angle from the molecular alignment direction is 30 ± 10 °, and the slow axis of the retardation plate is a liquid crystal molecule twist viewed from the surface side with respect to the liquid crystal molecule alignment direction on the surface side substrate surface of the liquid crystal cell. The transmission axis of the front-side polarizing plate and the transmission axis of the back-side polarizing plate are substantially orthogonal to each other, and the retardation of the retardation plate is 910 ± 20 nm, Δn of cell
It is desirable that the value of d is 600 ± 60 nm.

[Sixth Invention] The present invention is intended for a reflective / transmissive color liquid crystal display device, and includes a liquid crystal cell in which liquid crystal molecules are twist-aligned and a surface side of the liquid crystal cell. A front surface side polarizing plate arranged, a back surface side polarizing plate arranged on the back surface side of the liquid crystal cell, a retardation plate arranged between the back surface side polarizing plate and the liquid crystal cell, and the back surface side polarizing plate. A half mirror arranged on the back side of the plate, and the liquid crystal molecule twist angle of the liquid crystal cell is 120.
In addition to ± 20 °, the transmission axis of the front-side polarizing plate is slanted with respect to the liquid crystal molecule alignment direction on the front-side substrate surface of the liquid crystal cell, and the slow axis of the retardation plate is the back-side polarizing plate. It is characterized in that it is slanted with respect to the transmission axis of.

In the present invention, the deviation angle between the transmission axis of the front-side polarizing plate and the alignment direction of liquid crystal molecules on the front-side substrate surface of the liquid crystal cell is 30 ± 10 °, the slow axis of the retardation plate and the back-side polarizing plate. The angle of deviation from the transmission axis of is about 45 °, and
The slow axis of the retardation plate is shifted by 75 ± 10 ° in a direction opposite to the liquid crystal molecule twist direction viewed from the front surface side with respect to the liquid crystal molecule orientation direction on the back surface side substrate surface of the liquid crystal cell, and the front surface side The transmission axis of the polarizing plate and the transmission axis of the back side polarizing plate are made substantially orthogonal to each other, and the retardation of the retardation plate is 910 ± 20 nm, and Δn of the liquid crystal cell is
It is desirable that the value of d is 600 ± 60 nm.

[0036]

The color liquid crystal display device according to the first aspect of the invention is for displaying light from a light source incident from the back surface side. In this liquid crystal display device, the incident light from the back surface side is
The polarizing action of the back-side polarizing plate makes it linearly polarized and enters the liquid crystal cell, and the light passing through this liquid crystal cell enters the front-side polarizing plate through the retardation plate and is transmitted through this front-side polarizing plate. Light is emitted to the front surface side of the liquid crystal display device.

Further, in this liquid crystal display device, since the transmission axis of the back side polarizing plate is slanted with respect to the liquid crystal molecule alignment direction on the back side substrate surface of the liquid crystal cell, the light is incident through the back side polarizing plate. When the linearly polarized light passes through the liquid crystal cell, it becomes elliptically polarized light having different polarization states depending on the wavelength due to the birefringence effect of the liquid crystal layer, and then, while passing through the retardation plate, the elliptical polarization having different polarization state due to the birefringence effect. It becomes polarized light, and light of the polarized component that passes through the front-side polarizing plate is emitted to the front surface side of the liquid crystal display device, and the emitted light is colored in a color corresponding to the ratio of each wavelength light in the light.

The color liquid crystal display device of the second invention is similar to the liquid crystal display device of the first invention, in which light from the light source is incident from the back surface side for display. In this liquid crystal display device, , The incident light from the back surface side becomes linearly polarized light by the polarization effect of the back surface side polarizing plate and enters the retardation plate, and the light passing through this retardation plate passes through the liquid crystal cell to the front surface side polarizing plate. The light that is incident and that has passed through the front surface side polarization plate is emitted to the front surface side of the liquid crystal display device.

Further, in this liquid crystal display device, since the slow axis of the retardation plate is deviated obliquely with respect to the transmission axis of the back side polarizing plate, the linearly polarized light incident through the back side polarizing plate has a phase difference. In the process of passing through the plate, the birefringence effect causes elliptically polarized light with different polarization states depending on the wavelength, and then in the process of passing through the liquid crystal cell, due to the birefringence effect of the liquid crystal layer, elliptically polarized light with different polarization states. The light of the polarization component that passes through the side polarizing plate is emitted to the surface side of the liquid crystal display device, and the emitted light is colored in a color corresponding to the ratio of each wavelength light in the light.

The color liquid crystal display device of the third invention uses external light such as natural light or indoor illumination light and reflects the light incident from the front surface side by the reflection plate on the rear surface side for display. In a liquid crystal display device, incident light from the front surface side becomes linearly polarized light by the polarizing action of the front surface side polarizing plate and enters the retardation plate, and light passing through this retardation plate passes through the liquid crystal cell. Light incident on the back-side polarizing plate and passing through the back-side polarizing plate is reflected by a reflecting plate, passes through the back-side polarizing plate, the liquid crystal cell, the retardation plate, and the front-side polarizing plate, and Emit to the front side.

Further, in this liquid crystal display device, since the slow axis of the retardation plate is deviated obliquely with respect to the transmission axis of the front surface side polarizing plate, the linearly polarized light incident through the front surface side polarizing plate is
In the process of passing through the retardation plate, the birefringence effect causes elliptically polarized light having different polarization states for each wavelength, and then in the process of passing through the liquid crystal cell, due to the birefringence effect of the liquid crystal layer, elliptically polarized light having a different polarization state. , The light of the polarization component transmitted through the back side polarizing plate passes through this back side polarizing plate and is colored in a color corresponding to the ratio of each wavelength light in the light, and this colored light is reflected by the reflection plate. , Is emitted to the front surface side of the liquid crystal display device.

The color liquid crystal display device of the fourth invention uses external light such as natural light or indoor illumination light, and the light incident from the front surface side is reflected on the back surface side similarly to the liquid crystal display device of the third invention. In this liquid crystal display device, the incident light from the surface side is converted into linearly polarized light by the polarization action of the front surface side polarizing plate and enters the liquid crystal cell. The light passing through the cell enters the back-side polarizing plate through the retardation plate, and the light passing through the back-side polarizing plate is reflected by the reflecting plate, and the back-side polarizing plate, the retardation plate, and the liquid crystal cell. The light is emitted to the front surface side of the liquid crystal display device through the front surface side polarizing plate.

Further, in this liquid crystal display device, since the transmission axis of the front surface side polarizing plate is slanted with respect to the alignment direction of the liquid crystal molecules on the front surface side substrate surface of the liquid crystal cell, the light enters through the front surface side polarizing plate. When the linearly polarized light passes through the liquid crystal cell, it becomes elliptically polarized light having different polarization states depending on the wavelengths due to the birefringence effect of the liquid crystal layer, and then, while passing through the retardation plate, the elliptical polarization having different polarization states due to the birefringence effect. It becomes polarized light, of which the light of the polarization component that passes through the back side polarizing plate passes through this back side polarizing plate and is colored in a color corresponding to the ratio of each wavelength light in the light. It is reflected by and is emitted to the front surface side of the liquid crystal display device.

The color liquid crystal display device of the fifth aspect of the invention performs reflection type display utilizing external light in a bright place where the amount of external light (natural light, indoor illumination light, etc.) is sufficient, and the amount of external light is dark. In a place, a transmissive display using light from a light source is performed, and in the case of a reflective display, external light that enters the liquid crystal display device from its front surface side is linearly polarized by the polarizing action of the front surface side polarizing plate. Then, the light that has passed through this retardation plate enters the back-side polarizing plate through the liquid crystal cell and is reflected by the half mirror among the light that has passed through this back-side polarizing plate. The emitted light passes through the back-side polarizing plate, the liquid crystal cell, the retardation plate, and the front-side polarizing plate, and is emitted to the front side of the liquid crystal display device.

In the case of the transmissive display, of the light (light from the light source) that enters the liquid crystal display device from the back side,
The light transmitted through the half mirror becomes linearly polarized light by the polarization effect of the back side polarizing plate and enters the liquid crystal cell, and the light passing through the liquid crystal cell enters the front side polarizing plate through the retardation plate. The light transmitted through the front surface side polarizing plate is emitted to the front surface side of the liquid crystal display device.

In the case of the reflection type display, in this liquid crystal display device, since the slow axis of the retardation plate is slanted with respect to the transmission axis of the front surface side polarizing plate, it passes through the front surface side polarizing plate. The incident linearly polarized light becomes elliptically polarized light having different polarization states depending on the wavelength due to its birefringence effect in the process of passing through the retardation plate, and the polarization state is further changed due to the birefringence effect of the liquid crystal layer in the process of passing through the liquid crystal cell. Different elliptically polarized light, of which the light of the polarization component that passes through the back side polarizing plate passes through this back side polarizing plate and is colored in a color corresponding to the ratio of each wavelength light in the light, this colored light The light is reflected by the half mirror and emitted to the front surface side of the liquid crystal display device.

Further, in the case of the transmissive display, in this liquid crystal display device, since the transmission axis of the back side polarizing plate is slanted with respect to the liquid crystal molecule alignment direction on the back side substrate surface of the liquid crystal cell, the back side Linearly polarized light that has entered through the polarizing plate
In the process of passing through the liquid crystal cell, the birefringence effect of the liquid crystal layer causes elliptically polarized light having different polarization states for each wavelength, and then in the process of passing through the retardation plate, elliptically polarized light having a different polarization state due to the birefringent effect. The light of the polarization component that passes through the front-side polarizing plate is emitted to the front side of the liquid crystal display device, and the emitted light is colored in a color corresponding to the ratio of each wavelength light in the light.

The color liquid crystal display device of the sixth aspect of the invention, like the liquid crystal display device of the fifth aspect of the invention, performs reflection type display utilizing outside light in a bright place where the amount of outside light is sufficient.
In a dark place where the amount of external light is small, a transmissive display that uses light from a light source is performed.In the case of a reflective display, external light that enters the liquid crystal display device from the surface side is a surface side polarized light. The light that has passed through the liquid crystal cell enters the back-side polarizing plate through the retardation plate and is transmitted through the back-side polarizing plate while the light that has passed through the liquid crystal cell becomes linearly polarized light due to the polarization effect of the plate. The light reflected by the half mirror is emitted to the front surface side of the liquid crystal display device through the back surface side polarizing plate, the phase difference plate, the liquid crystal cell and the front surface side polarizing plate.

In the case of transmissive display, of the light (light from the light source) that enters the liquid crystal display device from the back side,
The light transmitted through the half mirror becomes linearly polarized light by the polarization effect of the back side polarizing plate and enters the retardation plate, and the light passing through this retardation plate enters the front side polarizing plate through the liquid crystal cell. Then, the light transmitted through the front surface side polarizing plate is emitted to the front surface side of the liquid crystal display device.

Further, in the case of the reflection type display, in this liquid crystal display device, the transmission axis of the front surface side polarizing plate is slanted with respect to the alignment direction of the liquid crystal molecules on the front surface side substrate surface of the liquid crystal cell. Linearly polarized light that has entered through a polarizing plate becomes elliptically polarized light that has different polarization states for each wavelength due to the birefringence effect of the liquid crystal layer in the process of passing through the liquid crystal cell, and then the birefringence effect in the process of passing through the retardation plate. Results in elliptically polarized light with a different polarization state.
The light of the polarization component that passes through the back side polarizing plate passes through this back side polarizing plate and is colored into a color corresponding to the ratio of each wavelength light in the light, and this colored light is reflected by the half mirror and the liquid crystal The light is emitted to the front surface side of the display device.

In the case of the transmissive display, in this liquid crystal display device, since the transmission axis of the back side polarizing plate is deviated obliquely with respect to the slow axis of the retardation plate, the light is incident through the back side polarizing plate. When the linearly polarized light passes through the retardation plate, it becomes elliptically polarized light whose polarization state varies depending on the wavelength due to its birefringence effect, and then, while passing through the liquid crystal cell, the elliptical polarization state in which the polarization state further changes due to the birefringence effect of the liquid crystal layer. It becomes polarized light, and light of the polarized component that passes through the front-side polarizing plate is emitted to the front surface side of the liquid crystal display device, and the emitted light is colored in a color corresponding to the ratio of each wavelength light in the light.

That is, in any of the color liquid crystal display devices of the first to sixth inventions, the birefringence effect of the retardation plate and the liquid crystal layer of the liquid crystal cell is used without using the color filter.
Light is colored by the polarizing action of a pair of polarizing plates. According to this color liquid crystal display device, the loss of the amount of transmitted light can be reduced as compared with the case of transmitting light through a color filter. However, it is possible to obtain a bright color display by increasing the light transmittance.

Moreover, in the above color liquid crystal display device, the alignment state of the liquid crystal molecules changes according to the magnitude of the voltage applied between the electrodes provided on both substrates of the liquid crystal cell, which causes the birefringence of the liquid crystal layer. Since the effect changes, by controlling the voltage applied to the liquid crystal cell, the polarization state of the elliptically polarized light can be changed and the transmitted light can be colored in another color. Colors can be displayed.

Further, in the above color liquid crystal display device, since the liquid crystal molecules of the liquid crystal cell are twist-aligned at a large twist angle of 120 ± 20 °, the liquid crystal molecules are in an initial twist alignment state (twist in which the liquid crystal molecules are most laid down). The birefringence effect in the (alignment state) is large, and therefore the colored light can be greatly changed.

Further, the color liquid crystal display device of the first aspect of the invention is a transmissive type in which light is incident from the back surface side for display. In this color liquid crystal display device, the transmission axis of the back side polarizing plate is The deviation angle from the orientation of the liquid crystal molecules on the back side substrate surface of the liquid crystal cell is set to 30 ± 10 °, and the slow axis of the retardation plate is set to the orientation direction of the liquid crystal molecules on the front side substrate surface of the liquid crystal cell. , As well as shifting the liquid crystal molecule from the surface side by 15 ± 10 ° in the direction opposite to the twist direction,
The transmission axis of the front-side polarizing plate is made substantially orthogonal to the transmission axis of the back-side polarizing plate, the retardation of the retardation plate is 910 ± 20 nm, and the Δnd value of the liquid crystal cell is 600 ±.
When the thickness is 60 nm, the three primary colors of red, green and blue can be displayed by controlling the voltage applied to the liquid crystal cell, and
It is possible to increase the difference between the voltages for obtaining the display colors of red, green, and blue to facilitate the voltage control for switching the display colors.

Further, the color liquid crystal display device of the second invention is also of a transmission type. In this color liquid crystal display device, the shift angle between the slow axis of the retardation plate and the transmission axis of the back side polarizing plate is Is about 45 °, and the slow axis of this retardation plate is 75 ± 10 in the direction opposite to the twist direction of the liquid crystal molecules viewed from the front surface side with respect to the liquid crystal molecule alignment direction on the back surface side of the liquid crystal cell. The transmission axis of the front-side polarizing plate is substantially orthogonal to the transmission axis of the back-side polarizing plate, and the retardation of the retardation plate is 910 ± 20n.
If m and the value of Δnd of the liquid crystal cell are 600 ± 60 nm, the three primary colors of red, green and blue can be displayed by controlling the voltage applied to the liquid crystal cell, and these red, green,
The voltage difference for obtaining the blue display color can be increased to facilitate the voltage control for switching the display color.

On the other hand, although the color liquid crystal display device of the third invention is of a reflection type, in this color liquid crystal display device, the deviation angle between the slow axis of the retardation plate and the transmission axis of the front side polarizing plate is Is approximately 45 °, and the slow axis of the retardation plate is 15 ± 10 in the direction opposite to the liquid crystal molecule twist direction viewed from the surface side with respect to the liquid crystal molecule alignment direction on the surface side substrate surface of the liquid crystal cell. The transmission axis of the back side polarizing plate is made substantially orthogonal to the transmission axis of the front side polarizing plate, and the retardation of the retardation plate is 910 ± 20n.
If m and the value of Δnd of the liquid crystal cell are 600 ± 60 nm, the three primary colors of red, green and blue can be displayed by controlling the voltage applied to the liquid crystal cell, and these red, green,
The voltage difference for obtaining the blue display color can be increased to facilitate the voltage control for switching the display color.

The color liquid crystal display device of the fourth invention is also of a reflection type. In this color liquid crystal display device, liquid crystal molecule alignment in the transmission axis of the front surface side polarizing plate and the front surface side substrate surface of the liquid crystal cell. Deviation angle from direction is 30 ± 10 °
And, while the slow axis of the retardation plate is shifted by 75 ± 10 ° in a direction opposite to the liquid crystal molecule twist direction viewed from the front surface side with respect to the liquid crystal molecule alignment direction on the back surface side substrate surface of the liquid crystal cell, The transmission axis of the back-side polarizing plate is made substantially orthogonal to the transmission axis of the back-side polarizing plate, and the retardation of the retardation plate is 910 ± 20 nm.
If the value of is set to 600 ± 60 nm, the three primary colors of red, green, and blue can be displayed by controlling the voltage applied to the liquid crystal cell, and each of the red, green, and blue display colors can be obtained. Can be increased to facilitate voltage control for switching display colors.

Further, although the color liquid crystal display device of the fifth aspect of the invention is of a reflective / transmissive type, in this color liquid crystal display device, the slow axis of the retardation plate and the transmission axis of the front side polarizing plate are used. Is about 45 °, the deviation angle between the transmission axis of the back side polarizing plate and the liquid crystal molecule alignment direction on the back side substrate surface of the liquid crystal cell is 30 ± 10 °, and the slow axis of the retardation plate is Is shifted by 15 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front side with respect to the liquid crystal molecule orientation direction on the front surface side substrate surface of the liquid crystal cell, and the transmission axis of the front surface side polarizing plate and the back surface side The transmission axes of the polarizing plates are substantially orthogonal to each other, the retardation of the retardation plate is 910 ± 20 nm, and the Δnd value of the liquid crystal cell is 600 ±.
When the thickness is 60 nm, red and red are produced by controlling the voltage applied to the liquid crystal cell in both reflective display and transmissive display
It is possible to display the three primary colors of green and blue, and it is also possible to increase the difference between the voltages for obtaining these red, green, and blue display colors to facilitate voltage control for switching the display colors. it can.

The color liquid crystal display device of the sixth aspect of the invention is also of a reflective / transmissive type, and in this color liquid crystal display device, the transmission axis of the front surface side polarizing plate and the front surface side substrate surface of the liquid crystal cell are arranged. Deviation angle from liquid crystal molecule alignment direction is 3
The deviation angle between the slow axis of the 0 ± 10 ° retardation plate and the transmission axis of the back side polarizing plate is set to about 45 °, and the slow axis of the retardation plate is set on the back side substrate surface of the liquid crystal cell. The liquid crystal molecule alignment direction is shifted by 75 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front side, and the transmission axis of the front side polarizing plate and the transmission axis of the back side polarizing plate are substantially orthogonal to each other. Then, the retardation of the retardation plate is set to 91.
0 ± 20 nm, Δnd value of liquid crystal cell is 600 ± 60 n
If m is set, the three primary colors of red, green, and blue can be displayed by controlling the voltage applied to the liquid crystal cell in both reflective display and transmissive display, and these red,
By increasing the difference between the voltages for obtaining the green and blue display colors, it is possible to facilitate the voltage control for switching the display colors.

[0061]

【Example】

[Embodiment of the First Invention] FIG. 1 is a sectional view of a color liquid crystal display device showing an embodiment of the first invention. This color liquid crystal display device is a transmissive display device that displays light by making light incident from the back surface side, and includes a liquid crystal cell 20 in which molecules of liquid crystal LC are twist-aligned, and a front surface side (upper side in the drawing) of the liquid crystal cell 20. Front side polarizing plate 31 arranged on the back side of the liquid crystal cell 20 (lower side in the figure), the front side polarizing plate 31 and the liquid crystal cell 20.
And a retardation film 33 arranged between the and.

The liquid crystal cell 20 has transparent electrodes 23 and 24.
Liquid crystal LC is sandwiched between a pair of transparent substrates (for example, glass substrates) 21 and 22 on which the alignment films 25 and 26 are formed, and the pair of substrates 21 and 22 have electrode forming surfaces. Are bonded to each other via a frame-shaped seal material 27, and the liquid crystal LC is sealed in a region between the substrates 21 and 22 surrounded by the seal material 27.

The liquid crystal LC is a nematic liquid crystal having a positive dielectric anisotropy, and its molecules are formed by the alignment films 25 and 26 provided on the substrates 21 and 22, respectively.
The orientation directions on the two surfaces are regulated, and the two substrates 21 and 22 are twisted. The alignment films 25 and 2
Reference numeral 6 denotes a horizontal alignment film made of polyimide or the like, and these alignment films 25 and 26 are subjected to an alignment treatment (for example, a rubbing treatment) for controlling the alignment direction of the liquid crystal molecules.

The liquid crystal cell 20 is, for example, an active matrix type liquid crystal cell in which a thin film transistor is used as an active element, and the transparent electrode 23 formed on one substrate 21 is formed on a counter electrode in the form of a single film and on the other substrate 22. The formed transparent electrodes 24 are a plurality of pixel electrodes arranged in a matrix.

Although not shown in FIG. 1, the thin film transistors (active elements) are arranged on the substrate 22 on which the pixel electrodes 24 are formed so as to correspond to the respective pixel electrodes 24. A gate line for supplying a gate signal and a data line for supplying a data signal are wired, and the pixel electrodes 24 are connected to the corresponding thin film transistors.

In this liquid crystal display device, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °.
And the polarizing plate 32 on the back side, which is the light incident side.
Of the retardation plate 33 disposed between the front surface side polarizing plate 31 and the liquid crystal cell 20 is slanted with respect to the liquid crystal molecule alignment direction on the rear surface side substrate 21 surface of the liquid crystal cell 20. The axis and the transmission axis of the front-side polarizing plate 31,
The orientation is as follows.

FIG. 2 shows both substrates 21 of the liquid crystal cell 20,
Liquid crystal molecule alignment direction on 22 planes and a pair of polarizing plates 3
FIG. 3 is a plan view showing transmission axes of 1, 32 and a slow axis of a retardation plate 33.

As shown in FIG. 2, the liquid crystal molecule alignment direction 21a (alignment treatment direction of the alignment film 25) on the front surface side substrate 21 surface (alignment film 25 surface) of the liquid crystal cell 20 is a reference line (horizontal line in the figure) O In contrast to the figure, it is counterclockwise shifted by 30 ± 10 °,
The liquid crystal molecule orientation direction 22a (orientation processing direction of the orientation film 26) on the back surface side substrate 22 surface (orientation film 26 surface) is deviated from the reference line O by 30 ± 10 ° in the clockwise direction in the figure,
The liquid crystal molecules are twisted in a clockwise direction in the figure, that is, in a clockwise direction when viewed from the surface side, with a twist angle of 120 ± 20 °.

Further, the transmission axis 32a of the rear surface side polarizing plate 32 arranged on the rear surface side of the liquid crystal cell 20, that is, on the light incident side is
Since the transmission axis 32a of the back side polarizing plate 32 is substantially parallel to the reference line O, the transmission axis 32a of the liquid crystal molecules viewed from the front side with respect to the liquid crystal molecule alignment direction 22a on the back side substrate 22 surface of the liquid crystal cell 20. There is a deviation of 30 ± 10 ° in the direction opposite to the twist direction (counterclockwise in the figure).

On the other hand, the retardation plate 33 is a uniaxially stretched film made of polycarbonate or the like, and the slow axis (stretching axis) 33a of the retardation plate 33 is counterclockwise in the figure with respect to the reference line O. Therefore, the slow axis 33a of the retardation plate 33 is located in the direction shifted by about 45 °,
With respect to the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface, the liquid crystal molecule twist direction is deviated by 15 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front surface side.

Further, the transmission axis 31a of the surface side polarizing plate 31 arranged on the surface side of the liquid crystal cell 20, that is, on the light emitting side,
Since the transmission axis 31a of the front-side polarizing plate 31 is displaced from the reference line O by approximately 90 °, the transmission axis 31a of the front-side polarizing plate 31 is a liquid crystal molecule seen from the front side with respect to the slow axis 33a of the retardation plate 33. It is deviated by approximately 45 ° in the direction opposite to the twist direction and is substantially orthogonal to the transmission axis 32a of the back side polarizing plate 32.

In FIG. 1, reference numeral 40 denotes a light source arranged on the back side of the liquid crystal display device.
Is composed of a light guide plate 41 facing almost the entire back surface of the back side polarizing plate 32, and a light source lamp 42 arranged to face one end surface of the light guide plate 41. The light guide plate 4
Reference numeral 1 denotes a transparent plate made of acrylic resin or the like, on the entire back surface of which a reflective film 41a made of an aluminum vapor deposition film or the like is formed. Illumination light from a light source lamp 42 enters the light guide plate 41 from one end surface thereof and The light is guided through the inside of the light guide plate 41, and is emitted from the entire front surface toward the back surface side polarizing plate 32.

The liquid crystal display device displays the illumination light from the light source 40 from the back surface side, and in this liquid crystal display device, the light incident from the back surface side is reflected by the back surface side polarizing plate 32. The polarized light turns into linearly polarized light and enters the liquid crystal cell 20, and the light passing through the liquid crystal cell 20 enters the front surface side polarizing plate 31 through the retardation plate 33 and is transmitted through the front surface side polarizing plate 31. Light is emitted to the front surface side of the liquid crystal display device.

In this liquid crystal display device, the transmission axis 32a of the back side polarizing plate 32 is deviated obliquely with respect to the liquid crystal molecule alignment direction 22a on the back side substrate 22 of the liquid crystal cell 20, so that the back side polarization is performed. The linearly polarized light incident through the plate 22 becomes elliptically polarized light having different polarization states for each wavelength due to the birefringence effect of the liquid crystal layer in the process of passing through the liquid crystal cell 20, and then the birefringence thereof in the process of passing through the retardation plate 33. Due to the effect, elliptically polarized light having a different polarization state is further generated, of which the light of the polarization component that passes through the front surface side polarizing plate 31 is emitted to the front surface side of the liquid crystal display device, and this emitted light is converted into light of each wavelength light in the light. Color in the color corresponding to the ratio.

As described above, the liquid crystal display device described above does not use a color filter, and the retardation plate 33 and the liquid crystal cell 20 are not used.
The light is colored by the birefringence effect of the liquid crystal layer and the polarization effect of the pair of polarizing plates 31 and 32. According to this liquid crystal display device, the loss of the amount of transmitted light is greater than that in the case of transmitting through the color filter. Therefore, it is possible to increase the light transmittance and obtain a bright color display.

That is, the color filter absorbs light having a wavelength other than the wavelength range corresponding to the color and colors the light.
Since this color filter also absorbs light in the wavelength range corresponding to that color with a considerably high absorptivity, in a liquid crystal display device that colors light with the color filter, the wavelength that becomes colored light of the light that enters the display device. The amount of colored light passing through the color filter is considerably reduced as compared with the amount of light in the band.

In this respect, since the liquid crystal display device of the above-mentioned embodiment colors light without using a color filter,
Light is not absorbed by the color filter, and the retardation plate 33 and the liquid crystal LC of the liquid crystal cell 20 only change the polarization state of the transmitted light and hardly absorb the light.

Therefore, the amount of the colored light which is changed in polarization state due to these birefringence effects and which is transmitted through the front surface side polarizing plate 31 and is emitted out of the linearly polarized light which is incident through the rear surface side polarizing plate 32. The amount of light in the wavelength band that becomes the colored light is almost the same, so that colored light of high brightness can be obtained.

Further, in the liquid crystal display device in which light is colored by the color filter, the display color is determined by the color of the color filter, so that one pixel cannot display a plurality of colors. According to the liquid crystal display device, one pixel can display a plurality of colors.

That is, in the liquid crystal display device of the above embodiment,
Since the alignment state of the liquid crystal molecules changes according to the magnitude of the voltage applied between the electrodes 23 and 24 provided on both substrates 21 and 22 of the liquid crystal cell 20, and thereby the birefringence effect of the liquid crystal layer changes. By controlling the voltage applied to the liquid crystal cell 20, the polarization state of the elliptically polarized light can be changed and the transmitted light can be colored in another color.

Moreover, in the liquid crystal display device of the above embodiment,
Since the liquid crystal molecules of the liquid crystal cell 20 are twist-aligned at a large twist angle of 120 ± 20 °, the birefringence effect when the liquid crystal molecules are in the initial twist alignment state (the twist alignment state in which the liquid crystal molecules are most collapsed) is obtained. It is large and therefore the colored light can be changed significantly.

The display color of this liquid crystal display device will be described. For example, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 1
20 °, the transmission axis 32a of the back side polarizing plate 32 and the liquid crystal cell 2
Liquid crystal molecule alignment direction 22a on the back side substrate 22 surface of 0
The deviation angle between the slow axis 33a of the retardation film 33 and the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20 is 15 degrees, and the transmission axis 31a of the front surface side polarizing plate 31 is 30 degrees. And the retardation axis 33a of the retardation plate 33 is 4
5 ° (the transmission axis 31a of the front surface side polarizing plate 31 is orthogonal to the transmission axis 32a of the back surface side polarizing plate 32), the retardation of the retardation plate 33 is 910 nm, Δnd of the liquid crystal cell 20 (refractive index anisotropy of the liquid crystal LC). The product of Δn and liquid crystal layer thickness d) is 6
When it is set to 00 nm (for example, Δn = 0.1, d = 6 μm), the display color of each pixel changes to three primary colors of red, green, and blue according to the applied voltage.

That is, FIG. 3 shows changes in the transmittance of light of each color of red, green, and blue with respect to the voltage applied to the liquid crystal cell 20 of the liquid crystal display device. In this liquid crystal display device,
As the applied voltage to the liquid crystal cell 20 is increased, the transmittance of light of each color changes as shown in the figure.
Applied voltages V0, V1 and V are selected by selecting points where the transmittance of light of one of green and blue is sufficiently higher than the transmittance of the other two colors.
If you set 2, you can display the three primary colors of red, green and blue.

In FIG. 3, V0 is a voltage at which the liquid crystal molecules hardly rise from the initial twist alignment state. When the applied voltage is V0, the transmittance of green light is high and the red and blue light is Since the transmission is extremely small, the display color at this time is green with extremely high color purity.

When the applied voltage is V1, not only the blue light but also the red and green lights are transmitted to some extent, but the blue light transmittance is high and the red and green light transmittances are very low. The display color at this time is also blue, which has a sufficiently satisfactory color purity.

Further, when the applied voltage is V2, not only red light but also green and blue light are transmitted to some extent, but the transmittance of red light is high and the transmittance of green and blue light is considerably low. The display color at this time is also red with a sufficiently satisfactory color purity.

Therefore, according to this liquid crystal display device,
By controlling the voltage applied to the liquid crystal cell 20, the three primary colors of red, green and blue can be displayed, and by displaying different colors in a plurality of adjacent pixels, the red, green,
It is also possible to display a mixed color of a plurality of colors of blue.

Further, according to this liquid crystal display device, as shown in FIG. 3, the voltage V0 at which the display color of "green" is obtained,
Since there is a large difference between the voltage V1 for obtaining the "blue" display color and the voltage V2 for obtaining the "red" display color, the voltage control for switching the display color can be facilitated.

The liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °, and the deviation angle between the transmission axis 32a of the back side polarizing plate 32 and the liquid crystal molecule orientation direction 22a on the back side substrate 22 of the liquid crystal cell 20 is 30. ± 10 °, the deviation angle between the slow axis 33a of the retardation plate 33 and the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20 is 15 ± 10 °,
The deviation angle between the transmission axis 31a of the front-side polarizing plate 31 and the slow axis 33a of the retardation plate 33 is approximately 45 ° (the transmission axis 31a of the front-side polarizing plate 31 is substantially orthogonal to the transmission axis 32a of the back-side polarizing plate 32). ), The retardation of the retardation plate 33 is 910 ± 20.
nm, and Δnd of the liquid crystal cell 20 may be 600 ± 60 nm. Within this range, the change in the transmittance of light of each color of red, green, and blue with respect to the voltage applied to the liquid crystal cell 20 is almost the same as that in FIG. Therefore, the three primary colors of red, green, and blue can be displayed by controlling the voltage applied to the liquid crystal cell 20, and the difference between the voltages for obtaining these red, green, and blue display colors is increased, The voltage control for switching the display color can be facilitated.

Such an effect is obtained by increasing the liquid crystal molecule twist angle of the liquid crystal cell 20 to 120 ± 20 °, and
1, 32 and the direction of the slow axis of the retardation plate 33, the retardation of the retardation plate 33, and the liquid crystal cell 20.
Is obtained by setting Δnd in the above range.

That is, FIG. 4 and FIG. 5 show the liquid crystal cell 2
The liquid crystal molecule twist angle of 0 is set to approximately 90 ° (the same twist angle as in the TN mode liquid crystal display device), and the directions of the transmission axes of the polarizing plates 31 and 32 and the slow axis of the retardation plate 33 and the retardation plate 33 are set. FIG. 7 shows changes in transmittance of light of red, green, and blue with respect to applied voltage in two types of liquid crystal display devices (hereinafter, referred to as comparative devices) in which retardation and Δnd of the liquid crystal cell are different from those in the above-described embodiment. ing.

Each of these comparison devices is shown in FIG.
The deviation angle of the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20 with respect to the reference line O shown in FIG. Turn clockwise about 45 °
And the transmission axis 32a of the back side polarizing plate 32 is the reference line O
With respect to the figure, the surface side polarizing plate 3 is shifted counterclockwise by 135 °.
The transmission axis 31a of No. 1 is orthogonal to the transmission axis 32a of the back-side polarizing plate 32, and the slow axis 33a of the retardation plate 33 is parallel to the reference line O. In the first comparison device, The retardation of the retardation film 33 is 580 nm, and the Δnd of the liquid crystal cell 20 is 540 nm.
I am trying.

The change in the transmittance of the light of each color of red, green and blue with respect to the applied voltage of the first comparison device (where the retardation of the retardation plate 33 was 620 nm) was changed by the transmission of red light and green light. The change is as shown in FIG. 4 in which the rate difference is small, and therefore, the display colors of this first comparison device are only two colors, orange and blue, which are mixed colors of red and green.

In this first comparison device, the difference in transmittance between the red light and the green light when the applied voltage is V0 is large to some extent, and the display color when the applied voltage is V0 is orange close to red. Is the color.

Further, the second comparison device (the phase difference plate 33
The difference in the transmittance of light of each color of red, green, and blue with respect to the applied voltage of the retardation of 580 nm) is such that the difference in transmittance between red light and green light is smaller than that in the first comparison device. Therefore, the display colors of the second comparison device are only two colors, orange and blue. Further, the second comparison device has a lower blue light transmittance than the first comparison device, and therefore the definition of blue display color is poor.

As can be seen by comparing FIG. 4 and FIG. 5 with FIG. 3, in the comparison device in which the liquid crystal molecule twist angle of the liquid crystal cell 20 is approximately 90 °, the voltage applied to the liquid crystal cell 20 is controlled. The display color obtained by is 2 of orange and blue.
Although only the colors are used, if the liquid crystal molecule twist angle of the liquid crystal cell 20 is increased to 120 ± 20 ° as in the above embodiment, the three primary colors of red, green and blue are displayed by controlling the voltage applied to the liquid crystal cell 20. In addition, it is possible to increase the difference between the voltages for obtaining these red, green, and blue display colors to facilitate the voltage control for switching the display colors.

The liquid crystal display device of the above-mentioned embodiment is red,
The three primary colors of green and blue are displayed. The display colors of this liquid crystal display device are the transmission axes 31a, 3 of the polarizing plates 31, 32.
2a and the direction of the slow axis 33a of the retardation plate 33, the retardation of the retardation plate 33, and the Δnd of the liquid crystal cell. Therefore, by selecting these conditions, the display color can be arbitrarily selected. .

In the above embodiment, the liquid crystal cell 20 is of the active matrix type using thin film transistors as active elements.
It may be an active matrix type liquid crystal cell using a two-terminal non-linear resistance element such as IM as an active element, or may be a simple matrix type or a segment display type.

[Embodiment of the Second Invention] FIG. 6 is a sectional view of a color liquid crystal display device showing an embodiment of the second invention.
This color liquid crystal display device is a transmissive display device that displays light by making light incident from the back surface side, and includes a liquid crystal cell 20 in which molecules of liquid crystal LC are twist-aligned, and a front surface side (upper side in the drawing) of the liquid crystal cell 20. Front side polarizing plate 31 disposed in
And a rear surface side polarizing plate 32 arranged on the rear surface side (lower side in the figure) of the liquid crystal cell 20, and a retardation plate 33 arranged between the rear surface side polarizing plate 32 and the liquid crystal cell 20. Has been done.

The liquid crystal cell 20 is, for example, an active matrix type liquid crystal cell having a thin film transistor as an active element, and its configuration is the same as that shown in FIG. Attached and omitted.

In this liquid crystal display device, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °.
And the polarizing plate 32 on the back side, which is the light incident side.
The slow axis of the retardation plate 33 disposed between the liquid crystal cell 20 and the liquid crystal cell 20 is slanted with respect to the transmission axis of the back-side polarizing plate 32. The transmission axis of the polarizing plate 31 on the front side, which is the emitting side, is oriented as follows.

FIG. 7 shows both substrates 21 of the liquid crystal cell 20,
Liquid crystal molecule alignment direction on 22 planes and a pair of polarizing plates 3
FIG. 3 is a plan view showing transmission axes of 1, 32 and a slow axis of a retardation plate 33.

As shown in FIG. 7, the liquid crystal molecule alignment direction 21a (alignment treatment direction of the alignment film 25) on the front surface side substrate 21 surface (alignment film 25 surface) of the liquid crystal cell 20 is a reference line (horizontal line in the figure) O On the other hand, it shifts clockwise by 30 ± 10 °,
The liquid crystal molecule alignment direction 22a (alignment treatment direction of the alignment film 26) on the rear surface side substrate 22 surface (alignment film 26 surface) is shifted counterclockwise by 30 ± 10 ° with respect to the reference line O.
The liquid crystal molecules are twisted counterclockwise in the figure, that is, counterclockwise when viewed from the surface side, with a twist angle of 120 ± 20 °.

The transmission axis 32a of the back side polarizing plate 32 arranged on the back side of the liquid crystal cell 20, that is, on the light incident side is
The reference axis O is deviated by approximately 90 °, and the slow axis 33a of the phase difference plate 33 is deviated in the clockwise direction in the figure by approximately 45 ° with respect to the reference line O.

Therefore, the slow axis 33a of the retardation plate 33
Is shifted by about 45 ° in the same direction (counterclockwise in the figure) as the twist direction of the liquid crystal molecules as viewed from the front side with respect to the transmission axis 32a of the back side polarizing plate 32, and the back side substrate 22 surface of the liquid crystal cell 20 is With respect to the liquid crystal molecule alignment direction 22a in FIG.

Further, the transmission axis 31a of the surface side polarizing plate 31 arranged on the surface side of the liquid crystal cell 20, that is, on the light emitting side is
The transmission axis 31a of the front surface side polarizing plate 31 is substantially parallel to the reference line O, and therefore, the liquid crystal molecule twist viewed from the front surface side with respect to the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20. 30 ± 1 in the opposite direction
It is offset by 0 ° and is substantially orthogonal to the transmission axis 32a of the back side polarizing plate 32.

In FIG. 6, reference numeral 40 denotes a light source arranged on the back side of the liquid crystal display device. This light source 40
1 is the same as that shown in FIG. 1, and therefore the description thereof will be omitted by giving the same symbols to the drawing.

The liquid crystal display device displays the illumination light from the light source 40 from the back surface side. In this liquid crystal display device, the light incident from the back surface side is reflected by the back surface side polarizing plate 32. The polarized light turns into linearly polarized light and enters the retardation plate 33, and the light passing through the retardation plate 33 enters the front surface side polarizing plate 31 through the liquid crystal cell 20 and transmits through the front surface side polarizing plate 31. The emitted light is emitted to the front surface side of the liquid crystal display device.

In this liquid crystal display device, since the slow axis 33a of the retardation plate 33 is deviated obliquely with respect to the transmission axis 32a of the back side polarizing plate 32, a straight line incident through the back side polarizing plate 32 is incident. The polarized light becomes elliptically polarized light having a different polarization state for each wavelength due to its birefringence effect in the process of passing through the retardation plate 33, and further has a different polarization state due to the birefringence effect of the liquid crystal layer in the process of passing through the liquid crystal cell 20. It becomes elliptically polarized light, of which the light of the polarization component that passes through the front surface side polarizing plate 31 is emitted to the front surface side of the liquid crystal display device, and the emitted light is colored in a color corresponding to the ratio of each wavelength light in the light. To do.

As described above, in the above liquid crystal display device, the retardation plate 33 and the liquid crystal cell 20 are used without using the color filter.
The light is colored by the birefringence effect of the liquid crystal layer and the polarization effect of the pair of polarizing plates 31 and 32. According to this liquid crystal display device, the loss of the amount of transmitted light is greater than that in the case of transmitting through the color filter. Therefore, it is possible to increase the light transmittance and obtain a bright color display.

Moreover, in this liquid crystal display device, the electrodes 23 and 2 provided on both substrates 21 and 22 of the liquid crystal cell 20.
The orientation state of the liquid crystal molecules changes according to the magnitude of the voltage applied between the four, and the birefringence effect of the liquid crystal layer changes accordingly. Therefore, by controlling the voltage applied to the liquid crystal cell 20, the elliptically polarized light The transmitted light can be colored in another color by changing the polarization state of, and thus one pixel can display a plurality of colors.

In this liquid crystal display device, the liquid crystal cell 2
Since the liquid crystal molecules of 0 are twist-aligned with a large twist angle of 120 ± 20 °, the liquid crystal molecules are in the initial twist alignment state (the liquid crystal molecules are in the most twisted alignment state).
The effect of birefringence is large in the case of, so that the colored light can be greatly changed.

The display color of this liquid crystal display device will be described. For example, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 1
20 °, the slow axis 33a of the retardation plate 33 and the back side polarizing plate 3
The deviation angle between the second transmission axis 32a and the transmission axis 32a is 45 °, the deviation angle between the slow axis 33a of the retardation plate 33 and the liquid crystal molecule orientation direction 22a on the rear surface side substrate 22 of the liquid crystal cell 20 is 75 °, and the front surface side polarizing plate The deviation angle between the transmission axis 31a of the liquid crystal cell 31 and the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20 is 3
0 ° (the transmission axis 31a of the front surface side polarizing plate 31 and the transmission axis 32a of the back surface side polarizing plate 32 are orthogonal to each other), the retardation of the retardation plate 33 is 910 nm, and the value of Δnd of the liquid crystal cell 20 is 600 nm (for example, Δn = 0.1, d = 6 μm), the display color of each pixel is red according to the applied voltage,
Change to the three primary colors of green and blue.

Therefore, according to this liquid crystal display device,
By controlling the voltage applied to the liquid crystal cell 20, the three primary colors of red, green and blue can be displayed, and by displaying different colors in a plurality of adjacent pixels, the red, green,
It is also possible to display a mixed color of a plurality of colors of blue.

Red against the applied voltage of this liquid crystal display device,
The change in the transmittance of light of each color of green and blue is almost the same as the change shown in FIG. 3, and therefore red, green, and
It is possible to obtain a blue display color, and the difference between the voltage for obtaining a "green" display color, the voltage for obtaining a "blue" display color, and the voltage for obtaining a "red" display color. Is large, the voltage control for switching the display color can be facilitated.

The liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °, and the shift angle between the slow axis 33a of the retardation plate 33 and the transmission axis 32a of the back side polarizing plate 32 is about 45.
The deviation angle between the slow axis 33a of the retardation plate 33 and the liquid crystal molecule alignment direction 22a on the rear surface side substrate 22 surface of the liquid crystal cell 20 is 75 ± 10 °, the transmission axis 31a of the front surface side polarizing plate 31 and the liquid crystal cell 20. Of the liquid crystal molecule alignment direction 21a on the surface of the front side substrate 21 of 30 ± 10 ° (the front side polarizing plate 3
1 and the transmission axis 32a of the back side polarizing plate 32 are substantially orthogonal to each other, and the retardation of the retardation plate 33 is 910.
± 20 nm, Δnd of the liquid crystal cell 20 is 600 ± 60 nm
In this range, the change in the transmittance of light of each color of red, green, and blue with respect to the voltage applied to the liquid crystal cell 20 is almost the same as that in FIG. The three primary colors of red, green, and blue can be displayed by controlling, and the voltage difference for switching the display colors can be easily increased by increasing the difference between the voltages for obtaining these red, green, and blue display colors. can do.

The liquid crystal display device of the above embodiment is
The three primary colors of green and blue are displayed. The display colors of this liquid crystal display device are the transmission axes 31a, 3 of the polarizing plates 31, 32.
2a and the direction of the slow axis 33a of the retardation plate 33, the retardation of the retardation plate 33, and the Δnd of the liquid crystal cell. Therefore, by selecting these conditions, the display color can be arbitrarily selected. .

Furthermore, in the above embodiment, the liquid crystal cell 20 is of the active matrix type in which thin film transistors are used as active elements.
It may be an active matrix type liquid crystal cell using a two-terminal nonlinear resistance element such as MIM as an active element, or may be a simple matrix type or a segment display type.

[Embodiment of the Third Invention] FIG. 8 is a sectional view of a color liquid crystal display device showing an embodiment of the third invention.
This color liquid crystal display device is a reflection type display device in which light incident from the front surface side is reflected on the back surface side for display, and a liquid crystal cell 20 in which molecules of liquid crystal LC are twist-aligned and a front surface side of the liquid crystal cell 20. The front-side polarizing plate 31 arranged on the upper side in the figure, the back-side polarizing plate 32 arranged on the back side of the liquid crystal cell 20 (lower side in the figure), the front-side polarizing plate 31 and the liquid crystal cell 20. And a retardation plate 33 disposed between the back side polarizing plate 32 and the back side polarizing plate 32.

The liquid crystal cell 20 is, for example, an active matrix type liquid crystal cell having a thin film transistor as an active element, and its configuration is the same as that shown in FIG. Attached and omitted.
The reflection plate 34 is made of a metal film such as aluminum, and the surface thereof is a roughened scattering reflection surface.

In this liquid crystal display device, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °.
In addition, the slow axis of the retardation plate 33 disposed between the front surface side polarizing plate 31 and the liquid crystal cell 20 is set to the front surface side polarizing plate 31.
And the slow axis of the retardation plate 33 and the transmission axis of the back side polarizing plate 32 are oriented as follows.

FIG. 9 shows both substrates 21 of the liquid crystal cell 20,
Liquid crystal molecule alignment direction on 22 planes and a pair of polarizing plates 3
FIG. 3 is a plan view showing transmission axes of 1, 32 and a slow axis of a retardation plate 33.

As shown in FIG. 9, the liquid crystal molecule alignment direction 21a (alignment treatment direction of the alignment film 25) on the front surface side substrate 21 surface (alignment film 25 surface) of the liquid crystal cell 20 is a reference line (horizontal line in the figure) O In contrast to the figure, it is counterclockwise shifted by 30 ± 10 °,
The liquid crystal molecule orientation direction 22a (orientation processing direction of the orientation film 26) on the back surface side substrate 22 surface (orientation film 26 surface) is deviated from the reference line O by 30 ± 10 ° in the clockwise direction in the figure,
The liquid crystal molecules are twisted in a clockwise direction in the figure, that is, in a clockwise direction when viewed from the surface side, with a twist angle of 120 ± 20 °.

Further, the transmission axis 31a of the front side polarizing plate 31
Is shifted by approximately 90 ° with respect to the reference line O, and the slow axis 33a of the phase difference plate 33 is shifted by approximately 45 ° counterclockwise in the figure with respect to the reference line O.

Therefore, the slow axis 3 of the retardation plate 33 is
3a is deviated from the transmission axis 31a of the surface polarizing plate 31 by approximately 45 ° in the same direction (clockwise in the figure) as the twist direction of the liquid crystal molecules viewed from the surface side, and the front surface side substrate 21 of the liquid crystal cell 20. The liquid crystal molecule alignment direction 21a on the surface is displaced by 15 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front side (counterclockwise in the figure).

Further, the transmission axis 32a of the back side polarizing plate 32
Is substantially parallel to the reference line O, and therefore, the transmission axis 32a of the back side polarizing plate 32 is the liquid crystal as viewed from the front side with respect to the liquid crystal molecule alignment direction 22a on the back side substrate 22 of the liquid crystal cell 20. 30 in the direction opposite to the molecular twist direction
It is offset by ± 10 ° and is substantially orthogonal to the transmission axis 31a of the front-side polarizing plate 31.

The above liquid crystal display device uses external light such as natural light or indoor illumination light and reflects the light incident from the front surface side by the reflection plate 34 on the rear surface side for display. In this liquid crystal display device, The incident light from the front surface side becomes linearly polarized light by the polarization effect of the front surface side polarizing plate 31 and enters the retardation plate 33, and the light passing through the retardation plate 33 passes through the liquid crystal cell 20. Light incident on the back side polarizing plate 32 and passing through the back side polarizing plate 32 is reflected by the reflecting plate 34, and the back side polarizing plate 32, the liquid crystal cell 20, the phase difference plate 33, and the front side polarizing plate 31 are formed. And the light is emitted to the surface side of the liquid crystal display device.

In this liquid crystal display device, the slow axis 33a of the retardation plate 33 is the transmission axis 31a of the front side polarizing plate 31.
Since the linearly polarized light incident through the front surface side polarizing plate 31 becomes an elliptically polarized light having a different polarization state for each wavelength due to its birefringence effect in the process of passing through the retardation plate 33, since it is obliquely displaced with respect to Then, in the process of passing through the liquid crystal cell 20, due to the birefringence effect of the liquid crystal layer, elliptically polarized light having a different polarization state is obtained, and among them, the light of the polarization component that passes through the back surface side polarization plate 31 passes through this back surface side polarization plate 31. The colored light is colored in a color corresponding to the ratio of light of each wavelength in the light, and the colored light is reflected by the reflecting plate 34 and emitted to the front surface side of the liquid crystal display device.

As described above, in the liquid crystal display device, the phase difference plate 33 and the liquid crystal cell 20 are used without using the color filter.
The light is colored by the birefringence effect of the liquid crystal layer and the polarization effect of the pair of polarizing plates 31 and 32. According to this liquid crystal display device, the loss of the amount of transmitted light is greater than that in the case of transmitting through the color filter. Therefore, it is possible to obtain a bright color display by increasing the light transmittance even though it is of a reflective type.

Moreover, in this liquid crystal display device, the electrodes 23 and 2 provided on both substrates 21 and 22 of the liquid crystal cell 20.
The orientation state of the liquid crystal molecules changes according to the magnitude of the voltage applied between the four, and the birefringence effect of the liquid crystal layer changes accordingly. Therefore, by controlling the voltage applied to the liquid crystal cell 20, the elliptically polarized light The transmitted light can be colored in another color by changing the polarization state of, and thus one pixel can display a plurality of colors.

In this liquid crystal display device, the liquid crystal cell 2
Since the liquid crystal molecules of 0 are twist-aligned with a large twist angle of 120 ± 20 °, the liquid crystal molecules are in the initial twist alignment state (the liquid crystal molecules are in the most twisted alignment state).
The effect of birefringence is large in the case of, so that the colored light can be greatly changed.

The display color of this liquid crystal display device will be described. For example, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 1
20 °, the slow axis 33a of the retardation plate 33 and the front surface side polarizing plate 3
The deviation angle from the transmission axis 31a of 1 is 45 °, the deviation angle between the slow axis 33a of the retardation plate 33 and the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20 is 15 °, and the back surface side polarizing plate The deviation angle between the transmission axis 32a of 32 and the liquid crystal molecule alignment direction 22a on the rear surface side substrate 22 of the liquid crystal cell 20 is 3
0 ° (the transmission axis 31a of the front surface side polarizing plate 31 and the transmission axis 32a of the back surface side polarizing plate 32 are orthogonal to each other), the retardation of the retardation plate 33 is 910 nm, and the value of Δnd of the liquid crystal cell 20 is 600 nm (for example, Δn = 0.1, d = 6 μm), the display color of each pixel is red according to the applied voltage,
Change to the three primary colors of green and blue.

Therefore, according to this liquid crystal display device,
By controlling the voltage applied to the liquid crystal cell 20, the three primary colors of red, green and blue can be displayed, and by displaying different colors in a plurality of adjacent pixels, the red, green,
It is also possible to display a mixed color of a plurality of colors of blue.

Red against the applied voltage of this liquid crystal display device,
The change in the transmittance of light of each color of green and blue is almost the same as the change shown in FIG. 3, and therefore red, green, and
It is possible to obtain a blue display color, and the difference between the voltage for obtaining a "green" display color, the voltage for obtaining a "blue" display color, and the voltage for obtaining a "red" display color. Is large, the voltage control for switching the display color can be facilitated.

The liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °, and the shift angle between the slow axis 33a of the retardation plate 33 and the transmission axis 31a of the front-side polarizing plate 31 is about 45.
The deviation angle between the slow axis 33a of the retardation plate 33 and the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20 is 15 ± 10 °, and the transmission axis 32a of the rear surface side polarizing plate 32 and the liquid crystal cell 20. Of the back surface side substrate 22 surface of the liquid crystal molecule alignment direction 22a is 30 ± 10 ° (front side polarizing plate 3
1 and the transmission axis 32a of the back side polarizing plate 32 are substantially orthogonal to each other, and the retardation of the retardation plate 33 is 910.
± 20 nm, Δnd of the liquid crystal cell 20 is 600 ± 60 nm
In this range, the change in the transmittance of light of each color of red, green, and blue with respect to the voltage applied to the liquid crystal cell 20 is almost the same as that in FIG. The three primary colors of red, green, and blue can be displayed by controlling, and the voltage difference for switching the display colors can be easily increased by increasing the difference between the voltages for obtaining these red, green, and blue display colors. can do.

The liquid crystal display device of the above embodiment is
The three primary colors of green and blue are displayed. The display colors of this liquid crystal display device are the transmission axes 31a, 3 of the polarizing plates 31, 32.
2a and the direction of the slow axis 33a of the retardation plate 33, the retardation of the retardation plate 33, and the Δnd of the liquid crystal cell. Therefore, by selecting these conditions, the display color can be arbitrarily selected. .

Further, in the above embodiment, the liquid crystal cell 20 is of the active matrix type using thin film transistors as active elements.
It may be an active matrix type liquid crystal cell using a two-terminal nonlinear resistance element such as MIM as an active element, or may be a simple matrix type or a segment display type.

[Embodiment of the Fourth Invention] FIG. 10 is a sectional view of a color liquid crystal display device showing an embodiment of the fourth invention. This color liquid crystal display device is a reflection type display device that reflects light entering from the front surface side on the back surface side and displays it.
A liquid crystal cell 20 in which the molecules of the liquid crystal LC are twist-aligned,
A front surface side polarizing plate 31 arranged on the front surface side (upper side in the drawing) of the liquid crystal cell 20, and a back surface side polarizing plate 32 arranged on the back surface side (lower side in the drawing) of the liquid crystal cell 20,
It is composed of a retardation plate 33 arranged between the back side polarizing plate 32 and the liquid crystal cell 20, and a reflection plate 34 arranged on the back side of the back side polarizing plate 32.

The liquid crystal cell 20 is, for example, an active matrix type liquid crystal cell using thin film transistors as active elements, and its configuration is the same as that shown in FIG. Attached and omitted.
The reflection plate 34 is made of a metal film such as aluminum, and the surface thereof is a roughened scattering reflection surface.

In this liquid crystal display device, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °.
At the same time, the transmission axis of the front surface side polarizing plate 31 is slanted with respect to the liquid crystal molecule alignment direction on the surface of the front surface side substrate 21 of the liquid crystal cell 20, and is further arranged between the back surface side polarizing plate 32 and the liquid crystal cell 20. The slow axis of the retardation plate 33 and the transmission axis of the back side polarizing plate 32 are oriented as follows.

FIG. 11 shows both substrates 2 of the liquid crystal cell 20.
FIG. 3 is a plan view showing a liquid crystal molecule alignment direction on surfaces 1 and 22, a transmission axis of a pair of polarizing plates 31 and 32, and a slow axis of a retardation plate 33.

As shown in FIG. 11, the liquid crystal molecule alignment direction 21a (alignment treatment direction of the alignment film 25) on the front surface side substrate 21 surface (alignment film 25 surface) of the liquid crystal cell 20 is a reference line (horizontal line in the figure) O. With respect to the reference line O, the liquid crystal molecule alignment direction 22a (alignment treatment direction of the alignment film 26) on the back side substrate 22 surface (alignment film 26 surface) is shifted by 30 ± 10 ° in the clockwise direction in the figure. The liquid crystal molecules are shifted counterclockwise by 30 ± 10 °, and the liquid crystal molecules are twisted counterclockwise in the figure, that is, counterclockwise when viewed from the surface side, with a twist angle of 120 ± 20 °.

On the other hand, the transmission axis 31a of the front side polarizing plate 31
Is substantially parallel to the reference line O. Therefore, the transmission axis 31a of the front-side polarizing plate 31 is the liquid crystal seen from the front side with respect to the liquid crystal molecule alignment direction 21a on the front-side substrate 21 surface of the liquid crystal cell 20. It is deviated by 30 ± 10 ° in the same direction as the twist direction of the molecule.

Further, the slow axis 33a of the retardation plate 33 is in a direction deviated from the reference line O by approximately 45 ° in the clockwise direction in the figure, and therefore, the slow axis 33a of the retardation plate 33 is formed.
Is deviated by 75 ± 10 ° from the liquid crystal molecule orientation direction 22a on the rear surface side substrate 22 of the liquid crystal cell 20 in the direction opposite to the liquid crystal molecule twist direction viewed from the front surface side (clockwise in the figure).

Further, the transmission axis 32a of the back side polarizing plate 32
Is in a direction shifted by approximately 90 ° with respect to the reference line O, and therefore, the transmission axis 32a of the back side polarizing plate 32 is
Is shifted by about 45 ° in the same direction (clockwise in the drawing) as the liquid crystal molecule twist direction viewed from the surface side with respect to the slow axis 33a of the retardation plate 33, and the surface side polarizing plate 31
Is almost orthogonal to the transmission axis 31a.

The liquid crystal display device uses external light such as natural light or indoor illumination light and reflects the light incident from the front surface side by the reflection plate 34 on the rear surface side for display. In this liquid crystal display device, The incident light from the front surface side becomes linearly polarized light by the polarization effect of the front surface side polarizing plate 31 and enters the liquid crystal cell 20, and the light passing through the liquid crystal cell 20 passes through the phase difference plate 33 and the rear surface. Light incident on the side polarizing plate 32 and passing through the back side polarizing plate 32 is reflected by the reflecting plate 34, and the back side polarizing plate 32, the retardation plate 33, the liquid crystal cell 20, and the front side polarizing plate 31 are connected to each other. The light is sequentially emitted to the surface side of the liquid crystal display device.

In this liquid crystal display device, the transmission axis 31a of the front surface side polarizing plate 31 has the front surface side substrate 2 of the liquid crystal cell 20.
Since the liquid crystal molecules are obliquely displaced with respect to the liquid crystal molecule orientation direction 21a on one surface, the linearly polarized light that has entered through the front surface side polarizing plate 31 passes through the liquid crystal cell 20 and, due to the birefringence effect of the liquid crystal layer, is different for each wavelength. The elliptically polarized light has a different polarization state, and then the elliptically polarized light having a different polarization state due to the birefringence effect in the process of passing through the retardation plate 33,
Of these, the light of the polarization component that passes through the back-side polarizing plate 32 passes through the back-side polarizing plate 32 and is colored in a color corresponding to the ratio of each wavelength light in the light.
It is reflected by and is emitted to the front surface side of the liquid crystal display device.

As described above, in the liquid crystal display device, the phase difference plate 33 and the liquid crystal cell 20 are used without using the color filter.
The light is colored by the birefringence effect of the liquid crystal layer and the polarization effect of the pair of polarizing plates 31 and 32. According to this liquid crystal display device, the loss of the amount of transmitted light is greater than that in the case of transmitting through the color filter. Therefore, it is possible to obtain a bright color display by increasing the light transmittance even though it is of a reflective type.

Moreover, in this liquid crystal display device, the electrodes 23 and 2 provided on both substrates 21 and 22 of the liquid crystal cell 20.
The orientation state of the liquid crystal molecules changes according to the magnitude of the voltage applied between the four, and the birefringence effect of the liquid crystal layer changes accordingly. Therefore, by controlling the voltage applied to the liquid crystal cell 20, the elliptically polarized light The transmitted light can be colored in another color by changing the polarization state of, and thus one pixel can display a plurality of colors.

In this liquid crystal display device, the liquid crystal cell 2
Since the liquid crystal molecules of 0 are twist-aligned with a large twist angle of 120 ± 20 °, the liquid crystal molecules are in the initial twist alignment state (the liquid crystal molecules are in the most twisted alignment state).
The effect of birefringence is large in the case of, so that the colored light can be greatly changed.

The display color of this liquid crystal display device will be described. For example, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 1
20 °, the transmission axis 31a of the front-side polarizing plate 31 and the liquid crystal cell 2
Liquid crystal molecule orientation direction 21a on the front side substrate 21 surface of 0
The deviation angle between the slow axis 33a of the retardation plate 33 and the liquid crystal molecule alignment direction 22a on the back surface side substrate 22 of the liquid crystal cell 20 is 75 degrees, and the transmission axis 32a of the back surface side polarizing plate 32 is 30 degrees. And a deviation angle between the liquid crystal molecule alignment direction 22a on the back surface side substrate 22 of the liquid crystal cell 20 is 45 ° (the transmission axis 32a of the back surface side polarizing plate 32 is the transmission axis 31 of the front surface side polarizing plate 31).
(orthogonal to a) and the retardation of the retardation plate 33 is 91
When the value of 0 nm and Δnd of the liquid crystal cell 20 is 600 nm (for example, Δn = 0.1, d = 6 μm), the display color of each pixel changes to three primary colors of red, green, and blue according to the applied voltage. .

Therefore, according to this liquid crystal display device,
By controlling the voltage applied to the liquid crystal cell 20, the three primary colors of red, green and blue can be displayed, and by displaying different colors in a plurality of adjacent pixels, the red, green,
It is also possible to display a mixed color of a plurality of colors of blue.

Red against the applied voltage of this liquid crystal display device,
The change in the transmittance of light of each color of green and blue is almost the same as the change shown in FIG. 3, and therefore red, green, and
It is possible to obtain a blue display color, and the difference between the voltage for obtaining a "green" display color, the voltage for obtaining a "blue" display color, and the voltage for obtaining a "red" display color. Is large, the voltage control for switching the display color can be facilitated.

The liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °, and the transmission axis 31 of the front-side polarizing plate 31.
The deviation angle between a and the liquid crystal molecule alignment direction 21a on the surface of the front surface side substrate 21 of the liquid crystal cell 20 is 30 ± 10 °, and the phase difference plate 3
The deviation angle between the slow axis 33a of No. 3 and the liquid crystal molecule alignment direction 22a on the rear substrate 22 surface of the liquid crystal cell 20 is 75 ± 10.
The deviation angle between the transmission axis 32a of the back side polarizing plate 32 and the liquid crystal molecule orientation direction 22a on the back side substrate 22 surface of the liquid crystal cell 20 is approximately 45 ° (the transmission axis 32a of the back side polarizing plate 32).
Is approximately orthogonal to the transmission axis 31a of the front-side polarizing plate 31), the retardation of the retardation film 33 is 910 ± 20 nm, and the Δnd of the liquid crystal cell 20 is 600 ± 60 nm. Red against the applied voltage of
Since the change in the transmittance of light of each color of green and blue is almost the same as that of FIG. 3, red by controlling the voltage applied to the liquid crystal cell 20,
It is possible to display the three primary colors of green and blue, and to increase the difference between the voltages for obtaining the display colors of red, green, and blue to facilitate the voltage control for switching the display colors.

The liquid crystal display device of the above embodiment is
The three primary colors of green and blue are displayed. The display colors of this liquid crystal display device are the transmission axes 31a, 3 of the polarizing plates 31, 32.
2a and the direction of the slow axis 33a of the retardation plate 33, the retardation of the retardation plate 33, and the Δnd of the liquid crystal cell. Therefore, by selecting these conditions, the display color can be arbitrarily selected. .

Further, in the above embodiment, the liquid crystal cell 20 is of the active matrix type using thin film transistors as active elements.
It may be an active matrix type liquid crystal cell using a two-terminal nonlinear resistance element such as MIM as an active element, or may be a simple matrix type or a segment display type.

[Embodiment of the Fifth Invention] FIG. 12 is a sectional view of a color liquid crystal display device showing an embodiment of the fifth invention. This color liquid crystal display device has a reflective / transmissive display function that has a reflective display function of displaying light reflected from the front surface side by reflecting on the back surface side and a transmissive display function of displaying light by incident light from the back surface side. And the liquid crystal cell 20 in which the molecules of the liquid crystal LC are twist-aligned, and the front surface side polarizing plate 3 arranged on the front surface side (upper side in the drawing) of the liquid crystal cell 20.
1, a back surface side polarizing plate 32 arranged on the back surface side (lower side in the drawing) of the liquid crystal cell 20, and the front surface side polarizing plate 31.
And a liquid crystal cell 20 and a retardation plate 33, and a half mirror 3 arranged on the back side of the back side polarizing plate 32.
5 and.

The liquid crystal cell 20 is, for example, an active matrix type liquid crystal cell having a thin film transistor as an active element, and its configuration is the same as that shown in FIG. Attached and omitted.

The half mirror 35 is a semi-transmissive reflection plate that reflects and transmits incident light at a certain reflectance and transmittance, and the surface of the half mirror 35 is a roughened scattering reflection surface. ing.

In this liquid crystal display device, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °.
In addition, the slow axis of the retardation plate 33 disposed between the front surface side polarizing plate 31 and the liquid crystal cell 20 is set to the front surface side polarizing plate 31.
Is obliquely shifted with respect to the transmission axis of the back side polarizing plate 32, and the transmission axis of the back surface side polarizing plate 32 is slanted with respect to the liquid crystal molecule alignment direction on the back surface side substrate 22 surface of the liquid crystal cell 20.

FIG. 13 shows both substrates 2 of the liquid crystal cell 20.
FIG. 3 is a plan view showing a liquid crystal molecule alignment direction on surfaces 1 and 22, a transmission axis of a pair of polarizing plates 31 and 32, and a slow axis of a retardation plate 33.

As shown in FIG. 13, the liquid crystal molecule alignment direction 21a (alignment treatment direction of the alignment film 25) on the front surface side substrate 21 surface (alignment film 25 surface) of the liquid crystal cell 20 is a reference line (horizontal line in the figure) O In contrast, the liquid crystal molecule alignment direction 22a (alignment treatment direction of the alignment film 26) on the rear surface side substrate 22 surface (alignment film 26 surface) is shifted with respect to the reference line O by 30 ± 10 ° counterclockwise in the figure. The liquid crystal molecules are offset clockwise by 30 ± 10 °, and the liquid crystal molecules are twisted clockwise at a twist angle of 120 ± 20 °, that is, clockwise when viewed from the surface side.

On the other hand, the transmission axis 31a of the front side polarizing plate 31
Is shifted by approximately 90 ° with respect to the reference line O, and the slow axis 33a of the phase difference plate 33 is shifted by approximately 45 ° counterclockwise in the figure with respect to the reference line O.

Therefore, the slow axis 3 of the retardation plate 33 is
3a is the same as the twist direction of the liquid crystal molecules as viewed from the surface side with respect to the transmission axis 31a of the surface polarizing plate 31 (clockwise in the figure).
Is deviated by approximately 45 °, and is 15 ± 10 in the direction opposite to the liquid crystal molecule twist direction viewed from the front side (counterclockwise in the figure) with respect to the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20. Deviated.

In addition, the transmission axis 32a of the back side polarizing plate 32
Is substantially parallel to the reference line O. Therefore, the transmission axis 32a of the back side polarizing plate 32 is the liquid crystal seen from the front side with respect to the liquid crystal molecule alignment direction 22a on the back side substrate 22 of the liquid crystal cell 20. 3 in the direction opposite to the molecular twist direction
The surface side polarizing plate 31 is displaced by 0 ± 10 °.
Is almost orthogonal to the transmission axis 31a.

In FIG. 12, reference numeral 40 denotes a light source arranged on the back surface side of the liquid crystal display device so as to face almost the entire back surface of the half mirror 35. This light source 40
Are the same as those shown in FIG. 1, and the description thereof will be omitted by giving the same reference numerals to the drawings.

The liquid crystal display device performs a reflection type display utilizing outside light in a place where the amount of outside light (natural light, indoor illumination light, etc.) is sufficiently bright, and the light source 40 in a dark place where the amount of outside light is small. In the case of a reflective display, external light that enters the liquid crystal display device from its front surface side becomes linearly polarized light due to the polarization effect of the front surface side polarizing plate 31. While entering the retardation plate 33, the light passing through the retardation plate 33 passes through the liquid crystal cell 20 and enters the back surface side polarizing plate 32, and the back surface side polarizing plate 3
Of the light that has passed through 2, the light reflected by the half mirror 35 is the back-side polarizing plate 32, the liquid crystal cell 20, and the retardation plate 33.
Then, the light is emitted to the front side of the liquid crystal display device through the front side polarizing plate 31 and the front side polarizing plate 31 sequentially.

In the case of the transmissive display, of the light (light from the light source 40) that enters the liquid crystal display device from the back surface side, the light that has passed through the half mirror 35 is the polarization of the back surface side polarizing plate 32. The liquid crystal cell 20 becomes linearly polarized light by the action.
The light that has passed through the liquid crystal cell 20 enters the front surface side polarizing plate 31 through the retardation plate 33, and the light that has passed through the front surface side polarizing plate 31 exits to the front surface side of the liquid crystal display device. .

In the case of the reflection type display, in this liquid crystal display device, since the slow axis 33a of the retardation plate 33 is slanted with respect to the transmission axis 31a of the front surface side polarizing plate 31, the front surface side polarizing plate is formed. The linearly polarized light that has entered through 31 becomes elliptically polarized light having a different polarization state for each wavelength due to its birefringence effect in the process of passing through the retardation plate 33, and then the birefringence of the liquid crystal layer in the process of passing through the liquid crystal cell 20. Depending on the effect, it becomes elliptically polarized light having a different polarization state. Of these, the light of the polarization component that passes through the back surface side polarizing plate 31 passes through this back surface side polarizing plate 31 and has a color corresponding to the ratio of each wavelength light in the light. The colored light is reflected by the half mirror 35 and is emitted to the surface side of the liquid crystal display device.

In the case of transmissive display, in this liquid crystal display device, the transmission axis 31a of the back side polarizing plate 31 is the liquid crystal cell 2.
Liquid crystal molecule alignment direction 22a on the back side substrate 22 surface of 0
Since the linearly polarized light incident through the back-side polarizing plate 22 becomes elliptically polarized light having a different polarization state for each wavelength due to the birefringence effect of the liquid crystal layer in the process of passing through the liquid crystal cell 20, Then, in the process of passing through the retardation plate 33, elliptically polarized light whose polarization state is further different due to the birefringence effect thereof, of which the light of the polarization component transmitted through the front surface side polarizing plate 31 is emitted to the front surface side of the liquid crystal display device, This emitted light is colored in a color corresponding to the ratio of each wavelength light in the light.

As described above, in the liquid crystal display device, the phase difference plate 33 and the liquid crystal cell 20 are used without using the color filter.
The light is colored by the birefringence effect of the liquid crystal layer and the polarization effect of the pair of polarizing plates 31 and 32. According to this liquid crystal display device, the loss of the amount of transmitted light is greater than that in the case of transmitting through the color filter. Therefore, it is possible to obtain a bright color display by increasing the light transmittance in both the reflective display and the transmissive display.

Moreover, in this liquid crystal display device, the electrodes 23 and 2 provided on both substrates 21 and 22 of the liquid crystal cell 20.
The orientation state of the liquid crystal molecules changes according to the magnitude of the voltage applied between the four, and the birefringence effect of the liquid crystal layer changes accordingly. Therefore, by controlling the voltage applied to the liquid crystal cell 20, the elliptically polarized light The transmitted light can be colored in another color by changing the polarization state of, and thus one pixel can display a plurality of colors.

In this liquid crystal display device, the liquid crystal cell 2
Since the liquid crystal molecules of 0 are twist-aligned with a large twist angle of 120 ± 20 °, the liquid crystal molecules are in the initial twist alignment state (the liquid crystal molecules are in the most twisted alignment state).
The effect of birefringence is large in the case of, so that the colored light can be greatly changed.

The display color of this liquid crystal display device will be described. For example, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 1
20 °, the slow axis 33a of the retardation plate 33 and the front surface side polarizing plate 3
The angle of deviation from the transmission axis 31a of 1 is 45 °.
The deviation angle between the slow axis 33a of No. 3 and the liquid crystal molecule orientation direction 21a on the surface of the front surface side substrate 21 of the liquid crystal cell 20 is 15 °, and the transmission axis 32a of the back surface side polarizing plate 32 and the back surface side substrate 22 surface of the liquid crystal cell 20 are The deviation angle from the liquid crystal molecule alignment direction 22a is 30 ° (the transmission axis 32a of the back side polarizing plate 32 is orthogonal to the transmission axis 31a of the front side polarizing plate 31), the retardation of the retardation plate 33 is 910 nm, and the liquid crystal cell 20 When the value of Δnd is 600 nm (for example, Δn = 0.1, d = 6 μm), the display color of each pixel is red according to the applied voltage,
Change to the three primary colors of green and blue.

Therefore, according to this liquid crystal display device,
By controlling the voltage applied to the liquid crystal cell 20, the three primary colors of red, green and blue can be displayed, and by displaying different colors in a plurality of adjacent pixels, the red, green,
It is also possible to display a mixed color of a plurality of colors of blue.

Red against the applied voltage of this liquid crystal display device,
The change in the transmittance of light of each color of green and blue is almost the same as the change shown in FIG. 3, and therefore red, green, and
It is possible to obtain a blue display color, and the difference between the voltage for obtaining a "green" display color, the voltage for obtaining a "blue" display color, and the voltage for obtaining a "red" display color. Is large, the voltage control for switching the display color can be facilitated.

The liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °, and the shift angle between the slow axis 33a of the retardation plate 33 and the transmission axis 31a of the front-side polarizing plate 31 is approximately 45.
The deviation angle between the slow axis 33a of the retardation plate 33 and the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20 is 15 ± 10 °, and the transmission axis 32a of the rear surface side polarizing plate 32 and the liquid crystal cell 20. The deviation angle from the liquid crystal molecule alignment direction 22a on the back surface side substrate 22 is 30 ± 10 ° (the back surface side polarizing plate 3
2 has a transmission axis 32a substantially orthogonal to the transmission axis 31a of the front-side polarizing plate 31), and the retardation of the retardation plate 33 is 910 ±.
20 nm, Δnd of the liquid crystal cell 20 may be 600 ± 60 nm, and in this range, the change in the transmittance of light of each color of red, green, and blue with respect to the voltage applied to the liquid crystal cell 20 is almost the same as that in FIG. Therefore, the three primary colors of red, green, and blue can be displayed by controlling the voltage applied to the liquid crystal cell 20, and the difference between the voltages for obtaining these red, green, and blue display colors is increased, The voltage control for switching the display color can be facilitated.

The liquid crystal display device of the above embodiment is
The three primary colors of green and blue are displayed. The display colors of this liquid crystal display device are the transmission axes 31a, 3 of the polarizing plates 31, 32.
2a and the direction of the slow axis 40a of the retardation plate 40, the retardation of the retardation plate 33, and the Δnd of the liquid crystal cell. Therefore, by selecting these conditions, the display color can be arbitrarily selected. .

Furthermore, in the above embodiment, the liquid crystal cell 20 is of the active matrix type using thin film transistors as active elements.
It may be an active matrix type liquid crystal cell using a two-terminal nonlinear resistance element such as MIM as an active element, or may be a simple matrix type or a segment display type.

[Embodiment of Sixth Invention] FIG. 14 is a sectional view of a color liquid crystal display device showing an embodiment of the sixth invention. This color liquid crystal display device has a reflective / transmissive display function that has a reflective display function of displaying light reflected from the front surface side by reflecting on the back surface side and a transmissive display function of displaying light by incident light from the back surface side. And the liquid crystal cell 20 in which the molecules of the liquid crystal LC are twist-aligned, and the front surface side polarizing plate 3 arranged on the front surface side (upper side in the drawing) of the liquid crystal cell 20.
1, a back surface side polarizing plate 32 arranged on the back surface side (lower side in the figure) of the liquid crystal cell 20, and the back surface side polarizing plate 32.
And a liquid crystal cell 20 and a retardation plate 33, and a half mirror 3 arranged on the back side of the back side polarizing plate 32.
5 and.

The liquid crystal cell 20 is, for example, an active matrix type liquid crystal cell using thin film transistors as active elements, and its configuration is the same as that shown in FIG. Attached and omitted.
The half mirror 35 is the same as that shown in FIG.

In this liquid crystal display device, the liquid crystal molecule twist angle of the liquid crystal cell 20 is 120 ± 20 °.
At the same time, the transmission axis of the front surface side polarizing plate 31 is slanted with respect to the liquid crystal molecule alignment direction on the surface of the front surface side substrate 21 of the liquid crystal cell 20 so as to be arranged between the back surface side polarizing plate 32 and the liquid crystal cell 20. The slow axis of the phase difference plate 33 is slanted with respect to the transmission axis of the back side polarizing plate 32.

FIG. 15 shows both substrates 2 of the liquid crystal cell 20.
FIG. 3 is a plan view showing a liquid crystal molecule alignment direction on surfaces 1 and 22, a transmission axis of a pair of polarizing plates 31 and 32, and a slow axis of a retardation plate 33.

As shown in FIG. 15, the liquid crystal molecule alignment direction 21a (alignment treatment direction of the alignment film 25) on the front surface side substrate 21 surface (alignment film 25 surface) of the liquid crystal cell 20 is a reference line (horizontal line in the figure) O With respect to the reference line O, the liquid crystal molecule alignment direction 22a (alignment treatment direction of the alignment film 26) on the back side substrate 22 surface (alignment film 26 surface) is shifted by 30 ± 10 ° in the clockwise direction in the figure. The liquid crystal molecules are shifted counterclockwise by 30 ± 10 °, and the liquid crystal molecules are twisted counterclockwise in the figure, that is, counterclockwise when viewed from the surface side, with a twist angle of 120 ± 20 °.

On the other hand, the transmission axis 31a of the front-side polarizing plate 31
Is substantially parallel to the reference line O. Therefore, the transmission axis 31a of the front-side polarizing plate 31 is the liquid crystal seen from the front side with respect to the liquid crystal molecule alignment direction 21a on the front-side substrate 21 surface of the liquid crystal cell 20. It is offset by 30 ± 10 ° in the same direction as the twist direction of the molecule (counterclockwise in the figure).

Further, the slow axis 33a of the retardation plate 33 is in a direction deviated from the reference line O by approximately 45 ° in the clockwise direction in the figure, and therefore, the slow axis 33a of the retardation plate 33 is formed.
Is deviated by 75 ± 10 ° from the liquid crystal molecule orientation direction 22a on the rear surface side substrate 22 of the liquid crystal cell 20 in the direction opposite to the liquid crystal molecule twist direction viewed from the front surface side (clockwise in the figure).

Further, the transmission axis 32a of the back side polarizing plate 32
Is in a direction shifted by approximately 90 ° with respect to the reference line O, and therefore, the transmission axis 32a of the back side polarizing plate 32 is
Is shifted by about 45 ° in the same direction (clockwise in the drawing) as the liquid crystal molecule twist direction viewed from the surface side with respect to the slow axis 33a of the retardation plate 33, and the surface side polarizing plate 31
Is almost orthogonal to the transmission axis 31a.

Further, in FIG. 12, reference numeral 40 denotes a light source arranged on the back surface side of the liquid crystal display device so as to face almost the entire back surface of the half mirror 35. Since this light source 40 is the same as that shown in FIG. 1, the description thereof will be omitted by giving the same reference numerals to the drawing.

The above-mentioned liquid crystal display device performs a reflection type display utilizing outside light in a place where the amount of outside light (natural light or indoor illumination light) is sufficiently bright, and in a dark place where the amount of outside light is small, the light source 40 is used. In the case of a reflective display, external light that enters the liquid crystal display device from its front surface side becomes linearly polarized light due to the polarization effect of the front surface side polarizing plate 31. While entering the liquid crystal cell 20, the light passing through the liquid crystal cell 20 also enters the back surface side polarizing plate 32 through the phase difference plate 33, and the back surface side polarizing plate 3
Of the light that has passed through 2, the light reflected by the half mirror 35 is the back-side polarizing plate 32, the retardation film 33, and the liquid crystal cell 20.
Then, the light is emitted to the front side of the liquid crystal display device through the front side polarizing plate 31 and the front side polarizing plate 31 sequentially.

In the case of a transmissive display, of the light (light from the light source 40) that enters the liquid crystal display device from the back surface side, the light that has passed through the half mirror 35 is the polarization of the back surface side polarizing plate 32. By the action, it becomes a linearly polarized light and the phase difference plate 33
The light that has passed through the retardation plate 33 enters the front surface side polarizing plate 31 through the liquid crystal cell 20, and the light that has passed through the front surface side polarizing plate 31 exits to the front surface side of the liquid crystal display device. .

In the case of the reflection type display, in this liquid crystal display device, the transmission axis 31a of the front surface side polarizing plate 31 is slanted with respect to the liquid crystal molecule alignment direction 21a on the front surface side substrate 21 surface of the liquid crystal cell 20. Therefore, the front side polarizing plate 3
The linearly polarized light entering through 1 becomes elliptically polarized light having different polarization states for each wavelength due to the birefringence effect of the liquid crystal layer in the process of passing through the liquid crystal cell 20, and then the retardation plate 33.
The elliptically polarized light having a different polarization state due to its birefringence effect in the process of passing through the light, of which the light of the polarization component that passes through the back surface side polarizing plate 32 passes through the back surface side polarizing plate 32 and each wavelength in the light Color it according to the ratio of light,
This colored light is reflected by the half mirror 35 and emitted to the front surface side of the liquid crystal display device.

In the case of the transmissive display, in this liquid crystal display device, since the transmission axis 32a of the back side polarizing plate 32 is slanted with respect to the slow axis 33a of the retardation plate 33, the back side polarizing plate is formed. The linearly polarized light incident through 32 becomes elliptically polarized light having a different polarization state for each wavelength due to its birefringence effect in the process of passing through the retardation plate 33, and then the birefringence effect of the liquid crystal layer in the process of passing through the liquid crystal cell 20. Due to this, elliptically polarized light having a different polarization state is obtained, of which the light of the polarization component that passes through the front surface side polarizing plate 31 is emitted to the front surface side of the liquid crystal display device, and this emitted light is a ratio of the respective wavelength light in the light. Add a color corresponding to.

As described above, in the liquid crystal display device, the phase difference plate 33 and the liquid crystal cell 20 are used without using the color filter.
The light is colored by the birefringence effect of the liquid crystal layer and the polarization effect of the pair of polarizing plates 31 and 32. According to this liquid crystal display device, the loss of the amount of transmitted light is greater than that in the case of transmitting through the color filter. Therefore, it is possible to obtain a bright color display by increasing the light transmittance in both the reflective display and the transmissive display.

Furthermore, in the above embodiment, the liquid crystal cell 20 is of the active matrix type using thin film transistors as active elements.
It may be an active matrix type liquid crystal cell using a two-terminal nonlinear resistance element such as MIM as an active element, or may be a simple matrix type or a segment display type.

[0195]

In each of the color liquid crystal display devices of the first to sixth inventions, the birefringence effect of the retardation plate and the liquid crystal layer of the liquid crystal cell and the polarization of the pair of polarizing plates are used without using the color filter. The color liquid crystal display device can reduce the loss of the amount of transmitted light as compared with the case of transmitting light through a color filter. Can be raised to obtain a bright color display.

Moreover, in the above color liquid crystal display device, the alignment state of the liquid crystal molecules changes according to the magnitude of the voltage applied between the electrodes provided on both substrates of the liquid crystal cell, which causes the birefringence of the liquid crystal layer. Since the effect changes, by controlling the voltage applied to the liquid crystal cell, the polarization state of the elliptically polarized light can be changed and the transmitted light can be colored in another color. Colors can be displayed.

Further, in the above color liquid crystal display device, since the liquid crystal molecules of the liquid crystal cell are twist-aligned at a large twist angle of 120 ± 20 °, the liquid crystal molecules are in an initial twist alignment state (twist in which the liquid crystal molecules are most collapsed). The birefringence effect in the (alignment state) is large, and therefore the colored light can be greatly changed.

Further, the color liquid crystal display device of the first invention is a transmissive type in which light is incident from the back surface side for display. In this color liquid crystal display device, the transmission axis of the back side polarizing plate is The deviation angle from the orientation of the liquid crystal molecules on the back side substrate surface of the liquid crystal cell is set to 30 ± 10 °, and the slow axis of the retardation plate is set to the orientation direction of the liquid crystal molecules on the front side substrate surface of the liquid crystal cell. , As well as shifting the liquid crystal molecule from the surface side by 15 ± 10 ° in the direction opposite to the twist direction,
The transmission axis of the front-side polarizing plate is made substantially orthogonal to the transmission axis of the back-side polarizing plate, the retardation of the retardation plate is 910 ± 20 nm, and the Δnd value of the liquid crystal cell is 600 ±.
When the thickness is 60 nm, the three primary colors of red, green and blue can be displayed by controlling the voltage applied to the liquid crystal cell, and
It is possible to increase the difference between the voltages for obtaining the display colors of red, green, and blue to facilitate the voltage control for switching the display colors.

Further, the color liquid crystal display device of the second invention is also of a transmission type. In this color liquid crystal display device, the shift angle between the slow axis of the retardation plate and the transmission axis of the back side polarizing plate is Is about 45 °, and the slow axis of this retardation plate is 75 ± 10 in the direction opposite to the twist direction of the liquid crystal molecules viewed from the front surface side with respect to the liquid crystal molecule alignment direction on the back surface side of the liquid crystal cell. The transmission axis of the front-side polarizing plate is substantially orthogonal to the transmission axis of the back-side polarizing plate, and the retardation of the retardation plate is 910 ± 20n.
If m and the value of Δnd of the liquid crystal cell are 600 ± 60 nm, the three primary colors of red, green and blue can be displayed by controlling the voltage applied to the liquid crystal cell, and these red, green,
The voltage difference for obtaining the blue display color can be increased to facilitate the voltage control for switching the display color.

On the other hand, although the color liquid crystal display device of the third invention is of a reflection type, in this color liquid crystal display device, the shift angle between the slow axis of the retardation plate and the transmission axis of the front side polarizing plate is Is approximately 45 °, and the slow axis of the retardation plate is 15 ± 10 in the direction opposite to the liquid crystal molecule twist direction viewed from the surface side with respect to the liquid crystal molecule alignment direction on the surface side substrate surface of the liquid crystal cell. The transmission axis of the back side polarizing plate is made substantially orthogonal to the transmission axis of the front side polarizing plate, and the retardation of the retardation plate is 910 ± 20n.
If m and the value of Δnd of the liquid crystal cell are 600 ± 60 nm, the three primary colors of red, green and blue can be displayed by controlling the voltage applied to the liquid crystal cell, and these red, green,
The voltage difference for obtaining the blue display color can be increased to facilitate the voltage control for switching the display color.

The color liquid crystal display device of the fourth invention is also of a reflection type, but in this color liquid crystal display device, liquid crystal molecule alignment on the transmission axis of the front surface side polarizing plate and on the front surface side substrate surface of the liquid crystal cell. Deviation angle from direction is 30 ± 10 °
And, while the slow axis of the retardation plate is shifted by 75 ± 10 ° in a direction opposite to the liquid crystal molecule twist direction viewed from the front surface side with respect to the liquid crystal molecule alignment direction on the back surface side substrate surface of the liquid crystal cell, The transmission axis of the back-side polarizing plate is made substantially orthogonal to the transmission axis of the back-side polarizing plate, and the retardation of the retardation plate is 910 ± 20 nm.
If the value of is set to 600 ± 60 nm, the three primary colors of red, green, and blue can be displayed by controlling the voltage applied to the liquid crystal cell, and each of the red, green, and blue display colors can be obtained. Can be increased to facilitate voltage control for switching display colors.

Further, although the color liquid crystal display device of the fifth invention is of a reflective / transmissive type, in this color liquid crystal display device, in this color liquid crystal display device, the slow axis of the retardation plate and the transmission axis of the front side polarizing plate are used. Is about 45 °, the deviation angle between the transmission axis of the back side polarizing plate and the liquid crystal molecule alignment direction on the back side substrate surface of the liquid crystal cell is 30 ± 10 °, and the slow axis of the retardation plate is Is shifted by 15 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front side with respect to the liquid crystal molecule orientation direction on the front surface side substrate surface of the liquid crystal cell, and the transmission axis of the front surface side polarizing plate and the back surface side The transmission axes of the polarizing plates are substantially orthogonal to each other, the retardation of the retardation plate is 910 ± 20 nm, and the Δnd value of the liquid crystal cell is 600 ±.
When the thickness is 60 nm, red and red are produced by controlling the voltage applied to the liquid crystal cell in both reflective display and transmissive display
It is possible to display the three primary colors of green and blue, and it is also possible to increase the difference between the voltages for obtaining these red, green, and blue display colors to facilitate voltage control for switching the display colors. it can.

The color liquid crystal display device according to the sixth aspect of the invention is also of a reflective / transmissive type, and in this color liquid crystal display device, the transmission axis of the front surface side polarizing plate and the surface side substrate surface of the liquid crystal cell are Deviation angle from liquid crystal molecule alignment direction is 3
The deviation angle between the slow axis of the 0 ± 10 ° retardation plate and the transmission axis of the back side polarizing plate is set to about 45 °, and the slow axis of the retardation plate is set on the back side substrate surface of the liquid crystal cell. The liquid crystal molecule alignment direction is shifted by 75 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front side, and the transmission axis of the front side polarizing plate and the transmission axis of the back side polarizing plate are substantially orthogonal to each other. Then, the retardation of the retardation plate is set to 91.
0 ± 20 nm, Δnd value of liquid crystal cell is 600 ± 60 n
If m is set, the three primary colors of red, green, and blue can be displayed by controlling the voltage applied to the liquid crystal cell in both reflective display and transmissive display, and these red,
By increasing the difference between the voltages for obtaining the green and blue display colors, it is possible to facilitate the voltage control for switching the display colors.

[Brief description of drawings]

FIG. 1 is a sectional view of a color liquid crystal display device showing an embodiment of the first invention.

FIG. 2 is a plan view showing alignment directions of liquid crystal molecules on both substrate surfaces of a liquid crystal cell, transmission axes of a pair of polarizing plates, and slow axes of retardation plates.

[FIG. 3] Similarly, red for the voltage applied to the liquid crystal cell,
The figure which shows the change of the light transmittance of each color of green and blue.

FIG. 4 is a diagram showing changes in the transmittance of light of each color of red, green, and blue with respect to the voltage applied to the liquid crystal cell of the first comparative device in which the liquid crystal molecule twist angle of the liquid crystal cell is approximately 90 °.

FIG. 5 is a diagram showing changes in the transmittance of light of each color of red, green, and blue with respect to the voltage applied to the liquid crystal cell in the second comparative device in which the liquid crystal molecule twist angle of the liquid crystal cell is approximately 90 °.

FIG. 6 is a sectional view of a color liquid crystal display device showing an embodiment of the second invention.

FIG. 7 is a plan view showing alignment directions of liquid crystal molecules on both substrate surfaces of a liquid crystal cell, transmission axes of a pair of polarizing plates, and slow axes of retardation plates.

FIG. 8 is a sectional view of a color liquid crystal display device showing an embodiment of the third invention.

FIG. 9 is a plan view showing alignment directions of liquid crystal molecules on both substrate surfaces of a liquid crystal cell, transmission axes of a pair of polarizing plates, and slow axes of retardation plates.

FIG. 10 is a sectional view of a color liquid crystal display device showing an embodiment of the fourth invention.

FIG. 11 is a plan view showing alignment directions of liquid crystal molecules on both substrate surfaces of a liquid crystal cell, transmission axes of a pair of polarizing plates, and slow axes of retardation plates.

FIG. 12 is a sectional view of a color liquid crystal display device showing an embodiment of the fifth invention.

FIG. 13 is a plan view showing alignment directions of liquid crystal molecules on both substrate surfaces of a liquid crystal cell, transmission axes of a pair of polarizing plates, and slow axes of retardation plates.

FIG. 14 is a sectional view of a color liquid crystal display device showing an embodiment of the sixth invention.

FIG. 15 is a plan view showing alignment directions of liquid crystal molecules on both substrate surfaces of a liquid crystal cell, transmission axes of a pair of polarizing plates, and slow axes of retardation plates.

FIG. 16 is a sectional view of a conventional color liquid crystal display device.

FIG. 17 is a plan view showing a liquid crystal molecule alignment direction on both substrate surfaces of a liquid crystal cell and transmission axes of a pair of polarizing plates.

[Explanation of symbols]

 20 ... Liquid crystal cell 21 ... Front side substrate 21a ... Liquid crystal molecule orientation direction 22 ... Back side substrate 22a ... Liquid crystal molecule orientation direction 23, 24 ... Transparent electrode 25, 26 ... Alignment film LC ... Liquid crystal 31 ... Surface side polarizing plate 31a ... Transmission Axis 32 ... Backside polarizing plate 32a ... Transmission axis 33 ... Phase difference plate 33a ... Slow axis 34 ... Reflector 35 ... Half mirror 40 ... Light source

Claims (12)

[Claims] 1. A transmissive color liquid crystal display device for displaying light by allowing light to enter from a back surface side, wherein a liquid crystal cell in which liquid crystal molecules are twist-aligned, and a front surface side disposed on the front surface side of the liquid crystal cell. A liquid crystal of the liquid crystal cell, comprising a polarizing plate, a back side polarizing plate arranged on the back side of the liquid crystal cell, and a retardation plate arranged between the front side polarizing plate and the liquid crystal cell. The molecular twist angle is 120 ± 2
The color liquid crystal display device is characterized in that the transmission axis of the back side polarizing plate is obliquely shifted with respect to the liquid crystal molecule alignment direction on the back side substrate surface of the liquid crystal cell while being set at 0 °. 2. The deviation angle between the transmission axis of the back side polarizing plate and the liquid crystal molecule orientation direction on the back side substrate surface of the liquid crystal cell is 30 ± 1.
It is 0 °, and the slow axis of the retardation plate is 15 ± 1 in the direction opposite to the liquid crystal molecule twist direction viewed from the surface side with respect to the liquid crystal molecule alignment direction on the surface side substrate surface of the liquid crystal cell.
While being shifted by 0 °, the transmission axis of the front-side polarizing plate is substantially orthogonal to the transmission axis of the back-side polarizing plate.
2. The color liquid crystal display device according to claim 1, wherein the retardation of the retardation plate is 910 ± 20 nm, and the value of Δnd of the liquid crystal cell is 600 ± 60 nm. 3. A transmissive color liquid crystal display device for displaying light by allowing light to enter from a back surface side, wherein a liquid crystal cell in which liquid crystal molecules are twist-aligned and a front surface side arranged on the front surface side of the liquid crystal cell. A liquid crystal of the liquid crystal cell, comprising a polarizing plate, a rear surface side polarizing plate arranged on the rear surface side of the liquid crystal cell, and a retardation plate arranged between the rear surface side polarizing plate and the liquid crystal cell. The molecular twist angle is 120 ± 2
A color liquid crystal display device, wherein the retardation plate is set at 0 ° and the slow axis of the retardation plate is slanted with respect to the transmission axis of the back surface polarizing plate. 4. The shift angle between the slow axis of the retardation plate and the transmission axis of the back side polarizing plate is about 45 °, and the slow axis of the retardation plate is the back side substrate surface of the liquid crystal cell. The liquid crystal molecule alignment direction in is shifted by 75 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front surface side, and the transmission axis of the front surface side polarizing plate is almost the same as the transmission axis of the back surface side polarizing plate. They are orthogonal to each other, and the retardation of the retardation plate is 9
10 ± 20 nm, Δnd value of the liquid crystal cell is 600 ±
The color liquid crystal display device according to claim 3, wherein the color liquid crystal display device has a thickness of 60 nm. 5. A reflection type color liquid crystal display device which reflects light incident from the front surface side on the back surface side and displays the liquid crystal cell, wherein liquid crystal molecules are twist-aligned, and a liquid crystal cell on the front surface side of the liquid crystal cell. A front surface side polarizing plate disposed, a back surface side polarizing plate disposed on the back surface side of the liquid crystal cell, a retardation plate disposed between the front surface side polarizing plate and the liquid crystal cell, and the back surface side polarizing plate. A reflection plate disposed on the back side of the plate, and the liquid crystal molecule twist angle of the liquid crystal cell is 120 ± 2.
A color liquid crystal display device, wherein the retardation plate is set at 0 ° and the slow axis of the retardation plate is obliquely shifted with respect to the transmission axis of the front-side polarizing plate. 6. The shift angle between the slow axis of the retardation plate and the transmission axis of the front-side polarizing plate is approximately 45 °, and the slow axis of the retardation plate is the front-side substrate surface of the liquid crystal cell. With respect to the liquid crystal molecule alignment direction in, the liquid crystal molecule is twisted by 15 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front side, and the transmission axis of the back side polarizing plate is almost the same as the transmission axis of the front side polarizing plate. They are orthogonal to each other, and the retardation of the retardation plate is 9
10 ± 20 nm, Δnd value of the liquid crystal cell is 600 ±
The color liquid crystal display device according to claim 5, having a thickness of 60 nm. 7. A reflection type color liquid crystal display device for displaying light reflected from the front surface side by reflecting on the back surface side, wherein a liquid crystal cell in which liquid crystal molecules are twist-aligned and a liquid crystal cell on the front surface side of the liquid crystal cell are provided. A front surface side polarizing plate arranged, a back surface side polarizing plate arranged on the back surface side of the liquid crystal cell, a retardation plate arranged between the back surface side polarizing plate and the liquid crystal cell, and the back surface side polarizing plate. A reflection plate disposed on the back side of the plate, and the liquid crystal molecule twist angle of the liquid crystal cell is 120 ± 2.
The color liquid crystal display device is characterized in that the transmission axis of the polarizing plate on the front surface side is slanted with respect to the alignment direction of liquid crystal molecules on the surface of the front surface side substrate of the liquid crystal cell, while being set at 0 °. 8. The deviation angle between the transmission axis of the front-side polarizing plate and the orientation direction of liquid crystal molecules on the front-side substrate surface of the liquid crystal cell is 30 ± 1.
It is 0 °, and the slow axis of the retardation plate is 75 ± 1 in the direction opposite to the liquid crystal molecule twist direction viewed from the front side with respect to the liquid crystal molecule alignment direction on the back side substrate surface of the liquid crystal cell.
While being offset by 0 °, the transmission axis of the back side polarizing plate is substantially orthogonal to the transmission axis of the back side polarizing plate, and
The color liquid crystal display device according to claim 7, wherein the retardation of the retardation film is 910 ± 20 nm, and the value of Δnd of the liquid crystal cell is 600 ± 60 nm. 9. A color liquid crystal display device having a reflective display function of displaying light incident from the front surface side by reflecting it on the rear surface side, and a transmissive display function of making light incident from the rear surface side to display it. A liquid crystal cell in which liquid crystal molecules are twist-aligned, a front surface side polarizing plate arranged on the front surface side of the liquid crystal cell, a back surface side polarizing plate arranged on the back surface side of the liquid crystal cell, and the front surface side polarizing plate. A retardation plate disposed between the liquid crystal cell and the liquid crystal cell, and a half mirror disposed on the back side of the back side polarizing plate, and the liquid crystal molecule twist angle of the liquid crystal cell is 120 ± 2.
At the same time as 0 °, the slow axis of the retardation plate is slanted with respect to the transmission axis of the front surface side polarizing plate, and the transmission axis of the back surface side polarizing plate is a liquid crystal molecule on the back surface side substrate surface of the liquid crystal cell. A color liquid crystal display device, which is slanted with respect to the alignment direction. 10. A deviation angle between the slow axis of the retardation plate and the transmission axis of the front surface side polarizing plate is approximately 45 °, and the transmission axis of the back surface side polarizing plate and the liquid crystal molecule alignment direction on the back surface side substrate surface of the liquid crystal cell. Is 30 ± 10 °, and the slow axis of the retardation plate is opposite to the liquid crystal molecule twist direction viewed from the surface side with respect to the liquid crystal molecule alignment direction on the surface side substrate surface of the liquid crystal cell. The transmission axis of the front-side polarizing plate and the transmission axis of the back-side polarizing plate are substantially orthogonal to each other, and the retardation of the retardation plate is 910 ± 20 nm. The value of Δnd of the liquid crystal cell is 6
The color liquid crystal display device according to claim 9, wherein the color liquid crystal display device has a thickness of 00 ± 60 nm. 11. A color liquid crystal display device having a reflective display function of displaying light incident from the front surface side by reflecting the light on the rear surface side and a transmissive display function of displaying light by incident light from the rear surface side. , A liquid crystal cell in which liquid crystal molecules are twist-aligned, a front surface side polarizing plate arranged on the front surface side of the liquid crystal cell, a back surface side polarizing plate arranged on the back surface side of the liquid crystal cell, and this back surface side polarizing plate A retardation plate disposed between the liquid crystal cell and the liquid crystal cell, and a half mirror disposed on the back side of the back side polarizing plate, and the liquid crystal molecule twist angle of the liquid crystal cell is 120 ± 2.
While making 0 °, the transmission axis of the front-side polarizing plate is slanted with respect to the liquid crystal molecule alignment direction on the front-side substrate surface of the liquid crystal cell, and the slow axis of the retardation plate is set to the back-side polarizing plate. A color liquid crystal display device characterized by being slanted with respect to the transmission axis. 12. The deviation angle between the transmission axis of the front-side polarizing plate and the orientation direction of liquid crystal molecules on the front-side substrate surface of the liquid crystal cell is 30 ±.
The deviation angle between the slow axis of the 10 ° phase difference plate and the transmission axis of the back side polarizing plate is about 45 °, and the slow axis of the phase difference plate is the liquid crystal on the back side substrate surface of the liquid crystal cell. With respect to the molecular orientation direction, the liquid crystal molecule is twisted by 75 ± 10 ° in the direction opposite to the liquid crystal molecule twist direction viewed from the front side, and the transmission axis of the front-side polarizing plate and the transmission axis of the back-side polarizing plate are substantially parallel to each other. The color liquid crystal display device according to claim 11, wherein the retardation plates are orthogonal to each other, and the retardation of the retardation plate is 910 ± 20 nm, and the value of Δnd of the liquid crystal cell is 600 ± 60 nm.