JPH06308483A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve transmitivity by coloring transmitted light without using a color filter and thereby to satisfactorily enhance the display brightness. CONSTITUTION:The device is provided with a liquid crystal cell 30 for controlling colors in which liquid crystals 38 are encapsulated between substrates 31 and 32 forming trans-parent electrodes 33, 34 and molecules there of 38a are twist-oriented, a liquid crystal cell 40 for coloring in which liquid crystals 46 are encapsulated between a pair of transparent substrates 51 and 52 and molecules thereof 46a are twist-oriented, one sheet of polarizing plate 51 and a reflecting plate 52. The polarizing plate 51 is arranged at a front side of the liquid crystal cell 30 for controlling colors, the reflecting plate 52 is arranged at the rear side of the liquid crystal cell 30 for controlling colors and the liquid crystal cell 40 for coloring is arranged between the polarizing plate 51 and the liquid crystal cell 30 for controlling colors. Further, a transmission axis of the polarizing plate 51 is inclined at a prescribed angle to a liquid crystal molecule orientation direction in the liquid crystal cell 40 for coloring at the side of the substrate 51 opposite to the polarizing plate.

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. FIG. 4 is a cross-sectional view of a conventional color liquid crystal display device. This liquid crystal display device includes a liquid crystal cell 10 having a color filter and a liquid crystal cell 1.
It is composed of a pair of polarizing plates 21 and 22 which are arranged with 0 interposed therebetween.

The liquid crystal cell 10 has transparent electrodes 13 and 14
And a pair of upper and lower transparent substrates 11 and 12 on which the alignment films 15 and 16 are formed are bonded to each other via a frame-shaped sealing material 18, and are surrounded by the sealing material 18 between the two substrates 11 and 12. A liquid crystal 19 is sealed in a closed region. One substrate of the liquid crystal cell 10, for example, the lower substrate 12 in the figure,
A color filter 17 for coloring the transmitted light is provided.

The color filter 17 is provided on the substrate 12
The transparent electrode 14 on the substrate 12 side is formed on a protective film (not shown) that covers the color filter 17. Further, as the liquid crystal cell 10,
Generally, the molecules 19a of the liquid crystal 19 are twist-aligned between the substrates 11 and 12 at a twist angle of about 90 °.
N (Twisted Nematic) type is used.

The pair of polarizing plates 21 and 22 are arranged such that their transmission axes are substantially parallel to each other, and the transmission axes of these polarizing plates 21 and 22 are liquid crystal on one substrate side of the liquid crystal cell 10. It is almost parallel to the molecular orientation direction.

There are two types of liquid crystal display devices, a transmissive type and a reflective type in which a reflecting plate is arranged on the back surface.
A color liquid crystal display device equipped with a color filter is generally
It is of a transmissive type as shown in FIG.

In the color liquid crystal display device, a light source (not shown) is arranged on the back surface side thereof, and both substrates 1 of the liquid crystal cell 10 are arranged.
The display is driven by applying a voltage between the electrodes 13 and 14 of the electrodes 1 and 12, and the light from the light source is linearly polarized by the polarizing plate 22 on the incident side (the lower side in FIG. 4) and is incident on the liquid crystal cell 10. Incident.

The linearly polarized light that has entered the liquid crystal cell 10 passes through the color filter 17 and the liquid crystal layer, and the liquid crystal cell 1
0 is emitted, but in that case, light having a wavelength other than the wavelength band corresponding to the color of the color filter 17 is absorbed by the color filter 17, so that the light emitted from the liquid crystal cell 10 is colored in the color of the color filter 17. Become light.

When no voltage is applied between the electrodes 13 and 14 of the liquid crystal cell 10, that is, when the liquid crystal molecules 19a are twist-aligned, the light passing through the liquid crystal cell 10 is polarized by the liquid crystal 19. , The linearly polarized light in a direction substantially orthogonal to the linearly polarized light that has entered the liquid crystal cell 10 when it has finished passing through the liquid crystal layer, the linearly polarized light that has exited the liquid crystal cell 10 at this time is the exit side (upper side in FIG. 4). Polarizing plate 2
1 is absorbed, and the display is in a dark (black) state.

On the other hand, when a voltage is applied between the electrodes 13 and 14 of the liquid crystal cell 10, the liquid crystal molecules 19a rise and orient substantially vertically to the surfaces of the substrates 11 and 12, and the polarization effect of the liquid crystal 19 is almost eliminated. The linearly polarized light that has entered the cell 10 exits the liquid crystal cell 10 as it is. And
At this time, the linearly polarized light emitted from the liquid crystal cell 10 is transmitted through the emission side polarizing plate 21, and the display becomes a bright display of the color colored by the color filter 17.

[0011]

However, since the above-mentioned conventional color liquid crystal display device colors the transmitted light by using the color filter 17, it has a problem that the light transmittance is low and therefore the display is dark. There is.

This is due to the absorption of light by the color filter 17. Since the color filter 17 also absorbs light in the wavelength band corresponding to the color with a considerably high absorption rate, coloring through the color filter 17 is performed. The light becomes light in which the amount of light is significantly reduced compared to the light in the wavelength band before entering the color filter 17, and the display becomes dark.

Although the color liquid crystal display device shown in FIG. 4 is of a transmissive type, if a reflection plate is arranged on the back surface of this color liquid crystal display device to form a reflection type device, light is incident from the front side of the device. Since the light reflected by the reflecting plate on the back surface and emitted to the front surface side passes through the color filter 17 twice and the light amount is doubly reduced, the display is considerably darkened and becomes almost unusable as a display device.

It is an object of the present invention to provide a color liquid crystal display device capable of coloring transmitted light without using a color filter to increase the light transmittance and sufficiently increase the display brightness. It is a thing.

[0015]

A color liquid crystal display device of the present invention comprises a first liquid crystal cell in which liquid crystal is enclosed between a pair of transparent substrates having transparent electrodes and molecules of the liquid crystal are twist-aligned between the substrates. A second liquid crystal cell in which liquid crystal is enclosed between a pair of transparent substrates and molecules of which are twist-arranged between the two substrates; a polarizing plate; and a reflecting plate. The liquid crystal cell is arranged on the front surface side, the reflection plate is arranged on the back surface side of the first liquid crystal cell, and the second liquid crystal cell is arranged between any one of the polarizing plate and the reflection plate and the liquid crystal cell. The polarizing plate is arranged and the transmission axis of the polarizing plate is slanted by a predetermined angle with respect to the alignment direction of the liquid crystal molecules on the polarizing plate facing substrate side of the second liquid crystal cell.

As an embodiment of the present invention, the value of Δn · d and the liquid crystal molecule twist angle of the second liquid crystal cell are substantially equal to the Δn · d and the liquid crystal molecule twist angle of the first liquid crystal cell, respectively. There is an example in which the liquid crystal molecule twist direction of the second liquid crystal cell is opposite to the liquid crystal molecule twist direction of the first liquid crystal cell. Further, in the present invention, it is desirable that the deviation angle between the transmission axis of the polarizing plate and the liquid crystal molecule alignment direction on the polarizing plate facing substrate side of the second liquid crystal cell is 45 ± 5 °.

[0017]

This color liquid crystal display device is of a reflection type in which light incident from the front surface side is reflected by the reflection plate on the rear surface side and displayed. The light passes through the second liquid crystal cell, is reflected by the reflection plate, and again passes through the second and first liquid crystal cells and the polarizing plate to be emitted.

In this color liquid crystal display device, the linearly polarized light incident through the polarizing plate is polarized by the polarization action of these liquid crystal cells in the process of passing through the first and second liquid crystal cells in which the liquid crystal molecules are twist-aligned. The state of light is changed, and in the process of being reflected by the reflection plate and passing through the second and first liquid crystal cells again, the state of polarization is further changed and enters the polarizing plate.

When a voltage is applied between the electrodes of the first liquid crystal cell, the polarization effect of the first liquid crystal cell changes due to the change of the alignment state of the liquid crystal molecules. The light that is polarized by the liquid crystal cell of
When a voltage is not applied to the liquid crystal cell of (the liquid crystal molecules are in a twisted orientation), the light has a different polarization state and enters the polarizing plate, and further the liquid crystal molecules rise vertically and are aligned. The polarization effect of the first liquid crystal cell is almost eliminated, and the linearly polarized light that has entered through the polarizing plate enters the polarizing plate only by the polarization effect of the second liquid crystal cell.

Therefore, the light enters through the polarizing plate and
The polarization state of the light that passes through the liquid crystal cell and the second liquid crystal cell twice each and enters the polarizing plate again changes depending on the alignment state of the liquid crystal molecules of the first liquid crystal cell, and enters the polarizing plate in a certain state. The emitted light becomes almost linearly polarized light, and in other states it becomes non-linearly polarized light.

As in the above embodiment, the value of Δn · d and the liquid crystal molecule twist angle of the second liquid crystal cell are made substantially equal to the Δn · d and the liquid crystal molecule twist angle of the first liquid crystal cell, respectively. When the liquid crystal molecule twist direction of the second liquid crystal cell is set to be opposite to the liquid crystal molecule twist direction of the first liquid crystal cell, the second liquid crystal is formed when a voltage is not applied between the electrodes of the first liquid crystal cell. The polarization effect of the cell and the polarization effect of the first liquid crystal cell are opposite to each other, and the light whose polarization state has been changed by the polarization effect of one of the second liquid crystal cell and the first liquid crystal cell is the other polarization effect. Is again converted into linearly polarized light, and this linearly polarized light enters the polarizing plate.

When the alignment state of the liquid crystal molecules of the first liquid crystal cell is changed by applying a voltage, the light incident on the polarizing plate becomes non-linearly polarized light, and when the liquid crystal molecules are vertically aligned, the first liquid crystal is formed. The polarization effect of the cell disappears, and the light incident on the polarizing plate becomes non-linearly polarized light which is polarized only by the polarization effect of the second liquid crystal cell.

If the light incident on the polarizing plate is the same linearly polarized light as when it is incident, all the wavelength light is transmitted through the polarizing plate. When the incident light is non-linearly polarized light, only the light of the wavelength of the polarization component that passes through the polarizing plate out of the light is emitted through the polarizing plate, and the emitted light becomes colored light.

Therefore, according to the color liquid crystal display device of the present invention, it is possible to color the transmitted light without using a color filter as in the conventional liquid crystal display device, and therefore the amount of the colored light is incident on the display device. The amount of light in the wavelength band that becomes the colored light out of the
By increasing the light transmittance, the brightness of the display can be sufficiently increased.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a color liquid crystal display device. This color liquid crystal display device includes a first liquid crystal cell 30.
And a second liquid crystal cell 40, one polarizing plate 51, and one reflecting plate 52, the polarizing plate 51 being the first
Of the liquid crystal cell 30 is arranged on the front surface (upper surface in the drawing) side, the reflection plate 52 is arranged on the back surface (lower surface in the drawing) side of the first liquid crystal cell 30, and the second liquid crystal cell 40 is arranged in the first liquid crystal cell 40. It is arranged between the liquid crystal cell 30 and the polarizing plate 51.

The second liquid crystal cell 40 is used for coloring the display, and the first liquid crystal cell 30 is used for controlling the display color. In this embodiment, both liquid crystal cells 30, A TN type is used as 40.

Hereinafter, the second liquid crystal cell 40 is referred to as a coloring cell, and the second liquid crystal cell is referred to as a color control cell. The color control cell 30 includes a pair of upper and lower transparent substrates 31, on which transparent electrodes 33, 34 are formed and alignment films 35, 36 are formed thereon.
32 is bonded via a frame-shaped sealing material 37, and a liquid crystal 38 is sealed in a region surrounded by the sealing material 37 between the substrates 31 and 32. The molecules 38a of the liquid crystal 38 are
A twist orientation of approximately 90 ° is provided between the substrates 31 and 32.

On the other hand, in the coloring cell 40, a pair of upper and lower transparent substrates 41 and 42 in which only the alignment films 43 and 44 are formed without providing transparent electrodes are joined via a frame-shaped sealing material 45,
A liquid crystal 46 is enclosed in a region surrounded by the sealing material 45 between the two substrates 41 and 42, and molecules 46a of the liquid crystal 46 are also twisted between the two substrates 41 and 42.

In this embodiment, the coloring cell 40 has Δn · d (refractive index anisotropy Δ of the liquid crystal 46).
The product of n and the liquid crystal layer thickness d) is Δn · of the color control cell 30.
d (product of refractive index anisotropy Δn of liquid crystal 38 and liquid crystal layer thickness d)
And the twist angle of the liquid crystal molecules 46a is substantially equal to the liquid crystal molecule twist angle (approximately 90 °) of the color control cell 30, and the twist direction of the liquid crystal molecules 46 is opposite to the twist direction of the liquid crystal molecule of the color control cell 30. I am using one. In this embodiment, the same liquid crystal material is used for the liquid crystals 38 and 46 of the erasing cell 30 and the coloring cell 40, and the liquid crystal layer thickness d of both cells 30 and 40 is made substantially equal.

The polarizing plate 51 is arranged such that its transmission axis is slanted by a predetermined angle with respect to the alignment direction of liquid crystal molecules on the polarizing plate facing substrate (upper substrate) 41 side of the coloring cell 40. There is.

That is, FIG. 2 is a plan view showing the liquid crystal molecule alignment direction of the color control cell 30, the liquid crystal molecule alignment direction of the coloring cell 40, and the transmission axis of the polarizing plate 51 in the color liquid crystal display device. In the figure, 31a indicates the liquid crystal molecule alignment direction on the upper substrate 31 side of the color control cell 30, and 32a indicates the liquid crystal molecule alignment direction on the lower substrate 32 side of the color control cell 30. Further, 41a indicates the liquid crystal molecule alignment direction on the upper substrate 41 side of the coloring cell 40, and 42a indicates the liquid crystal molecule alignment direction on the lower substrate 42 side of the coloring cell 40.

As shown in FIG. 2, the liquid crystal molecule alignment directions 31a and 32a on the substrates 31 and 32 of the color control cell 30 are as follows.
The molecules 38a of the liquid crystal 38 of the color control cell 30 are displaced from each other by about 90 °, and the twist direction of the molecule 38a is indicated by an arrow T in the figure.
As indicated by 1, the twist orientation is counterclockwise in the figure from the lower substrate 32 side to the upper substrate 31 side at a twist angle of approximately 90 °.

The liquid crystal molecule alignment direction 41a on the upper substrate 41 side of the coloring cell 40 is parallel and opposite to the liquid crystal molecule alignment direction 31a on the upper substrate 31 side of the color control cell 30, and the lower substrate 42. Liquid crystal molecule orientation direction 4 on the side
2a is parallel to and in the same direction as the liquid crystal molecule alignment direction 32a on the lower substrate 32 side of the color control cell 30. Then, the molecules of the coloring cell 40 are indicated by arrows T in the twist direction.
As shown in FIG. 2, from the lower substrate 41 side of the coloring cell 40 toward the upper substrate 42 side, in the direction opposite to the liquid crystal molecule twist direction T1 of the color control cell 30 (clockwise in the figure), approximately 90 °.
Twisted at a twist angle of °.

On the other hand, in FIG. 2, 51a is a polarizing plate 51.
Of the coloring cell 40.
It is deviated by a predetermined angle with respect to the liquid crystal molecule alignment direction 41a on the upper substrate 41 side. In this example,
The transmission axis 51a of the polarizing plate 51 and the upper substrate 4 of the coloring cell 40
The deviation angle ψ from the liquid crystal molecule alignment direction 41a on the 1 side is 4
It is set to 5 °.

The color liquid crystal display device is of a reflection type in which light (natural light or light from an illumination light source) incident from the front surface (upper surface) side is reflected by the reflection plate 52 on the rear surface side for display. The incident light from the side passes through the polarizing plate 51, the coloring cell 40, and the color control cell 30, is reflected by the reflecting plate 52, and is emitted again through the color control cell 30, the coloring cell 40, and the polarizing plate 51. .

In this color liquid crystal display device, the linearly polarized light incident through the polarizing plate 51 is changed to the coloring cell 40.
And the color control cell 30 in which the liquid crystal molecules are twist-aligned, the polarization state is changed by these polarization effects, and the light is reflected by the reflection plate 52 and passes through the color control cell 30 and the coloring cell 40 again. In the process, the polarization state is further changed and the light enters the polarizing plate 51.

That is, external light (natural light or light from an illumination light source) is linearly polarized by the polarizing plate 51 and enters the coloring cell 40. The transmission axis 51a of the polarizing plate 51 and the coloring cell 40 polarizing plate facing substrate (upper substrate)
Since the liquid crystal molecule alignment direction 41a on the 41 side is obliquely deviated by a predetermined angle (45 ° in this embodiment), the linearly polarized light incident on the coloring cell 40 is changed to the coloring cell 40.
In the process of passing through, it becomes elliptically polarized light due to its polarization effect.

The coloring cell 40 is a liquid crystal cell having no electrode for applying a voltage to the liquid crystal 46,
The polarization characteristic of the coloring cell 40 is always constant (however, there is a characteristic change due to temperature).

Liquid crystal molecules 38a of the color control cell 30
Are twisted, the coloring cell 40 is
The light passing through the color control cell 30 passes through the color control cell 30.
The light whose polarization state has been changed by the polarization action of 0 and which is reflected by the reflection plate 52 enters the color control cell 30 again, is polarized by this color control cell 30, and is further polarized by the coloring cell 40 and is thus a polarizing plate. It is incident on 51.

On the other hand, the electrodes 33, 3 of the color control cell 30
When a voltage is applied to the liquid crystal molecules 38a of the color control cell 30, the alignment state of the liquid crystal molecules 38a is changed from the twist alignment state to the substrate 31,
The value of Δn · d of the color control cell 30 is apparently small, as it rises with respect to the 32nd surface.
The polarization effect in the color control cell 30 is reduced.

That is, the polarization action of the color control cell 30 is
Depending on Δn · d of the color control cell 30, the liquid crystal 38
Apparently, the refractive index anisotropy Δn of A becomes smaller as the liquid crystal molecules 38a rise and orient due to the application of a voltage. Therefore, Δn · d of Δn · d The value becomes smaller and the polarization effect by the color control cell 30 becomes smaller.

Further, since the value of Δn is apparently "0" when the liquid crystal molecules 38a are vertically oriented in a vertical orientation, the apparent Δn · d of the color control cell 30 is finally "0". Become.

Therefore, the electrodes 33, 3 of the color control cell 30 are
When a voltage is applied between the four, the light subjected to the polarization effect by the coloring cell 40 and the color control cell 30 due to the change in the polarization effect in the color control cell 30 is in a voltage non-applied state (the liquid crystal molecule 38a is When light having a polarization state different from that in the twisted orientation) is incident on the polarizing plate 51 and the liquid crystal molecules 38a rise vertically and are oriented, the color control cell 3
The polarization effect due to 0 is almost eliminated, and the linearly polarized light that has entered through the polarizing plate 51 is incident on the polarizing plate 51 only by the polarizing effect due to the coloring cell 40.

Therefore, the light enters through the polarizing plate 51,
The polarization state of the light that passes through the coloring cell 40 and the color control cell 30 twice and enters the polarizing plate 51 again changes depending on the alignment state of the liquid crystal molecules of the color control cell 30. The incident light becomes the same linearly polarized light as that at the time of incidence, and becomes non-linearly polarized light in other states.

That is, in this embodiment, the coloring cell 4 is
The value of Δn · d of 0 and the liquid crystal molecule twist angle are made substantially equal to the Δn · d and liquid crystal molecule twist angle of the color control cell 30, respectively, and the twist direction T2 of the liquid crystal molecule 46a is set to the liquid crystal molecule twist direction T1 of the color control cell 30. Therefore, in the state where no voltage is applied to the color control cell 30, the polarization effect of the coloring cell 40 and the polarization effect of the color control cell 30 are opposite to each other, and the light passes through the coloring cell 40. The light (elliptically polarized light) is converted back to linearly polarized light by the polarization effect of the color control cell 30.

The light that has been returned to the linearly polarized light is reflected by the reflection plate 52 and is incident on the polarizing plate 51 under the polarization effect of the color control cell 30 and the polarization effect of the coloring cell 40. At this time, the light (elliptically polarized light) that has passed through the color control cell 30 is returned to the linearly polarized light by the polarization action of the coloring cell 30.

Therefore, in the state where no voltage is applied to the color control cell 30, the light which enters the polarizing plate 51 through the coloring cell 40 and the color control cell 30 passes through the polarizing plate 51 from the outside. When the voltage is applied to the color control cell 30, the light that enters the polarizing plate 51 through the coloring cell 40 and the color control cell 30 becomes non-linearly polarized light.

If the light incident on the polarizing plate 51 is the same linearly polarized light as when the light is incident, then all the wavelength light is incident on the polarizing plate 5.
1, so that the outgoing light becomes uncolored light at this time, and when the light incident on the polarizing plate 51 is non-linearly polarized light, only the wavelength light of the polarization component which passes through the polarizing plate 51 among the lights. Is emitted through the polarizing plate 51, and the emitted light becomes colored light.

Therefore, according to the color liquid crystal display device described above, the transmitted light can be colored without using a color filter as in the conventional color liquid crystal display device, and therefore the amount of the colored light is incident on the display device. Since it is almost the same as the amount of light in the wavelength band that becomes pre-colored light,
By increasing the light transmittance, the brightness of the display can be sufficiently increased.

That is, in the conventional color liquid crystal display device, the light amount of the colored light passing through the color filter is considerably reduced as compared with the light amount of the wavelength band which becomes the colored light of the light incident on the display device. In the color liquid crystal display device,
Such a decrease in light amount hardly occurs. For this reason,
Even if the color liquid crystal display device of the above embodiment is a reflection type, the display brightness is sufficient.

The brightness of the display in the color liquid crystal display device will be described. The intensity I of the light emitted from the display device is 90 ° when the liquid crystal molecule twist angles of the color control cell 30 and the display cell 40 are 90 °, respectively. It is expressed by the following equation (1).

[0052]

[Equation 1]

The value of the light intensity I obtained by the equation (1) is
At the time of white display, that is, when the emitted light is uncolored light, the intensity is almost 1/2 of all wavelength light (visible light) entering the display device, and thus a sufficiently bright display can be obtained.

Further, in the conventional color liquid crystal display device, the display color is determined by the color of the color filter, but in the color liquid crystal display device of the above embodiment, the color control cell 3 is used.
The display color can be changed by controlling the voltage applied to 0.

FIG. 3 is a CIE chromaticity diagram of the color liquid crystal display device. Here, Δn · d of the coloring cell 40 (Δn ₁ d ₁ in the above formula (1)) and Δn of the color control cell 30 are shown.
The chromaticity is shown when the value of d (Δn ₂ d ₂ in the above formula (1)) is set to 900 nm.

As shown in the chromaticity diagram, the display color of the color liquid crystal display device is in the zero voltage state as the voltage applied to the color control cell 30 is increased, that is, the liquid crystal molecules 38a are twisted. The initial display color when the liquid crystal molecules are in the maximum display state, that is, the final display color when the liquid crystal molecules 38a are vertically oriented in the vertical direction, changes in the middle, and the light intensity I of the display is high and the color purity is high. Also becomes a high display color.

In the color liquid crystal display device, the emitted light becomes uncolored light in the voltage 0 state in which no voltage is applied to the color control cell 30, so that the initial display color, that is, the liquid crystal molecule 38a of the color control cell 30 is generated. The display color is "white" when is in the twist orientation state.

Further, the Δn · d of the coloring cell 40 is 900.
Since the deviation angle ψ between the transmission axis 51a of the polarizing plate 51 and the liquid crystal molecule alignment direction 41a of the coloring cell 40 on the polarizing plate facing substrate 41 side is 45 °, the liquid crystal molecules 38a are perpendicular to the color control cell 30. The final display color when a voltage for rising orientation is applied, that is, the display color when the polarization effect by the color control cell 30 is lost and the transmitted light is only subjected to the polarization effect by the coloring cell 40 is “green”, The change in the display color with increasing voltage applied to the color control cell 30 is white (initial display color) → yellow → blue → yellow → blue → green (final display color).

Therefore, the color liquid crystal display device described above is
By controlling the voltage applied to the color control cell 30,
The display color can be arbitrarily changed to each of the above colors. In the above embodiment, the color control cell 30 and the coloring cell 40 are used.
A TN type liquid crystal cell having a liquid crystal molecule twist angle of about 90 ° was used as the color control cell 30 and the coloring cell 40.
A ST1 N (super twisted nematic) type liquid crystal molecule in which twist alignment is performed at a twist angle of 180 to 270 ° may be used.

Further, in the above embodiment, the value of Δn · d and the liquid crystal molecule twist angle of the coloring cell 40 are made substantially equal to the Δn · d and the liquid crystal molecule twist angle of the color control cell 30, respectively, and the liquid crystal molecule twist direction T2 is set. Was reversed to the liquid crystal molecule twist direction T1 of the color control cell 30, but the coloring cell 40
The value of Δn · d and the liquid crystal molecule twist angle of the color control cell 30 may be different from each other. In that case, the liquid crystal molecule twist direction T2 of the coloring cell 40 and the liquid crystal molecule twist direction T1 of the color control cell 30 are different from each other. May be in the same direction.

In this case also, the light enters through the polarizing plate 51,
The polarization state of the light that passes through the coloring cell 40 and the color control cell 30 twice and enters the polarizing plate 51 again changes depending on the alignment state of the liquid crystal molecules of the color control cell 30. Since the incident light becomes linearly polarized light and becomes non-linearly polarized light in other states, it is possible to obtain a color display similar to that in the above-mentioned embodiment.

In the above embodiment, the deviation angle ψ between the transmission axis 51a of the polarizing plate 51 and the liquid crystal molecule alignment direction 41a of the coloring cell 40 on the polarizing plate facing substrate 41 side is 45 °. ψ may be arbitrarily selected. However, in order to sufficiently obtain the coloring effect of the coloring cell 40, it is desirable that the shift angle ψ be 45 ± 5 °.

In the above embodiment, the coloring cell 40 is arranged between the color control cell 30 and the polarizing plate 51, but the coloring cell 40 is arranged between the color control cell 30 and the reflection plate 52. You may.

[0064]

The color liquid crystal display device of the present invention includes a liquid crystal cell for color control in which liquid crystal is enclosed between a pair of transparent substrates having transparent electrodes and the molecules of which are twist-aligned between the substrates, and a pair of liquid crystal cells for color control. A liquid crystal cell for coloring, in which liquid crystal is enclosed between transparent substrates and the molecules of which are twist-aligned between both substrates, a polarizing plate, and a reflector, the polarizing plate being the surface of the liquid crystal cell for color control. A color control liquid crystal cell between the polarizing plate and one of the polarizing plate and the color control liquid crystal cell. Since the transmission axis of the polarizing plate is slanted by a predetermined angle with respect to the liquid crystal molecule alignment direction on the polarizing plate facing substrate side of the coloring liquid crystal cell, the transmitted light is colored without using a color filter. To increase the light transmittance and display Brightness can be sufficiently high.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a liquid crystal molecule alignment direction of a color control cell, a liquid crystal molecule alignment direction of a coloring cell, and a transmission axis of a pair of polarizing plates according to an embodiment of the present invention.

FIG. 3 is a CIE chromaticity diagram of a color liquid crystal display device according to an embodiment of the present invention.

FIG. 4 is a sectional view of a conventional color liquid crystal display device.

[Explanation of symbols]

 30 ... 1st liquid crystal cell (for color control) 31, 32 ... Transparent substrate 31a, 32a ... Liquid crystal molecule alignment direction 33, 34 ... Transparent electrode 35, 36 ... Alignment film 38 ... Liquid crystal 38a ... Liquid crystal molecule 40 ... Second Liquid crystal cells (for coloring) 41, 42 ... Transparent substrates 41a, 42a ... Liquid crystal molecule orientation direction 51 ... Polarizing plate 51a ... Transmission axis 52 ... Reflector

Claims (3)

[Claims] 1. A first liquid crystal cell in which liquid crystal is sealed between a pair of transparent substrates having transparent electrodes and molecules of the liquid crystal are twist-arranged between both substrates, and liquid crystal is sealed between a pair of transparent substrates. Second twisted array between both substrates
Liquid crystal cell, one polarizing plate, and a reflecting plate, the polarizing plate is arranged on the front surface side of the first liquid crystal cell, and the reflecting plate is arranged on the rear surface side of the first liquid crystal cell. In addition, the second liquid crystal cell is arranged between the liquid crystal cell and any one of the polarizing plate and the reflection plate, and the transmission axis of the polarizing plate is the polarizing plate counter substrate of the second liquid crystal cell. A color liquid crystal display device, which is slanted at a predetermined angle with respect to the liquid crystal molecule alignment direction on the side. 2. The value of Δnd and the liquid crystal molecule twist angle of the second liquid crystal cell are substantially equal to the Δnd and the liquid crystal molecule twist angle of the first liquid crystal cell, respectively, and the liquid crystal molecule twist of the second liquid crystal cell is set. The color liquid crystal display device according to claim 1, wherein a direction is opposite to a liquid crystal molecule twist direction of the first liquid crystal cell. 3. The deviation angle between the transmission axis of the polarizing plate and the liquid crystal molecule alignment direction on the polarizing plate facing substrate side of the second liquid crystal cell is 45.
It is ± 5 °. Claim 1 or Claim 2 characterized by the above-mentioned.
The color liquid crystal display device described in 1.