JPH1039296A - Reflection type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the constitution, to increase the degree of freedom in the constitution of a liquid crystal layer, and to enable the development to a multicolor display, etc., by providing a liquid crystal display device with a liquid crystal layer, etc., to allow the passage of linearly polarized light holding or rotating its plane of polarization. SOLUTION: When the liquid crystal layer 3 does not rotate the plane of polarization, the linearly polarized light passed through the liquid crystal layer 3 passes a phase plate 4 and is reflected by a mirror 5 while its polarization state is maintained. The light again passes the phase plate 4 and the liquid crystal layer 3 and arrives again at the polarizing plate 2 while maintaining its polarization state. The linearly polarized light of this time is approximately parallel with the light transmission axis of the polarizing plate 2 and is, therefore, recognized as a bright display state (a). On the other hand, in the case the liquid crystal layer 3 rotates the plane of polarization by approximately 45 deg., the linearly polarized light paste the liquid crystal layer 3 passes the phase plate 4 and changes to the circularly polarized light which is reflected and inverted by the mirror 5. The circularly polarized light is thereafter passes again the liquid crystal layer 3. Since the light is the linearly polarized light having the plate of polarization approximately perpendicular to the light transmission axis of the polarizing plate 2, the light is recognized as the dark display state (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device.

[0002]

2. Description of the Related Art A reflection type liquid crystal display device comprising a polarizing plate, a liquid crystal layer and a mirror is disclosed in Japanese Patent Application Laid-Open No. 4-116515. According to the present invention, the twist angle of the liquid crystal layer, Δnd
(Product of optical anisotropy Δn and thickness d) and optimization of the polarization state of the incident light allow linearly polarized light that has passed through the polarizing plate to enter when no voltage is applied to the liquid crystal layer. The liquid crystal layer changes the light into circularly polarized light, then the light is reflected by a mirror and passed through the liquid crystal layer again to change the light into linearly polarized light perpendicular to the incident light to obtain a dark display state. A bright display state is obtained by reflecting the incident linearly polarized light by a mirror while maintaining its polarization state substantially and reaching the polarizing plate again. However, the twist angle of the liquid crystal layer and Δnd (optical anisotropy) (Product of the property and thickness) and the polarization state of the incident light are almost limited, so the degree of freedom in designing and manufacturing the liquid crystal layer (liquid crystal cell) is considerably small. Is There is a problem that it is disadvantageous.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a simple structure and a large degree of freedom in the structure of a liquid crystal layer. It is an object of the present invention to provide a possible reflection type liquid crystal display device.

[0004]

According to the present invention, in order to solve the above-mentioned problems, a substrate for holding a liquid crystal layer, a polarizing plate, and linearly polarized light by the polarizing plate are held or substantially 45 °. ° a liquid crystal layer that can be rotated and passed through,
There is provided a reflection type liquid crystal display device comprising at least a phase plate disposed so that birefringence does not occur in incident light that passes through the liquid crystal layer while retaining the polarization plane, and a mirror. FIG. 1 shows one configuration example of the liquid crystal display device of the present invention. The incident light 1 passes through the polarizing plate 2 and enters the liquid crystal layer 3 in a state of linearly polarized light. The liquid crystal layer does not rotate the plane of polarization of the linearly polarized light as necessary, or
It is configured to be able to rotate 5 °. The phase plate 4 is disposed such that the slow axis of the liquid crystal layer side surface is substantially parallel to the light transmission axis of the polarizing plate 2. As shown in FIG. 1A, when the liquid crystal layer 3 does not rotate the plane of polarization, the linearly polarized light that has passed through the liquid crystal layer 3 passes through the phase plate 4 and is reflected by the mirror 5 while maintaining its polarization state. Then, the light passes through the phase plate 4 and the liquid crystal layer 3 again while maintaining its polarization state, and reaches the polarizing plate 2 again. At this time, the linearly polarized light that has reached the polarizing plate 2 is substantially parallel to the light transmission axis of the polarizing plate 2, and thus is recognized as a bright display state by an observer. On the other hand, FIG.
(B), the liquid crystal layer 3 makes the polarization plane 2 approximately 45 °.
When rotating, the linearly polarized light that has passed through the liquid crystal layer 3 changes to circularly polarized light by passing through the phase plate 4, and the direction of rotation is inverted when reflected by a mirror. Thereafter, when the light passes through the liquid crystal layer 3 again, it becomes linearly polarized light having a plane of polarization substantially perpendicular to the light transmission axis of the polarizing plate 2 and reaches the polarizing plate. One of the main features of the present invention is that the means for converting linearly polarized light and circularly polarized light between the polarizing plate and the mirror is provided by both the liquid crystal layer and the phase plate. It is only necessary to have a function of rotating approximately 45 degrees as necessary, which means that the degree of freedom in designing and manufacturing is large. The angle of about 45 ° is preferably in the range of about 45 ° ± 5 °.

The liquid crystal layer 3 only needs to have a function of not rotating the plane of linear polarization deflected by the polarizing plate and a function of rotating the plane of polarization of linearly polarized light by approximately 45 ° as required. As an example of achieving such a function, there is a twisted nematic liquid crystal cell configured so that liquid crystal molecules have a twist angle of approximately 45 ° in the thickness direction of the liquid crystal layer 3. In this case, the liquid crystal molecule alignment regulating direction on the polarizing plate 2 side of the liquid crystal layer 3 is disposed substantially parallel to the light transmission axis of the polarizing plate 2 so as not to cause birefringence. FIG. 2 shows a configuration example of the liquid crystal layer. A liquid crystal layer 30 is sandwiched between the lower substrate 11 and the upper substrate 12. Reference numerals 21 and 22 denote transparent electrodes for applying a voltage to the liquid crystal layer, and reference numerals 31 and 32 denote alignment films for aligning the liquid crystal. As a liquid crystal material, a normal nematic liquid crystal is used, and since the configuration is simple, it is advantageous in terms of cost. When no voltage is applied to the liquid crystal layer, the liquid crystal molecules between the two substrates are continuously twisted by approximately 45 ° in the thickness direction of the liquid crystal layer, so that the linearly polarized light that has passed through the polarizing plate follows the twist of the liquid crystal molecules. Polarization plane is approximately 45 °
It will be twisted. On the other hand, when a voltage is applied to the liquid crystal layer, the liquid crystal molecules are arranged along the direction of the electric field (the thickness direction of the liquid crystal layer), so that the twisted structure is eliminated, and the linearly polarized light that has passed through the polarizing plate maintains the direction of the polarization plane. It passes through the liquid crystal layer as it is.

As another example of a preferable liquid crystal layer, a thickness of the liquid crystal layer is approximately between two substrates disposed so that the direction of the alignment treatment of both substrates is different from the direction of the twist of the liquid crystal molecules by approximately 225 °. A cholesteric liquid crystal having a 1.6 times natural pitch is sandwiched, and the liquid crystal molecules are switched by applying an electric field between two stable alignment states of about 45 ° twisted in the thickness direction and about 405 ° twisted in the thickness direction. A liquid crystal cell that can be used. In this case, the liquid crystal molecule alignment regulating direction on the polarizing plate side of the liquid crystal layer is disposed substantially parallel to the light transmission axis of the polarizing plate so as not to generate extra birefringence. The configuration of this liquid crystal layer is almost the same as that of the above-described 45 ° twisted nematic liquid crystal cell, and can be described with reference to FIG. The difference is that the liquid crystal material is obtained by adding a cholesteric liquid crystal to a nematic liquid crystal, and a liquid crystal composition exhibiting a cholesteric liquid crystal phase as a whole is preferably used. The liquid crystal molecules are aligned in a direction slightly inclined from the substrate surface by the alignment film. The natural helical pitch P of the liquid crystal is set to be approximately 1.6 times the thickness d of the liquid crystal layer, and is configured such that the state of being twisted by 225 ° becomes stable when the alignment is not regulated by the alignment film. However,
When the direction of the alignment treatment is configured to be different by approximately 135 ° between the upper and lower substrates, the 225 ° twist is accompanied by the splay deformation of the liquid crystal, so that the elastic energy increases and becomes unstable.
Instead, the 45 ° twisted state and the 405 ° twisted state are stable. Both orientation states can be switched by the waveform of the applied voltage. In the 45 ° twisted state, the linearly polarized light that has passed through the liquid crystal layer changes to circularly polarized light by passing through the phase plate, and its direction of rotation is reversed when reflected by the mirror. Thereafter, when the light passes through the liquid crystal layer again, the light reaches the polarizing plate as linearly polarized light having a polarization plane substantially perpendicular to the light transmission axis of the polarizing plate, and is recognized as a dark display state by an observer. On the other hand, in the 405 ° twisted state, the light that has passed through the liquid crystal layer and has passed through the phase plate due to birefringence caused by a large twist angle becomes elliptically polarized light, is reflected by the mirror, and is again reflected by the phase plate and liquid crystal layer. Is not linearly polarized light substantially perpendicular to the light transmission axis of the polarizing plate as in the case of a 45 ° twisted state, but the retardation of the liquid crystal layer (optical anisotropy and By selecting the product of thickness Δnd), a bright display state can be obtained. Further, in this case, when the alignment regulating direction of the liquid crystal layer on the polarizing plate side is not parallel to the light transmission axis, the display at the time of 405 ° twist is not bright. About 45 °, about 13
5 °, approximately 225 ° and approximately 405 ° are preferably in the range of approximately 45 ° ± 5 °, 135 ° ± 5 °, 225 ° ± 5 ° and 405 ° ± 5 °, respectively.

As the phase plate, a stretched film of polycarbonate, polyvinyl alcohol, triacetyl cellulose, polyethylene, polypropylene, etc., a liquid crystal cell with homogeneous alignment, an aligned polymer liquid crystal, and a homogeneous alignment in the liquid crystal state of the polymer liquid crystal Can be used as an alignment-fixed polymer liquid crystal in which is fixed in a solid state. The phase plate may be used alone, or a plurality of phase difference plates may be used. When the liquid crystal substrate is a film substrate, the substrate itself can be used as a retardation plate by adjusting Δnd of the substrate. With this configuration, the number of components can be reduced, and the thickness of the display device can be reduced. The above-mentioned phase plate can be used as the phase plate, and the wavelength range of visible light, which is called a quarter-wave plate, is particularly 500 nm to 600 nm.
A phase plate having a retardation (product ΔnD of optical anisotropy Δn and thickness D) of about そ の of that wavelength, and further setting the slow axis of the phase plate to the phase in the liquid crystal layer. By arranging the liquid crystal layer substantially in parallel with the alignment regulation direction on the plate side, a dark display state when the liquid crystal layer rotates the polarization plane by approximately 45 ° as described above is displayed darker, and a large contrast is obtained as a monochrome display device. It is possible to obtain a ratio.

As described above, when a quarter-wave plate is used as a phase plate, a good black-and-white display device can be obtained. However, a specific retardation different from the quarter-wave plate is used. When the liquid crystal layer rotates the plane of polarization by approximately 45 °, the linearly polarized light that has passed through the liquid crystal layer changes to elliptically polarized light by passing through the phase plate, and is reflected by the mirror and re-phased. The light passing through the plate enters the liquid crystal layer at an angle other than 90 ° with respect to the alignment regulating direction on the phase plate side, so that a display state colored by birefringence is obtained. As a result, white and white are obtained. , The two-color switching between the colored state and the above-mentioned colored state becomes possible. Therefore, a multi-color display can be realized by using a phase plate having a partially different retardation.
Depending on how different retardations are arranged on the phase plate, for example, it is possible to make display colors different for each of a plurality of relatively large areas in the entire display device, and in the case of a dot matrix, The display color may be different for each. As a method of manufacturing a phase plate having a partially different retardation, a method of partially changing a thickness D of a phase plate having a uniform refractive index anisotropy Δn, and a method of manufacturing a material having a different refractive index anisotropy Δn, A method in which a material having a certain refractive index anisotropy Δn is fixedly formed on a supporting substrate, a method in which the material having a certain refractive index anisotropy Δn is fixedly formed on the supporting substrate, or a method in which Δn is changed by irradiating light, There is a method in which an electric field is partially applied to the oriented polymer liquid crystal film in a heated state, and cooling is performed while maintaining the applied state. As the high-molecular liquid crystal, a polymer or the like in which a mesogen group is bonded to an acrylic, methacryl or siloxane main chain via a bent-chain spacer is particularly preferably used.

Further, by arranging the liquid crystal layer so that the alignment regulating direction of the liquid crystal layer on the side of the polarizing plate has a certain angle that is not substantially parallel to the light transmission axis of the polarizing plate, the liquid crystal layer can be polarized. Is rotated by approximately 45 °, a display state colored by birefringence is obtained. As a result, a bright display (white) when the liquid crystal layer does not rotate the plane of polarization and the colored state described above are obtained. Switching between two colors becomes possible. The coloring due to birefringence obtained at this time can be changed depending on the angle between the alignment control direction of the liquid crystal layer on the polarizing plate side and the light transmission axis of the polarizing plate. Further, in this case, even when the twist angle of the liquid crystal molecules in the thickness direction of the liquid crystal layer is not approximately 45 ° when no voltage is applied to the liquid crystal layer, coloring can be obtained. Therefore, the alignment regulating direction on the polarizing plate side of the liquid crystal layer is
As a method of changing the alignment control direction on the polarizing plate side of the liquid crystal layer, a method of performing rubbing while masking so as not to rub any part when performing rubbing on an alignment film such as polyimide, SiO ₂₎ Deposition from various directions while masking so as not to overlap when obliquely depositing ₂ etc., irradiating linear polarized light to a prepolymer film having photopolymerizability or a polymer film having photodegradability and There is a method of aligning liquid crystal molecules in a direction depending on the direction (parallel or vertical).

Further, in order to form a colored display state in the reflection type liquid crystal display device of the present invention, a color filter may be used. By using a color filter, a bright reflective color display can be achieved.
The color filter itself is arranged adjacent to one of the polarizing plate, the liquid crystal layer, the phase plate, the mirror,
Alternatively, a substance having a function as a color filter may be directly formed on any of a polarizing plate, a liquid crystal layer, a phase plate, and a mirror. In this case, when a quarter wavelength wave is used and the alignment control direction of the liquid crystal layer on the polarizing plate side is substantially parallel to the light transmission axis of the polarizing plate, the use of a color filter is effective.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction and operation of the reflection type liquid crystal display device of the present invention will be specifically described below based on embodiments.

Example 1 A glass substrate having a transparent electrode was coated with polyimide (AL-3046 manufactured by Japan Synthetic Rubber) and rubbed. Another substrate subjected to the same treatment and the previous substrate were overlapped via a silica bead spacer so that the alignment treatment surfaces faced each other, and liquid crystal was injected into a gap between the substrates. As the liquid crystal, a nematic liquid crystal ZLI-3276-0 manufactured by Merck was used.
0.2% of a chiral nematic liquid crystal S811 made by Merck which induces a clockwise twist at 00 (Δn = 0.1037)
Liquid crystal whose pitch was adjusted to 48 μm by addition was used. The thickness of the liquid crystal layer was adjusted to 6.0 μm according to the particle size of the spacer. Further, the rubbing direction in the upper and lower directions was configured to differ by 225 ° from the twisting direction of the liquid crystal. On top of this cell,
The polarizing plate is placed so that its light transmission axis is substantially parallel to the rubbing direction of the upper substrate of the cell, and is further placed under the cell by 1/4.
A reflection type liquid crystal display device was manufactured by installing a wave plate so that its slow axis was substantially parallel to the rubbing direction of the upper substrate of the cell, and further installing a mirror thereunder. This display device displayed good black when no voltage was applied between the transparent electrodes on the upper and lower substrates, and displayed bright white when a voltage was applied. Further, as the phase plate, the retardation was 0.05 and 0.3 instead of the quarter wave plate.
When a voltage was not applied between the transparent electrodes of the upper and lower substrates when compared with the case where a quarter-wave plate was used, there was much light leakage and the contrast ratio as a display device was reduced. .

Example 2 A glass substrate having a transparent electrode was coated with polyimide (AL-3046 manufactured by Japan Synthetic Rubber) and rubbed. Another substrate subjected to the same treatment and the previous substrate were overlapped via a silica bead spacer so that the alignment treatment surfaces faced each other, and liquid crystal was injected into a gap between the substrates. As the liquid crystal, the nematic liquid crystal ZLI-5080 (Δ
n = 0.0864), a liquid crystal whose pitch was adjusted to 5.1 μm by adding 1.48% of a chiral nematic liquid crystal S811 manufactured by Merck which induces clockwise twist. The thickness of the liquid crystal layer was adjusted to 3.2 μm according to the particle size of the spacer. Further, the rubbing direction in the upper and lower directions was configured to differ by 225 ° from the twisting direction of the liquid crystal. A polarizing plate is disposed on the cell such that the light transmission axis is substantially parallel to the rubbing direction of the upper substrate of the cell. Was arranged so as to be substantially parallel to the rubbing direction of the upper substrate, and a mirror was further provided therebelow to produce a reflection type liquid crystal display device. This display device shows good black when the liquid crystal molecules are twisted by approximately 45 ° between the two substrates according to the drive waveform, and shows approximately 405
° When the twisted state was selected, a bright display state was shown. The response time of this display device (the time required for a change of 90% of the total change in transmittance change) is 5 msec.
c, showing a response time much shorter than that of the normal TN (twisted nematic) type.

Embodiment 3 In the reflection type liquid crystal display device manufactured in Embodiment 1, a color filter is formed between the polarizing plate and the upper substrate so that three colors of R, G, and B are arranged corresponding to each pixel. And driving by applying a voltage corresponding to the image signal, a bright multi-color display was obtained.

Embodiment 4 Instead of using a quarter-wave plate, the lower substrate of the cell has a thickness of 300 μm with a retardation of 0.13.
A reflective liquid crystal display device was manufactured in the same manner as in Example 1, except that the polycarbonate film of m was used so that its slow axis was substantially parallel to the rubbing direction of the upper substrate. This display device displays good black when no voltage is applied between the transparent electrodes on the upper and lower substrates, and displays bright white when a voltage is applied, and has almost the same display performance as the display device of Example 1. showed that. The liquid crystal display device of the present embodiment is smaller in thickness than the display device of the first embodiment,
The weight was also light.

Example 5 A reflection type liquid crystal display device was manufactured in the same manner as in Example 1 except that a phase plate having a partially different retardation was used. The phase plate to which a partially different retardation is applied is obtained by fixing a stretched film of a siloxane-based polymer liquid crystal having a mesogen in a side chain between two electric field applying substrates on which electrodes are formed, and heating the phase plate. It was fabricated by partially applying an electric field and then cooling to room temperature. The retardation of the treated part was controlled by the electric field application condition. The liquid crystal display device manufactured using the phase plate obtained as described above is white when an electric field is applied, and as shown in Table 1, when no electric field is applied, corresponding to each retardation, blue, green, yellow, orange, A color such as red was displayed, and a multi-color liquid crystal display device was obtained.

[0017]

[Table 1]

Example 6 A reflection type liquid crystal display device was manufactured in the same manner as in Example 1 except that a liquid crystal cell treated so that the rubbing directions of the substrate on the polarizing plate side were partially different was used. The rubbing treatment of the substrate on the polarizing plate side was performed for each set rubbing direction using a SUS masking member having a thickness of 50 μm and performing a rubbing treatment in a predetermined direction with only a desired portion exposed. . The liquid crystal display device manufactured using the liquid crystal cell obtained in this manner has white, when no electric field is applied, and, when no electric field is applied, as shown in Table 2, corresponding to each rubbing direction, purple, blue, green, yellow, Colors such as orange and red were displayed, and a multi-color liquid crystal display device was obtained.

[0019]

[Table 2]

Hereinafter, embodiments of the present invention will be described. 1. A substrate sandwiching the liquid crystal layer, a polarizing plate, a liquid crystal layer capable of passing linearly polarized light by the polarizing plate while maintaining the polarization plane or rotating by approximately 45 °, and a liquid crystal layer holding the polarization plane. A reflection type liquid crystal display device comprising at least a phase plate disposed so that birefringence does not occur in incident light that has passed therethrough, and a mirror.

2. As the liquid crystal layer, a twisted nematic liquid crystal cell configured so that liquid crystal molecules can have a twist angle of about 45 ° in the thickness direction of the liquid crystal layer is used, and the liquid crystal molecule alignment regulation on the polarizing plate side of the liquid crystal layer is used. Is arranged in a direction substantially parallel to the light transmission axis of the polarizing plate.

3. As a liquid crystal layer, a natural pitch of about 1.6 times the thickness of the liquid crystal layer is formed between two substrates arranged such that the alignment direction of the two substrates is different from the twist direction of the liquid crystal molecules by about 225 °. A liquid crystal cell that sandwiches a cholesteric liquid crystal having a liquid crystal cell that can be switched by applying an electric field between two stable alignment states of a state in which liquid crystal molecules are twisted approximately 45 ° in the thickness direction and a state in which the liquid crystal molecules are twisted approximately 405 °, and 1. The reflective liquid crystal display device according to the above 1, wherein the liquid crystal molecule alignment regulation on the polarizing plate side of the liquid crystal layer is disposed substantially parallel to the light transmission axis of the polarizing plate.

4. The reflection type liquid crystal according to any one of the above 1 to 3, wherein a quarter-wave plate is used as a phase plate, and a slow axis of the phase plate is disposed substantially in parallel with a liquid crystal molecule alignment regulating direction on the polarizing plate side of the liquid crystal layer. Display device.

5. 4. The reflective liquid crystal display device according to 4, wherein the phase plate has a retardation of about ４ with respect to a wavelength of 500 nm to 600 nm.

6. A quarter-wave plate is used as the phase plate, and the slow axis of the phase plate is disposed substantially in parallel with the alignment regulating direction of the liquid crystal layer on the phase plate side.
At least one of a polarizing plate, a liquid crystal layer, a phase plate, and a mirror
2. The reflection-type liquid crystal display device according to the above item 2, which is arranged adjacent to the two.

7. 6. The reflective liquid crystal display device according to 6, wherein the color filter is formed directly on at least one of a polarizing plate, a liquid crystal layer, a phase plate, and a mirror. 8. 2. The reflection type liquid crystal display device according to the above item 2, wherein the phase plate partially differs in retardation (Δnd).

9. 2. The reflection type liquid crystal display device according to the above item 2, wherein the liquid crystal molecule alignment regulation on the polarizing plate side of the liquid crystal layer is disposed so as to have two or more different types of alignment regulation.

10. The liquid crystal layer arrangement direction of the liquid crystal layer on the side of the polarizing plate is not substantially parallel to the light transmission axis of the polarizing plate, and birefringence is given to incident light after passing through the polarizing plate. Reflective liquid crystal display device.

(11) 2. The reflective liquid crystal display device according to the above item 2, wherein a liquid crystal layer which has been subjected to an alignment treatment so as to have two or more different types of alignment regulating directions is used as the liquid crystal layer. 12. The reflective liquid crystal display device of any one of 1 to 11, wherein the substrate has the optical function of the phase plate, and the phase plate is omitted. 13. 13. The reflective liquid crystal display device according to the above item 12, wherein the substrate is a film substrate.

[0030]

【effect】

1. (1) The liquid crystal layer may adjust the plane of polarization of the incident linearly polarized light to approximately 4
What is necessary is just to have a function of rotating by 5 °, and the degree of freedom in design and fabrication is greater than in the prior art in which there were many restrictions on the liquid crystal layer. 2. Claim 2 A twisted nematic liquid crystal cell in which liquid crystal molecules have a twist angle of about 45 ° in the thickness direction of the liquid crystal layer is not significantly different from a normal twisted nematic liquid crystal cell in a manufacturing process, and a liquid crystal material is used. However, a normal nematic liquid crystal is used, and the structure is simple, so that it is advantageous in terms of cost. 3. The liquid crystal cell of the present invention has high time-division driving characteristics and high responsiveness, and is therefore particularly suitably used for display applications requiring a large-capacity, high-contrast display. 4. Claims 4, 5, 6, and 7 Reflective bright multi-color display including white can be performed without requiring special lighting means such as a backlight. 5. According to a simple operation of adjusting the angle between the liquid crystal layer (liquid crystal cell) and the polarizing plate, a bright two-color display of a reflection type including white without requiring special illumination means such as a backlight can be realized. . 6. Claim 9 The number of parts can be reduced, which leads to cost reduction, and also makes it possible to reduce the thickness of the device.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing the configuration and operation of one example of a reflection type liquid crystal display device of the present invention. (A) This is the case of a liquid crystal layer that allows linearly polarized light to pass while retaining the plane of polarization. (B) This is the case of a liquid crystal layer that passes linearly polarized light by rotating the plane of polarization by approximately 45 °.

FIG. 2 is a schematic sectional view of a reflection type liquid crystal display device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Incident light 2 Polarizer 3 Liquid crystal layer 4 Phase plate 5 Mirror 11 Lower substrate 12 Upper substrate 21 Transparent electrode 22 Transparent electrode 30 Liquid crystal layer 31 Alignment film 32 Alignment film

Claims (9)

[Claims] 1. A substrate sandwiching a liquid crystal layer, a polarizing plate, and linearly polarized light by the polarizing plate, the polarization plane of which is maintained or substantially 45 °.
At least a liquid crystal layer that can be rotated and passed therethrough, a phase plate that is arranged so that birefringence does not occur in incident light that passes through the liquid crystal layer while retaining the polarization plane, and a mirror. The configured reflective liquid crystal display device. 2. As a liquid crystal layer, a twisted nematic type liquid crystal cell configured so that liquid crystal molecules can have a twist angle of about 45 ° in a thickness direction of the liquid crystal layer is used, and the liquid crystal layer has a polarizing plate side. 2. The reflection type liquid crystal display device according to claim 1, wherein the liquid crystal molecule alignment regulation is disposed in a direction substantially parallel to the light transmission axis of the polarizing plate. 3. A liquid crystal layer having a liquid crystal layer thickness of about 1.6 between two substrates disposed so that the direction of alignment treatment of both substrates is different from the direction of twist of liquid crystal molecules by about 225 °. A liquid crystal sandwiching a cholesteric liquid crystal having twice the natural pitch and capable of switching between two stable alignment states, that is, a state in which liquid crystal molecules are twisted at about 45 ° and a state at which they are twisted at about 405 ° by applying an electric field. 2. The reflection type liquid crystal display device according to claim 1, wherein a cell is used, and a liquid crystal molecule alignment regulation on the polarizing plate side of the liquid crystal layer is disposed substantially parallel to a light transmission axis of the polarizing plate. 4. The liquid crystal display device according to claim 1, wherein a quarter-wave plate is used as the phase plate, and a slow axis of the phase plate is disposed substantially parallel to a liquid crystal molecule alignment regulating direction on the polarizing plate side of the liquid crystal layer. 4. The reflective liquid crystal display device according to 2, 3 or 4. 5. A quarter-wave plate is used as a phase plate, a slow axis of the phase plate is disposed substantially parallel to a direction of alignment control on the side of the phase plate in the liquid crystal layer, and a color filter is polarized. 3. The reflection type liquid crystal display device according to claim 2, wherein the reflection type liquid crystal display device is disposed adjacent to any one of a plate, a liquid crystal layer, a phase plate, and a mirror. 6. The phase plate is partially retarded (Δ
3. The reflection type liquid crystal display device according to claim 2, wherein nD) is different. 7. The reflection type liquid crystal display device according to claim 2, wherein the liquid crystal molecule alignment regulation on the polarizing plate side of the liquid crystal layer is arranged so as to have two or more different alignment regulations. 8. The liquid crystal layer according to claim 1, wherein the liquid crystal molecule alignment regulating direction on the polarizing plate side of the liquid crystal layer is not substantially parallel to the light transmission axis of the polarizing plate, and birefringence is given to incident light after passing through the polarizing plate. 3. The reflective liquid crystal display device according to 2. 9. The method according to claim 1, wherein the substrate has the optical function of the phase plate, and the phase plate is omitted.
3. The reflective liquid crystal display device according to 3, 4, 5, 6, 7, or 8.