JP3216584B2 - Liquid crystal display device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bright reflective liquid crystal display panel using a guest-host liquid crystal and not using a polarizing plate.

[0002]

2. Description of the Related Art A display device using a nematic liquid crystal has several modes depending on the orientation of liquid crystal molecules. The most widespread is a twisted nematic (TN) liquid crystal, and there are also a homeotropic (vertical) orientation or a homogeneous (horizontal) orientation birefringence mode, a guest-host mode, and the like.

Since the TN liquid crystal and the birefringent mode liquid crystal require two polarizing plates, one polarized light of natural light is absorbed. Therefore, even in an ideal state, the transmittance does not become 50% or more. And about 30%, and particularly in a reflective liquid crystal using external light, a very dark display is obtained.

[0004] Therefore, it has been practiced to eliminate a polarizing plate or to use one polarizing plate by using a guest-host liquid crystal in which a dichroic dye (guest) is dissolved in a liquid crystal (host). The dichroic dye is aligned along the liquid crystal molecules and has an absorption axis along the long axis of the liquid crystal molecules, so when the liquid crystal molecules are horizontally aligned, they absorb the polarized light in the liquid crystal alignment direction and are aligned vertically. The absorption becomes smaller. In the guest-host liquid crystal, when the cell thickness or the concentration of the dye is increased, the contrast increases and the transmittance decreases. However, even if the cell thickness and the dye concentration are changed, the ratio of the logarithm of the transmittance between the bright state and the dark state is constant. This ratio is called a dichroic ratio (absorbance ratio) and is a performance index of a dichroic dye or a guest-host liquid crystal display.

[0005] The dichroic ratio of the dichroic dye is determined by measuring the absorbance (logarithm of transmittance) of polarized light parallel to the orientation (long axis of the molecule) and the absorbance of polarized light perpendicular to the orientation of the homogeneously oriented guest-host liquid crystal. This is the ratio of the absorbance of the homeotropically aligned guest-host liquid crystal panel. The dichroic ratio of a positive type dichroic dye having sufficient solubility and using a normal nematic liquid crystal as a host is at most 10 to 11.

However, the dichroic ratio of the guest-host liquid crystal display is an absorbance ratio of a change in light and dark based on the orientation deformation due to an electric field, and is smaller than the dichroic ratio of the dichroic dye itself.

As a bright mode without using a polarizing plate,
For example, there is a phase change guest host mode as shown in FIG. When a guest-host liquid crystal in which a dichroic dye and a cholesteric liquid crystal having a relatively short twist pitch are mixed is sandwiched between substrates, a twist helix is perpendicular to the substrate except for the vicinity of the substrate interface as shown in FIG. Orientation. At this time,
The incident light is absorbed by the dye. For example, if a black dye is used, black display is performed. When a voltage is applied to this liquid crystal, first, the helical axis becomes horizontal to the substrate as shown in FIG.
When a voltage is further applied, the twist is released and a vertical orientation shown in FIG. 6C is obtained. At this time, since the absorbance of the dye is small, the color of the reflector behind it looks bright.

In the phase change guest-host mode, since natural light enters without using a polarizing plate, the dichroic ratio of the display does not exceed about half of the dichroic ratio Dp of the dye itself; (Dp + 1) / 2 or more. In addition, the incident linearly polarized light undergoes birefringence of liquid crystal molecules and rotates while deviating from the molecular long axis, which is the absorption axis of the dye, so that the absorbance in the dark state decreases,
The dichroic ratio is further reduced. If the brightness is increased to about 50%, the contrast is reduced to about 5.

On the other hand, as a bright liquid crystal display mode, there is a method that utilizes switching between a scattering state and a transmission state of liquid crystal without a polarizing plate. There are a dynamic scattering mode due to the disorder of the orientation of the liquid crystal, and a polymer dispersed liquid crystal in which the liquid crystal is dispersed in a polymer matrix and scattered by a refractive index difference between the polymer and the liquid crystal. Among them, the dynamic scattering mode has a problem in long-term reliability because the liquid crystal is doped with ionic impurities, and is not used at present. On the other hand, there are several types of polymer-dispersed liquid crystals depending on the preparation method and the distribution shape of the polymer, and in any case, when the refractive index of the liquid crystal viewed from the viewing angle direction matches the refractive index of the polymer. When the two layers have different refractive indices, scattering occurs. For example, when a positive nematic liquid crystal is dispersed in a capsule or network in an acrylic resin whose refractive index is almost equal to the ordinary light refractive index of the liquid crystal, the liquid crystal molecules stand when a voltage is applied, and the liquid crystal and the acrylic react to incident light. When the voltage is not applied, the liquid crystal is randomly oriented, and the difference between the extraordinary light refractive index and the refractive index of the polymer and the disorder of the orientation of the liquid crystal molecules cause no alignment. Scattering occurs.

In addition, a liquid crystal monomer is made compatible with the nematic liquid crystal by several percent, and then sandwiched between substrates subjected to alignment treatment, and the liquid crystal monomer is irradiated with ultraviolet light while the liquid crystal and the monomer are both aligned. There is a reverse mode in which the polymer is polymerized in the aligned state, the refractive index is the same when no voltage is applied and the liquid crystal molecules are transparent when the voltage is applied, and the liquid crystal molecules stand up.

In these scattering type liquid crystals, back scattering
(Reflection) does not occur much because the difference in the refractive index between the liquid crystal and the polymer is small. Switching between the forward scattering state and the transparent state gives only a slight contrast in a reflective display. Therefore, polymer-dispersed liquid crystals are mainly used in projection displays using a special optical system using slits.

As means for enhancing the contrast of such a type of liquid crystal that switches between forward scattering and a transparent state,
For example, Japanese Patent Application Laid-Open No. 54-105998 discloses a method of installing a retroreflector and a louver behind a light scattering type liquid crystal. FIG. 7 is a configuration diagram of the liquid crystal display. When external light 69 enters from a certain direction, the liquid crystal is scattered by turbulence.
When it is at 0, the light 68 passing through the louver 71 returns in the opposite direction by the retroreflective plate 72 and is scattered by the liquid crystal layer and reaches the eyes of the observer. The black can be seen, so the contrast can be added. The above-mentioned retroreflector is a so-called three-mirror in which three mirror surfaces 80, 81, and 82 are arranged orthogonally as shown in FIG. 8A, or a transparent bead 83 as shown in FIG.
Is known in which a metal reflective film 84 is deposited on the rear half of the substrate. In the three-mirror, the light reflected three times on the mirror like the light ray 85 in FIG. 8A always returns to the original direction. Some light is diffused without being reflected up to twice. In the bead type, the refractive index of the beads is set so that the light incident on the beads 83 is focused on the metal reflective film 84, so that the incident light 88 close to the optical axis returns to the original direction. However, due to the aberration, the light 89 separated from the optical axis is diffused and reflected from the original direction.
In any case, since there is no recursive property depending on the incident conditions, if only the retroreflector is placed behind the liquid crystal layer, even if the scattering liquid crystal is in a transparent state, light enters the observer's eyes and does not appear black. Therefore, a louver is used as described in JP-A-54-105998.

[0013]

The guest-host liquid crystal can display a bright image because the polarizing plate can be eliminated, but the contrast is insufficient as described above. Similarly, if a retroreflector and a louver are used in a scattering type liquid crystal without a polarizing plate and illumination is made in a direction perpendicular to the louver, the illumination will be dark, and the position of the illumination and the viewing angle at which contrast can be obtained will be limited. Becomes severe.

In a polymer-dispersed liquid crystal panel in which scattering occurs when a voltage is applied to the guest-host liquid crystal, the dichroic dye is irradiated with ultraviolet rays, so that the dichroic dye is easily decomposed and the driving voltage is reduced. Get higher.

Accordingly, it is a main object of the present invention to obtain a liquid crystal display element which is not only bright but also has a high contrast and a wide viewing angle.

[0016]

In order to achieve the above object, a liquid crystal display device according to the present invention comprises a guest host liquid crystal region containing a dichroic dye and a liquid crystal polymer region between a pair of substrates.
Have a liquid crystal layer present, small-shaped light absorption of the dichroic dye
In the state, the liquid crystal layer has strong light scattering and large light absorption
Liquid crystal display device with low light scattering at the time of
Before bonding the pair of substrates to each other,
And the mesogenic groups of the liquid crystalline polymer
Guest host liquid crystal molecules on the board interface are the same when no voltage is applied
Horizontally oriented in azimuth .

[0017]

[0018]

Further , the liquid crystal display element of the present invention comprises a liquid crystal layer containing a guest-host liquid crystal containing a dichroic dye between substrates.
When the light absorption of the dichroic dye is small,
Strong light scattering, light scattering when light absorption is large
A weak liquid crystal display element, wherein at least one liquid of the substrate
The orientation treatment is different from the surrounding surface
Orientation treatment that causes pretilt in the opposite direction
Small area is distributed and orientation direction in plan view
Is uniform .

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention comprises a liquid crystal layer containing a dichroic dye, and further, when the dichroic dye has a large light absorption (for example, when no voltage is applied). When the light scattering property of the dichroic dye is weak and the light absorption of the dichroic dye is small (for example, when a voltage is applied), the light scattering property of the liquid crystal layer is increased to increase not only the brightness but also the contrast. What you want to do.

Therefore, hereinafter, the liquid crystal display device according to the embodiment of the present invention will be described in detail.

(Embodiment 1) FIG. 1 is a sectional view of a liquid crystal display device according to Embodiment 1 of the present invention. In FIG. 1, a lower substrate 1 and an upper substrate 2 made of glass are shown.
On top, transparent electrodes 3 each made of indium tin oxide
a, 3b and the electrode 4 are formed. Here, for example, the thickness of the substrate is 0.7 mm, the electrode 4 is a 20 mm square,
Each of a and 3b has a rectangular shape having a width of 9.8 mm and a length of 20 mm as a pixel region.
A polyimide horizontal alignment film 5 is formed on the electrodes 3a, 3b and 4 by printing. After rubbing the upper substrate 2 from right to left on the paper and the lower substrate 1 in the opposite direction, the two substrates Are sandwiched between 7 micron spherical spacers, a sealing resin is applied around the spacers and bonded together to form empty cells. The spacer and the seal are omitted in FIG.

Next, the liquid crystal layer injected into the empty cell formed as described above will be described.

First, a chiral nematic liquid crystal having a twist pitch of about 15 μm obtained by mixing 0.5% by weight of a chiral agent S-1011 with a fluorine-based positive nematic liquid crystal having a birefringence of 0.08 is used. 1 type dichroic dye
By dissolving the weight%, a black guest host liquid crystal 7 is prepared. Next, 9.9% by weight of a liquid crystalline monomer 9a represented by the following chemical formula and 0.1% by weight of a photopolymerization initiator of Ciba-Geigy are mixed with 90% by weight of the guest-host liquid crystal to obtain an isotropic phase. After heating to form a well-mixed mixed solution, the mixed solution is poured into an empty cell.

[0025]

Embedded image

At this time, it was confirmed by observation with a polarizing microscope that the mixed solution exhibited a chiral nematic phase, and was uniformly oriented by being twisted 180 degrees counterclockwise in the horizontal direction as on the electrode 3a in FIG. Was done. Next, in this state, the liquid crystal monomer 9a is polymerized by irradiating ultraviolet rays at 1 joule / cm ² with an ultra-high pressure mercury lamp.
There is a state in which the guest-host liquid crystal region containing the dichroic dye and the liquid-crystalline polymer region in which the liquid-crystalline monomer is polymerized, and the mesogen group of the liquid-crystalline polymer and the guest-host liquid crystal molecule on the substrate interface have the same orientation. In the absence of an electric field, a light streak-like pattern can be seen with a microscope, but with a naked eye, a substantially uniform alignment state was maintained and black.
On the other hand, when a voltage of 15 volts was applied, the absorption of the dye was reduced and the color became lighter, and at the same time, light scattering occurred and the film became cloudy. When observed under a microscope, a streak-like pattern was clearly visible. The guest-host liquid crystal 7 responding to the voltage was present between the thin-colored polymer network 9b. It is considered that a polymer network 9b which was polymerized in the oriented state was observed.

Next, as shown in FIG. 1, a retroreflective plate 10 in which 300 nm of silver 10b is applied by vapor deposition to a prism sheet 10a (20 μm at the bottom of the prism) formed by pressing an acrylic resin with a mold is provided behind the cell. It was installed in. In addition,
As shown in the perspective view of FIG. 2A, the shape of the prism is such that three orthogonal planes are defined as one unit, and the prisms are spread as shown in the plan view of FIG. 2B.

The liquid crystal display element of the first embodiment of the present invention shown in FIG. 1 formed as described above is used in an ordinary office where fluorescent lamps are installed on the ceiling at intervals of about 2 m using a luminance meter. When the display performance was measured by using
The contrast between black display at volts and white display at 15 volts application is about 10: 1, and the reflectance of white display (brightness of magnesium oxide with respect to a standard white plate) is 60%, which is very bright and high. Black and white display of contrast was confirmed.

As a comparative example with respect to the liquid crystal display device of the present embodiment, the following two liquid crystal display devices were prepared.

As a first comparative example, only the same chiral nematic guest-host liquid crystal as described in the present embodiment (ie, no liquid crystal monomer and no polymerization initiator was added) was placed in the same empty cell as above. 7 μm thick 1
A commercially available silver scattering reflector used for a TN liquid crystal or the like was placed behind a cell twisted by 80 degrees to prepare a cell. When the display performance was measured, the reflectance was almost saturated.
The reflectivity was 60% in white display of volts, and the contrast with black display of 0 volts was 4: 1.

As a second comparative example, a transmission / scattering switching type produced by the same method as that of this embodiment except that no dichroic dye is contained on the same prism sheet as that of this embodiment. Created one with cells. When the display performance was measured, the reflectance of white was very bright at 90% because no pigment was contained, but the contrast was very small at 2.5.

Further, the dichroic dye used in the present embodiment is dissolved in a host liquid crystal without chiral, injected into a homogeneous cell, and the dichroic ratio Dp of the dichroic dye itself is measured to be 9.8. Met. In the conventional guest-host mode without a polarizing plate, theoretically, the dichroic ratio as a display does not become (Dp + 1) /2=5.4 or more, but the dichroic ratio of the liquid crystal display element of the present embodiment is , White reflectance is 6
0% and the reflectance of black is 60% / 10 = 6%.
og (0.06) / log (0.6) = 5.5,
The dichroic ratio is larger than the theoretical limit, and high-quality display having both brightness and high contrast, which cannot be realized by the conventional guest-host liquid crystal mode, can be realized. Note that the liquid crystal display element in this embodiment does not use a louver, and thus has an advantage that the position of illumination and the viewing angle are not easily limited.

This is because, in the liquid crystal display device of the present invention, the contrast according to the level of absorption of the dichroic dye and the contrast of scattering / transparency are synchronized, thereby contributing to higher quality.

In detail, the state when no voltage is applied is shown on the left side of FIG. 1. When no voltage is applied, the absorption of the dichroic dye is large. Due to the absorption of light and the scattering of the liquid crystal layer is small, the incident light goes almost straight and is reflected by the retroreflector 10, and a considerable part of the light is reflected by the retroreflector like the output light 12a. Since the light returns to the light source 13 side and does not enter the eyes 14a of the observer, the display is further darkened.
Conversely, the state at the time of voltage application is shown on the right side of FIG. 1. Since the guest-host liquid crystal molecules 7 rise by voltage application like the liquid crystal on the electrode 3b, light absorption by the dichroic dye is reduced. At the same time, the liquid crystal layer is scattered forward due to the non-uniformity of the refractive index between the liquid crystal molecules and the polymer network 9b. Then, the light reflected by the retroreflector is again scattered on the return path, and the outgoing light 1
The display becomes very bright because it enters the observer's eyes 14b as in 2b.

As described above, the liquid crystal display device of the present invention
The problem of low contrast, which has been the problem of conventional guest-host liquid crystals or scattering liquid crystals, has been solved by using a retroreflective plate and a scattering and dichroic liquid crystal layer. The problem is solved by combining them so as to enhance the contrast. Note that, in this embodiment mode, a reverse mode polymer-dispersed liquid crystal using a liquid crystal monomer is used as the liquid crystal layer. However, the present invention is not limited to this. Any mode can be used if it can be enlarged. For example, if a negative dichroic dye, which absorbs more when the liquid crystal molecules stand up, is used as the dichroic dye, even a normal polymer-dispersed liquid crystal that forms a capsule in an electric field-free state and scatters can be used. Since the absorption of the dye is enhanced when the liquid crystal layer is in a transparent state at the time of application, the dye can be used for the liquid crystal display device of the present invention. However, there is no practical negative dichroic dye at present.

(Embodiment 2) In Embodiment 1 described above, a bright and high-contrast liquid crystal display device can be realized. However, after a liquid crystal monomer and a polymerization initiator are mixed in a guest host liquid crystal, Since the liquid crystalline monomer is polymerized, impurities such as a polymerization initiator are mixed in the guest host liquid crystal, and the dichroic dye is decomposed when the liquid crystalline monomer is polymerized by irradiating ultraviolet rays. there is a possibility. In addition, since the liquid crystal layer has a structure in which a polymer obtained by polymerizing a liquid crystal monomer is dispersed in a liquid crystal layer, the driving voltage tends to increase.

Therefore, a guest-host liquid crystal display element according to the second embodiment of the present invention, in which scattering occurs when light absorption is small without dispersing a polymer, will be described below with reference to the drawings.

FIG. 3 is a cross-sectional view of the liquid crystal display device according to the present embodiment. The liquid crystal display device according to the present embodiment employs a so-called alignment division method (partially different alignment processes). By changing the magnitude and direction of the pretilt of the liquid crystal molecules on the alignment film, scattering is generated by applying a voltage so that the liquid crystal molecules have a substantially uniform alignment when no electric field is applied, and exhibit a non-uniform alignment by applying a voltage. Has become.

The liquid crystal display device according to the present embodiment is formed as follows. First, after rubbing the polyimide alignment film 5 formed on the lower substrate 1 in FIG. 3, using a mask made of a photoresist, as shown in the plan view of FIG. If the resist is removed by rubbing in the opposite direction after opening the opening 31 of 10 μm square, a large number of minute portions 5 a having a pretilt different from the periphery and in the opposite direction can be distributed. Thereafter, an empty cell is formed, a chiral agent is added so that the twist pitch becomes twice the cell thickness of 7 microns, and a guest-host liquid crystal containing a positive dichroic dye is injected into the empty cell. In the liquid crystal display element of the present embodiment thus formed, when no electric field is applied , the orientation is almost uniform in plan view like the liquid crystal on the electrode 3a in FIG. When a voltage is applied, the liquid crystal in the region rubbed in the opposite direction, such as the liquid crystal on the alignment film 5a on the electrode 3b in FIG. An alignment defect occurs between the portion and the 180-degree twist-aligned portion, and the alignment becomes inhomogeneous and scattering occurs (at this time, absorption of the dichroic dye decreases).

Therefore, according to the present embodiment, scattering occurs when a voltage is applied (when the absorption by the dichroic dye is reduced), so that not only a bright but also high-contrast liquid crystal display element can be obtained. Can be.

Actually, if the same retroreflective plate as that shown in FIG. 1 is arranged behind this liquid crystal panel, the scattering is weaker than that of the polymer dispersion type, so that the viewing angle is slightly narrowed and the white reflectance is reduced. Although the contrast is reduced to 50%, the contrast is 7: 1.
And 4: 1 in the case where the orientation division is not performed. Further, even when a commercially available silver reflector is placed instead of the retroreflector behind the liquid crystal panel of the present embodiment,
Except for the viewing angle direction close to the direction in which the illumination is specularly reflected, the contrast was 5.5: 1, which was slightly improved compared to the case where the orientation division was not performed. In this case, the reflectance is 6
0%, which is higher than in the case of retroreflection. Even in the case of using retroreflection, if scattering of the liquid crystal layer is weak, if a member other than the liquid crystal layer such as a reflector or a forward scattering film is provided with a weak scattering property, the retroreflectivity is weakened and the contrast is slightly increased. It falls, but it is possible to increase the brightness.

According to the present embodiment, since the polymer is not formed in the liquid crystal layer, the driving voltage can be reduced to 5 volts.

In this embodiment, since it is desirable that the orientation is substantially uniform when no voltage is applied,
Very good display performance was obtained when the pretilt was 10 degrees or less and the pretilt was 5 degrees or more from the viewpoint of domain stability when an electric field was applied.

Embodiment 3 Hereinafter, a liquid crystal display device according to Embodiment 3 of the present invention will be described with reference to the drawings. In this embodiment mode, the liquid crystal layer has a guest-host liquid crystal region containing a dichroic dye and a liquid crystal polymer region in which a liquid crystal monomer is polymerized. Embodiment 2 is the same as Embodiment 1 in that the guest-host liquid crystal molecules are horizontally aligned in the same direction. However, in forming the above-described polymer region, the liquid crystal monomer is previously contained in the guest-host liquid crystal. Rather than mixing the polymerization initiator with UV irradiation
Embodiment 4 is different from Embodiment 1 in that a polymer region is selectively formed on a substrate in advance.

FIG. 5 is a sectional view of the liquid crystal display device according to the present embodiment, and can be formed by the following process.

First, a horizontal alignment film 5 of polyimide is applied on the lower substrate 1 having the electrodes 3a and 3b, baked, and then subjected to a rubbing treatment from the back to the front of the paper. On top of that, 15% by weight of a commercially available cyano nematic liquid crystal for TN was mixed with the liquid crystal monomer of the above formula (1), and a solution obtained by dissolving the mixture in ethanol was dried with a spinner to a thickness of 1.5 μm. Was applied. The nematic liquid crystal was mixed because the liquid crystal monomer of the formula (1) had a nematic phase only in a slight temperature range of 81 ° C. to 83 ° C.
This is because the temperature range of the nematic phase of the mixture was widened from 62 ° C. to 83 ° C. by mixing a cyano-based nematic liquid crystal exhibiting a nematic phase up to 0 ° C. If the nematic phase of the liquid crystalline monomer alone was wide, It is better to apply only the monomer.

In this state where the mixture is diluted with ethanol and applied, the liquid crystalline monomer mixture is not oriented. Then, after heating to 85 ° C. to completely evaporate the ethanol,
When the liquid crystalline monomer mixture was gradually cooled to 0 ° C. to have a nematic phase, the liquid crystalline monomer was oriented in the rubbing direction. Then, the temperature is kept at 70 ° C., and the same opening 31 as in FIG.
When the ultraviolet rays are irradiated with a photomask having the above, the liquid crystalline monomer 9a in the irradiated portion is polymerized while being oriented, and the solid-state convex portion 60 can be formed. The mixed cyano nematic liquid crystal is confined in a polymer. On the other hand, a solid-state projection 61 is also formed on the upper substrate 2 by the same method as that performed on the lower substrate 1.

Thereafter, the upper and lower substrates are separated by a 7-micron spacer, the rubbing directions are made orthogonal, and the substrates are bonded together as shown in FIG. 5 so that the projections do not overlap. The guest host liquid crystal 7 containing the black positive dichroic dye was injected. Further, the same retroreflective plate as in FIG. 1 was arranged behind the liquid crystal panel, and a voltage was applied to observe the display.

As a result, when no voltage is applied, as shown on the electrode 3a in FIG.
The film exhibited N orientation, hardly any scattering was observed, and a favorable black display was obtained due to the light absorption of the dichroic dye and the recurrence of the reflector.
On the other hand, when a voltage of 5 volts is applied, the liquid crystal molecules rise as on the electrode 3b, the light absorption of the dichroic dye decreases, the black color becomes thinner, and at the same time, the scattering occurs, and the reflectance becomes 6%.
A bright display of 0% was obtained. The contrast with black display is 8: 1, which is higher than 4: 1 of the conventional guest-host liquid crystal twisted by 180 degrees.

Further, by making the rubbing direction of the upper substrate 2 orthogonal, it is possible to confirm that the direction of scattering is widened and bright, and furthermore, by providing a convex portion on the upper substrate 2, the scattering property is enhanced. The height of the projections was 1 to 2 microns, and the scattering property was high. Also, instead of a retroreflective plate behind the liquid crystal display element of the present embodiment, even when a commercially available silver reflector is placed, except for a viewing angle close to the direction in which illumination is specularly reflected,
The contrast was 5: 1, which was slightly improved from the conventional one.

As described above, the liquid crystal display device of the present invention has been described together with the embodiments. However, according to the present invention, the contrast of the conventional guest-host liquid crystal or scattering liquid crystal without a polarizing plate can be improved. It was confirmed that the viewing angle was also widened.

In the embodiment, the retroreflective plate composed of three mirrors is placed outside the cell. However, since a parallax due to the thickness of the glass is generated, especially when the pixel is small, a resin film is formed inside the cell. It is preferable that the prism shape is formed by pressing or the like and silver or aluminum is vapor-deposited. Also in this case, the arrangement behind the liquid crystal layer is the same. Also,
In the embodiment, black-and-white display is performed by a black guest host liquid crystal.However, the liquid crystal display element of the present invention can be used for color display in combination with a color filter or for color display using a dichroic dye. It is valid.

[0053]

The liquid crystal display device of the present invention uses a scattering type guest-host liquid crystal and further combines with a retroreflective plate to provide a liquid crystal display device having a liquid crystal display device, which is compared with a conventional guest-host liquid crystal without a polarizing plate and a scattering type liquid crystal. A high-contrast bright reflective display can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of a retroreflective plate of a liquid crystal display element according to an embodiment of the present invention.

FIG. 3 is a sectional view of a liquid crystal display element according to Embodiment 2 of the present invention.

FIG. 4 is an enlarged plan view of a substrate surface of a liquid crystal display device according to an embodiment of the present invention.

FIG. 5 is a sectional view of a liquid crystal display element according to Embodiment 3 of the present invention.

FIG. 6 is a sectional view of a conventional liquid crystal display element.

FIG. 7 is a cross-sectional view of a conventional liquid crystal display element.

FIG. 8 is a configuration diagram of a retroreflector.

[Explanation of symbols]

 Reference Signs List 1 upper substrate 2 lower substrate 3a electrode 3b electrode 4 electrode 5 alignment film 7 guest host liquid crystal 9a liquid crystalline monomer 9b polymer network 10 retroreflector 11a incident light 11b incident light 12a emission light 12b emission light 13 light source 14a observer 14b Observer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-43741 (JP, A) JP-A-4-110925 (JP, A) JP-A-10-260407 (JP, A) JP-A-7- 49502 (JP, A) JP-A-5-119302 (JP, A) JP-A-3-96920 (JP, A) JP-A-6-186542 (JP, A) JP-A 8-220540 (JP, A) JP-A-49-127643 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1334 G02F 1/1335 G02F 1/1337 505 G02F 1/137 500 G02F 1/139

Claims (5)

(57) [Claims] Claims: 1. A guest comprising a dichroic dye between a pair of substrates
It has a liquid crystal layer in which the host liquid crystal region and the liquid crystal polymer region is present, before the state small light absorption of the dichroic dye
The light scattering property of the liquid crystal layer is strong, and the light absorption is large.
Sometimes a liquid crystal display element having a low light scattering property,
Before the polymer region is bonded to the pair of substrates,
While being formed on the substrate, the liquid crystalline polymer
Mesogen groups and the guest-host liquid crystal component on the substrate interface
A liquid crystal display device whose elements are horizontally aligned in the same direction when no voltage is applied . 2. A liquid crystal layer containing a guest-host liquid crystal containing a dichroic dye between substrates , and light absorption of the dichroic dye is provided.
Is small, the light scattering property of the liquid crystal layer is strong,
Liquid crystal display device with low light scattering when light absorption is large
Wherein at least one liquid crystal layer of the substrate is in contact with
The orientation of the surface is different from that of the surroundings, and
The minute area that has been subjected to the alignment process that causes
A liquid crystal display element which is clothed and has a uniform orientation direction in plan view . 3. A retroreflective plate behind a liquid crystal layer.
3. The method according to claim 1, wherein
A liquid crystal display device according to any of the above. 4. An alignment film subjected to an alignment treatment is formed.
A step of applying a liquid crystalline monomer on a substrate and optionally
The liquid crystalline monomer is polymerized and
Remove the liquid crystalline monomer that was not
Forming a liquid crystalline polymer region on the
The substrate on which the region is formed and the opposite substrate
Forming a cell, and including a dichroic dye in the empty cell
Encapsulating guest-host liquid crystal
Child manufacturing method . 5. After forming an orientation film on a substrate, the orientation film is turned around.
Micro-aligned to generate pre-tilt in the direction
After distributing the regions, two substrates are formed between the substrate and the substrate facing the substrate.
Enclosing a guest-host liquid crystal containing a coloring dye.
When the light absorption of the dichroic dye is small,
When the light scattering property of the liquid crystal layer is strong and the light absorption is large
Light scattering property is low, and the orientation direction in plan view is uniform.
A method for manufacturing a liquid crystal display device .