JPH0933957A - Liquid-crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal display device with which the orientation at a high operating speed is easy in spite of low driving voltage by preferably horizontally orienting a ferroelectric nematic liquid crystal material between two substrates. SOLUTION: One or 2 pieces of electrodes 15, 16 subjected to a horizontal orientation treatment and transparent insulating substrates 11, 12 covered with oriented films 17, 18 are disposed to face each other. A liquid crystal layer 10 packed with the ferroelectric nematic liquid crystal material exists therebetween. Polarizers 13, 14 of which the axes of polarization have a specified angle are respectively adhered to the outer side of the substrates 11, 12. In such a case, p-type dielectric constant anisotropic liquid crystals having the spontaneous polarization parallel with liquid crystal directors are preferably selected for the ferroelectric nematic liquid crystal material packed in the liquid crystal layer 10. Both surfaces of oriented films 17, 18 in contact with the liquid crystal layer 10 do not have horizontal orientation. Then, the driving of the liquid crystal display device with the driving voltage lower than the driving voltage for a display device formed by using the conventional nematic liquid crystals is made possible while the advantages of such liquid crystal display device are effectively utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more specifically, it uses a ferroelectric nematic liquid crystal material.
The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art Generally, solids have a positional order and a molecular orientation, and have a positional order and a directional order. . The liquid crystal is
Since it has a part of the directional order and the positional order found in solids, it can be said to be a phase or state that is distinguished from liquids and solids. Since a liquid crystal substance generally has a directional order, it is an anisotropic substance whose physical properties differ depending on the direction. The liquid crystal molecules are generally in the shape of thin and long rods, and these long molecules have a property of macroscopically preferentially aligning with each other in a certain direction. The arrangement direction is represented by a director (director), and the degree of directional order existing in the liquid crystal is indicated by the relationship with this director. That is, if the angle that each liquid crystal molecule makes with the director is θ,
An average value of (3 cos ² θ−1) / 2 is used as an order parameter to measure the degree of directional order of the liquid crystal. The liquid crystal order parameter generally decreases with increasing temperature and exhibits values between about 0.3 and 0.9. Such liquid crystals can be roughly classified into three types according to their order. That is, it is nematic, cholesteric, chiral nematic, smectic, or the like.

The nematic liquid crystal has no regularity in the position of the molecules, and has only the directional order in which the forces between the molecules exist to keep the molecules parallel to each other. This liquid crystal material is mainly used in display devices. Since the chiral nematic liquid crystal or cholesteric liquid crystal has a molecular force to keep the directions of the molecules at a small angle with each other, the director is not fixed in one direction of the space like the nematic liquid crystal, and the whole liquid crystal layer is not fixed. Rotate. This property of the liquid crystal is called chirality, and when the director rotates a full turn through the liquid crystal layer, this distance is called a pitch. For nematic liquid crystals that are not chiral nematic, the alignment (alignm
It is possible to allow the director to rotate through the entire liquid crystal layer by ent), again using the term pitch. The substance on the chiral nematic liquid crystal is
Besides display devices, it is used not only when measuring pressure, temperature, magnetic field, ultrasonic waves or electromagnetic fields, but also when making polarizing plates. The smectic liquid crystal is the same as the above 2
The alignment is more regular than that of the two types of liquid crystals, forming a layered structure. The smectic liquid crystal phase has not only directional order but also positional order. That is, the liquid crystal molecules have a tendency to form a layer by themselves, and there is no regularity in the position of the molecules when viewed from above the liquid crystal layer surface, but there is regularity in the direction perpendicular to the liquid crystal layer surface. To have. Therefore, there is directional order while maintaining the regularity of the molecular position in one direction.

On the other hand, among smectic liquid crystals, liquid crystals having ferroelectricity exist, but smectic C ^* liquid crystals have such properties. Recently, this smectic C
^* Research on liquid crystal display devices using liquid crystal phase materials is actively underway. Smectic C ^* liquid crystal is a phase that is inclined with respect to a plane perpendicular to the liquid crystal layer. Smectic C is used when it is composed of optically inactive molecules, and smectic C is used when it is composed of optically active molecules. , Has a spiral motion according to the layer, and is called a smectic C ^* liquid crystal phase. This phase is called a ferroelectric liquid crystal phase because of the presence of molecular permanent dipoles. At this time, the dipole direction is perpendicular to the liquid crystal director. In the case of the ordinary smectic C phase, rotation symmetry (rotation symmetry about an axis perpendicular to the director)
ary symmetry) and inversion symmetry with respect to a plane parallel to the smectic layer perpendicular to the axis, but if the molecule has a chiral part, the inversion symmetry collapses and the dipole becomes perpendicular to the molecule. Child moment (dipole
moment, there is macroscopic spontaneous polarization (spont
aneous polarization or permanent polar
represents the ferroelectricity.

However, the general smectic C ^*
Since the molecules make a spiral motion according to the smectic layer in the phase, the macroscopic spontaneous polarization for one period or one pitch becomes zero. Therefore, the ferroelectric liquid crystal is improper
It is also called ferroelectric liquid crystal. Such a spiral structure is
It can be solved by applying an electric field externally, but in an electric field above the critical value, the spiral structure is completely solved and macroscopic spontaneous polarization exists. A liquid crystal display device using such a smectic C ^* liquid crystal has various problems such as a difficulty in alignment and a weak layered structure, which are currently being developed in various places.

The liquid crystal has an electric susceptib
It can be said to have anisotropy because the physical properties such as ility) and magnetic susceptibility differ in the direction of the director and the direction perpendicular to it. This is because, as described above, rod-shaped molecules that are not spatially symmetrical have a directional order in which they are arranged in a certain direction. For example, since the electric susceptibility differs between the direction of the director and the direction perpendicular thereto, the permittivity also differs depending on the direction. If the permittivity in the direction of the liquid crystal director is εh and the permittivity in the direction perpendicular thereto is εt, there are the following two.

[0007]

[Equation 1]

The former is a p-type (positive) dielectric anisotropy, and the latter is an n-type (negative).
Is called the dielectric anisotropy of. When n∧ is the director, when the DC electric field E _vector is applied, the electric displacement (electric d
isplacement) D _vector is as follows.

[0009]

[Equation 2]

The electrostatic energy is as follows.

[0011]

(Equation 3)

In order to reach a stable state, it is necessary to minimize its value. Therefore, in the case of a liquid crystal having a p-type dielectric anisotropy, that is, when Δε> 0, the director changes the electric field. When the director is perpendicular to the electric field, it becomes stable when the director is perpendicular to the electric field.
Therefore, in the case of the p-type dielectric anisotropy liquid crystal, the director tends to be arranged in parallel to the applied electric field, and conversely, in the case of the n-type dielectric anisotropy liquid crystal, the application is performed. It tends to align perpendicular to the applied electric field.

A liquid crystal display device is manufactured by using such properties of liquid crystal. Among them, a twisted nematic system, which is a typical case using a nematic liquid crystal substance, is described.
A detailed description will be given with reference to the drawings. 1A and 1B show a general twisted nematic liquid crystal display device using a liquid crystal material having a p-type dielectric anisotropy, and FIG. 1A shows that a voltage is applied. FIG. 1B shows a state in which a voltage is applied. In this method, a liquid crystal substance having p-type dielectric anisotropy is filled between two transparent substrates 11 and 12 on which transparent electrodes are respectively formed (this is called a "liquid crystal cell"), and then each Polarizing plates 13 and 14 are provided outside the substrates 11 and 12, respectively, and transparent electrodes 15 and
The alignment films 17 and 18 on 16 are processed so that the directors of the liquid crystal molecules on the two transparent electrode surfaces are twisted by 90 °. If you choose the thickness of the liquid crystal cell and the liquid crystal material well,
The rotation of the polarization direction can be made to follow the twist of the director. When a voltage is applied to the transparent electrodes on both sides in such a state, liquid crystal molecules excluding the molecules immediately above the surfaces of the substrates 11 and 12 are aligned vertically to the substrates 11 and 12. The arrows in FIGS. 1A and 1B represent directors.

The operation of such a twisted nematic liquid crystal display device will be described in detail. In the "OFF" state, the liquid crystal cell acts like a light guide. The linearly polarized light passing through one polarizing plate 13 rotates in the polarization direction when passing through the twisted liquid crystal layer. When the light passes through the liquid crystal layer and reaches the other substrate 11, the polarization direction of the light is rotated by 90 °. Two polarizing plates 1
If 3 and 14 are arranged vertically, this light should pass through the second polarizing plate. However, the two polarizing plates 1
Assuming that the polarization axes of 3 and 14 are parallel to each other,
Since the polarization direction of light is perpendicular to this, it cannot pass through.
In the “ON” state, a voltage is applied between the two substrates 11 and 12. Since the liquid crystal has p-type dielectric anisotropy, the liquid crystal director tries to align it in the direction of the electric field in the remaining portion except the vicinity of the substrates 11 and 12. At this time, the tilt angle can be adjusted electrically,
Such director tilt eliminates the waveguide effect of the liquid crystal layer. That is, the light that has passed through the first polarizing plate 13 and has been changed reaches the second polarizing plate 14 with almost no change in its polarization direction. If the polarization axes of the two polarizing plates 13 and 14 are perpendicular to each other, this light is emitted from the second polarizing plate 1.
However, if the two polarizing plates 13 and 14 are parallel to each other, this light almost passes through the second polarizing plate. As explained above, "OFF" where light does not pass
The state and the "ON" state in which light passes are obtained, and gradation display is possible by appropriately adjusting the applied voltage. Fig. 1 (a)
The twisting angle of the liquid crystal director (twiste
The d angle) is 90 °, but in the so-called super twisted nematic mode, the twist angle is 220 ° or 270 °, which is larger.

[0015]

However, in the case of the conventional twisted nematic system or super twisted nematic system, only the dielectric anisotropy of the liquid crystal is used, so that the liquid crystal display device is driven. There is a problem that the driving voltage applied sometimes is high.

The present invention has been made to solve the above-mentioned problems of the prior art. An object of the present invention is to provide a liquid crystal display device which can be easily aligned at a high operating speed despite a low driving voltage. To provide.

[0017]

The above object is achieved by the invention described in the claims. That is, the characteristic configuration of the liquid crystal display device of the present invention is that a liquid crystal layer made of a ferroelectric nematic liquid crystal substance is provided between a pair of transparent substrates to which a voltage can be applied. The possibility of the presence of ferroelectric nematic liquid crystals has long been predicted ("Novel Ferroelectric Fluids",
Rolfe G. Petschek and Kimbrly M. Wiefling, Physic
al Review Letters 1987 vol. 59, No. 3, pp. 343-346;
"Ferroelectric Nematic Liquid Crystals: Realizab
ility and Molecular Constraints ", P. Palffy-Muhora
y, MA Lee and Rolfe G. Petschek, Physical Review
Letters 1988 vol. 60, No. 22, pp. 2303-2306; "Fer
roelectric nematic liquid-crystal Phases of dipola
r hard ellipsiods ", Marc Baus and Jean-Lois Colot,
PhsicalReview A 1989 col. 40, No. 9, pp. 5444-544
6). In particular, the applicant is Mol. Cryst. Liq. Cryst. 1994, Vo
l. 254, pp. 395-403 "FERRO ELECTRIC"
LIQUID CRYSTALLINE ORDERING OF RIGID RODS WITH DIP
In a paper entitled "OLAR INTERACTIONS", the conventional isotropic-nematic: I
-N), nematic-ferroelectric nematic phase
o-electric nematic: N-FN) and direct isotropic-ferroelectric nematic:
A state diagram representing the I-FN) potential was presented.

Recently, a paper proving the existence of such a ferroelectric nematic substance has been published. In particular, the existence of a ferroelectric nematic substance in which the direction of spontaneous polarization is parallel to the direction of the liquid crystal director has been reported. Generally, in the case of a ferroelectric substance having spontaneous polarization or permanent polarization, it has a property that the polarization tends to be parallel to an applied electric field. Therefore, in the case of a ferroelectric nematic liquid crystal substance to which an electric field is applied, an effect having both the property of the liquid crystal itself that tends to be parallel or perpendicular to the electric field and the property of polarization that tends to be parallel to the electric field appears. Even if a small potential difference is applied, the direction of the liquid crystal director can be easily changed. In the liquid crystal display device according to the present invention using such a property of the ferroelectric liquid crystal, a pair of transparent substrates to which a voltage can be applied face each other, and a ferroelectric nematic liquid crystal substance is filled between them. There is a liquid crystal layer.

The liquid crystal material preferably has a spontaneous polarization parallel to the liquid crystal director. In this case, the liquid crystal is p
It should have a dielectric anisotropy of the mold. The two substrates may be processed for horizontal alignment, and the directions of horizontal alignment may be offset by 0 ° to 360 °, and the liquid crystal director may be rotated by that angle. A chiral additive may be added to the liquid crystal layer to control the pitch of the liquid crystal layer, and the liquid crystal director may have a thickness of 0.
It is possible that the rotation is between 0 ° and 360 °. At this time, a value obtained by dividing the gap between the two substrates by the pitch of the liquid crystal layer may be between 0.0 and 1.0. Further, the ratio of the gap between the two substrates and the pitch of the liquid crystal layer is preferably 1: 4. The product of the optical anisotropy of the liquid crystal substance and the gap between the substrates may be 0.1 μm to 2.0 μm. Polarizers may be attached to the two substrates, and the polarization axes of the two polarizers may be shifted by the rotation angle of the liquid crystal molecules or the rotation angle of the liquid crystal molecules plus ± 90 °. Good. Also, the polarization axes of the two polarizers can be parallel or orthogonal to each other. A phase difference plate may be attached to one or both of the two substrates to improve the viewing angle characteristics.

Of the two substrates, the light emitting means for emitting light may be attached to one of the substrates, or alternatively, a reflecting plate may be attached to use natural light. The liquid crystal display device having such a structure operates similarly to the conventional twisted nematic type or super twisted nematic type. Below,
The operation will be described in detail. In the “OFF” state where no voltage is applied, the liquid crystal molecules are maintained in a twisted horizontal alignment state. Of course, there is an initial tilt angle here. When light polarized in such a state enters through one substrate, the light rotates in the polarization direction while passing through the twisted liquid crystal layer. When the light passes through the liquid crystal layer and reaches the substrate on the other side, the polarization direction of the light is rotated by the amount of rotation of the liquid crystal director. If the polarization axes of the two polarizers are arranged so that they are offset by the twisted angle of the liquid crystal director, this light will pass through the second polarizer. However, if the polarization axes of the two polarizers are arranged so as to be offset by ± 90 ° from the twisted angle of the liquid crystal director, the light polarization direction is perpendicular to the polarization axis of the second polarizer, so the light will pass. I can't.

In the “ON” state in which an electric field is applied, the horizontally aligned liquid crystal substance has a permanent polarization parallel to the liquid crystal director, so that the liquid crystal substance tries to change its direction to be parallel to the direction of the electric field. In particular, when the liquid crystal has a p-type dielectric anisotropy, the nature of the liquid crystal itself tends to cause the molecules to go in the direction parallel to the electric field. The direction of liquid crystal molecules can be changed even in an electric field lower than that of a substance. Moreover, since the angle formed by the liquid crystal director and the substrate can be adjusted appropriately by adjusting the electric field strength, gradation display is possible. Therefore, the light that is incident on one of the substrates and is polarized has its polarization direction rotated according to the angle at which the liquid crystal molecules are tilted, or otherwise reaches the other substrate without rotating.
Consider the case where the electric field is large enough that the liquid crystal molecules are aligned perpendicular to most substrates. If the polarization axes of the two polarizers are parallel, this light will pass through the second polarizer. However, if the polarization axes of the two polarizing plates are arranged so as to be offset by ± 90 °, the light cannot pass through because the polarization direction of light is perpendicular to the polarization axis of the second polarizer.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A liquid crystal display device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 (a) and 1 (b) described above. Fig. 1 (a) shows "OF when no voltage is applied.
1B shows the state of "F", and FIG. 1B shows the state of "ON" in which a voltage is applied. As shown in FIGS. 1A and 1B, this liquid crystal display device has a horizontal alignment treatment 1 or 2.
The transparent insulating substrates 11 and 12 covering the individual electrodes 15 and 16 and the alignment films 17 and 18 face each other. In between is a liquid crystal layer 10 filled with a ferroelectric nematic liquid crystal material. Then, on the outside of the substrates 11 and 12,
Polarizers 13 and 14 whose polarization axes form a constant angle are attached. As the ferroelectric nematic liquid crystal material filled in the liquid crystal layer 10, it is preferable to select a p-type dielectric anisotropy liquid crystal whose spontaneous polarization is parallel to the liquid crystal director. When a chiral additive such as S811 and CB15 is mixed with such a liquid crystal substance, even a nematic substance has chirality, and by adjusting the amount of the mixed chiral additive, the liquid crystal substance is adjusted. You can adjust the pitch of.

Both surfaces of the alignment films 17 and 18 in contact with the liquid crystal layer 10 are horizontally aligned. Generally, an alkylphenol
(alkylphenol) derivative, hexadecyltrimethylammonium bromid
e) or other surface active agent, polyimide resin (polyimide) coating, SiOx tetragonal vapor deposition, Langmuir-Blodgett dep method (Langmuir-Blodgett dep
After the alignment adsorbent is applied by an osition method), the liquid crystal substances existing between the substrates are horizontally aligned on the substrates 11 and 12 by rubbing in a desired direction.
Such horizontal alignment treatment can be performed on one substrate or both substrates. When performing horizontal alignment processing on both substrates, it is desirable to shift the horizontal alignment directions of both substrates, but the angle between the horizontal alignment directions of both substrates is in the range of 0 ° to 360 °. It can be arbitrarily selected.

If the distance between both substrates is d and the pitch of the liquid crystal is p, d / p is arbitrary and the director of the liquid crystal is
It is possible to rotate the liquid crystal layer 10 at any angle under the applied voltage, but it is preferable to rotate the liquid crystal layer 10 between about 0.0 and 1.0. And this value is 1/4
In the “off” state, the liquid crystal director can be rotated through 90 ° throughout the liquid crystal layer 10. Further, even if the orientation is horizontal, the initial tilt angle can be given within the range of about 0 ° to 180 °.

The operation of the liquid crystal display device according to the present embodiment having the above structure will be described in detail. As shown in FIG. 1A, which represents a state in which no voltage is applied, the liquid crystal molecules of the liquid crystal layer 10 maintain the horizontal alignment state in the “off” state in which no voltage is applied. In this state, the first polarizer 13
When the changed light passes through the substrate 11 and is vertically incident on the substrate 11, the light has its polarization direction rotated according to the rotation of the liquid crystal director, and the outer substrate 12 and the polarizer 14 are rotated.
To reach. If the angle formed by the polarization axis of the second polarizer 14 and the polarization axis of the first polarizer 13 is the same as the rotation angle of the liquid crystal director throughout the liquid crystal layer 10, the light that reaches the second polarizer 14 Has its polarization direction parallel to the second polarizer 14 and therefore passes through the second polarizer 14. However, if the angle formed by the polarization axis of the second polarizer 14 and the polarization axis of the first polarizer 13 is equal to the value obtained by adding ± 90 ° to the rotation angle of the liquid crystal director throughout the liquid crystal layer 10, The light that reaches the second polarizer 14 has its polarization direction parallel to the second polarizer 14, and thus,
It passes through the second polarizer. However, if the angle formed by the polarization axis of the second polarizer 14 and the polarization axis of the first polarizer 13 is equal to the value obtained by adding ± 90 ° to the rotation angle of the liquid crystal director throughout the liquid crystal layer 10, The light that reaches the second polarizer 14 has the second polarization direction 1
4 and thus cannot pass through the second polariser 14.

FIG. 1B shows a shape in which the liquid crystal director is changed by applying a voltage. When an electric field is applied, the horizontally aligned liquid crystal substance is a ferroelectric substance having a director's parallel permanent polarization, and therefore the director tries to align it in parallel to the electric field. Further, if the liquid crystal material has a p-type dielectric anisotropy, the director tends to more easily align parallel to the electric field. If the electric field is strong enough, all liquid crystal molecules can be aligned parallel to the electric field, but otherwise maintain a constant angle that is not parallel to the electric field. And the substrate 1
Since the horizontal aligning force is stronger as it gets closer to the surface of Nos. 1 and 12, it becomes closer to horizontal as it gets closer to the surface of the substrate. Then, it is assumed that a sufficiently strong electric field is applied, the liquid crystal directors are arranged substantially perpendicularly to the substrates 11 and 12, and light is incident perpendicularly to the first substrate. Light that has passed through the linear polarizer 13 will be polarized parallel to the plane of the substrate 11. Passing through the first substrate 11,
The linearly polarized light passes through the liquid crystal layer without any influence and reaches the second substrate 12. If the polarization axes of the two polarizers 13 and 14 are orthogonal to each other, the polarization direction of light is perpendicular to the polarization axis of the second polarizer 14, so that the second polarizer 14 is You cannot pass.
However, if the polarization axes of the two polarizers 13 and 14 are parallel to each other, the polarization direction of light is parallel to the polarization axis of the second polarizer 14, and therefore passes through the second polarizer 14. At this time, the degree to which light passes through the liquid crystal cell is such that the two substrates 1
Depending on the distance d between 1 and 12, the refractive index anisotropy Δn, the wavelength λ of the incident light, etc., when the polarizers are parallel to each other,
This can be expressed by a mathematical formula as follows.

[0027]

## EQU4 ## T = 1− (sin ² (π / 2) Sqrt [1+
u ² ]) / (1 + u ² )

Here, Sqrt [1 + u ² ] is (1+
u ² ), where T is the transmittance of unpolarized monochromatic light, u = 2d (Δn / λ). As can be seen from this equation, T is μ = 0, Sqrt [3], Sqr
At t [15] and Sqrt [35], the maximum value is reached, and Sqr
From t [3], they are called the first maximum, the second maximum, and so on. Since the wavelength of visible light is approximately 0.4 μm to 0.7 μm, it is desirable that dΔn be 2 μm or less if the third maximum is used. Particularly, 0.08 μm to 2 μm
It is desirable to do so.

FIG. 2 shows a change in transmittance with respect to a voltage applied to a ferroelectric nematic liquid crystal display device manufactured by a conventional twisted nematic method when the liquid crystal director is rotated by 90 ° throughout the liquid crystal layer. This is shown in comparison with a conventional twisted nematic liquid crystal display device. When the thickness of the liquid crystal layer having a dielectric anisotropy Δε = + 5 is set to 5 μm and the polarizers are arranged so that the polarization axes of the two polarizers are orthogonal to each other, the result is the same as in the graph of FIG. It can be seen that the transmissivity changes even at a lower voltage than when a nematic liquid crystal material is used, and the transmissivity with respect to the applied voltage changes abruptly as the value of the spontaneous polarization p increases. As described above, the liquid crystal display device of this embodiment is applicable to display devices using various liquid crystals. For example, it can be used for a matrix type liquid crystal display device and the like.

[0030]

As described above, according to the present invention, the ferroelectric nematic liquid crystal material is aligned horizontally between the two substrates, preferably in the horizontal direction, thereby utilizing the advantages of the conventional liquid crystal display device using the nematic liquid crystal. A liquid crystal display device that can be driven with a driving voltage smaller than that of a display device using a conventional nematic liquid crystal, can easily solve the alignment problem that appears in the conventional ferroelectric smectic C ^* liquid crystal display device, and can provide a liquid crystal display device with a high operating speed. It was

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device for explaining a conventional technique and an embodiment of the present invention, in which (a) is an “off” state and (b) is an “on” state.

FIG. 2 is a graph showing changes in applied voltage and transmittance of the liquid crystal display device according to the embodiment of the present invention.

[Explanation of symbols]

 10 Liquid crystal layer 11, 12 Substrate 13, 14 Polarizing plate

Claims (18)

[Claims] 1. A pair of transparent substrates to which a voltage can be applied,
A liquid crystal display device having a liquid crystal layer made of a ferroelectric nematic liquid crystal substance. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal material of the liquid crystal layer is a ferroelectric nematic material having spontaneous polarization parallel to the liquid crystal director. 3. The liquid crystal display device according to claim 2, wherein the material of the liquid crystal layer has p-type dielectric anisotropy. 4. The liquid crystal display device according to claim 1, wherein the two substrates are horizontally aligned. 5. The horizontal alignment direction of the two substrates is 0 °.
5. The liquid crystal display device according to claim 4, wherein the liquid crystal director is shifted by 360 ° to 360 °, and the liquid crystal director is rotated by that angle. 6. The liquid crystal display device according to claim 1, wherein a chiral additive is contained in the liquid crystal layer for adjusting the pitch of the liquid crystal layer. 7. The liquid crystal display device according to claim 6, wherein the liquid crystal director of the liquid crystal material of the liquid crystal layer is rotated by 0 ° to 360 ° through the entire liquid crystal layer. 8. The liquid crystal display device according to claim 5, wherein a value obtained by dividing the gap between the two substrates by the pitch of the liquid crystal layer is 0.0 to 1.0. 9. The liquid crystal display device according to claim 8, wherein a ratio of a gap between the two substrates and a pitch of the liquid crystal layer is 1: 4. 10. The product of the refractive index anisotropy of the liquid crystal material of the liquid crystal layer and the gap between the substrates is 0.1 μm to 2.0 μm.
10. The liquid crystal display device according to claim 9. 11. The liquid crystal display device according to claim 5, wherein a polarizer is attached to each of the two substrates. 12. The liquid crystal display device according to claim 11, wherein the polarization axes of the two polarizers are displaced from each other by a rotation angle of liquid crystal molecules of the liquid crystal layer. 13. The liquid crystal display device according to claim 11, wherein the polarization axes of the two polarizers are displaced from each other by an angle obtained by adding ± 90 ° to a rotation angle of liquid crystal molecules of the liquid crystal layer. 14. The liquid crystal display device according to claim 11, wherein the polarization axes of the two polarizers are parallel to each other. 15. The liquid crystal display device according to claim 11, wherein the polarization axes of the two polarizers are orthogonal to each other. 16. The retardation plate is attached to one of the two substrates or to the front of the two substrates.
The liquid crystal display device according to 3, 5, or 7. 17. On one of the two substrates,
6. A light emitting means for emitting light is attached.
Alternatively, the liquid crystal display device according to item 7. 18. On one of the two substrates,
The liquid crystal display device according to claim 1, wherein a reflective plate is attached.