JP2001075130A - Liquid crystal device and liquid crystal display provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a display of assigning intensity levels performable. SOLUTION: A chiral-smectic liquid crystal having a structure (intra-plane chevron structure) shown by the graph is utilized for a liquid crystal panel. This intra-plane chevron structure consists of a first region A1 wherein a layer normal direction 4 is inclined to one side (left side in the graph) to the direction R of uniaxially aligning treatment and a second region A2 wherein the layer normal direction 4 is inclined to the other side (right side in the graph) to the direction R of the uniaxially aligning treatment. In ether region A1 or A2, liquid crystal molecules are unistable in a direction (cf. mark 6) nearly along the direction R of the uniaxially aligning treatment. As memory properties are lost in this structure, the liquid crystal panel is capable of displaying assigning intesity levels in accordance with applied voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element used for a flat panel display, a projection display, a printer, and the like, and a liquid crystal device provided with the liquid crystal element.

[0002]

2. Description of the Related Art As a liquid crystal panel (liquid crystal element) for displaying various information using a liquid crystal, there is a liquid crystal panel using a nematic liquid crystal, a ferroelectric liquid crystal, or an antiferroelectric liquid crystal. Among them, liquid crystal panels using ferroelectric liquid crystals or antiferroelectric liquid crystals have the advantage of a faster response speed than liquid crystal panels using nematic liquid crystals, and are expected to be widely used in the future. . Hereinafter, this matter will be described in detail.

Conventionally, an active matrix type liquid crystal panel using a nematic liquid crystal and having an active element such as a transistor disposed in each pixel has been developed. Such liquid crystal panels include, for example, AppliedP by M. Schadt and W. Helfrich.
physics Letters Vol. 18, No. 4 (19
Twisted nematic shown on pages 127 to 128 (published February 15, 71)
Nematic) mode is widely used.

Further, recently, in-plane switching (In-Plane Switch) using a lateral electric field has been proposed.
(hing) mode has been announced, and the viewing angle characteristic which has been a drawback of the twisted nematic mode liquid crystal display has been improved.

Further, a super twisted nematic (super twisted nematic) is a typical example of a nematic liquid crystal panel using no active element as described above.
Nematic mode).

As described above, the liquid crystal panel using such a nematic liquid crystal has various modes.
In any of the modes, there is a problem that the response speed of the liquid crystal takes several tens of milliseconds or more.

[0007] To improve the disadvantages of the conventional nematic liquid crystal panel, a device using a liquid crystal exhibiting bistability has been proposed by Clark and Lagerwell (Japanese Patent Application Laid-Open No. Sho 56). -107216, U.S. Pat.
Specification). As the liquid crystal exhibiting this bistability, a ferroelectric liquid crystal exhibiting a chiral smectic C phase is generally used. Since the ferroelectric liquid crystal performs inversion switching by spontaneous polarization, a very fast response speed can be obtained and a bistable state having a memory property can be developed. Further, since the viewing angle characteristics are also excellent, it is considered that they are suitable as a high-speed, high-definition, large-area display element or a light valve.

On the other hand, recently, antiferroelectric liquid crystals exhibiting three stability have attracted attention. This antiferroelectric liquid crystal also performs reversal switching by spontaneous polarization similarly to the ferroelectric liquid crystal, so that a very fast response speed can be obtained. This liquid crystal material is characterized in that no spontaneous polarization exists when no electric field is applied, because the liquid crystal molecules have a molecular arrangement structure in which the liquid crystal molecules cancel each other when no electric field is applied.

More recently, a thresholdless antiferroelectric liquid crystal developed to drive the antiferroelectric liquid crystal with an active matrix element has been reported.

A ferroelectric liquid crystal and an antiferroelectric liquid crystal which perform inversion switching by such spontaneous polarization are liquid crystals exhibiting a smectic liquid crystal phase. In other words, the realization of a liquid crystal panel using a smectic liquid crystal is expected in the sense that the problem concerning the response speed of the conventional nematic liquid crystal can be solved.

[0011]

Incidentally, the above-mentioned ferroelectric liquid crystal or the like can basically display only binary values,
It was difficult to display a gradation in a pixel.

In order to enable gradation display, various types of devices such as "thresholdless antiferroelectric liquid crystal", "short pitch type ferroelectric liquid crystal", and "polymer stable ferroelectric liquid crystal" are used. Liquid crystals have been proposed, but none are in the research and development stage and have yet to be commercialized.

Accordingly, an object of the present invention is to provide a liquid crystal element capable of gradation display.

Another object of the present invention is to provide a liquid crystal device capable of gradation display.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes a pair of substrates, at least one of which is subjected to a uniaxial orientation treatment and arranged at a predetermined distance, A chiral smectic liquid crystal arranged in the gap between the pair of substrates, and a pair of electrodes arranged to sandwich the chiral smectic liquid crystal,
And, in a liquid crystal element driven by applying a voltage to the chiral smectic liquid crystal through the pair of electrodes, the chiral smectic liquid crystal has a layer normal direction on one side with respect to the uniaxial alignment processing direction. 1st tilt
An in-plane chevron structure composed of a region and a second region in which the layer normal direction is inclined to the other side with respect to the direction of the uniaxial alignment treatment, and in the first region and the second region, liquid crystal molecules are formed. It is characterized in that it is stable in a direction substantially along the direction of the uniaxial orientation treatment.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the present invention will be described.

(1) First, the structure of the liquid crystal element according to the present invention will be described with reference to FIG.

A liquid crystal element according to the present invention, as indicated by a symbol P in FIG. 1, has a pair of substrates 1a and 1b arranged at a predetermined distance from each other, and is disposed in a gap between the pair of substrates 1a and 1b. And a pair of electrodes 3a and 3b arranged so as to sandwich the chiral smectic liquid crystal 2, and at least one of the substrates 1a or 1b is subjected to a uniaxial orientation treatment. . The liquid crystal element P is driven by applying a voltage to the chiral smectic liquid crystal 2 via the pair of electrodes 3a and 3b, and performs gray scale display.

(2) Next, the structure of the chiral smectic liquid crystal 2 used in the present invention will be described with reference to FIGS.

As shown in FIG. 2, the chiral smectic liquid crystal 2 used in the present invention has a stripe texture parallel to the uniaxial orientation processing direction R. The basic structure is as follows. Unlike a normal chevron structure which bends in a shape of "K" to compensate, an in-plane chevron structure which compensates for a decrease in the layer interval by changing the layer normal direction 4 is provided. That is,
In the in-plane chevron structure, the layer normal direction 4 is inclined to one side (the left side in the drawing) with respect to the direction R of the uniaxial orientation processing.
The region A ₁ and the layer normal direction 4 correspond to the direction R of the uniaxial orientation treatment.
The other side and the second region A ₂ inclines (right side in the figure), made, in any of the areas A _1, A _2, the direction in which liquid crystal molecules are substantially along the direction R of the uniaxial aligning treatment (codes to 6), that is, the liquid crystal molecules are mono-stabilized by setting the stable position of the liquid crystal molecules substantially to the uniaxial alignment processing direction R (the darkest optical axis when sandwiched between crossed Nicol polarizers in the state where no electric field is applied). (Having only one).

Here, the "uniaxial orientation direction" refers to the case where * both the substrates 1a and 1b are uniaxially oriented and the uniaxial directions are parallel and the same direction. In the case where uniaxial orientation processing is performed only on one side of both substrates 1a and 1b, this is the processing direction itself. * The uniaxial orientation processing is performed on both substrates 1a and 1b, and the uniaxial processing direction is applied. Are crossed with each other, it corresponds to the direction of 1/2 of those cross angles.

The first region A ₁ and the second region A
The area ratio of ₂ may be approximately 1: 1 (details will be described later).

As shown in FIG. 3, the chiral smectic liquid crystal 2 used in the present invention may be a liquid crystal in which the above-mentioned in-plane chevron structure 7 and a normal chevron structure 8 coexist. In this case, the layer inclination angle of the in-plane chevron structure (the angle indicated by the symbol δp in FIG. 2 and the angle formed by the layer normal direction 4 and the uniaxial orientation processing direction R) and the layer of the normal chevron layer structure It is preferable that the inclination angle (see reference numeral δo in FIG. 4) be substantially equal.

(3) The above-mentioned in-plane chevron structure has lost the memory property. The reason is that the conventional SSFLC
This will be described in comparison with the above.

(3-1) In the conventional SSFLC, two states parallel to the substrate in the SmC ^* phase are stabilized to exhibit bistability, that is, memory properties. This memory property will be described with reference to FIGS.

FIG. 4 is a schematic diagram showing the relationship among the layer tilt angle δo, the molecular tilt angle Θ, and the pretilt angle α. FIG. 5 shows the C-director at the molecular position in FIG.

As shown in this figure, since a general smectic C-phase liquid crystal shows a relationship of Θ> δo, it exists at two stable molecular positions in a chevron kink portion, and this state is a memory state. It is an expression principle.

(3-2) On the other hand, in the cell forming the in-plane chevron structure, as described above, a stripe texture parallel to the uniaxial alignment processing direction R is formed under observation with a polarizing microscope, Its basic structure is different from the ordinary chevron structure in which the decrease in the distance between the smectic layers is compensated by bending in the shape of a "<", as shown in FIG. It has a compensation structure. Therefore, when considering a model in which the layer of the in-plane chevron portion is completely perpendicular to the substrate as shown in this figure, the layer inclination angle δp
It is necessary to match with the layer inclination angle δo bent in the shape of “”.

On the other hand, the alignment direction of the liquid crystal molecules having such an in-plane chevron structure is at a position shifted from the layer normal direction 4 by the molecular tilt angle Θ as in the case of other structures as long as the liquid crystal is SmC ^* liquid crystal. Should be the most stable. Above all, two states parallel to the substrate should be stable like other SSFLCs. However, as can be seen from FIG. 2, in the case of the in-plane chevron structure, one of the stable states parallel to the two substrates is uniaxially oriented. The orientation substantially coincides with the direction R (reference numeral 6), and strictly speaking, the orientation is shifted in the direction (た −δp) from the uniaxial orientation direction R, while the other direction is far away from the uniaxial orientation direction R, Strictly, the alignment is performed in a direction shifted from the uniaxial alignment processing direction R by (Θ + δp). Therefore, especially when the binding force of the uniaxial alignment processing of the substrate is strong, as described above, the liquid crystal molecules are stabilized only in the direction 6 substantially along the direction R of the uniaxial alignment processing, and the memory property is lost. Will be.

(4) Next, the principle of developing the in-plane chevron structure will be considered.

When an X-ray measurement is performed on an actual liquid crystal element having an in-plane chevron structure, a measurement result showing a normal "<" shape is obtained. Therefore, in an actual liquid crystal element, the in-plane chevron structure is not formed on the entire surface, but as shown in FIG. It is expected that the layer structure is a mixture of the above. As shown in this figure, it can be said that the in-plane chevron structure is a layer structure developed when the chevron structures having different inclination directions are dense.

Therefore, in order to develop such an in-plane chevron structure, it is necessary that C1 and C2 have a cell configuration that can be generated with equal probability. In other words, when the uniaxial orientation processing directions (for example, rubbing directions) of the upper and lower substrates are parallel and the same direction, and a cell configuration having a certain pretilt angle occurs, an energy difference occurs between C1 and C2. I'll get them all together. However, when the uniaxial orientation directions of the upper and lower substrates are set in opposite directions (anti-parallel), C1 and C2 are not distinguished, so that a cell configuration in which C1 and C2 can be generated with equal probability can be realized. That is, in order to develop the above-described in-plane chevron structure, both the pair of substrates 1a and 1b are subjected to uniaxial orientation processing, and their uniaxial orientation directions are parallel and reversed (anti-parallel and substantially parallel). Anti-parallel).

Furthermore, was subjected to detailed observations, plane chevron structure as described above is formed in the SmA phase, the result which it is held until SmC ^* phase, stripe texture in a temperature range showing the SmC ^* phase Often observed. Therefore, in order to form a chevron structure as described above, * the chiral smectic liquid crystal 2 is a liquid crystal having a smectic A phase (SmA phase) at least on the high temperature side in the phase sequence; * the layer spacing in the smectic A phase It is considered necessary that the in-plane chevron structure already decreases in the smectic A phase in the smectic A phase.

(5) Next, the inversion behavior of liquid crystal molecules with respect to an electric field when such a layer structure is formed will be described.

When no voltage is applied to the chiral smectic liquid crystal 2 used in the present invention, as shown in FIG. 6B, between the two adjacent regions A ₁ and A ₂ ,
The directions of spontaneous polarization are opposite to each other.

When a voltage of one polarity is applied to the liquid crystal 2 in this state, only _one area A ₁ or A ₂ responds to the electric field, and when a voltage of another polarity is applied, the other area A ₁ or A ₂ is applied. only the area A ₂ or A ₁ is responsive to the electric field. FIG. 3A shows one region A when a positive voltage is applied.
Figure 1 (c) shows that only ₁ responds to the electric field.
Only other region A ₂ indicates a state in response to the electric field in the case of applying a negative voltage.

For this reason, if the polarizers are arranged in crossed Nicols so that the liquid crystal element P is in the darkest state in the state where no voltage is applied, one of the regions A according to the voltage of one polarity
The transmitted light intensity of ₁ or A ₂ increases, and the transmitted light intensity of the other region A ₂ or A ₁ increases according to the voltage of the other polarity,
Analog gradation control is possible regardless of the polarity of the applied voltage.

When the area ratio between the first region A ₁ and the second region A ₂ is set to approximately 1: 1, a constant transmittance is obtained regardless of the polarity whether the applied voltage is the same. Is obtained, driving using polarity reversal becomes possible.

(6) Next, each component constituting the liquid crystal element P will be described.

For the substrates 1a and 1b, a highly transparent material such as glass or plastic may be used.

As the electrodes 3a and 3b, a transparent electrode made of ITO (indium tin oxide) or the like may be used.

Further, the method of performing uniaxial orientation treatment on the substrate includes the following: * Inorganic substances (for example, silicon monoxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride, silicon carbide) , Boron nitride, etc.) and organic substances (for example, polyvinyl alcohol, polyimide, polyimide amide, polyester, polyamide, polyester imide, polyparaxylene, polycarbonate, polyvinyl acetal, polyvinyl chloride, polystyrene, polysiloxane,
A thin film of cellulose resin, melamine resin, urea resin, acrylic resin, or the like (see reference numerals 5a and 5b in FIG. 1) is formed by a coating method, a vapor deposition method, a sputtering method, or the like, and the surface is formed of velvet, cloth, paper, or the like. A method of rubbing with a fibrous material, and a method of vapor-depositing an oxide or a nitride of SiO or the like from an oblique direction of the substrate can be exemplified. This uniaxial orientation treatment may be performed on both substrates 1a and 1b, or may be performed on only one substrate 1a or 1b.

On the other hand, the present invention may be applied to a simple matrix type liquid crystal element or an active matrix type liquid crystal element. In the latter case, analog gray scale display is performed in combination with the active element. Can be.

On the other hand, the liquid crystal device P includes the above-described liquid crystal element P, a driving circuit (not shown) for supplying a gradation signal to the liquid crystal element P, and a light source (not shown) for illuminating the liquid crystal element P. Should be configured.

The pitch of the chiral smectic liquid crystal 2 is preferably longer than twice the gap between the substrates 1a and 1b.

Furthermore, an alignment state having only one darkest optical axis in the absence of an electric field is not an antiferroelectric liquid crystal.

Next, the effect of this embodiment will be described.

According to the present embodiment, gradation display within one pixel is possible.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

In this embodiment, a liquid crystal panel (liquid crystal element) P shown in FIG. 1 was prepared.

Incidentally, the average particle size is 2.0 μm in the substrate gap.
m silica beads were arranged as spacers to define the substrate gap.

The substrates 1a and 1b have a thickness of 1.1 m.
A glass substrate with a thickness of 700 m was used for the transparent electrodes 3a and 3b. Further, the orientation control film 5
A polyimide film having a thickness of 200 ° was used for a and 5b. Further, a liquid crystal composition LC is prepared by using the following liquid crystal compound.
-1 was adjusted.

[0053]

Embedded image The physical property parameters of the liquid crystal composition LC-1 are shown below.

[0054] Spontaneous polarization (30 ° C.): Ps = 0.57 nC / cm ² Tilt angle (30 ° C.): Θ = 22.2 ° SmC ^* Spiral pitch in phase (30 ° C.): 20 μm or more (because of long pitch) A method for manufacturing the above-described liquid crystal panel P will be described.

First, transparent electrodes 3a and 3b were formed on the surfaces of the glass substrates 1a and 1b.

Next, a polyimide precursor having the following repeating unit PI-a is applied by spin coating so as to cover the transparent electrodes 3a and 3b, and then pre-dried at a temperature of 80 ° C. for 5 minutes. Then, heating and baking is performed at a temperature of 200 ° C. for 1 hour, and the above-described alignment control film 5a,
5b was formed.

[0057]

Embedded image The surfaces of the respective alignment control films 5a and 5b were subjected to a rubbing treatment (uniaxial orientation treatment) using a nylon cloth. For this rubbing treatment, a rubbing roll having a diameter of 10 cm with nylon (NF-77 / manufactured by Teijin) stuck to the outer peripheral surface was used, the pushing amount was 0.3 mm, and the feeding speed was 10 cm / s.
ec, the number of rotations was 1000 rpm, and the number of times of feeding was four times.

Thereafter, silica beads are sprayed on the surface of one of the substrates 1a (more precisely, the surface of the orientation control film 5a) so that the rubbing directions of the substrates 1a and 1b are opposite to each other (anti-parallel). Bonded.

The pretilt angle of the cell measured by a crystal rotation method was 2.1 °.

Next, the above liquid crystal composition LC-1 was injected into the gap between the substrates at a temperature of an isotropic phase, and the liquid crystal was gradually cooled to a temperature at which a chiral smectic liquid crystal phase was exhibited.

The present inventor uses the liquid crystal panel P prepared in this way to obtain (1) the alignment state of the liquid crystal, (2) the optical response,
(3) Inclination angle of the layer and (4) Temperature change of the layer interval in the SmA layer were examined. Hereinafter, each will be described.

(1) State of alignment of liquid crystal The present inventor observed the state of alignment of the liquid crystal of the liquid crystal panel P with a polarizing microscope.

As a result, the liquid crystal 2 has a texture consisting of two regions A ₁ and A ₂ in a * SmA phase in the form of stripes (stripes) parallel to the rubbing axis direction R. It was found that a similar striped structure was present even after gradually cooling to (30 ° C.). The angle formed between the extinction positions in the absence of an electric field between the adjacent stripes was about 4 °.

When a positive voltage and a negative voltage were applied to the liquid crystal 2, each of the stripe-shaped regions A
It has been found that ₁ and A ₂ each respond only to an electric field of one polarity. Further, the angle (δp) formed by the half of the angle formed by the extinction position and the rubbing axis direction R in each of the regions A ₁ and A ₂ measured while applying an electric field of ± 10 V to the cell is left and right. It was found that the temperature was about 20.0 ° C., which was almost the same as the value of δo, which is the inclination angle of the smectic layer at 30 ° C., 21.1 °.

(2) Optical Response In order to measure the electro-optical response of the liquid crystal panel P, the inventor applied the above liquid crystal panel to a polarizing microscope equipped with a photomultiplier under crossed nicols, and rubbing direction R
The polarization axis was adjusted so as to provide a dark field.

Then, when a rectangular wave of 0.1 Hz at ± 8 V was applied, the optical response could draw a double hysteresis curve having a threshold around ± 4 V with respect to the applied voltage, as shown in FIG. all right.

Since the transmitted light intensity in the white display state when the positive electric field is applied matches the transmitted light intensity in the white display state when the negative electric field is applied, the two stripes A
It is considered that the area ratio of ₁ and A ₂ is almost 1: 1.

In the liquid crystal panel P having such a double hysteresis characteristic, a clear threshold characteristic is used to
In a simple matrix driving element, for example, as shown in FIG. 8, a bias voltage ± V1 is applied, and a positive / negative pulse voltage (± V2) is further superimposed to use a dark state, a bright state and a mixture thereof. It can be expected that the memory effect of the analog gray level is exhibited.

(3) Measurement of Layer Incline Angle δp (Preparation of X-ray Measurement Cell) As the substrate glasses 1a and 1b, glass having a thickness of 80 μm (trade name, manufactured by Corning Incorporated) was used to minimize absorption of X-rays. A sheet for X-ray measurement was prepared basically in the same manner as described above, except that a sheet (sheet) was used and silica beads of 1.4 μm were used as spacers. The rubbing direction was made to be opposite (anti-parallel).

(Measurement of Tilt Angle of Layer) Basically, a method disclosed by Clark and Lagerwal (Japan)
Display '86, Sep. 30 to Oct. 2,
1986, pp. 456-458) or the method of Ouchi et al. (JJAP, 27 (5) (1988) pp.
L725-728).

As a measuring apparatus, an X-ray diffractometer of MAC Science Co., Ltd. of a rotating anti-cathode method was used, and Kα ray of copper was used as an analysis line. The layer spacing of the liquid crystal was measured by applying a bulk liquid crystal on glass having a thickness of 80 μm and performing a 2θ / θ scan in the same manner as in ordinary powder X-ray diffraction.

The liquid crystal composition LC-1 was injected into the previously prepared cell for X-ray measurement at the temperature of the isotropic phase, and was gradually cooled to room temperature (30 ° C.) to prepare a cell. Thereafter, the cell was subjected to θ scan by adjusting the X-ray detector to the diffraction angle 2θ at which the layer interval was obtained, and δp at room temperature (30 ° C.) was calculated by the method described in the above-mentioned literature. As a result, θ was 69.1 ° and 11
Two sharp peaks were observed at 1.8 °, indicating that the liquid crystal composition LC-1 had a chevron structure in which the layer inclination angle δp was 21.4 ° in the antiparallel rubbing cell. . FIG. 9 shows the measurement results.

Further, the cell was heated to 45 ° C.
After the formation of the phase A, the inclination angle δp of the layer was measured in the same manner. As a result, two peaks were observed at θ of 78.4 ° and 101.7 °, and the liquid crystal composition LC-1 showed SmA
It was found that the phase had a chevron structure. FIG. 10 shows the measurement results.

(4) Temperature Change of Layer Interval in SmA Phase The method of measuring the layer interval will be described in more detail.

The liquid crystal composition L was formed on a glass substrate having a thickness of 80 μm.
C-1 was applied to a surface of about 5 mm square so that the surface became smooth, and the peak obtained by ordinary powder X-ray diffraction method was
The layer spacing d was determined by applying the above diffraction condition equation.

The measurement temperature was set at 3 ° C. after the temperature at which the liquid crystal composition LC-1 was brought to an isotropic liquid state in order to increase the smoothness of the diffraction surface, and was 1 ° C. from the temperature range of the SmA phase to the vicinity of the AC transition point. The measurement was performed by lowering the temperature every ° C. The automatic temperature controller used in the experiment showed a control accuracy of about ± 0.3 ° C. at each temperature.

As a result, the layer interval d = 2 at 46 ° C.
For 9.824 °, the layer spacing at 45 ° C. d = 29.
It was 5858 °, and it was confirmed that the layer interval decreased in the SmA phase with a decrease in temperature.

[0078]

As described above, according to the present invention,
It is possible to perform gradation display within one pixel.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of the structure of a liquid crystal element according to the present invention.

FIG. 2 is a schematic view showing an in-plane chevron structure.

FIG. 3 is a schematic diagram showing a coexistence state of an in-plane chevron structure and a normal chevron structure.

FIG. 4 is a diagram showing a relationship between a layer tilt angle, a molecular tilt angle, and a pretilt angle in a conventional SSFLC.

FIG. 5 is a view showing a C-director at a molecular position in FIG. 4;

FIG. 6 is a diagram illustrating the inversion behavior of liquid crystal molecules in the present invention.

FIG. 7 is a diagram showing a relationship between an applied voltage and transmittance.

FIG. 8 is a diagram showing a relationship between an applied voltage and transmittance.

FIG. 9 is a diagram showing a measurement result of a diffraction angle at room temperature.

FIG. 10 is a view showing a measurement result of a diffraction angle in an SmA phase.

[Explanation of symbols]

1a, 1b glass substrate (substrate) 2 chiral smectic liquid crystal 3a, 3b transparent electrode (electrode) P crystal panel (liquid crystal device) 4-layer normal direction R rubbing direction (the direction of the uniaxial alignment treatment) A ₁ the first region A ₂ second 2 area 7 In-plane chevron structure 8 Normal chevron structure

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masahiro Terada 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Makoto Mori 3-30-2 Shimomaruko, Ota-ku, Tokyo Kia Non-corporation (72) Inventor Takashi Moriyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H088 GA04 HA03 HA08 HA28 JA17 KA13 MA13

Claims (10)

[Claims] 1. A pair of substrates, at least one of which is subjected to a uniaxial orientation treatment and arranged at a predetermined distance, a chiral smectic liquid crystal arranged in a gap between the pair of substrates, and the chiral smectic liquid crystal And a pair of electrodes arranged so as to sandwich the chiral smectic liquid crystal, and driven by applying a voltage to the chiral smectic liquid crystal through the pair of electrodes, wherein the chiral smectic liquid crystal is a layer method An in-plane chevron structure including a first region in which the line direction is inclined to one side with respect to the direction of the uniaxial orientation treatment, and a second region in which the layer normal direction is inclined to the other side with respect to the direction of the uniaxial orientation treatment. And liquid crystal molecules in the first region and the second region are stabilized in a direction substantially along the direction of the uniaxial alignment treatment. Child. 2. The liquid crystal according to claim 1, wherein the chiral smectic liquid crystal is a liquid crystal having a smectic A phase on its high temperature side, a liquid crystal in which the in-plane chevron structure coexists with a normal chevron structure, and a layer tilt of the in-plane chevron structure. The liquid crystal element according to claim 1, wherein an angle is substantially equal to a layer inclination angle of the ordinary chevron structure. 3. The liquid crystal device according to claim 1, wherein an area ratio between the first region and the second region is approximately 1: 1. 4. The liquid crystal element according to claim 2, wherein a layer interval in the smectic A phase decreases with a decrease in temperature, and the smectic A phase already has the in-plane chevron structure. . 5. The device according to claim 1, wherein a uniaxial alignment process is performed on both of the pair of substrates, and the directions of the uniaxial alignment processes are parallel and opposite to each other. Liquid crystal element. 6. The liquid crystal device according to claim 1, wherein the uniaxial alignment process is a rubbing process. 7. The liquid crystal device according to claim 1, wherein a pitch of the chiral smectic liquid crystal is longer than twice a gap between the substrates. 8. The liquid crystal device according to claim 1, wherein the alignment state having only one darkest optical axis in the absence of an electric field is not an antiferroelectric liquid crystal. . 9. The liquid crystal device according to claim 1, wherein an analog gray scale display is performed in combination with an active device. 10. A liquid crystal device comprising: the liquid crystal element according to claim 1; a driving circuit that supplies a gradation signal to the liquid crystal element; and a light source that illuminates the liquid crystal element.