JP2000111923A - Liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal element realizing a uniform alignment of liquid crystal molecules and a wide driving margin, and having a faster switching characteristic than any conventional one. SOLUTION: The liquid crystal element is provided with a first region which has a uniaxial alignment regulating function toward liquid crystal and a second region which has a weaker uniaxial alignment regulating function toward the liquid crystal than the first region or essentially has no regulating function on substrates. In the case the liquid crystal is subjected to lowering of the temperature between the substrates, a transition to a liquid crystal phase takes place from a region in contact with the first region and succeedingly, a region where the transition to the liquid crystal phase takes place continuously expands along an axial direction of the uniaxial alignment regulating function in the first region to form an aligned state. In this case the first region is formed with a photosensitive material comprising photosensitive polyimide or photosensitive polyamideimide resin having photosensitive monomers covalently bonded in its skeleton.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device, and more particularly to a liquid crystal device excellent in controlling the alignment of liquid crystal and used for a light valve used in a flat panel display, a projection display, a printer, and the like.

[0002]

2. Description of the Related Art Conventionally, in a nematic liquid crystal display device, an active matrix (for example, a TF) in which an active element such as a transistor is disposed in each pixel.
A liquid crystal element called T) is being developed. At present, as a mode of a nematic liquid crystal used for a liquid crystal display device using this TFT, for example, M. Shut (M.
Schadt) and W. Helfrich (W. He)
Ifrich), "Applied Physics"
Letters, Vol. 18, No. 4 (February 1, 1971
5th edition) Twisted Nemat shown on pages 127 to 128
ic) 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. In addition, as a typical example of a nematic liquid crystal display element that does not use an active element such as a TFT described above, a super twisted nematic (Su)
per Twisted Nematic) mode. As described above, there are various modes in such a liquid crystal display device using a nematic liquid crystal, but in any of these modes, there is a problem that the response speed of the liquid crystal takes several tens of milliseconds or more. did.

As an improvement over such a conventional nematic liquid crystal device, a device using a liquid crystal exhibiting bistability has been proposed by Clark and Lagerwall (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 light valve.

On the other hand, recently, antiferroelectric liquid crystals exhibiting three stability have attracted attention. This antiferroelectric liquid crystal 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
When an electric field is not applied, the liquid crystal molecules have a molecular alignment structure that cancels out each other's spontaneous polarization. Therefore, it is characterized in that there is no spontaneous polarization when no electric field is applied. More recently, a thresholdless antiferroelectric liquid crystal developed to drive this antiferroelectric liquid crystal by an active matrix element has been reported.

[0006] The ferroelectric liquid crystal and the antiferroelectric liquid crystal which perform inversion switching by such spontaneous polarization are liquid crystals exhibiting a smectic liquid crystal phase. That is, the realization of a liquid crystal display device using a smectic liquid crystal is expected in the sense that the problem relating to the response speed of the conventional nematic liquid crystal can be solved.

[0007]

In a smectic liquid crystal display device having such excellent features, particularly in the case of a device using a ferroelectric liquid crystal which performs inversion switching by spontaneous polarization, it controls the alignment of the liquid crystal in the device. In particular, the electric field generated by the anti-electric field, i.e., the spontaneous polarization of the liquid crystal in the device, is generated by reducing the thickness of the alignment control layer made of an ordinary insulating material for regulating the uniaxial alignment and increasing the electric capacity of the alignment control layer. The electric field in the reverse direction is reduced, the switching characteristics are improved, and the driving margin is increased. Since the generation of the anti-electric field becomes more conspicuous as the spontaneous polarization increases, it is essential to reduce the thickness of the insulating alignment control film, especially when using a liquid crystal material with a large spontaneous polarization to improve the response speed. Becomes

On the other hand, a liquid crystal element using a chiral smectic liquid crystal such as a ferroelectric liquid crystal or an antiferroelectric liquid crystal uses a principle of switching by a response of the liquid crystal by application of a pulse electric field, so that it is effectively used. The magnitude of the voltage applied to the liquid crystal layer is determined by the capacity ratio (reverse ratio) of the layers (the liquid crystal layer, the alignment control layer, and the like) included in the liquid crystal element. Therefore, in order to effectively increase the voltage applied to the liquid crystal layer and obtain higher-speed switching characteristics, the capacitance of the alignment control layer is designed to be sufficiently larger than the capacitance of the liquid crystal layer. Should be designed to be sufficiently smaller than the thickness of the liquid crystal layer.

However, as the thickness of the orientation control layer is reduced, it becomes more difficult for the orientation control layer to function to perform desired orientation control on liquid crystal molecules. As a result, according to the above-described design concept of the chiral smectic liquid crystal element, it is extremely difficult to improve the switching characteristics (suppress the anti-electric field and increase the driving margin), improve the response speed, and achieve uniform alignment. Further, with respect to a manufacturing process for forming an alignment film uniformly, it becomes more difficult to strictly control the thinner the film thickness.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to realize a liquid crystal element having a wide driving margin while realizing uniform liquid crystal molecular alignment and having higher switching characteristics. In particular, it is an object of the present invention to provide a liquid crystal device using a chiral smectic liquid crystal or a liquid crystal exhibiting ferroelectricity or antiferroelectricity.

[0011]

That is, the present invention provides a first region having a liquid crystal between a pair of substrates, and having at least one substrate having a uniaxial alignment regulating force with respect to the liquid crystal; A second region having a weak uniaxial alignment regulating force with respect to the liquid crystal or having substantially no uniaxial alignment regulating force compared to the outer first region, wherein the liquid crystal is a liquid crystal liquid when the temperature is lowered between the substrates. In the phase-liquid crystal phase transition process, a transition from the region in contact with the first region to the liquid crystal phase occurs, and the liquid crystal phase transition region is continuously formed along the axial direction of the uniaxial alignment regulating force of the first region. In the liquid crystal element in which the alignment state is enlarged and formed, the first region is formed of a photosensitive polyimide or a photosensitive polyamideimide resin having a photosensitive monomer covalently bonded in a skeleton. A liquid crystal device characterized by the following.

In the present invention, the photosensitive material is (1)
It is preferable to comprise a polymer having a structure represented by the following general formula (I) as a main component and (2) at least one of a photopolymerization initiator and a photosensitizer as required.

[0013]

Embedded image (Where R is

[0014]

Embedded image Selected from.

L represents 1 or 2, and the carboxyl group is bonded ortho to the carbonyl group constituting the main chain. m and n are each independently 0 or 1,
o is an integer of 2 to 10. R ₁ represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms. In addition, the photosensitive material may comprise (1) a polymer having a structure represented by the following general formula (II) as a main component, and (2) at least one of a photopolymerization initiator and a photosensitizer as required. Is preferred.

[0016]

Embedded image (Wherein, m and n are each independently 0 or 1,
o is an integer of 2 to 10. R ₁ represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms. )

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A liquid crystal device according to the present invention has a liquid crystal between a pair of substrates and at least one substrate has a uniaxial alignment regulating force for the liquid crystal, and a first region outside the first region. Has a second region in which the uniaxial alignment regulating force for the liquid crystal is weak or substantially has no uniaxial alignment regulating force as compared with the first region, and the liquid crystal has a liquid phase -A transition from a region in contact with the first region to a liquid crystal phase occurs during a phase transition process of the liquid crystal phase, and the liquid crystal phase transition region continuously expands along the axial direction of the uniaxial alignment regulating force of the first region. In the liquid crystal element in which the alignment state is formed, the first region is formed of a photosensitive material composed of a photosensitive polyimide or a photosensitive polyamide-imide resin in which a photosensitive monomer is covalently bonded in a skeleton. Features.

Hereinafter, embodiments of the liquid crystal device of the present invention will be described in detail with reference to the drawings. 1 and 2 show a first embodiment of the liquid crystal device of the present invention. FIG. 1 is a plan view of one embodiment of one substrate 12a (a substrate on which an alignment control film having a uniaxial alignment regulating force is selectively provided) constituting the liquid crystal element of the present invention, as viewed from the upper surface side. Is a cross-sectional view showing a structure of the liquid crystal element 1 using the substrate 12a shown in FIG. 1 as one of the substrates (a cross section taken along line aa 'of the substrate shown in FIG. 1).

As shown in FIG. 2, the basic structure of the liquid crystal element 1 is such that a liquid crystal 11 composed of a liquid crystal composition is provided with a pair of substrates 12a,
12b.

On the substrate 12a, an electrode 13a for applying an electric field to the liquid crystal 11 is provided, and on the electrode 13a, an orientation control layer 15a is interposed via a base layer 14a serving as a base.
Are selectively provided in a planar shape such as a stripe pattern shape shown in FIG. The alignment control layer 15a is made of a material which is made of an insulating material or the like and which exerts a uniaxial alignment regulating force on the liquid crystal by performing an appropriate treatment. Here, at least the upper surface thereof, that is, the surface which is in contact with the liquid crystal parallel to the substrate 12a ( In R1), a uniaxial alignment treatment is performed, and the liquid crystal has a uniaxial alignment regulating force.

That is, in the substrate 12a, corresponding to the selectively provided alignment control layer 15a, at least a first region (a region constituting the plane R1) having a uniaxial alignment regulating force with respect to the liquid crystal and other portions. At the second region (surface R)
2), and the uniaxial alignment regulating force for the liquid crystal in at least the plane substantially parallel to the substrate in the first region is larger than the uniaxial alignment regulating force in the second region, or The uniaxial alignment regulating force of the surface R2 in contact with the liquid crystal in the second region is zero.

On the other hand, the liquid crystal 11
An electrode 13b for applying an electric field is provided, and an alignment control layer 15b that is in contact with the liquid crystal 11 and can contribute to the alignment control of the liquid crystal is formed on the electrode 13b. Substrates 1la and 1lb provided with such electrodes and orientation control layers
Oppose each other with a certain distance therebetween via a spacer 16.

A polarizing plate is provided on the outer surfaces of the substrates 1la and 1lb as required. Further, a light source is provided as necessary behind the liquid crystal element 1 as viewed from the observer side (not shown).

In the liquid crystal element 1 having the above-described structure, an electric field is applied to the liquid crystal layer 11 by the electrodes 13a and 13b in accordance with a switching signal from a signal power supply (not shown), and switching is performed. It is modulated at 11.

In the liquid crystal element 1 having the above-described structure, the alignment control layer 15a and the underlayer
a, by appropriately setting the material, processing method, conditions, and the like of the alignment control layer 15b and the liquid crystal 11, the liquid crystal 11 can be selectively provided in the liquid crystal-liquid crystal phase transition process when the temperature is lowered. The transition from the first region in contact with the surface R1 of the alignment control layer 15a in the direction parallel to the substrate to the liquid crystal phase occurs, and the axial direction of the uniaxial alignment processing regulating force of the alignment control layer 15a (axial direction of the uniaxial alignment processing) Is characterized in that the liquid crystal phase transition region grows intermittently along the line, and the liquid crystal phase transition region further expands toward the plane R2 to form an alignment state.

Hereinafter, formation of this alignment state will be described with reference to FIGS. 3 (A) to 3 (C) show FIG.
In the formation of the alignment state from the liquid crystal region in contact with the selectively formed alignment control layer 15a on the substrate 12a, the direction of the uniaxial alignment regulation (the direction of the uniaxial alignment treatment performed on the alignment control layer 15a) U The liquid crystal is set to be substantially perpendicular to the longitudinal direction of the alignment control layer 15a, and a smectic liquid crystal is used as a liquid crystal, and a change in a state of a phase transition process to a smectic liquid crystal phase when the temperature is lowered ((A), (B), (C)). FIG. 3 is an explanatory diagram schematically showing observations of the temperature in the order of decreasing temperature observed by a polarizing microscope.

First, as shown in FIG. 3A, when the temperature of the liquid crystal is lowered (cooled) from a higher order phase than the smectic liquid crystal phase, the surface R1 of the alignment control layer 15a having a strong uniaxial alignment control force on the substrate 12a. From the upper liquid crystal, a region N called a butene, which is a smectic nucleus that appears in the smectic liquid crystal phase transition, is generated.

Subsequently, by further lowering the temperature of the liquid crystal, as shown in FIG. 3 (B), the bone N becomes a uniaxial alignment processing direction U which is a direction perpendicular to the longitudinal direction of the uniaxial alignment control layer 15a, that is, the smectic layer. Grow in the normal direction. Normally, the smectic liquid crystal phase has anisotropy of growth in that it tends to grow in the normal direction of the smectic layer. According to this characteristic, it is determined by the nucleus of the generated bone N as shown in FIG. Along the normal direction of the smectic layer (corresponding to the uniaxial alignment processing direction U), the liquid crystal region corresponding to the portion where the uniaxial alignment regulating force between the lines of the alignment control layer 15a does not substantially exist or is weak (see FIG. 2). In the cross-sectional view, an underlayer 14 is formed between adjacent lines of the orientation control layer 15a.
(a) (a liquid crystal region corresponding to a portion R2 in contact with the liquid crystal). Here, due to the anisotropy of the growth of the smectic liquid crystal in the liquid crystal itself, the smectic layer direction is uniformly arranged even in the alignment state of the liquid crystal formed in the portion where the alignment control force does not exist.

When the temperature is further reduced, FIGS. 3 (B) to 3 (C)
As shown in (1), the bone N starts growing not only in the direction U in which the uniaxial orientation is regulated, but also in a direction perpendicular to that direction (the longitudinal direction of the orientation control layer 15a). At this time, the batone N not only grows thicker as a whole but also grows so that a branch appears from the side of the batone. The branch gradually grows in the direction of the smectic layer (the longitudinal direction of the orientation control layer 15a). As shown in FIG. Growth progresses.

As described above, the entire region between the substrates in the device is cooled until it becomes a smectic phase, and finally, in the liquid crystal region corresponding to all of the portion where the alignment control layer 15a exists and the portion where it does not exist, An alignment state is formed in which the smectic layers are uniformly arranged in the longitudinal direction of the alignment control layer 15a.

On the other hand, FIGS. 4 (A) to 4 (C) show the direction of uniaxial orientation regulation (orientation) with respect to the formation of the orientation state from the orientation control layer 15a selectively formed on the substrate 12a shown in FIGS. The direction of the uniaxial alignment treatment (U) applied to the control layer 15a is set substantially (parallel) to the longitudinal direction of the alignment control layer 15a, and a smectic liquid crystal is used as the liquid crystal. FIG. 4 is an explanatory diagram schematically showing a change in the state of the phase transition process into a state (the temperature decreases in the order of (A), (B), and (C)) observed by a polarizing microscope.

First, as shown in FIG.
As in the case of (A), when the temperature of the liquid crystal is lowered from a higher-order phase than the smectic liquid crystal phase, the liquid crystal on the surface R1 of the alignment control film 15a having a strong uniaxial alignment regulating force on the substrate 12a shifts the smectic liquid crystal phase. A region N called batone, which is the nucleus of the smectic expressed in the above, is generated.

Subsequently, by further lowering the temperature of the liquid crystal, as shown in FIG. 4 (B), the B-tone N becomes as shown in FIG. The uniaxial orientation processing direction U, which is the normal direction of the smectic layer determined by the nuclei of the Battone N generated in the above, i.e., the same direction as the longitudinal direction of the uniaxial orientation control layer 15a. Here, since the growth direction of the above-mentioned battone due to the anisotropy of battone growth and the longitudinal direction of the pattern of the orientation control layer 15a having the uniaxial orientation regulating force coincide with each other, as shown in FIG. Grows more quickly on the surface R1 of the orientation control layer 15a.

When the temperature is further reduced, FIGS.
As shown in the figure, the bone N starts to grow not only in the longitudinal direction of the orientation control layer 15a but also in the direction perpendicular to that direction. At this time, the batone N not only gradually grows thicker as a whole, but also grows so that a branch appears from the side of the batone, corresponding to a portion where the uniaxial orientation regulating force between the lines is substantially nonexistent or weak. 2 (the liquid crystal region corresponding to the portion R2 where the underlayer 14a is in contact with the liquid crystal between the lines of the adjacent alignment control layer 15a in the cross-sectional view of FIG. 2). Finally, the B tones N grown from the island line portions of the adjacent alignment control layers 15a are finally joined to form an alignment state in which the smectic layer is substantially uniform.

As described above, the entire region between the substrates in the device is cooled until it becomes a smectic phase, and finally, in the liquid crystal region corresponding to all of the portion where the alignment control layer 15a exists and the portion where it does not exist, An alignment state is formed in which the smectic layers are uniformly arranged perpendicular to the longitudinal direction of the alignment control layer 15a.

In such a liquid crystal element, the alignment control layer (1) having a uniaxial alignment regulating force, which is usually insulative, in the element.
5a) is a nucleus (Battone) serving as a starting portion for forming an alignment state
Is provided in a pattern shape necessary for supplying the liquid crystal, and a uniform alignment state is reliably formed on the entire surface of the element by the process of forming the alignment state as described above. In addition, the amount of the orientation control layer (15a) made of an insulating material that electrically obstructs the driving of the liquid crystal and has a uniaxial orientation regulation force is reduced as much as possible. As a result, the effective voltage applied to the liquid crystal during driving by the pulse voltage can be increased. In this way, it is possible to make the alignment state uniform and to speed up the liquid crystal driving (switching).

With respect to the members constituting the liquid crystal element 1,
This will be described in more detail. A highly transparent material such as glass or plastic is preferably used for the substrates 12a and 12b, and a transparent electrode such as ITO is used for the electrodes 13a and 13b. A metal electrode may be provided in contact with the transparent electrode to reduce the temperature (not shown).

As a liquid crystal material constituting the liquid crystal 11, a chiral smectic liquid crystal exhibiting ferroelectricity or antiferroelectricity is preferably used. In this case, the cell gap (distance between substrates) is set to 0.5 to 5 in order to realize bistability based on the Clark and Ragawell models described above.
It is preferably about μm. Nematic liquid crystal can also be used as a liquid crystal material.

In particular, in the present invention, the above-mentioned chiral smectic liquid crystal, which does not have a cholesteric phase at a reduced temperature, is suitably used as the liquid crystal material. For example, in the case of a liquid crystal exhibiting antiferroelectricity, most of the synthesized liquid crystal materials do not have a cholesteric phase. Alternatively, in the case of a liquid crystal exhibiting ferroelectricity, a chevron structure is eliminated, and a layered structure called a bookshelf, that is, a structure in which the smectic layer is substantially perpendicular to the substrate, or a structure close thereto is revealed, and a high-contrast structure is obtained. In order to realize a good liquid crystal element, as an example, a liquid crystalline compound having a perfluoroether side chain (the 4th 1993 International Conference on Ferroelectric Liquid Crystal P-46, Marc D. Radcli)
However, such a liquid crystal material is a material capable of exhibiting a structure of a smectic layer close to a bookshelf and having a small layer tilt angle due to the characteristics of the material itself, and does not have a cholesteric phase. , A liquid crystal material exhibiting an isotropic phase-smectic liquid crystal phase transition.

As the liquid crystal material exhibiting the bookshelf layer structure, specifically, a structure in which a terminal portion of a fluorocarbon and a hydrocarbon portion are bonded by a central nucleus,
A chiral smectic liquid crystal composition containing at least one fluorine-containing liquid crystal compound having a smectic mesophase or a latent smectic mesophase can be used. The term "compound having a latent smectic mesophase" as used herein refers to a compound having a smectic mesophase or a compound having another potential smectic mesophase under appropriate conditions, even if the compound does not itself exhibit a smectic mesophase. Below refers to compounds that express a smectic mesophase. In the structure of the fluorine-containing liquid crystal compound, the central nucleus refers to at least two aromatic rings,
Selected from an aliphatic ring, a substituted aromatic ring, and a substituted heteroaromatic, and these rings are mutually represented by -COO-, -COS-,-
It may be bonded by a group selected from the group consisting of HC = N- and -COSe-. These rings may or may not be fused. Heteroatoms in the heteroaromatic ring include at least one atom selected from N, 0, and S. Non-adjacent methylene groups in the aliphatic ring may be replaced by O.

Specific examples of the formulation of the above-mentioned fluorine-containing liquid crystal compound or a chiral smectic liquid crystal composition containing the same are described in JP-A-63-27451, JP-A-2-142755, and US Pat. No. 5,262. 08
No. 2, WO 93/22396, U.S. Pat.
7, 813 and the like.

Incidentally, it does not show the cholesteric phase described above,
A liquid crystal material exhibiting an isotropic phase-smectic liquid crystal phase transition is:
With respect to the alignment formation, the anisotropy of the above-mentioned battone growth is remarkable, and after a minute nucleus of the smectic liquid crystal phase is generated, the battone grows rapidly in the normal direction of the smectic layer and further into the smectic layer. Through the process of rapid expansion of the area. Therefore, in the element using the liquid crystal material, distribution is provided in the uniaxial alignment regulating force or the wettability with the liquid crystal at the interface of the substrate in contact with the liquid crystal,
The smectic liquid crystal phase is provided with selectivity at the minute nucleation position, and in the growth region after the nucleation of the batene, the above-mentioned difference in the gross orientation of the batne, even if there is no alignment control force especially at the interface between the substrate and the liquid crystal. Orientation is formed by anisotropy. Therefore, such a liquid crystal material is selectively arranged on a substrate by patterning or the like as in an alignment control layer 15a having a uniaxial alignment regulating force as shown in FIGS. Is particularly suitable for a structure in which the ratio of

The alignment control layer 15a having a uniaxial alignment regulating force with respect to the liquid crystal is provided in a predetermined pattern. As described above, the material of the underlayer 14a in contact with the liquid crystal between the line portions is not limited. Due to the combination with the surface characteristics, the liquid crystal region in contact with the surface R1 of the line portion becomes a nucleation (batteriness generation) portion at the time of transition to a liquid crystal phase in the process of forming the liquid crystal alignment state as described with reference to FIGS. It works to be. That is, the surface R of the line portion of the orientation control layer 15a
The liquidus-liquid crystal phase transition temperature of the liquid crystal region corresponding to 1 is the liquidus-liquid crystal phase transition temperature of the liquid crystal region at a portion not corresponding to the surface R1 of the line portion (a portion corresponding to the surface R2 between the line portions). Higher.

The orientation control layer 15a is preferably formed by subjecting a film of a predetermined material provided on the substrate (on the underlayer 14a) to a uniaxial orientation treatment.

As the photosensitive material of the alignment control layer 15a having the strong uniaxial alignment regulating force, it is preferable to use polyimide or polyamide imide from the viewpoints of heat resistance and stability as a film and various other film physical properties. .

As a method for imparting photosensitivity to polyimide or polyamide imide, it is possible to perform a treatment at a low temperature during heating and sintering. After bonding the photosensitive groups, the photosensitive portion is applied to the substrate in a precursor state, and is heated and baked after patterning to obtain a polyimide or polyamideimide, so that the photosensitive portion volatilizes, so that the polyimide or polyamideimide main skeleton substantially remains. It is preferable to use a polyimide or polyamide imide resin designed as follows. More specifically, a photosensitive composition containing (1) a polymer having a structure represented by the following general formula (I) as a main component and (2) at least one of a photopolymerization initiator and a photosensitizer as required. A conductive material can be used.

[0047]

Embedded image (Where R is

[0048]

Embedded image Selected from.

L represents 1 or 2, and the carboxyl group is bonded ortho to the carbonyl group constituting the main chain. m and n are each independently 0 or 1,
o is an integer of 2 to 10. R ₁ represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms. )

In the structure represented by the general formula (I),
From the viewpoint of ease of raw material procurement

[0051]

Embedded image And more preferably

[0052]

Embedded image Is used. m and n both preferably represent 1, and o preferably represents an integer of 4 to 8.

The specific structure of the polyimide represented by the general formula (I) includes, for example, the following repeating unit structures.

[0054]

Embedded image

[0055]

Embedded image

[0056]

Embedded image

[0057]

Embedded image

[0058]

Embedded image

[0059]

Embedded image

[0060]

Embedded image

[0061]

Embedded image

As the photopolymerization initiator or photosensitizer used in the present invention, various known materials can be used. For example, benzophenone, Michler's ketone,
4,4'-diethylaminobenzophenone, xanthone, thioxanthone, 2-chlorothioxanthone, 2-
Methylthioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, acetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, benzyl,
Ethyl anthraquinone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4'-isopropyl-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl 2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, isopropyl benzoin ether, isobutyl benzoin ether, benzoin methyl ether, benzoin ethyl ether,
2,2-diethoxybenzophenone, camphorquinone, benzuanthrone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone,
N-phenyl-glycine, p-hydroxy-N-phenylglycine, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, p-tolyl disulfide, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 3,3 '-Carbonyl-
Examples thereof include bis (7-diethylamino) coumarin and the like, but are not limited thereto. The amount of the photopolymerization initiator or photosensitizer to be added is 0.05 to 2 parts by weight per 100 parts by weight of the polymer material (the photosensitive monomer portion bound to the photosensitive polyimide or photosensitive polyamideimide skeleton).
It is preferred to use 0 parts by weight.

The photosensitive material of the present invention is prepared by a spin coating method,
After coating on the substrate (layer 14a) by a method such as immersion, spraying, printing, etc., pre-baking is performed for several minutes to tens of minutes at a temperature of 30 to 150 ° C. using a heating means such as an electric furnace or a hot plate. By this, most of the solvent in the coating film is removed. Put a negative mask on this coating, X-ray,
The pattern is formed by irradiating an actinic ray such as an electron beam, an ultraviolet ray or a visible light ray. Thereafter, the unexposed portions are dissolved and removed with a developer to obtain a relief pattern.

As the developing solution, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and the like, methanol, ethanol, isopropyl alcohol, water and the like are used alone or in combination. As a developing method, a system such as spray, paddle, immersion, and ultrasonic wave can be used. Next, the relief pattern is rinsed with a rinse liquid such as methanol, ethanol, or isopropyl alcohol. Since the polymer of the relief pattern obtained by development is in the form of a precursor, it is patterned by heating it at a temperature of 150 to 450 ° C., preferably 150 to 300 ° C. for several tens to several hours by the above-mentioned heating means. The photosensitive component cured by actinic radiation is decomposed and volatilized by heat to obtain a polyimide relief pattern substantially consisting of a main skeleton. Thereafter, the surface is rubbed with a fibrous material such as velvet, cloth or paper to form an orientation control layer.

The pattern of the orientation control layer 15a preferably has a stripe shape as shown in FIG.
According to the degree of the uniaxial alignment regulating force of the alignment control layer, or according to the unit of optical modulation of the liquid crystal element or the size of the pixel,
It is also possible to select various shapes such as a lattice shape and an eyeride shape. However, regarding the dimensions of the pattern in the region of the alignment control layer 15a, at least uniaxial alignment control is performed in consideration of both the uniformity of the alignment state in the device as described above and the speeding up of liquid crystal driving (switching). More preferably, the total plane area of the substrate provided with the region of the alignment control layer 15a having a force is smaller than the total plane area of the region of the substrate where the alignment control layer is not provided.

The relationship between the pattern shape of the alignment control layer 15a having the uniaxial alignment regulating force and the axial direction of the uniaxial alignment regulating force (the direction of the uniaxial alignment treatment) also indicates the above-mentioned alignment characteristics of the liquid crystal material and the alignment control layer. It can be determined according to the uniaxial orientation regulating force or the like.

When a liquid crystal exhibiting a smectic liquid crystal phase is used as the liquid crystal 11, as shown in FIGS. 4A to 4C, the alignment control layer 15a is formed into a stripe shape, and a uniaxial alignment treatment is performed in parallel with the stripe direction. When the direction is set and the alignment state is formed, particularly when the line distance of the alignment control layer 15a is excessively large, there is no uniaxial alignment control force on the substrate surface for a wide liquid crystal region between the lines. As shown in FIG. 4C, the branch generated from the smectic liquid crystal phase is not linear, but grows in a bent state, and the smectic layer may be formed in a bent state. As a result, after cooling the entire surface of the device to a smectic liquid crystal phase, the smectic layer direction may be non-uniform in the liquid crystal region near the center between the lines of the alignment control layer 15a where the uniaxial alignment regulating force exists. Occurs.

On the other hand, as shown in FIGS.
When the alignment control layer 15a is formed in a stripe shape and a uniaxial alignment processing direction is set perpendicular to the stripe direction to form an alignment state, a branch generated from a smectic liquid crystal phase as shown in FIG. However, it grows almost linearly along the stripe line of the orientation control layer 15a, and the smectic layer can be easily formed uniformly in the line direction. Therefore, when a liquid crystal exhibiting a smectic liquid crystal phase is used as the liquid crystal 11, it is more preferably continuous or substantially continuous in the direction of the smectic layer to be formed, in order to maintain uniformity in the layer direction in the growth process of the branch during alignment formation. That is, a stripe pattern perpendicular to the axial direction of the uniaxial alignment regulating force (for example, the rubbing axis in the above-described rubbing process).

When the pattern of the orientation control layer 15a is a stripe pattern as shown in FIG. 1, the longitudinal direction is the same as the direction of the smectic layer (along the axial direction of the uniaxial orientation regulating force). Wherein the length of the smectic layer in the normal direction of one stripe (line) portion of the alignment control layer is such that the alignment control layer between adjacent stripes (lines) of the alignment control layer is It is preferable that the length is shorter than the length in the normal direction of the portion where the smectic layer is not provided.

When the pattern of the orientation control layer 15a is a stripe pattern as shown in FIG. 1, the setting of the interval between the lines is important in relation to the obtained orientation state. In particular, in the case of a stripe pattern substantially similar (parallel) to the axial direction of the uniaxial alignment regulating force as shown in FIG. 4, particularly by reducing the distance between stripe lines, as shown in FIG. As a result, the growing area of the batney increases, and when the branch grows from the batney, the growth distance until joining with the branch grown from the batney on the adjacent line becomes shorter. Thus, especially in the case of using a liquid crystal exhibiting a smectic liquid crystal phase, the uniformity of the smectic layer in the layer direction is improved. However, as described above, the area in which the alignment control layer 15a made of an insulating material is in contact with the liquid crystal is reduced as much as possible, and the liquid crystal region to which a voltage is applied to the liquid crystal without passing through the liquid crystal is enlarged. It is necessary to provide a certain distance between these lines.

For example, in the case of the structure as shown in FIGS. 3 and 4, it is preferable to set the line width to about 2 to 20 μm and set the line interval in the range of 10 to 50 μm.
In addition, the thickness of the stripe pattern is set to 50 to 5000 mm,
Preferably, it is 200 to 1000 °.

On the other hand, the layer 14a constituting the plane R2 in contact with the liquid crystal 11 between the line portions of the alignment control layer 15a is used for the alignment control layer 15a so as to exhibit the alignment forming process shown in FIGS. Considering the relationship between the material to be formed and its characteristics, etc., the liquid crystal has substantially no uniaxial alignment regulating force or weak uniaxial alignment regulating force with respect to the liquid crystal as compared with the surface R1 on the alignment control layer 15a. In particular, a material is selected and used in which the insulating property that does not affect the driving characteristics of the chiral smectic liquid crystal is suppressed and the influence on the liquid crystal molecules is small.

In order to form the layer 14a as a layer having substantially no uniaxial alignment regulating force, for example, an inorganic film of a metal oxide or the like to which a uniaxial alignment regulating force cannot be substantially imparted even by a rubbing treatment or the like. It is preferable to use a material having high hardness. In this regard, the structure shown in FIG.
By omitting a, it is also possible to provide a pattern-shaped orientation control layer 15a on the transparent electrode 13a made of ITO or the like.

The layer 14a has a liquid crystal surface R2, as compared with the surface R1 of the alignment control layer 15a having a uniaxial alignment regulating force, so that the alignment forming process shown in FIGS. Keep molecular interactions low. Therefore, the surface R2 of the layer 14a is
In the direction of poor wettability with liquid crystal (stronger property of repelling droplets), in the direction of increasing contact angle, in the direction of decreasing surface energy dispersion term (γd), or increasing the surface energy hydrogen bonding term It is preferable to select a material, or a forming method and a processing method thereof as necessary according to the direction. Thus, the liquid phase-liquid crystal phase transition temperature of the liquid crystal region corresponding to the surface R1 of the line portion of the alignment control layer 15a is the liquid phase-liquid crystal phase transition temperature of the liquid crystal region at the portion corresponding to the surface R2 between the line portions. It is possible to realize the above-described favorable alignment forming process by increasing the height.

Specifically, as the layer 14a, a material such as a ladder type polysiloxane film or an organically modified silica film having a surface energy dispersion term relatively lower than that of the orientation control layer 13a polyimide can be used.

Further, as the layer 14a, the orientation control layer 15
In addition to having a small effect on liquid crystal molecules as compared with the material used for a, the volume resistance value should be in the range of l × 10 ⁴ to l × 10 ¹⁰ Ωcm in order to improve the driving characteristics of the liquid crystal. preferable. In order to obtain such characteristics, for example, if necessary, a film made of a polycrystalline or amorphous metal oxide, a film made of a polycrystalline or amorphous semiconductor, and a fine particle (conductive fine particle) formed of an insulating base material Alternatively, a film dispersed in a binder can be used. The film made of the polycrystalline or amorphous metal oxide, the film made of the polycrystalline or amorphous semiconductor, and the fine particles may be added with a conductivity controlling impurity as necessary, and the conductivity is adjusted.

As the film made of the polycrystalline or amorphous metal oxide, for example, a film of an oxide of a Group 12 element such as ZnO, CdO, ZnCdO _x , GeO ₂ , SnO ₂ , GeS
Examples include oxide films of Group 4 elements and Group 14 elements such as nO _x , TiO ₂ , ZrO ₂ , and TiZrO _x .

Examples of the film made of the polycrystalline or amorphous semiconductor include a film of a Group 14 semiconductor such as Si and SiC. Examples of the fine particles include oxides of the above-described Group 12 elements, oxides of the Group 4 elements, oxides of the Group 14 elements,
Fine particles of a group III semiconductor.

As the conductivity controlling impurity added to the polycrystalline or amorphous metal oxide, the polycrystalline or amorphous semiconductor or the fine particles as necessary, the conductive doping to the oxide of the Group 12 element may be used. The property control impurities include, for example, Group 13 elements such as B, Al, Ga, and In as n-type impurities (donors / impurities that enhance electron conduction) and p-type impurities (impurities / impurities that increase hole conductivity). Tribe, 11
Group elements such as Cu, Ag, Au, and Li are used. Examples of the conductivity control impurities doped into the oxides and semiconductors of Group 14 elements include P, As, Sb, and Bi as Group 15 elements as n-type impurities and B and Group 13 elements as P-type impurities. Al, Ga, In and the like can be mentioned.

For such conductivity controlling impurities,
A donor is used when the surface potential of the substrate having the orientation control layer containing the material to which the impurity is added is positive, and an acceptor is used when the surface potential is negative. Combination) and the crystal state (the crystal defect density), but the concentration of free electrons or free holes in the material in the state where impurities are added is 1.0 × 10 ¹¹ to 1. 0 × 10 ¹⁴ atm / cm
It is preferable to set it to about ³ . When a polycrystalline or amorphous material is used as a base material to which an impurity is added, 1.0 × 10 ¹⁷
１．０1.0 × 10 ²⁰ atm / cm ³ (approximately 0.01 to 1% with respect to the base material) is set as the actual addition amount.

Examples of the material serving as a binder for dispersing the fine particles include SiO _x , TiO _x , and ZrO.
_x , other oxide melting base materials, siloxane polymers and the like.

On the other hand, with respect to the alignment control layer 15b on the opposing substrate 12b, a uniaxial alignment control force is provided or another alignment control ability is provided according to the characteristics of the liquid crystal material used.

In the case of using a liquid crystal material exhibiting a phase transition series such as isotropic phase-smectic without taking the above-mentioned cholesteric phase, the alignment control layer 15a having a uniaxial alignment regulating force on one substrate 12a is opposed to the other substrate. 12
It is preferable that the orientation control layer 15b in b is a layer having substantially no uniaxial orientation regulating force. In this case, the alignment control layer 15b more preferably has the same function as the layer 14a having a small interaction with the liquid crystal molecules on the side of the opposing substrate 12a as described above, and a material usable as the layer 14a is used. Particularly preferably, the same material as that of the layer 14a is used. In this manner, the insulating property is suppressed at most of the interface between the two substrates substantially in contact with the liquid crystal 11, and the driving characteristics of the liquid crystal, particularly the chiral smectic liquid crystal, are improved.

In addition, in the liquid crystal device having the above structure, apart from the alignment control layers 15a and 15b and the layer 14a, an insulating film as a layer for preventing a short circuit between opposing substrates, a layer made of another organic material, an inorganic A layer made of a material may be provided.

The spacer 16 determines the distance between the substrates (cell gap), and for example, silica beads or the like are used. In addition to the spacer 16, the substrate 12
Adhesive particles made of a resin material such as an epoxy resin may be dispersed and arranged between the substrates in order to improve the adhesiveness between a and 12b.

However, the smectic liquid crystal display element has a problem in that the display burn-in characteristic when the same image is continuously displayed for a long time is relatively large as compared with the nematic liquid crystal display element. This problem is common to smectic liquid crystals, but the display burn-in problem has been particularly noticeable in ferroelectric liquid crystals having bistability. It can be understood that the display burn-in phenomenon which is a problem in the smectic liquid crystal, particularly the ferroelectric liquid crystal, is caused by an electrical factor and an orientational factor.

First, in the ferroelectric liquid crystal, spontaneous polarization induces the localization of ions. As a result, electrical asymmetry is generated and bistability is lost. Observed. This can be said to be a problem specific to ferroelectric liquid crystals.

On the other hand, it is considered that the image sticking phenomenon is a problem of molecular orientation at the interface between the surface of the orientation control film and the liquid crystal. This is a phenomenon that applies to all liquid crystal devices, but in liquid crystal devices, the molecular orientation direction of par near the center between the substrates changes the interface molecular orientation direction, and as a result, display characteristics are observed as display burn-in. It is.

That is, in a liquid crystal device in which at least one substrate is subjected to a uniaxial alignment treatment, the liquid crystal molecules in the vicinity of the substrate interface having a uniaxial alignment regulating force are arranged on the average in a direction in which the alignment is easy. However, the bulk molecular arrangement direction is affected by the direction of the electric field applied to the liquid crystal element, and the arrangement direction of these molecules is shifted. At that time, the liquid crystal molecules as a continuum in the thickness direction of the liquid crystal between the substrates reduce the increase in elastic free energy caused by the distortion of the molecular alignment direction between the substrate interface and the bulk, so that the orientation direction of the interface molecules themselves is reduced. Will change. At this time, the amount of change in the orientation of the interface molecules is considered to be more remarkable in a liquid crystal material having a larger continuum characteristic such as a larger elastic constant of Frank. Therefore, it is considered that the smectic liquid crystal, which is a higher-order liquid crystal phase, has relatively poor display burn-in characteristics as compared with the nematic liquid crystal.

Therefore, in the liquid crystal device of the present invention, in order to improve the above-described display burn-in characteristic, the liquid crystal portion between the pair of substrates is substantially continuous between the liquid crystal molecules near the substrate interface and the bulk liquid crystal molecules between the substrates. It is preferable that the first liquid crystal region in an aligned state and the second liquid crystal region in which liquid crystal molecules near a substrate interface and bulk liquid crystal molecules between the substrates are in a discontinuous alignment state are formed.

An element having such first and second liquid crystal regions is selectively provided on at least one of the substrates as shown in FIGS. 1 to 5 by an alignment control layer having a strong uniaxial alignment regulating force. It can be realized by the provided elements.

A liquid crystal device having such first and second liquid crystal regions will be described with reference to FIG.

In the figure, a liquid crystal element 10 has a liquid crystal 20.
Are sandwiched between substrates 22a and 22b having electrodes 23a and 23b for applying an electric field to the liquid crystal and alignment control layers 25a and 25b for controlling the alignment state of the liquid crystal. In such an element, the liquid crystal 20 is formed on the substrate by appropriately selecting the material of the alignment control layer 25a (and / or 25b) in contact with the liquid crystal and controlling the surface state and characteristics of the interface (R21, R22) in contact with the liquid crystal. A first liquid crystal region L1 in which liquid crystal molecules in a region L11 near the interface and a bulk liquid crystal molecule L12 in a region between the substrates are substantially continuously arranged, and a region L22 between a liquid crystal molecule in a region L21 near the substrate interface and the substrate. Are constituted by the second liquid crystal region L2 in which the bulk liquid crystal molecules are discontinuously arranged.

The operation of the liquid crystal device will be described. As described above, the image sticking phenomenon in the liquid crystal element is considered to be a phenomenon caused as a result of changing the direction of the interfacial molecular alignment in order to reduce the increase in the elastic free energy caused by the bulk alignment distortion. That is, the burn-in phenomenon can be said to occur when all of the liquid crystal portions in the device thickness direction such as the bulk portion and the interface portion between the substrates of the device behave as an elastic continuum.

Therefore, in the liquid crystal device having the structure shown in FIG. 16, in the liquid crystal region L2, the liquid crystal molecules in the region L21 near the interface of the alignment control layer 25a and the region L2 between the substrates are different.
_Since the bulk liquid crystal molecules in ₂₂ have discontinuous alignment, the occurrence of display burn-in is suppressed. Specifically, the liquid crystal alignment state in the region L21 is completely different from the bulk liquid crystal alignment state in the region L22, and the molecular alignment is controlled so that a continuum as a molecular group cannot be formed. More specifically, in the region L21, the alignment direction of the liquid crystal molecules is completely random, and in the region L22, the alignment direction of the liquid crystal molecules is orderly uniaxial (the alignment control layer 2).
5a). In the liquid crystal region L2, by adopting such an alignment state, the interface and the bulk become discontinuous alignment states, and the alignment state does not influence each other, that is, an element in which the alignment state does not change with time can be realized.

Note that L21, which is a region near the substrate interface constituting the liquid crystal region L2, and region L2, which corresponds to the bulk portion,
2. With respect to L11 which is a region near the substrate interface constituting the liquid crystal region L1 and a region L12 corresponding to the bulk portion, the regions L21 and L11 are located at the substrate interface (the orientation control layer 2).
100 ° from the interface between 5a (or 25b) and liquid crystal 20)
The regions L22 and L12 can be defined as a central portion between the substrates excluding the regions L21 and L11 from the substrate interface. The behavior of liquid crystal molecules in these regions is described in Appl. Phys.
Lett. Vo1.53 (24) P2397-2398
TIR (Total Internal Ref)
(Lection) method and SHG method.

Next, means for obtaining the above liquid crystal element,
In particular, adjustment of the orientation control layer 25a (25b) will be described. Usually, in a liquid crystal element, the molecular alignment direction of the entire cell is determined according to the alignment control direction applied to a pair of substrates.
That is, during the phase transition process from the liquid phase to the liquid crystal phase, the phase transition from molecules near the alignment control film to the liquid crystal phase. At that time, the molecules are arranged in accordance with the direction of the alignment treatment applied on the alignment control film, and when the cooling is further advanced, the phase transition to the liquid crystal phase extends to the bulk portion, and the entire cell becomes the liquid crystal phase. That is, in the ordinary liquid crystal element, since the molecular alignment is formed by the regulation of the interface, a continuous molecular alignment state is obtained between the interface and the bulk as in the region L1.

On the other hand, in order to obtain a discontinuous molecular arrangement state between the substrate interface and the bulk portion as in the above-described region L2,
A portion having a uniaxial orientation regulating force (a portion not subjected to uniaxial orientation treatment) and a portion having substantially no uniaxial orientation regulating force (a portion subjected to uniaxial orientation treatment) in the same substrate plane.
It is preferable to provide both. Specifically, the orientation control layer 2
The surface R21 in 5a is a portion having a uniaxial orientation regulating force, and R22 is a portion having substantially no uniaxial orientation regulating force or a portion having a relatively weak uniaxial orientation regulating force as compared with R21.

In the case of an element composed of a substrate having such a layer 25a having an alignment controlling ability, the liquid phase-liquid crystal phase transition is caused by the molecules near the interface of the liquid crystal region in the portion (R21) having the uniaxial alignment regulating force. It is generated from (L11) and expands to a liquid crystal region (L2) corresponding to a portion where alignment is not regulated. The order of the phase transition is apparent from the fact that the liquid crystal element generally has a higher uniaxial alignment regulating force, and thus has a higher phase transition temperature to a liquid crystal phase.

As described above, when the portion (R21) having the uniaxial orientation regulating force and the portion (R22) having substantially no uniaxial orientation regulating force are provided on the same substrate surface, particularly the uniaxial orientation regulating force is provided. The bulk alignment (L22) of the liquid crystal region corresponding to the portion (R22) having substantially no force is not affected by the interface (R22) of the liquid crystal region, but is a portion (R21) having an adjacent uniaxial alignment regulating force. Can be aligned in accordance with the alignment of the bulk portion (L12) of the liquid crystal region corresponding to. In particular, in a liquid crystal phase having a high crystallinity such as a smectic liquid crystal, after a uniform alignment is formed in a liquid crystal region (L1) corresponding to a portion (R21) having a uniaxial alignment regulating force, a portion where the uniaxial alignment is not regulated ( R
By performing crystal growth in the region (L2) corresponding to (22), the entire cell can be uniformly aligned regardless of whether or not the alignment at the substrate interface is restricted.

Since the smectic liquid crystal is a one-dimensional crystal with respect to the layer normal direction, the crystal growth direction at this time tends to progress toward the layer normal direction. Therefore, it is desirable that the portion (R21) having the uniaxial alignment regulating force is continuous or substantially continuous in the smectic layer direction.
On the other hand, at this time, the portion where the uniaxial orientation is not regulated (R22)
In the liquid crystal region (L2) corresponding to
The orientation direction of the molecules in 1) is in a random direction.
This means that the molecules in the region near the interface (L21) undergo a phase transition from the molecules in the region near the interface (L21) to the liquid crystal phase first, that is, even in the temperature range where the bulk portion (L22) shows the liquid phase, the molecules in the region near the interface (L21) remain in the interface (R22). This is because the alignment direction of the interface-neighboring region (L21), which is not necessarily uniaxially controlled, is forced to be in a random direction because the molecular arrangement is performed to some extent under the restriction described above. Thus, the bulk portion (L2
A liquid crystal element exhibiting a discontinuous alignment state (liquid crystal region L2) in the thickness direction of the liquid crystal 20, in which 2) is uniformly aligned and the interface vicinity region (L21) is randomly aligned, can be realized.

Regarding the interface R22 of the alignment control layer 25a corresponding to the liquid crystal region of L2, the surface state thereof is determined by calculating the surface roughness of the arithmetic mean roughness Ra of 2 nm or more and the root mean square roughness R
The surface roughness of which ms is 2.5 nm or more, or the surface roughness 5
% Is preferable.

By doing so, the rising angle (pretilt angle) of the molecules in the vicinity of the interface R22 and in the liquid crystal region (L21) becomes an angle following the surface irregularities. Become. That is, not only in the in-plane direction of the substrate (azimuth direction) but also in the rising direction from the substrate (polar angle direction), the liquid crystal region (L21) and the bulk region (L22) near the substrate interface have discontinuous molecular arrangement. Therefore, the effect of suppressing display burn-in is further increased.

Here, the arithmetic mean roughness Ra represents the average value of the absolute value of the deviation from the center plane to the surface in the quantitative plane, and the root mean square roughness Rms refers to the mean surface roughness from the central plane in the quantitative plane. Represents the square root of the average value of the square of the deviation up to. The surface roughness is expressed by the following equation according to the relationship with the surface area S 'including the surface irregularities when a film having the irregularities on a certain area S exists.

[0105]

## EQU1 ## Surface roughness = (S'-S) / S

In the liquid crystal element having the structure as shown in FIG. 16, for example, the liquid crystal 20 is divided into a plurality of units of a real driving region which are separated from each other, and these are all or selectively used for the liquid crystal in the real driving region. Can be used in such a manner as to be driven. In a liquid crystal element, such an actual driving area corresponds to a so-called pixel. In such an embodiment of the liquid crystal element, it is preferable that at least the actual driving region corresponds to the second liquid crystal region L2 and the space between the actual driving regions corresponds to the first liquid crystal region L1.

As described above, the first liquid crystal region (L1)
And the second liquid crystal region (L2) preferably has a portion (R
21) and by providing a portion (R22) having substantially no or relatively small uniaxial alignment regulating force, it can be formed corresponding to these. Therefore, FIGS. 1 and 2
In the structure as shown in the above, the device is manufactured by forming the orientation control layer 15a by patterning with the above-described photosensitive material, particularly by the configuration of the substrate and the device to which the above-described member processing is applied, as shown in FIGS. The first liquid crystal region (L) as shown in FIG.
1) An element having the second liquid crystal region (L2) can be obtained. The surface region R21 on the substrate to which the first liquid crystal region (L1) is provided in FIG. 16 is a surface region R1 substantially parallel to the substrate of the alignment control layer 15a having the uniaxial alignment regulating force in FIG. The surface region R22 on the substrate to which the second liquid crystal region (L2) is provided in FIG. 16 corresponds to the surface region R2 between the lines of the alignment control layer 15a in FIG.

That is, in the liquid crystal device having the structure shown in FIG. 2, the alignment control layer (15a) having a uniaxial alignment regulating force, which usually has an insulating property, forms a nucleus (battone) which becomes a starting portion of the formation of the alignment state. It is provided in a pattern shape necessary for supply, and as shown in FIGS. 3 to 5, a uniform alignment state is surely formed on the entire surface of the element by the alignment state forming process. Due to the relationship between the surface R1 of the layer 15a and the characteristics of the surface R2 of the layer 14a in the gap, the liquid crystal region corresponding to R1 is in a continuous alignment state as in the liquid crystal region L1 shown in FIG. In the liquid crystal region corresponding to R2 and R2, the regions L21 and L22 are in a discontinuous alignment state like the liquid crystal region L2 shown in FIG.

In particular, in order to favorably form the first liquid crystal region L1 and the second liquid crystal region L2 shown in FIG. 16 with the element structure shown in FIG. 2, the regions L21 and L22 are preferably arranged in a discontinuous arrangement. The region R2 is formed.

The surface state of the underlayer 14a is set to the above-mentioned predetermined roughness. For example, a direction in which the wettability with the liquid crystal is not good (the property of repelling liquid droplets is stronger), a direction in which the contact angle increases, a direction in which the surface energy dispersion term (γd) becomes smaller, or a surface energy hydrogen bond term It is preferable to use a material in the direction of increasing the surface roughness after roughening.

In order to obtain the liquid crystal region L2 and to obtain desired electric characteristics and surface characteristics, it is particularly preferable to use the above-mentioned fine particles (conductive fine particles) in the insulating base material and the binder as the underlayer 14a. Use a dispersed film. The conductivity is adjusted by adding a conductive impurity to the fine particles as necessary.

In the liquid crystal element 1 having the above structure, preferably,
The liquid crystal 11 is composed of a plurality of real driving regions in which liquid crystals between substrates are separated from each other. In the real driving region, the electrodes 12a and 12b respond to a switching signal from a signal power supply (not shown). An electric field is applied to the liquid crystal 11 to perform switching, and light passing through the liquid crystal 11 is modulated, so that at least a bright state and a dark state are formed.

Further, in the liquid crystal region corresponding to the alignment control layer 15a (all the liquid crystal regions in the thickness direction of the element corresponding to the region R1), the positions of the liquid crystal molecules in the region are fixed so as to show a dark state. It can also be converted. In particular, the difference between the surface potential of the region R1 of the orientation control layer 15a and the surface of the orientation control layer 15b facing this region is set to be larger than 50 mV, preferably larger than 100 mV, so that a dark state is always shown in the region between the opposing surfaces. To fix the position of the liquid crystal molecules.

In a matrix type liquid crystal element using a liquid crystal exhibiting ferroelectricity and having a pair of substrates having striped electrodes opposed to each other, a region corresponding to a region other than a portion where the electrodes of each substrate cross each other, that is, a pixel In the area between,
Since the molecular alignment state of the liquid crystal cannot be controlled by the electric field, light leakage may occur between pixels, and contrast in display may be deteriorated. Therefore, a black matrix such as a metal material is formed on the substrate corresponding to the inter-pixel region. A member is provided to shield light. However, the formation of the black matrix requires alignment and the like to correspond to the portions where the pixel electrodes intersect with each other, which leads to an increase in cost. The reflectance may increase, and the display quality may decrease.

Further, in a matrix type liquid crystal display device using an antiferroelectric liquid crystal, the alignment state of the liquid crystal between pixels may be slightly disturbed as compared with other regions. In this case as well, since light leakage between pixels may occur and contrast in display may be deteriorated, it is necessary to provide a member such as a black matrix made of a metal material or the like on a substrate corresponding to the region between pixels as described above to shield light. And the problem of deterioration of display quality arises.

Therefore, by providing the region where the dark state is fixedly formed as described above in correspondence with the inter-pixel region, a wide driving margin is realized while realizing a uniform liquid crystal molecule alignment, and a higher speed is realized. With a switching characteristic and a simple structure, light can be reliably shielded between actual driving regions, particularly between pixels of a display element, and a sufficient contrast can be ensured.

Next, a second embodiment of the liquid crystal device of the present invention will be described with reference to FIG. 2, the same symbols as those in FIG. 2 indicate the same members.

The basic structure of the liquid crystal element 1 according to the second embodiment shown in FIG. 17 is the same as that of the first embodiment shown in FIG. 2, and an electric field is applied to the liquid crystal 11 on the substrate 12a side. On the electrode 13a to be applied, an orientation control layer 15a is provided in a desired shape such as a stripe shape or a lattice shape via a base layer 14a and is in contact with the liquid crystal 11;
That is, at least in the plane substantially parallel to the substrate 12a (constituting the region R1), the liquid crystal 11 has a uniaxial alignment regulating force. Further, in a region that does not correspond to the orientation control layer 15a, a region where the layer 17a is provided on the underlayer 14a (R
It is in contact with the liquid crystal 11 in 2). Here, the layer 17a is made of a material which is made of an insulating material or the like and has a uniaxial alignment regulating force with respect to the liquid crystal by performing an appropriate process similarly to the alignment control layer 15a. By making the thickness extremely small, the uniaxial alignment regulating force on the liquid crystal in the region (R2) is relatively small as compared with the region (R1), so that the interaction with the liquid crystal is reduced.
Note that, on the opposing substrate 12b, an alignment control layer 15b that is in contact with the liquid crystal and can contribute to the alignment control of the liquid crystal is formed on the electrode 1lb that applies an electric field to the liquid crystal 11.

In the liquid crystal element 1 having the above structure, the liquid crystal 1
3 to 5 as in the first embodiment by appropriately setting the alignment control layer 15a, the layer 17a, the alignment control layer 15b, the material of the liquid crystal 11, the processing method, the conditions, and the like.
As shown in the figure, in the liquid crystal 11, during the phase transition process between the liquid phase and the liquid crystal phase of the liquid crystal when the temperature is lowered, the liquid crystal phase is shifted from the area in contact with the plane area R1 (first area) of the alignment control layer 15a in the direction parallel to the substrate. The liquid crystal layer transition region continuously grows along the axial direction of the uniaxial alignment regulating force (axial direction of the uniaxial alignment treatment) of the alignment control layer 15a, and further, the surface region R2 (the second Region), the phase transition region expands, and an alignment state is formed. In particular, the orientation control layer 15a and the relationship between the uniaxial alignment regulating force of the surface of the layer 17a and the interaction with the liquid crystal, that is, the intensity of the uniaxial orientation regulating force of the former surface is relatively increased, and By increasing the interaction of
The process of forming the above-described alignment state is effectively obtained.

The alignment control layer 15a corresponding to the first region plane (R1) where the liquid crystal phase transition occurs first can be formed by using the same material and processing as in the first embodiment. it can. On the other hand, for the layer 17 corresponding to a region other than the first region, for example, those exemplified as materials that can be used for the orientation control layer 15a can be used in the same manner. As a specific example, after forming a material layer (film) for forming the alignment control layer 15a on the entire surface on the underlayer 14a, the conditions for patterning using the above-described photosensitive material are adjusted to adjust the alignment control layer 15a. At the same time as forming the layer 1 of the same material and having a smaller thickness than the orientation control layer 15a between each line of the orientation control layer 15a.
7a can be obtained. In this case, in other words, the layer 17a
Are formed continuously with the line where the orientation control layer 15a protrudes with the thickness reduced between the lines. By performing a uniaxial orientation treatment after such patterning, the surface of the thick portion of the orientation control layer 15a (the first region (R
In (1), a strong uniaxial orientation regulating force is applied, and
On the surface of the portion 7a (corresponding to the second region R2), a relatively weak uniaxial alignment regulating force can be applied.

In the second embodiment, similarly to the first embodiment, a uniform alignment state can be reliably formed on the entire surface of the element by the steps shown in FIGS. In addition, when an insulating material is used for the alignment control layer 15a and a structure as shown in FIG. 17 is formed by the above-described patterning method, a uniaxial material made of an insulating material that is an electrical obstacle to driving of the liquid crystal. A layer 17a having a small thickness between the lines of the alignment control layer 15a having an alignment regulating force and having a reduced influence of insulating properties.
Only exists, electrically, the influence of the insulating layer is small, and the liquid crystal region to which a voltage is applied becomes large in the entire device.
In particular, the effective voltage applied to the liquid crystal during driving by a pulse voltage can be increased.

When the layer 17a constituting the second region (R2) is an insulating layer, the thickness is particularly determined using a smectic liquid crystal having spontaneous polarization as the liquid crystal.
It is important to set so that the switching of the liquid crystal molecules is not hindered by the reverse voltage that causes the spontaneous polarization of the liquid crystal to occur between the substrates of the element. Specifically, it is preferable that the total thickness of the insulating layers of both substrates corresponding to the region (R2) including the layer 17a be less than dl of the following formula (Al).

[0123]

Dl = V _th1 × ε / 2P _s (Al) V _th1 : threshold voltage partially inverted by a unipolar pulse having a pulse width of 1 ms ε: total dielectric constant of the insulating layers of both substrates corresponding to region R2 P _s : Spontaneous polarization of liquid crystal used (per unit area)

Expression (A1) is a value of a reverse voltage V _rev = V _th1 = 2P _s × S / C, C when the switching of the liquid crystal starts to be hindered by the reverse voltage generated by spontaneous polarization.
= Ε × S / dl (C is the liquid crystal capacity in the corresponding region R2,
(S is the area of the region) and the thickness of the insulating layer at that time is obtained.

On the other hand, the orientation control layer 15 in the first region Rl
The thickness of the region a includes at least the region R including the layer 15a.
l, the total thickness of the insulating layers on both substrates is equal to the above formula (A)
It is preferable to be not less than dl of 1), and it is particularly preferable to be not less than d2 of the following formula (A2).

[0126]

D2 = V _th2 × ε / 2P _s (A2) V _th2 : threshold voltage which is completely inverted by a unipolar pulse having a pulse width of 1 ms ε: total dielectric constant of the insulating layers of both substrates corresponding to region Rl P _s : Spontaneous polarization of liquid crystal used (per unit area)

Further, the layer 17a is preferable depending on the material of the underlying layer 14a, and also to reduce the chemical effect on the liquid crystal from the electrode 14a, particularly the effect of the movement of ions from the lower layer.

Incidentally, the strength of the alignment regulating force referred to in the present invention is defined below. When a liquid crystal material is injected into a cell having no alignment regulating force, unless a special external field such as a magnetic field or a temperature gradient is used, the molecular long axis generally aligns in a random direction. On the other hand, when a liquid crystal material is injected into a cell in which uniaxial alignment is controlled sufficiently firmly, the molecular long axis direction is generally aligned in a direction in which uniaxial alignment is controlled. The latter orientation is almost the same for both nematic and smectic liquid crystals, but the former orientation has a slight difference in texture between nematic and smectic. When the molecular long axis direction is oriented in a random direction, in the case of a smectic having a layer structure, a random layer structure is formed while exhibiting a geometric pattern called focal conic texture.

In the present invention, the weak alignment control force of the smectic liquid crystal means that when the smectic liquid crystal is injected into a cell whose uniaxial alignment is controlled, when such a focal conic texture appears in a part of the cell,
It is defined that the alignment control force of this cell is weak for this liquid crystal. Similarly, when a smectic liquid crystal is injected into a cell in which uniaxial alignment is controlled, the above-mentioned focal conic texture does not exist at all, and when the layer structure is controlled in one direction in an orderly manner, the alignment controlling force of this cell for this liquid crystal is controlled. Defined as weak. Then, the relative strength is determined based on the existence ratio of the focal conic texture. Since the definition of the strength is determined by the orientation, the degree of the strength changes as the type of liquid crystal changes. That is, the strength of the alignment regulating force in the present invention is not uniquely determined by the cell, but is defined by the combination of the cell and the liquid crystal.

FIG. 18 shows a third mode which is a further modification of the structure of the liquid crystal element of the second embodiment shown in FIG. The structure shown in the figure is a layer 18a (photosensitive material described above) formed from the same material as the orientation control layer 15a in FIG.
Is selectively provided, and a layer 19a which can be applied to the alignment control layer 15a with a small thickness from the upper side is formed on the entire surface to provide a uniaxial alignment regulating force. In this case, the surface (region Rl) of the layer 19a on the selectively provided layer 18a (on the line) and the surface (R1) of the layer 19a between the lines of the layer 18a.
In 2), the region Rl is a surface of a layer having a large total thickness of a material capable of imparting a uniaxial alignment regulating force. In comparison with this, the uniaxial alignment regulating force for the liquid crystal in the region R2 is relatively small. The interaction can be reduced, and the same effect as in the second embodiment can be obtained.

In the second and third embodiments as described above, the surface states of the regions R1 and R2 are changed by the alignment control layer 15a,
By selecting and adjusting the material, thickness, and processing conditions of the base layer 14a and the layers 17a, 18a, and 19a, the base layer 1
By roughening the surface 4a, the region Rl is changed to the surface region R21 of the substrate as described in FIG.
6 and the liquid crystal regions L1 and L2 shown in FIG.

Referring to FIG. 6, a fourth embodiment of the liquid crystal device of the present invention is shown. In the figure, the same reference numerals as those in FIGS. 1 and 2 denote the same members. In the embodiment shown in FIG.
a, the alignment control layer 15a made of the above-described photosensitive material having a uniaxial alignment control force in the surface region R1 in contact with the liquid crystal 11 is selectively provided in a pattern shape, and the alignment control layer 15a is also provided on the opposing substrate 12b. Layer 15b is likewise provided in a pattern.

The orientation control layer 15b is composed of the orientation control layer 1
5a, it has a uniaxial alignment regulating force in the surface region (R3) in contact with the liquid crystal.
A material usable as a and a uniaxial orientation treatment are selected and applied. The line portions of the patterns of the alignment control layers 15a and 15b are aligned with each other and completely oppose each other, and the axes of the uniaxial alignment regulating force or the uniaxial alignment processing directions of both alignment control layers are the same.

In such an element, in addition to the substrate 12a side,
Also on the substrate 12b side, a process of forming an alignment state as shown in FIGS. 3 to 5 proceeds, and a liquid crystal alignment is obtained.

Therefore, the surface region R4 which is in contact with the liquid crystal 11 between the lines of the alignment control layer 15b has a relatively weak uniaxial alignment regulating force with respect to the liquid crystal as compared with the region R3 or does not have a uniaxial alignment regulating force. It has no force and has a reduced effect on the liquid crystal molecules. The layer 14b constituting the layer 14b is made of the material used for the alignment control layer 15b, the characteristics thereof, and the like. It is formed by applying a material and a processing method that can be used for the semiconductor device.

Further, in the above device, the orientation control layer 15a,
15b is selected, and the difference in surface potential between the opposing surfaces (R1, R3) is preferably set to 50 mV as described above.
It is made larger, preferably larger than 100 mV, and the position of the liquid crystal molecules in the region sandwiched between them is fixed so that a dark state is always shown.

Further, in the above-described device, the regions R2 and R4 are formed by a thin layer different from the underlayer as in the second and third embodiments described above, and the uniaxial orientation control is performed as compared with the regions R1 and R3. The force may be weak, and the effect on the liquid crystal element may be reduced.

FIG. 7 shows a fifth embodiment of the liquid crystal device of the present invention. In the figure, the same reference numerals as those in FIGS. 1 and 2 denote the same members.

In the device having the structure shown in the figure, the electrodes 13a and 13b formed on the substrates 12a and 12b are formed in a stripe shape, and these are opposed to each other in a matrix. It is a pixel in the element. Then, on the substrate 12a side, the alignment control layer 1 having a uniaxial alignment control force made of the above-described photosensitive insulating material, particularly, polyimide or polyamideimide.
5a is provided in a pattern shape such that the line portions correspond to between the respective stripes of the electrode 13a on the same substrate. FIG. 8 shows the positional relationship of the pattern shape of the electrode 13a and the orientation control layer 15a on the substrate 12a side as viewed from above (other members are omitted in FIG. 8). Here, when the electrode 13a is a transparent electrode and a metal electrode is provided as described above, the orientation control layer 1 is also provided on the metal electrode.
It is preferable to make the line of 5a correspond.

The orientation state of the element having such a structure is basically determined by starting from the liquid crystal region corresponding to the uniaxial orientation control layer 15a by the processes shown in FIGS. It is formed. Furthermore, in this embodiment, the alignment control layer 15a made of an insulating material that is an electrical obstacle to the driving of the liquid crystal and has a uniaxial alignment regulating force is provided in the actual driving region of the liquid crystal due to the positional relationship with the electrode 13a on the same substrate. Alternatively, the effective voltage applied to the liquid crystal at the time of driving by the pulse voltage in the region substantially does not exist in the pixel portion can be increased. In this way, it is possible to achieve both uniform alignment and high-speed liquid crystal driving (switching). In particular, a remarkable effect is brought about with respect to the latter property. Further, when applied as a display element,
The pixel area to be driven effectively can be increased, and the aperture ratio can be improved.

In addition, in the device according to the fifth aspect, the alignment control layer 15a corresponding to between the actual driving regions or between the pixels.
By selecting the relationship between the materials of the facing alignment control layer 15b and the processing method, and preferably setting the surface potential difference of the facing surface as described above, a dark state is shown between these actual driving regions or between the pixels. The positions of the liquid crystal molecules in the same region are fixed so that the liquid crystal molecules can be positioned. Thus, in both the substrates 12a and 12b, the contrast is improved without providing a light-shielding member made of metal or the like between the actual driving regions, and the reflectance on the display surface is reduced. In order to make this effect more remarkable, the orientation control layer 15a as shown in FIG.
Is added in the same direction as the line of the electrode stripe 13a in the same figure, in a direction perpendicular to this direction, and corresponding to the space between the lines of the electrode stripe (13b) on the substrate (12b) side facing the same. It is particularly preferable to use a lattice-like pattern provided on the substrate.

In the element having the above structure, the surface of the layer 14a between the lines of the orientation control layer 15a is covered with a thin layer different from the layer 14a as in the second and third embodiments. The uniaxial alignment regulating force is weaker than the surface of the alignment control layer 15a, and the effect on the liquid crystal molecules can be reduced.

FIG. 9 shows a sixth embodiment of the liquid crystal device of the present invention. In the figure, the same reference numerals as those in FIGS. 1, 2 and 6 denote the same members.

In the device having the structure shown in the figure, the electrodes 13a and 13b formed on the substrates 12a and 12b are formed in stripes, and these are opposed to each other in a matrix. It is a pixel in the element. Then, on the substrate 12a side, the orientation control layer 1 made of an insulating material and having a uniaxial orientation regulating force.
5a is provided in a pattern shape such that the line portions correspond to between the respective stripes of the electrode 13a on the same substrate.

The positional relationship of the pattern shape of the electrode 13a and the orientation control layer 15a on the substrate 12a side as viewed from above is similar to that of FIG. 8 described above (other members are omitted in FIG. 8). . On the other hand, on the substrate 12b side, there is provided an orientation control layer 15b having a uniaxial orientation regulating force and made of an insulating material in a pattern shape such that the line portions face the orientation control layer 15a on the substrate 12a side. FIG.
0, the electrode 13b on the substrate 12b side and the orientation control layer 1
5B shows a positional relationship of the pattern shape of FIG. 5B as viewed from above (other members are omitted in the figure). Here, the electrode 13
When the transparent electrodes a and 13b are provided with metal electrodes as described above, it is preferable that the lines of the orientation control layers 15a and 15b also correspond to the metal electrodes. For the orientation control layer 15a and the orientation control layer 15b, at least one of the materials described in the first embodiment described above and a material that can be used as the orientation control layer 15a and a uniaxial orientation treatment are selected and applied. The directions of the uniaxial alignment treatment in both alignment control layers are preferably the same.

The alignment state of the device having such a structure is basically shown in FIGS. 3 to 5 starting from the liquid crystal regions corresponding to the uniaxial alignment control layers 15a and 15b in both substrates, as in the fourth embodiment. It is formed by such a process. Further, in this embodiment, the alignment control layers 15a and 15b made of an insulating material that is an obstacle to the driving of the liquid crystal and have a uniaxial alignment regulating force are provided on the electrodes 13a and 1b on the same substrate.
Due to the positional relationship with 3b, the effective voltage applied to the liquid crystal at the time of driving by the pulse voltage in the actual driving region or the pixel portion of the liquid crystal can be increased substantially in the actual driving region or the pixel portion of the liquid crystal. In this way, it is possible to achieve both uniform alignment and high-speed liquid crystal driving (switching).
In particular, a remarkable effect is brought about with respect to the latter property.
Further, when the present invention is applied to a display element, the area of a pixel to be driven effectively can be increased, and the aperture ratio is improved.

Then, in the actual driving region of the liquid crystal, the layer 1
By adjusting the materials, surface conditions, and the like of 4a and 14b, the molecules in the liquid crystal region near the substrate interface and the liquid crystal molecules in the bulk region are discontinuous, as in the regions L21 and L22 of the liquid crystal region L2 described in FIG. An array state can also be formed.

In this way, both the uniformity of the alignment state and the high-speed driving (switching) of the liquid crystal are realized, and the burn-in during driving is suppressed. Further, when the present invention is applied as a display element, the area of a pixel to be driven effectively can be increased, and the aperture ratio is improved.

In addition, in the device of the sixth aspect, the alignment control layer 15a corresponding to between the actual driving regions or between the pixels.
By selecting the material and processing method of the facing alignment control layer 15b and preferably setting the difference in surface potential of the facing surface as described above, a dark state is shown between these actual driving regions or between the pixels. Then, the positions of the liquid crystal molecules in the same region are fixed. In this manner, in both the substrates 12a and 12b, the reflectance on the display surface is suppressed without providing a light-shielding member made of metal or the like between the actual driving regions,
The contrast is improved. In order to make this effect more conspicuous, an orientation control layer 15a as shown in FIG. 8 is added to a substrate (FIG. 8) having a line portion in the same direction as that of the electrode stripe 13a in FIG. 12b)
A grid-like pattern corresponding to the space between the lines of the electrode stripe (13b) on the side is formed, and the alignment control layer 15b as shown in FIG. In addition, it is particularly preferable to form a grid pattern that is in the same direction as the line direction of the electrode stripe 13b and that corresponds to the space between the lines of the electrode stripe 13b.

In the element having the above structure, the second and third elements described above are used.
As in the third embodiment, the surfaces of the layers 14a and 14b between the respective lines of the orientation control layers 15a and 15b are changed to the layers 14a and 14b.
And another orientation control layer 15a, 15
The uniaxial alignment regulating force is weaker than that of the surface b, so that the action on the liquid crystal molecules can be reduced.

In the device according to the fifth and sixth embodiments, the electrodes 12a and 12b of both substrates form a matrix electrode structure, and can perform pattern display and pattern exposure. It is suitably used as a light bulb for displays, printers and the like.

In the fifth and sixth embodiments, in order to obtain a better alignment state, the alignment control layers 15a and 15
5b can also be provided in the above-described actual driving area or pixel where the electrodes 13a and 13b intersect. The thickness of the alignment control layer provided in the actual driving region or the pixel is preferably set to be larger in the above range (50 to 5000 °), more preferably 500 ° or more, and the liquid crystal region corresponding to the alignment control layer is set. To prevent the liquid crystal region from being completely driven by controlling the voltage applied to the electrodes 13a,
The drive characteristics of the liquid crystal in the entire intersection of 13b are improved.

The driving method of the liquid crystal element of the present invention is described in, for example, JP-A-59-193426 and JP-A-59-1.
93427, JP-A-60-156046,
The driving method described in JP-A-60-156047 can be used.

Hereinafter, simple matrix driving in the liquid crystal element of the present invention and important driving characteristics will be described in detail with reference to the drawings.

FIG. 11 is a plan view showing an example of the arrangement of matrix electrodes in a liquid crystal element. The scanning lines (S _{1 to} S _m ) of the scanning electrode group 52 are provided on the liquid crystal element (panel) 51.
A data line of the information electrode group 53 (I ₁ ~I _n) and are wired to cross each other, a liquid crystal is disposed between the scanning lines and data lines. Then, each intersection of the scanning line and the data line becomes a pixel as one display unit, and a voltage is applied from the scanning line and the data line to drive the liquid crystal. In the third and fourth embodiments, the electrodes 13a and 13b provided on the substrates 12a and 12b respectively correspond to the electrodes 52 and 53 shown in FIG.

FIGS. 12 and 13 show examples of waveforms of the driving method (multiplex driving) employed in the matrix electrode structure shown in FIG. The driving waveform shown in FIG.
This is a reset write type waveform in which black display is set with a positive polarity with respect to the scanning line side and the reset direction is set on the black display side. S ₀ indicates a scanning signal waveform applied to the scanning line, I ₁ indicates an information signal waveform applied to the data line (white display waveform), and I ₂ indicates an information signal waveform applied to the data line (black display waveform). . In the figure, (S ₀ −
I ₁ ) and (S ₀ -I ₂ ) are voltage waveforms applied to the selected pixel, and the pixel to which the voltage (S ₀ -I ₁ ) is applied becomes white display state, and the voltage (S ₀ -I _The pixel to which ₂ ) is applied enters a black display state (the reset is set to the black display side as described above).

In FIG. 13, (S ₂ −I ₀ ) and (S ₃ −
I ₀ ) is a driving waveform shown in FIG. 12. For example, the second pixel and the third pixel when “white, white, black, black” is displayed on four consecutive pixels on the same data line It is a time-lapse waveform applied.

In the driving waveforms shown in FIGS. 12 and 13, the write pulse width Δt applied to the pixels on the selected scanning line
In contrast, the reset pulse for clearing one line is 5 / 2Δt
, And a pulse that assists the reset pulse side after the write pulse is ΔΔt. Therefore, in the driving waveforms shown in FIGS. 12 and 13, the one-line scanning time (1H) is 4Δt minutes. However, as shown in FIG. 13, in addition to scanning without providing a time period in which the scanning waveforms overlap each other, a time period in which the scanning waveforms of two or more scanning lines (for example, adjacent scanning lines) overlap is provided (for example, 2Δ
It is also possible to shorten the practical one-line scanning time (1H) (for example, to 2Δt).

Each parameter scanning signal voltage V _s , information signal V _I , and drive voltage V of the drive waveforms shown in FIGS.
_op (V _s + V _I ), (Bias ratio: V _I / (V _s + V
_I )), The value of Δt is determined by the switching characteristics of the liquid crystal material used.

FIG. 14 shows a case where the above-mentioned bias ratio is fixed at 1 / 3.4 using the driving waveform shown in FIG. 12, the driving voltage V _op (V _s + V _I ) is fixed at 20 V, and This shows a final change in the transmittance T after the application of the drive waveform (after the selective application) in the corresponding pixel when the width Δt is changed.

In the figure, the solid line indicates the white waveform (S ₀ -I
₁₎ (black erase (reset) write white), the broken line is for the case the black waveform (S ₀ -I ₂₎ to (black erase (reset) retention) is applied. When a solid white waveform (S ₀ -I ₁ ) is applied, the state before the waveform of the pixel is applied is a black state, and writing to the white state completely with a pulse width of Δt ₁ or more is not possible. When Δt is larger than Δt ₂ , writing to the white state cannot be performed again (for example, the white display waveform (S ₀ -I shown in FIG. 12).
_The black state is restored by the application of a reverse polarity auxiliary pulse following the W pulse of ₁ )). In addition, a black waveform (S
₀ -I ₂ ), the state before the waveform of the pixel is applied is the opposite white state, and writing and holding to the black state are completely realized with a pulse width of Δt ₃ or more, and Δt
_At Δt greater than ₄ , the black state cannot be maintained (the white state is achieved by the application of the reverse polarity holding pulse subsequent to the B pulse of the black display waveform (S ₀ -I ₂ ) shown in FIG. 12). Become).

[0162] Usually, since Δt ₃ <Δt _1, referred to Delta] t ₁ with a threshold pulse width, smaller Delta] t ₂ or Delta] t ₄ (if Delta] t ₄ in FIG. 14) is referred to as a crosstalk pulse width.
(Δt ₂ is also called a white crosstalk pulse width, and Δt ₄ is also called a black crosstalk pulse width.)

A white display waveform (the white display waveform (S) shown in FIG. 12 where matrix driving is performed by a drive waveform having a pulse width between the threshold pulse width and the crosstalk pulse width.
₀ -I ₁ )), a reliable white display and a black waveform (FIG. 12).
The black display waveform (S ₀ -I ₂ ) shown in ( ₁ ) above enables reliable black display, and excellent white and black image display can be performed only by the difference in polarity on the information signal side.

By increasing the above-mentioned bias ratio, it is possible to increase the value of the crosstalk pulse width of Δt ₂ or Δt _4. However, increasing the bias ratio requires increasing the amplitude of the information signal. This means that image quality is not preferable because it causes an increase in flicker and a decrease in contrast. In our study, a bias ratio of about 1/3 to 1/5 was appropriate.

With respect to such driving characteristics, a characteristic of how much margin is provided for setting driving conditions is called a driving margin. As an index for quantitatively evaluating the driving margin, the above-described threshold pulse width Δt is used. A parameter “M2” representing the width of the value of ₁ and the crosstalk pulse width Δt ₄ (or Δt _{2 in} some cases) from the center value can be used.

[0166]

M2 = 1/2 (Δt ₄ −Δt ₁ ) / 1/2 (Δ
t ₄ ten Δt ₁₎

At a certain temperature, two states of black and white can be written to the selected pixel according to the two directions of the information signal as described above, and the non-selected pixels maintain the black or white state. The drive margin that can be performed differs depending on the liquid crystal material and the element configuration, and is unique. In addition, since the drive margins are different depending on the change in the environmental temperature, in an actual liquid crystal display device,
It is necessary to set optimal driving conditions for the liquid crystal material, element configuration, and environmental temperature. The larger the drive margin parameter M2 is, of course, the more advantageous the display element is.

In the evaluation of the driving characteristics (driving margin) shown in FIG. 14, the driving voltage V _op was fixed and the pulse width Δt was changed.
The drive voltage V _op may be changed, or both parameters may be changed.

The liquid crystal element of the present invention can be applied to an active matrix type element. That is,
A plurality of pixel electrodes are provided in a matrix on one substrate, and a two-terminal or three-terminal switching element is arranged corresponding to each pixel electrode, and is preferably at least arranged along an array of the switching elements in at least one direction. One of the substrates is provided with a first region provided with a strong uniaxial alignment regulating force by the photosensitive material described above, and the first region is formed, for example, as shown in FIGS.
An alignment state can be formed as shown in FIG.

[0170]

Hereinafter, the present invention will be described in detail with reference to specific examples, but the present invention is not limited to the following examples.

Example 1 Preparation of Liquid Crystal Composition Liquid crystal composition LC-1 was prepared using the following liquid crystal compounds (A) to (E).

[0172]

Embedded image

Weight ratio: Compound A / B / C / D / E = 45
/ 15/30/5/2 The physical property parameters are shown below.

[0174]

(Equation 5)

Preparation of Photosensitive Polyimide Resin Composition A 50 ml four-necked flask equipped with a stirrer, a nitrogen inlet tube, a discharge tube equipped with a calcium chloride tube, and a thermometer was previously replaced with nitrogen gas. 1.85 g (5.0 mmol) of a diamine represented by the following formula was added to this flask under a nitrogen stream.
l) and charged with special grade N, N-dimethylacetamide 15
was dissolved in ml. 1.09 pyromellitic anhydride
g (5.0 mmol) as a solid was added, and the solid content on the reaction vessel wall was reduced to a special grade N, N-dimethylacetamide 5m
l. Then, after reacting at 30 ° C. for 5 hours, the reaction solution was poured into methanol, and the precipitated polyamic acid was filtered and dried under reduced pressure.

[0176]

Embedded image

1.35 g of the obtained reaction product was dissolved in 8.65 g of dimethylacetamide to obtain a polyamic acid solution (A) having a solid concentration of 13.5%.

A 300 ml four-necked flask equipped with a stirrer, a nitrogen inlet tube, a discharge tube equipped with a calcium chloride tube, and a thermometer was previously replaced with nitrogen gas. In this flask, 10 g of the previously synthesized polyamic acid solution (A) (2.
36 mmol), and 16.74 g of special grade N, N-dimethylacetamide was added to obtain a solution (B). On the other hand, under a nitrogen stream, 5.7 g of a photopolymerization initiator Irgacure 651 (manufactured by Ciba Geigy) and a sensitizer Dytocure PAA
2.85 g (manufactured by Daito Chemical Industry Co., Ltd.) was treated with special grade N, N-dimethylacetamide Solution dissolved in Ig (C)
Was prepared.

To the solution (B) obtained above, 0.26 g of the solution (C) was added and mixed in an ultrasonic wave.
Pressure filtration using a filter with a pore size of
A photosensitive polyimide resin composition (PI-A) having a concentration of 3% (the solid content concentration of the polyamic acid was 5.0%) was prepared.

Preparation of Cell A matrix cell (simple matrix type cell) used in the embodiment was prepared as follows.

Cell A Here, a cell (empty cell) having the cross-sectional structure shown in FIG. 7 was prepared. A pair of 1.1 mm-thick glass substrates on which a stripe-patterned ITO film (thickness: about 70 nm, line width: 16 μm, interval between adjacent lines: 4 μm) was formed as a transparent electrode was prepared.

On one side of this glass substrate, an ethanol solution of ladder-type polysiloxane was applied by spin coating, followed by pre-drying at 80 ° C. for 5 minutes.
Heat drying was performed at 200 ° C. for one hour to obtain a polysiloxane layer having a thickness of 3 nm. The previously prepared photosensitive polyimide resin composition (PI-A) was applied onto the polysiloxane layer by spin coating, and then pre-dried at 100 ° C. for 5 minutes.

Next, a stripe-shaped mask pattern having a mask width of 16 μm and an interval of 4 μm was arranged on the polyimide film so that the mask portions corresponded to the lines of the ITO film pattern on the substrate. Subsequently, exposure was performed using a high-pressure mercury lamp at a UV intensity at which the amount of light energy at a wavelength of 254 nm was 1.44 J / cm ² . Next, development was performed for 15 seconds using a developing solution of dimethylformamide / ethanol = 5/5, followed by washing in ethanol and drying the substrate. Thereafter, the substrate is heated and baked at 200 ° C. for one hour, and a portion (width 4 μm) in which a stripe-shaped polyimide film exists on the substrate corresponding to a distance between the ITO film lines and a line corresponding to the ITO film does not exist at all. A polyimide film pattern consisting of portions (width 16 μm) was obtained.

Subsequently, the polyimide on the substrate was subjected to a rubbing treatment with a nylon cloth as a uniaxial orientation treatment. The conditions of the rubbing treatment were as follows: using a rubbing roll in which nylon (NF-77 / manufactured by Teijin) was attached to a roll having a diameter of 10 cm, a pushing amount of 0.3 mm, and a feeding speed of 10 cm.
/ Sec, rotation speed 1000 rpm. The number of times of feeding was four times. The direction of the rubbing treatment was set in a direction perpendicular to the stripe direction of the polyimide film.

A ladder-type polysiloxane ethanol solution was applied to the other glass substrate by spin coating. Then, after pre-drying at 80 ° C. for 5 minutes,
Heat drying was performed at 00 ° C. for 1 hour to obtain a borosiloxane layer having a thickness of 3 nm.

Subsequently, a spacer having an average particle size of 2.0 μm was formed on one of the substrates (the substrate on which the polyimide was applied) as a spacer.
And the other substrate is overlapped so that the electrodes of each substrate are orthogonal to each other and have a matrix electrode arrangement (arrangement as shown in FIG. 11), and a cell (empty) having a sectional structure as shown in FIG. Cell). The total thickness of the insulating film (polysiloxane layer) in the actual driving region (the portion where the electrodes of both substrates intersect) of the cell thus formed was 6 nm.

Cell B A pair of 1.1 mm-thick glass substrates having a stripe-patterned ITO film (about 70 nm in thickness, 16 μm in width of one line, and 4 μm in space between adjacent lines) formed as transparent electrodes were prepared.

A ladder-type polysiloxane ethanol solution was applied to one of the glass substrates by spin coating, followed by pre-drying at 80 ° C. for 5 minutes.
Heat drying was performed at 200 ° C. for one hour to obtain a polysiloxane layer having a thickness of 3 nm. On the polysiloxane layer, a polyimide (precursor) having the following repeating unit is applied by spin coating, then pre-dried at 80 ° C. for 5 minutes, and then baked at 200 ° C. for 1 hour. 5n thick
m was obtained.

[0189]

Embedded image

Subsequently, the polyimide on the substrate was subjected to a rubbing treatment as a uniaxial orientation treatment by the same method and under the same conditions as in the case of the cell A. On the other glass substrate,
A ladder-type polysiloxane ethanol solution was applied by a spin coating method. After that, pre-drying was performed at 80 ° C. for 5 minutes, and then heat drying was performed at 200 ° C. for 1 hour to obtain a polysiloxane layer having a thickness of 3 nm.

Subsequently, a spacer having an average particle size of 2.0 μm was formed on one of the substrates (the substrate on which polyimide was coated) as a spacer.
m silica beads were scattered, and the other substrate was overlapped such that the electrodes of each substrate were orthogonal to each other and arranged in a matrix electrode arrangement (arrangement as shown in FIG. 11) to form a cell (empty cell).

The total thickness of the insulating film (polysiloxane layer and polyimide film) in the actual driving region (the portion where the electrodes of both substrates cross) of the cell thus formed was 1 lnm.

Cell C Except that the thickness of the polyimide film was set to 2 nm,
A cell (empty cell) was prepared in the same manner and under the same conditions as the cell C. The total thickness of the insulating films (polysiloxane layer and polyimide film) in the actual driving region (the portion where the electrodes of both substrates intersect) of the prepared cell was 8 nm.

Cell D A pair of 1.1 mm-thick glass substrates on which a stripe-patterned ITO film (thickness: about 70 nm, line width: 16 μm, interval between adjacent lines: 4 μm) was formed as a transparent electrode was prepared.

A ladder-type polysiloxane ethanol solution was applied to these glass substrates by spin coating, followed by pre-drying at 80 ° C. for 5 minutes.
Heat drying was performed at 00 ° C. for 1 hour to obtain a polysiloxane layer having a thickness of 3 nm. Subsequently, the polysiloxane layers of these substrates were subjected to a rubbing treatment as a uniaxial orientation treatment in the same manner and under the same conditions as for the cell A.

Next, a spacer having a mean particle size of 2.0 μm was formed on one of the substrates (the substrate on the side subjected to the rubbing treatment) as a spacer.
m m silica beads were scattered, and the other substrate was overlapped so that the electrodes of each substrate were orthogonal to each other in a matrix electrode arrangement (arrangement as shown in FIG. 11) to form a cell (empty cell). The rubbing directions of the two substrates were set to be the same and parallel.

The total thickness of the insulating film (polysiloxane layer) in the actual driving region (the portion where the electrodes of both substrates intersect) of the cell thus formed was 6 nm. Note that the size of the cells A to D was 2.5 cm × 3.5 cm.

Each cell A created by the process described above
To D, the liquid crystal composition LC-1 was injected at an isotropic phase temperature,
The liquid crystal was cooled to a temperature showing a chiral smectic liquid crystal phase, and chiral smectic liquid crystal element samples A to D showing bistability were produced. When the cooling process of the liquid crystal was observed with a deflection microscope, in the cell A, a process of forming an alignment state due to generation and growth of a battone as shown in FIG. 3 was observed from around the transition temperature to the smectic A phase.

The samples were evaluated for (1) the uniformity of orientation and (2) the M2 margin (M2). (1) Evaluation of alignment uniformity A voltage was applied to the liquid crystal element in the state of a chiral smectic liquid crystal phase to switch the chiral smectic liquid crystal to one state, and the alignment uniformity was evaluated by visual observation with a deflection microscope. Table 1 shows the results.

[0200]

[Table 1]

(2) Measurement of M2 Margin (M2) A method of measuring the M2 margin will be described. First, a cell is installed between the deflecting plates arranged in crossed Nicols, and a driving waveform (V _op = 20 V, 1 / 3.3 bias, _1/1) shown in FIG.
(0 duty), the M2 margin was measured. A dark state (black display) and a bright state (white display) are written while changing the applied pulse waveform length Δt,
When the range of the applied pulse waveform length Δt in which the bright and dark states can be written becomes as shown in FIG.

[0202]

M2 = (Δt ₄ −Δt ₁ ) / (Δt ₄ + Δt)
₁ ), and the M2 margin was evaluated by changing the temperature of the samples A to D by several points. The results are shown in Table 2 below.

[0203]

[Table 2]

The M2 margin of the element C is only the area where normal switching is performed (only the area in a good alignment state), and the M2 margin of the element A is the area where no striped polyimide is arranged. In addition, since the device D was randomly oriented, the drive margin could not be measured.

From this result, it can be seen that, for the element B, the M2 margin at room temperature or higher is large, but the drive margin on the low temperature side is significantly deteriorated. This is expected to be due to the effect of the anti-electric field on the low temperature side. On the other hand, with respect to the device C having poor orientation, although the value of the M2 margin is small as a whole, the device C has a smaller orientation film thickness (thickness of the polyimide film) and a larger electric capacity of the orientation control layer than the device B. The amount of decrease in the margin on the low temperature side is small. On the other hand, in the element A, since no polyimide exists in a region where the electrodes of both substrates are opposed to each other, that is, an effective switching region, the electric capacity of the orientation control layer is large, and the decrease in the margin on the low temperature side is small.

As described above, the portion where the alignment control layer having the uniaxial alignment control force exists and the portion where the alignment control layer does not exist are mixed on the substrate, and the alignment state is changed from the liquid crystal region in contact with the portion of the alignment control layer. It has been proved that a good driving margin characteristic can be realized by forming a uniform alignment property by forming the liquid crystal layer and by eliminating the alignment control layer having the uniaxial alignment regulating force in the actual driving area of the liquid crystal.

Example 2 As a liquid crystal composition and a photosensitive polyimide resin composition,
Using the liquid crystal composition LC-1 and the photosensitive polyimide resin composition (PI-A) used in Example 1, a liquid crystal element was produced in the same manner as in Example 1.

Creation of Cell A matrix cell (simple matrix type cell) used in the embodiment was created as follows.

Cell a Here, a cell (empty cell) having the sectional structure shown in FIG. 7 was prepared. A pair of 1.1 mm-thick glass substrates on which a stripe-patterned ITO film (thickness: about 70 nm, line width: 16 μm, interval between adjacent lines: 4 μm) was formed as a transparent electrode was prepared.

On one side of this glass substrate, 30% by weight of antimony-doped SnO _x ultrafine particles (particle size: 100 °) was added and dispersed in a ladder-type polysiloxane base material, and the solid content concentration was 10% by weight. % Ethanol solution was applied by spin coating, followed by pre-drying at 80 ° C. for 5 minutes, followed by heat drying at 200 ° C. for 1 hour to obtain a fine particle dispersion layer having a film thickness of 200 nm. On the layer, the photosensitive polyimide resin composition (PI-A) prepared above was applied by spin coating, and then pre-drying was performed at 100 ° C. for 5 minutes.

Next, a stripe-shaped mask pattern having a mask width of 16 μm and an interval of 4 μm was arranged on the polyimide film so that the mask portion corresponded to the line of the ITO film pattern on the substrate. Subsequently, exposure was performed using a high-pressure mercury lamp at a UV intensity at which the amount of light energy at a wavelength of 254 nm was 1.44 J / cm ² . Next, development was performed for 15 seconds using a developing solution of dimethylformamide / ethanol = 5/5, followed by washing in ethanol and drying the substrate. Thereafter, the substrate is heated and baked at 200 ° C. for one hour, and a portion (width 4 μm) in which a stripe-shaped polyimide film exists on the substrate corresponding to a distance between the ITO film lines and a line corresponding to the ITO film does not exist at all. A polyimide film pattern consisting of portions (width 16 μm) was obtained.

Subsequently, the polyimide on the substrate was subjected to a rubbing treatment with a nylon cloth as a uniaxial orientation treatment. The conditions of the rubbing treatment were as follows: using a rubbing roll in which nylon (NF-77 / manufactured by Teijin) was attached to a roll having a diameter of 10 cm, a pushing amount of 0.3 mm, and a feeding speed of 10 cm.
/ Sec, rotation speed 1000 rpm. The number of times of feeding was four times. The direction of the rubbing treatment was set in a direction perpendicular to the stripe direction of the polyimide film.

On the other glass substrate, 30% by weight of antimony-doped SnOx ultrafine particles (particle size: 100 °) were added and dispersed in a ladder-type polysiloxane base material, and dispersed to obtain a solid content of 10% by weight. An ethanol solution was applied by a spin coating method. Thereafter, pre-drying was performed at 80 ° C. for 5 minutes, and then heat drying was performed at 200 ° C. for 1 hour to obtain a fine particle dispersion layer having a thickness of 200 nm.

Subsequently, a spacer having an average particle size of 2.0 μm was formed on one of the substrates (the substrate on which polyimide was applied) as a spacer.
And the other substrate is overlapped so that the electrodes of each substrate are orthogonal to each other and have a matrix electrode arrangement (arrangement as shown in FIG. 11), and a cell (empty) having a sectional structure as shown in FIG. Cell).

Cell b In the ladder type polysiloxane used for forming the fine particle dispersion layer. A cell (empty cell) was prepared in the same manner and under the same conditions as for the cell a, except that the weight ratio of the antimony-doped SnO _x ultrafine particles dispersed in the base material was changed from 30% to 50%.

Cell c Here, a cell (empty cell) having a sectional structure shown in FIG. 9 was prepared. A pair of 1.1 mm-thick glass substrates on which a stripe-patterned ITO film (thickness: about 70 nm, line width: 16 μm, interval between adjacent lines: 4 μm) was formed as a transparent electrode was prepared.

To each of these glass substrates, 30% by weight of antimony-doped SnO _x ultrafine particles (particle size: 100 °) were added and dispersed in a ladder-type polysiloxane matrix, and the solid content concentration was 10% by weight. % Ethanol solution by spin coating, then pre-drying at 80 ° C. for 5 minutes, and then heating and drying at 200 ° C. for 1 hour,
A fine particle dispersion layer having a thickness of 200 nm was obtained. On the polysiloxane layer, the photosensitive polyimide resin composition (PI-B) prepared above was applied by a spin coating method.
Pre-drying was performed at 00 ° C. for 5 minutes.

Next, a stripe-shaped mask pattern having a mask width of 16 μm and an interval of 4 μm was arranged on the polyimide film on one glass substrate such that the mask portions corresponded to the lines of the ITO film pattern on the substrate. . Subsequently, using a high-pressure mercury lamp, the wavelength was 365 nm.
At which the amount of light energy is 1.44 J / cm ²
Exposure was performed at V intensity. Next, after heating on a hot plate at 120 ° C. for 10 minutes to form a polyimide thin film on the entire surface of the polysiloxane layer, development is performed for 15 seconds using a developing solution of dimethylformamide / ethanol = 5/5, Subsequently, the substrate was washed in ethanol and dried. After that, it is heated and baked at 200 ° C. for 1 hour.
A portion (4 μm in width) where a stripe-shaped polyimide film exists on the substrate corresponding to the distance between the lines of the ITO film at a thickness of 50 nm and I
The part where the ultra-thin film exists corresponding to the line of the TO film (width 1)
6 μm).

Subsequently, the polyimide on the substrate was subjected to a rubbing treatment as a uniaxial orientation treatment by the same method and under the same conditions as in the case of the cell a. The direction of the rubbing process is
The direction was set in a direction perpendicular to the stripe direction of the polyimide film.

On the other glass substrate, a stripe-shaped mask pattern having a mask width of 16 μm and an interval of 4 μm was formed on the above-mentioned polyimide film, and the mask portion was formed on the polyimide film of the substrate.
It was arranged so as to be orthogonal to the line of the TO film pattern. Subsequently, exposure was performed using a high-pressure mercury lamp at a UV intensity at which the light energy amount at a wavelength of 365 nm was 1.44 J / cm ² . Then, place on a hot plate at 120 ° C for 1
After heating for 0 minutes to form a polyimide thin film on the entire surface of the polysiloxane layer, dimethylformamide /
Development was carried out for 15 seconds using a developing solution of ethanol = 5/5, followed by washing in ethanol and drying the substrate. Thereafter, the substrate is heated and baked at 200 ° C. for 1 hour, and a polyimide film having a portion (width 4 μm) of a stripe-shaped polyimide film orthogonal to the ITO film line on the substrate and a portion (width 16 μm) not present at all. Got the pattern.

Subsequently, the polyimide on the substrate was subjected to a rubbing treatment as a uniaxial orientation treatment by the same method and under the same conditions as in the case of the cell a. The direction of the rubbing process is
The direction was set in a direction perpendicular to the stripe direction of the polyimide film.

Subsequently, silica beads having an average particle size of 2.0 μm were dispersed as spacers on one of the substrates (the first substrate), and the other substrate was placed on a matrix electrode arrangement in which the electrodes of each substrate were orthogonal to each other (see FIG. 11). The alignment is performed so that the line portions of the polyimide film patterns on both substrates completely face each other, and the rubbing directions of the polyimide films are the same. A cell with a structure (empty cell) was created.

The total thickness of the fine particle dispersed film in the actual driving region (the portion where the electrodes of both substrates intersect) of the cell thus manufactured was 400 nm.

Cell d The cell ladder type polysiloxane used for forming the fine particle dispersion layer was changed to the cell c except that the weight ratio of the antimony-doped SnO _x ultrafine particles dispersed in the base material was changed from 30% to 50%. A cell (empty cell) was created in the same manner and under the same conditions. The size of cells a to d is 2.5c
m × 3.5 cm.

Further, in the actual driving regions (intersections of the electrodes of the two substrates) in the cells a to d, the surface roughness of each layer, which was the substrate surface in contact with the liquid crystal, was measured. The measurement was performed by forming a film of 1800 ° on a glass substrate or an ITO film under the same conditions as the above layers in the cells a to d, and using an atomic force microscope (NanoScope IIIa AFM Dim).
extension3000 unit / Digital In
instrument, using a Si cantilever manufactured by Olympus Optical Co., Ltd. as a probe) to obtain a scanning range of 3.0 μm.
The measurement was performed for m × 3.0 μm. Scan speed is 0.8H
z, the measurement environment was room temperature and air.

The results are shown in Table 3 below.

[0227]

[Table 3]

Each cell a created by the process described above
To d, injecting the liquid crystal composition LC-1 at an isotropic phase temperature,
The liquid crystal was cooled to a temperature showing a chiral smectic liquid crystal phase, and chiral smectic liquid crystal element samples a to d showing bistability were produced. When the cooling process of the liquid crystal was observed in a deflection microscope, in cells a to d, the formation of an alignment state due to the generation and growth of butene as shown in FIG. 3 was observed from around the transition temperature to the smectic A phase. .

These samples were evaluated for (1) orientation uniformity, (2) M2 margin (M2), and (3) display burn-in.

(1) Evaluation of Alignment Uniformity A voltage was applied to the liquid crystal element in the state of a chiral smectic liquid crystal phase to switch the chiral smectic liquid crystal to one state, and the alignment uniformity was evaluated by visual observation with a deflection microscope. Done. Table 4 shows the results.

[0231]

[Table 4]

(2) Measurement of M2 Margin (M2) In the same manner as in Example 1, the M2 margin was evaluated by changing the temperature of the samples a to d by several points. The results are shown in Table 5 below.

[0233]

[Table 5]

From these results, it is found that the elements a to d have little influence of the counter electric field because no polyimide film exists in the actual driving region, and the M2 margin on the low temperature side is almost equal to the room temperature.

As described above, the portion where the alignment control layer (polyimide film) having the uniaxial alignment control force exists on the substrate and the portion where the alignment control layer does not exist are mixed, and the liquid crystal region in contact with the alignment control layer portion is mixed. It is possible to obtain a uniform alignment property by forming an alignment state from the above, and to achieve good drive margin characteristics by eliminating the alignment control layer having the uniaxial alignment control force in the actual driving region of the liquid crystal. Proven.

(3) Evaluation of display burn-in For element samples a to d, stripe patterns of black display and white display were displayed using the drive waveforms shown in FIG. Is displayed, and then a driving condition (M2 margin) in which the entire cell is written in black and white in the same manner and under the same conditions as in 2) above
Was measured. The value of the M2 margin after 1000 hours and the M2 before the burn-in experiment (before displaying the same pattern)
The ratio with the value of the margin was taken to be the margin retention rate after 1000 hours. The measurement temperature of the storage rate was 30 ° C.
And

The results are shown in Table 6 below.

[0238]

[Table 6]

From these results, the element samples a to d in which no polyimide is present in the actual driving region exhibit a very high margin preservation rate, that is, a performance in which the burn-in phenomenon is suppressed and the driving characteristics are not deteriorated. In particular, it can be seen that the element sample in which the layer in contact with the liquid crystal in the actual driving region is made of conductive oxide fine particles exhibits a very high margin preservation rate due to the effect of minute surface irregularities.

[0240]

As described in detail above, according to the present invention,
A liquid crystal element in which both the alignment uniformity and the driving characteristics are improved, and furthermore the display burn-in phenomenon is suppressed, in particular, a liquid crystal element using a chiral smectic liquid crystal, in which the orientation of the smectic liquid crystal phase is uniform and the driving margin is improved. A liquid crystal element with reduced temperature dependency and with reduced image sticking is provided.

[Brief description of the drawings]

FIG. 1 is a plan view showing a structure of a substrate used for a liquid crystal element according to one embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of the liquid crystal element according to the first embodiment of the present invention.

FIG. 3 is a diagram schematically illustrating an example of a process of forming a liquid crystal alignment state in the liquid crystal element of the present invention.

FIG. 4 is a diagram schematically showing another example of a process of forming a liquid crystal alignment state in the liquid crystal element of the present invention.

FIG. 5 is a diagram schematically showing still another example of the process of forming the alignment state of the liquid crystal in the liquid crystal element of the present invention.

FIG. 6 is a cross-sectional view illustrating a structure of a liquid crystal element according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a structure of a liquid crystal element according to a third embodiment of the present invention.

8 is a diagram showing a positional relationship between an orientation control layer and electrodes on the substrate (12a) side shown in FIG.

FIG. 9 is a sectional view illustrating a structure of a liquid crystal element according to a fourth embodiment of the present invention.

10 is a diagram showing a positional relationship between an orientation control layer and electrodes on the substrate (12a) side shown in FIG.

FIG. 11 is a diagram showing an example of an electrode structure in an embodiment of the liquid crystal element of the present invention.

FIG. 12 is a diagram illustrating an example of a matrix driving method applied to the liquid crystal element of the present invention.

FIG. 13 is a diagram illustrating an example of a matrix driving method applied to the liquid crystal element of the present invention.

FIG. 14 is a diagram showing the relationship between the pulse width and the transmittance of the liquid crystal when the driving method shown in FIGS. 12 and 13 is used.

FIG. 15 shows a diagram using a chiral smectic liquid crystal.
FIG. 9 is a diagram for explaining a drive margin in an element having the characteristics shown in FIG.

FIG. 16 is a cross-sectional view illustrating a structure of a liquid crystal element according to another embodiment of the present invention.

FIG. 17 is a cross-sectional view illustrating a structure of a liquid crystal element according to another embodiment of the present invention.

FIG. 18 is a cross-sectional view illustrating a structure of a liquid crystal element according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal element 11 Liquid crystal 12a, 12b Substrate 13a, 13b Electrode 14a, 14b Underlayer 15a, 15b Alignment control layer 16 Spacer R1 1st area R2 2nd area N Battone

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasufumi Asao 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Makoto Mori 3-30-2 Shimomaruko, Ota-ku, Tokyo Kia Inside Non-corporation (72) Inventor Takashi Moriyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Satoshi Miura 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. F term (reference) 2H088 FA10 GA04 HA01 HA02 HA03 JA16 LA06 MA04 MA18 4H027 BA06 BA07 BC04 BD12 BD23 BD24 DE03 DN01

Claims (3)

[Claims] A first region having a liquid crystal between a pair of substrates and having at least one substrate having a uniaxial alignment regulating force with respect to the liquid crystal; and a first region outside the first region. The liquid crystal has a second region in which the uniaxial alignment regulating force with respect to the liquid crystal is weak or has substantially no uniaxial alignment regulating force, and the liquid crystal undergoes a liquid crystal-liquid phase transition process between the substrates when the temperature is lowered. A liquid crystal element in which a transition from a region in contact with the first region to a liquid crystal phase occurs, and the liquid crystal phase transition region continuously expands along the axial direction of the uniaxial alignment regulating force of the first region to form an alignment state. 3. The liquid crystal device according to claim 1, wherein the first region is formed of a photosensitive material comprising a photosensitive polyimide or a photosensitive polyamideimide resin in which a photosensitive monomer is covalently bonded in a skeleton. 2. The photosensitive material comprises: (1) a polymer having a structure represented by the following general formula (I) as a main component:
(2) The liquid crystal device according to claim 1, comprising at least one of a photopolymerization initiator and a photosensitizer as required. Embedded image (Wherein R is Selected from. L represents 1 or 2, and the carboxyl group is bonded ortho to the carbonyl group constituting the main chain. m and n are each independently 0 or 1, and o is an integer of 2 to 10. R ₁ represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms. ) 3. The photosensitive material comprises: (1) a polymer having a structure represented by the following general formula (II) as a main component:
(2) The liquid crystal device according to claim 1, comprising at least one of a photopolymerization initiator and a photosensitizer as required. Embedded image (Wherein, m and n are each independently 0 or 1,
o is an integer of 2 to 10. R ₁ represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms. )