JP2010256496A - Liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element capable of suppressing generation of orientation defects such as zigzag defects to raise contrast, and to provide a method of manufacturing the same. <P>SOLUTION: The liquid crystal display element has: a first substrate; a first electrode layer which is formed on the first substrate; an alignment layer for reactive crystal which is formed on the first electrode layer; a fixed liquid crystal layer side substrate which is formed on the alignment layer for the reactive liquid crystal and has a fixed liquid crystal layer constituted by fixing a hybrid-aligned reactive liquid crystal; a counter substrate which is arranged so as to face the fixed liquid crystal layer of the fixed liquid crystal layer side substrate; and a ferroelectric liquid crystal layer which is formed between the fixed liquid crystal layer and the counter substrate and includes ferroelectric liquid crystal, wherein the reactive liquid crystal is hybrid-aligned from the side of the alignment layer for the reactive liquid crystal toward the side of the ferroelectric liquid crystal layer so that a tilt angle gradually increases in the thickness direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal display element using a ferroelectric liquid crystal.

  Ferroelectric liquid crystal (FLC) is a liquid crystal suitable for high-speed devices because its response speed is as short as μs order. In particular, the field sequential color method, which is one of the methods for realizing color display, divides one pixel in time, so that a liquid crystal as a black-and-white shutter has high-speed response in order to obtain good moving image display characteristics. It is necessary to have a ferroelectric liquid crystal.

  On the other hand, ferroelectric liquid crystals are more difficult to align due to higher molecular ordering than nematic liquid crystals, and alignment defects such as zigzag defects are likely to occur. Such alignment defects cause a decrease in contrast due to light leakage. .

As a method for eliminating zigzag defects, a temperature gradient method for gradually cooling the panel from the edge and a method for giving a large pretilt angle are known, and an oblique vapor deposition method and a rubbing method are known for obtaining a large pretilt angle. ing.
In addition, as a method for preventing the occurrence of alignment defects that are not zigzag defects but are observed when a ferroelectric liquid crystal having a predetermined phase sequence is used, it is proposed to use a substrate having a pretilt angle of 4 ° or more. (Patent Document 1).
However, in the temperature gradient method, since the panel is gradually cooled from the end, there is a problem in productivity in the manufacturing process particularly in the case of a large panel. In addition, the oblique deposition method requires processing in a vacuum, has a problem in productivity, and has a problem in cost. Furthermore, with the rubbing method, it is difficult to stably obtain a high pretilt angle in a wide area. Further, when there are irregularities (steps) on the substrate surface, the alignment control force by rubbing treatment is weakened and zigzag defects are generated. .

JP 2001-142098 A

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a liquid crystal display element capable of suppressing the occurrence of alignment defects such as zigzag defects and improving the contrast, and a method for manufacturing the same. .

  The present inventors have proposed using an immobilized liquid crystal layer formed by immobilizing reactive liquid crystals as an alignment film for aligning ferroelectric liquid crystals (see, for example, JP-A-2005-258428). This fixed liquid crystal layer is formed by applying a reactive liquid crystal composition on a general alignment film such as a rubbing film or a photo-alignment film, aligning the reactive liquid crystal, and then polymerizing it. Reactive liquid crystal is aligned by the alignment regulating force such as rubbing film and photo-alignment film, and the alignment state of reactive liquid crystal is fixed in the fixed liquid crystal layer. It acts as an alignment film for alignment.

  As a result of intensive studies on the relationship between the alignment state of the reactive liquid crystal and the zigzag defect, the present inventors have used a reactive liquid crystal having a hybrid alignment in which the tilt angle gradually increases in the thickness direction. It has been found that the occurrence of alignment defects such as defects can be effectively suppressed, and the present invention has been completed based on this finding.

  That is, the present invention includes a first substrate, a first electrode layer formed on the first substrate, a reactive liquid crystal alignment film formed on the first electrode layer, and the reactive liquid crystal alignment film. A fixed liquid crystal layer side substrate having a fixed liquid crystal layer formed thereon and having a hybrid liquid crystal alignment reactive liquid crystal and having an alignment regulating force for ferroelectric liquid crystal, and the above-mentioned fixed liquid crystal layer side substrate A counter substrate disposed so as to face the fixed liquid crystal layer, and a ferroelectric liquid crystal layer formed between the fixed liquid crystal layer and the counter substrate and including a ferroelectric liquid crystal, and the reaction A liquid crystal display element, wherein the liquid crystal is hybrid-aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side to the ferroelectric liquid crystal layer side provide.

  According to the present invention, in the fixed liquid crystal layer, the reactive liquid crystal is hybrid aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side to the ferroelectric liquid crystal layer side. Therefore, the tilt angle of the fixed liquid crystal layer on the ferroelectric liquid crystal side can be made relatively large. In addition, the reactive liquid crystal is relatively similar in structure to the ferroelectric liquid crystal, and the interaction with the ferroelectric liquid crystal becomes strong, so that the alignment of the ferroelectric liquid crystal can be effectively controlled. Therefore, in the present invention, the fixed liquid crystal layer in which the reactive liquid crystal with hybrid alignment is fixed is formed in direct contact with the ferroelectric liquid crystal layer, thereby suppressing the occurrence of alignment defects such as zigzag defects. High contrast can be obtained.

  In the present invention, the reactive liquid crystal preferably exhibits a nematic phase. This is because the nematic phase is relatively easy to control the alignment among liquid crystal phases.

  Furthermore, in the present invention, the reactive liquid crystal preferably contains a polymerizable liquid crystal monomer. The polymerizable liquid crystal monomer can be aligned at a lower temperature than other polymerizable liquid crystal materials, that is, a polymerizable liquid crystal oligomer and a polymerizable liquid crystal polymer, and has high sensitivity in alignment, and can be easily aligned. Because you can.

  In the present invention, the counter substrate includes a second substrate, a second electrode layer formed on the second substrate, and a second alignment film formed on the second electrode layer, It is preferable that the ferroelectric liquid crystal layer is formed between the fixed liquid crystal layer and the second alignment film. This is because the alignment of the ferroelectric liquid crystal can be effectively controlled by sandwiching the ferroelectric liquid crystal between the fixed liquid crystal layer and the second alignment film.

  Moreover, the present invention forms a reactive liquid crystal layer containing reactive liquid crystal on a first substrate on which a first electrode layer and an alignment film for reactive liquid crystal are sequentially formed, and the reaction in the reactive liquid crystal layer is performed. The liquid crystal is hybrid-aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side and the alignment state of the reactive liquid crystal is fixed to form a fixed liquid crystal layer. A liquid crystal layer side substrate preparation step, a ferroelectric liquid crystal application step of applying a ferroelectric liquid crystal on the fixed liquid crystal layer, and the fixed liquid crystal layer side substrate and the counter substrate coated with the ferroelectric liquid crystal. A substrate bonding step of bonding, and a ferroelectric liquid crystal alignment step of aligning the ferroelectric liquid crystal sandwiched between the fixed liquid crystal layer side substrate and the counter substrate without performing an electric field application process. Liquid crystal display element characterized by To provide a method of manufacturing.

According to the present invention, since the reactive liquid crystal is hybrid-aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side, the tilt of the fixed liquid crystal layer on the ferroelectric liquid crystal side is tilted. The corner can be made relatively large. Further, since the ferroelectric liquid crystal is applied on the fixed liquid crystal layer, it is considered that the alignment regulating force of the fixed liquid crystal layer greatly contributes to the alignment of the ferroelectric liquid crystal. Furthermore, the reactive liquid crystal is relatively similar in structure to the ferroelectric liquid crystal, and the interaction with the ferroelectric liquid crystal becomes strong, so that the alignment of the ferroelectric liquid crystal can be effectively controlled. Therefore, in the present invention, it is possible to suppress the occurrence of alignment defects such as zigzag defects.
Further, according to the present invention, in addition to the above-described effects, the ferroelectric liquid crystal is aligned without performing an electric field application treatment, so that the alignment is maintained even when the temperature is raised above the phase transition temperature, and alignment defects are generated. Can be suppressed.

  In the above invention, the ferroelectric liquid crystal coating method is preferably an ink jet method. When filling a ferroelectric liquid crystal by a vacuum injection method, zigzag defects are likely to occur partially in the liquid crystal display element, whereas when filling a ferroelectric liquid crystal by a coating method, a ferroelectric property is obtained by an inkjet method in particular. When the liquid crystal is applied, zigzag defects are likely to occur on the entire liquid crystal display element. Therefore, when the ferroelectric liquid crystal is applied by the ink jet method, the method for producing a liquid crystal display element of the present invention is useful.

  Furthermore, in the present invention, the reactive liquid crystal preferably exhibits a nematic phase. This is because the nematic phase is relatively easy to control the alignment among liquid crystal phases.

  In the present invention, the reactive liquid crystal preferably contains a polymerizable liquid crystal monomer. The polymerizable liquid crystal monomer can be aligned at a lower temperature than other polymerizable liquid crystal materials, that is, a polymerizable liquid crystal oligomer and a polymerizable liquid crystal polymer, and has high sensitivity in alignment, and can be easily aligned. Because you can.

  Furthermore, in the present invention, the counter substrate includes a second substrate, a second electrode layer formed on the second substrate, and a second alignment film formed on the second electrode layer, It is preferable to sandwich the ferroelectric liquid crystal between the fixed liquid crystal layer and the second alignment film. This is because the orientation of the ferroelectric liquid crystal can be effectively controlled by sandwiching the ferroelectric liquid crystal between the fixed liquid crystal layer and the second alignment film.

  In the present invention, the reactive liquid crystal in which the hybrid alignment is fixed so that the tilt angle gradually increases in the thickness direction from the alignment layer side for the reactive liquid crystal toward the ferroelectric liquid crystal layer side is fixed. Since the liquid crystal layer is formed in direct contact with the ferroelectric liquid crystal layer, it is possible to suppress the occurrence of alignment defects such as zigzag defects.

It is a schematic sectional drawing which shows an example of the liquid crystal display element of this invention. It is a schematic diagram which shows an example of the fixed liquid crystal layer in the liquid crystal display element of this invention. It is a schematic diagram which shows a smectic layer structure. It is a schematic diagram which shows the other example of the fixed liquid crystal layer in the liquid crystal display element of this invention. It is a schematic diagram which shows a reverse domain. It is a schematic diagram which shows the behavior of a liquid crystal molecule. It is the graph which showed the change of the transmitted light amount with respect to the applied voltage of a ferroelectric liquid crystal.

  Hereinafter, the liquid crystal display element of the present invention and the manufacturing method thereof will be described in detail.

A. Liquid Crystal Display Element First, the liquid crystal display element of the present invention will be described.
The liquid crystal display element of the present invention includes a first substrate, a first electrode layer formed on the first substrate, an alignment film for reactive liquid crystal formed on the first electrode layer, and the reactive liquid crystal A fixed liquid crystal layer-side substrate having a fixed liquid crystal layer formed on an alignment film and having hybrid alignment aligned fixed liquid crystals and having an alignment regulating force for ferroelectric liquid crystals, and the above-mentioned fixed liquid crystal layer A counter substrate disposed to face the fixed liquid crystal layer of the side substrate, and a ferroelectric liquid crystal layer formed between the fixed liquid crystal layer and the counter substrate and including a ferroelectric liquid crystal, The reactive liquid crystal is hybrid-aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side toward the ferroelectric liquid crystal layer side. is there.

The liquid crystal display element of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of the liquid crystal display element of the present invention. As illustrated in FIG. 1, the liquid crystal display element 1 is a fixed liquid crystal layer side substrate in which a first electrode layer 3, a reactive liquid crystal alignment film 4, and a fixed liquid crystal layer 5 are sequentially formed on a first substrate 2. 10 is formed between the counter substrate 20 in which the second electrode layer 13 and the second alignment film 14 are sequentially formed on the second substrate 12, and the fixed liquid crystal layer 5 and the second alignment film 14. A ferroelectric liquid crystal layer 11 containing liquid crystal.

  FIG. 2 is a schematic diagram showing an alignment film for reactive liquid crystal, a fixed liquid crystal layer, and a ferroelectric liquid crystal layer in the liquid crystal display element shown in FIG. As illustrated in FIG. 2, in the fixed liquid crystal layer 5, the tilt angle of the liquid crystal molecules 5a gradually increases in the thickness direction from the reactive liquid crystal alignment film 4 side to the ferroelectric liquid crystal layer 11 side. Hybrid orientation. Further, in the fixed liquid crystal layer 5, the alignment state of such reactive liquid crystals is fixed.

  In the fixed liquid crystal layer, the reactive liquid crystal is hybrid aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side to the ferroelectric liquid crystal layer side as follows. For a good reason. That is, the liquid crystal molecules are aligned on the reactive liquid crystal alignment film side so as to be horizontal with respect to the reactive liquid crystal alignment film by anchoring energy with the reactive liquid crystal alignment film. In the device, on the ferroelectric liquid crystal layer side), in order to reduce the surface free energy, one end of the liquid crystal molecule is attracted to the internal molecule and tries to stand up. As a result, the tilt angle at the reactive liquid crystal alignment film side is small, the tilt angle at the air interface side is large, and the liquid crystal molecules located between the reactive liquid crystal alignment film side and the air interface side are continuous elastic bodies. Based on the theory, the tilt angle is changed with a continuous and uniform angle difference. The horizontal alignment includes a state in which the liquid crystal molecules have a predetermined pretilt angle, and does not necessarily mean that the angle between the optical axis of the liquid crystal molecules and the substrate is 0 °.

“Hybrid alignment” means that the tilt angle gradually changes in the thickness direction of the fixed liquid crystal layer. Specifically, the tilt angle on the reactive liquid crystal alignment film side of the fixed liquid crystal layer This means that the tilt angle on the ferroelectric liquid crystal layer side (air interface side) of the fixed liquid crystal layer is different. In the present invention, among the hybrid alignments, the tilt angle of the fixed liquid crystal layer on the ferroelectric liquid crystal layer side (air interface side) is larger than the tilt angle of the fixed liquid crystal layer on the reactive liquid crystal alignment film side. Hybrid alignment is adopted in which the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side to the air interface side.
The “tilt angle” refers to an angle formed between the optical axis of liquid crystal molecules and the substrate surface.

The ferroelectric liquid crystal forms a smectic layer structure in the smectic phase, and forms a chevron structure or a bookshelf structure in the chiral smectic C (SmC ^* ) phase as illustrated in FIG. In FIG. 3, reference numeral 11b denotes a smectic layer. The chevron structure has a C1 orientation and a C2 orientation, and an alignment defect occurs at the boundary between the C1 orientation and the C2 orientation or at the boundary between the chevron structure and the bookshelf structure. For example, the boundary between the C1 orientation and the C2 orientation is observed as a zigzag defect. Here, when a large pretilt angle is given, it is impossible to form the C1 orientation out of the C1 and C2 orientations, and only the C2 orientation is formed. As a result, zigzag defects can be eliminated.

According to the present invention, the reactive liquid crystal is hybrid-aligned in the fixed liquid crystal layer so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side to the ferroelectric liquid crystal layer side. Therefore, the tilt angle on the ferroelectric liquid crystal side of the fixed liquid crystal layer can be made relatively large. That is, a relatively large pretilt angle can be given.
In addition, when the fixed liquid crystal layer is formed on the reactive liquid crystal alignment film, the reactive liquid crystal is hybrid-aligned by the reactive liquid crystal alignment film, for example, by irradiating ultraviolet rays to polymerize the reactive liquid crystal. The alignment state of the reactive liquid crystal can be fixed. Thereby, it is possible to impart an alignment regulating force to the ferroelectric liquid crystal to the fixed liquid crystal layer. Further, since the reactive liquid crystal is fixed, it has an advantage that it is not affected by temperature or the like. Furthermore, the reactive liquid crystal is relatively similar in structure to the ferroelectric liquid crystal, and the interaction with the ferroelectric liquid crystal becomes strong, so that the alignment of the ferroelectric liquid crystal can be effectively controlled.
Therefore, in the present invention, the fixed liquid crystal layer in which the reactive liquid crystal with hybrid alignment is fixed is formed in direct contact with the ferroelectric liquid crystal layer, thereby suppressing the occurrence of alignment defects such as zigzag defects. High contrast can be obtained.

  Hereinafter, each component of the liquid crystal display element of the present invention will be described in detail.

1. Fixed liquid crystal layer side substrate The fixed liquid crystal layer side substrate used in the present invention includes a first substrate, a first electrode layer formed on the first substrate, and a reaction formed on the first electrode layer. A liquid crystal alignment film, and a fixed liquid crystal layer formed on the reactive liquid crystal alignment film and formed by immobilizing hybrid-aligned reactive liquid crystal and having an alignment regulating force on the ferroelectric liquid crystal. Is.
Hereinafter, each configuration of the fixed liquid crystal layer side substrate will be described.

(1) Immobilized liquid crystal layer The immobilized liquid crystal layer used in the present invention is formed on an alignment film for reactive liquid crystal, and is formed by immobilizing hybrid aligned reactive liquid crystal. The reactive liquid crystal is hybrid-aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side to the ferroelectric liquid crystal layer side. .

  The reactive liquid crystal used in the present invention preferably exhibits a nematic phase. This is because the nematic phase is relatively easy to control the alignment among liquid crystal phases.

  The reactive liquid crystal preferably contains a polymerizable liquid crystal material. This is because the alignment state of the reactive liquid crystal can be fixed. As the polymerizable liquid crystal material, any of a polymerizable liquid crystal monomer, a polymerizable liquid crystal oligomer, and a polymerizable liquid crystal polymer can be used, and among them, a polymerizable liquid crystal monomer is preferably used. The polymerizable liquid crystal monomer can be aligned at a lower temperature than other polymerizable liquid crystal materials, that is, a polymerizable liquid crystal oligomer and a polymerizable liquid crystal polymer, and has high sensitivity in alignment, and can be easily aligned. Because you can.

  The polymerizable liquid crystal monomer is not particularly limited as long as it is a liquid crystal monomer having a polymerizable functional group, and examples thereof include a monoacrylate monomer and a diacrylate monomer. These polymerizable liquid crystal monomers may be used alone or in combination of two or more.

  As the monoacrylate monomer and diacrylate monomer, those described in JP 2006-350322 A, JP 2006-323214 A, JP 2005-258429 A, JP 2005-258428 A, and the like are used. it can.

  Examples of the polymerizable liquid crystal monomer also include a compound represented by the following general formula (1) and a compound represented by the following general formula (2).

In the compound represented by the general formula (1), either or both of Y ¹ and Y ² is a group containing a reactive unsaturated double bond capable of causing polymerization via this group. From the viewpoint of polymerizability, vinyl group, acrylate group, acryloyl group, isopropenyl group, 4-vinylphenyl group, 1-chloroethenyl group, epoxy group, cyanate group or isocyanate group are particularly preferable. Y ¹ and Y ² may be the same as or different from each other. X ¹ and X ² are a direct bond, an ether group, an ester group or a carbonate group, or a group containing at least one of them, and may be the same or different from each other. In addition, each benzene ring constituting the mesogen in the central part may have 3 or less identical or different substituents described below. Examples of the substituent include a C1-C20 alkyl group, a C1-C20 alkoxy group, a C1-C20 alkoxycarbonyl group, a C1-C20 monoalkylaminocarbonyl group, a C1-C20 alkylcarbonyl group, and a C1-C20 alkyl group. Examples thereof include an alkylcarbonyloxy group, a C1-C20 alkylcarbonylamino group, a formyl group, a fluorine group, a chlorine group, a bromine group, a cyano group, a hydroxy group, and a nitro group.

In the compound represented by the general formula (2), R ¹ and R ² each represent hydrogen or a methyl group, but R ¹ and R ² are both hydrogen due to the wide temperature range showing a liquid crystal phase. preferable. Z may be hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group, or a nitro group, but is preferably chlorine or a methyl group. Moreover, a and b which show the chain length of the alkylene group which is a spacer of the (meth) acryloyloxy group and aromatic ring of both ends of a molecular chain can take arbitrary integers in the range of 2-12, respectively, The range is preferably 10 and more preferably 6-9. The compound of the general formula (2) in which a = b = 0 is poor in stability, is susceptible to hydrolysis, and has high crystallinity. Further, the compound of the general formula (2) in which a and b are each 13 or more has a low isotropic phase transition temperature (TI). Therefore, both of these compounds have a narrow temperature range exhibiting liquid crystallinity, and therefore a and b are preferably within the above ranges.

  Specific examples of the compound represented by the general formula (1) include the compounds exemplified below.

  Of the polymerizable liquid crystal monomers, diacrylate monomers are preferred. This is because the diacrylate monomer can be easily polymerized while maintaining the orientation state in a good state.

  The polymerizable liquid crystal monomer described above does not have to exhibit a nematic phase. These polymerizable liquid crystal monomers may be used as a mixture of two or more kinds as described above, because the composition in which these are mixed, that is, the reactive liquid crystal may exhibit a nematic phase. It is.

  The reactive liquid crystal is hybrid aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side to the ferroelectric liquid crystal layer side. Note that the hybrid alignment of the reactive liquid crystal means that, for example, the tilt angle of the fixed liquid crystal layer on the reactive liquid crystal alignment film side and the thickness of the fixed liquid crystal layer on the reactive liquid crystal alignment film is 1 This can be confirmed by measuring the tilt angle of the fixed liquid crystal layer on the ferroelectric liquid crystal layer side (air interface side) when formed at 0.0 μm or 0.5 μm. The tilt angle on the ferroelectric liquid crystal layer side (air interface side) of the fixed liquid crystal layer when the fixed liquid crystal layer is formed with a thickness of 1.0 μm or 0.5 μm on the alignment layer for reactive liquid crystal is fixed. If the tilt angle on the reactive liquid crystal alignment film side of the fluorinated liquid crystal layer is larger, it can be said that the reactive liquid crystal is hybrid-aligned. Here, the tilt angle on the ferroelectric liquid crystal layer side (air interface side) of the fixed liquid crystal layer when the fixed liquid crystal layer is formed with a thickness of 1.0 μm or 0.5 μm on the reactive liquid crystal alignment film. This is because the tilt angle of the actual fixed liquid crystal layer on the ferroelectric liquid crystal layer side (air interface side) is difficult to measure because the film thickness of the fixed liquid crystal layer is thin.

The tilt angle of the fixed liquid crystal layer on the reactive liquid crystal alignment film side, and the fixed liquid crystal layer when the fixed liquid crystal layer is formed with a thickness of 1.0 μm or 0.5 μm on the reactive liquid crystal alignment film. The tilt angle on the ferroelectric liquid crystal layer side can be obtained by a simulation method. A method by simulation will be described with reference to a schematic diagram of an immobilized liquid crystal layer shown in FIG. In FIG. 4, the upper side is the air interface side (ferroelectric liquid crystal layer side), and the lower side is the reactive liquid crystal alignment film side. Here, the fixed liquid crystal layer is divided (sliced) into a plurality of layers having the same tilt angle in the thickness direction, the tilt angle α _n and the phase difference Re _{n in} each layer are calculated, and the sum of these is calculated. By matching the phase difference amount Re with the actual measurement value, the tilt angle on the air interface side (ferroelectric liquid crystal layer side) and the tilt angle on the reactive liquid crystal alignment film side, which are undetermined parameters, can be obtained. .

Specifically, in FIG. 4, the division number n of the fixed liquid crystal layer is, for example, 100, the tilt angle on the air interface side (ferroelectric liquid crystal layer side) is α ₁ , and the tilt on the reactive liquid crystal alignment film side When the angle is α ₁₀₀ , the tilt angle α = α ₁ − (k−1) × (α ₁ −α ₁₀₀ ) / (100−1) is obtained in the k-th layer from the top. In this equation, the tilt angle α (rad) is considered to change with a continuous and uniform angle difference from the pretilt angle α ₁₀₀ to the tilt angle α ₁ on the ferroelectric liquid crystal layer side based on the continuous elastic body theory. Based on that.
In the k-th layer having the tilt angle α, a phase difference Re _k (nm) is generated based on the Scheffer equation represented by the following equation. The phase difference Re _k is a function of α and the incident angle ψ (rad).

Where λ is the wavelength (nm), n ₀ is the ordinary light refractive index, _ne is the extraordinary light refractive index, and d is the film thickness (nm). Note that the n ₀ and n _e is a value specific to the reactive liquid crystal which constitutes the fixed liquid crystal layer.

By summing the phase difference Re _k generated in each layer from k = 1 to 100, the phase difference amount Re of the entire fixed liquid crystal layer can be obtained as a function of the tilt angle α and the incident angle ψ. From this state, by changing the incident angle ψ by ± 45 ° from the normal direction of the substrate, and selecting the one in which the profile of the incident angle ψ and the phase difference amount Re agrees well with that of the actual measurement value, it is possible to determine the tilt angle alpha ₁₀₀ at a tilt angle alpha ₁ and alignment layer for reactive liquid crystal side at the air interface side (the ferroelectric liquid crystal layer side) is.

  In addition, regarding the tilt angle of the immobilized liquid crystal layer on the reactive liquid crystal alignment film side, the pretilt angle of the reactive liquid crystal alignment film is defined as the tilt angle of the fixed liquid crystal layer on the reactive liquid crystal alignment film side. You can also.

  When the tilt angle of the fixed liquid crystal layer on the ferroelectric liquid crystal layer side (air interface side) is arbitrarily adjusted within a predetermined range, the amount of leveling agent to be added to the reactive liquid crystal composition (if not added) The temperature and time of the pre-baking when the pre-baking is performed in the range of the liquid crystal phase temperature to the isotropic phase temperature of the reactive liquid crystal after the reactive liquid crystal composition is applied onto the reactive liquid crystal alignment film. The tilt angle can be controlled by adjusting (including the case of not pre-baking) or adjusting the molecular weight of the polymerizable liquid crystal monomer.

Specifically, the tilt angle on the air interface side can be reduced by increasing the amount of leveling agent added within a predetermined range. On the other hand, the tilt angle on the air interface side can be increased by not adding a leveling agent.
Further, by performing pre-baking, the tilt angle on the air interface side can be increased.
Furthermore, the tilt angle on the air interface side can be increased by lowering the molecular weight of the polymerizable liquid crystal monomer.

More specifically, the reactive liquid crystal composition applied on the reactive liquid crystal alignment film is pre-baked in the range of the isotropic phase transition temperature to the polymerization temperature without adding a leveling agent to the reactive liquid crystal composition. Thus, the reactive liquid crystal on the air interface side can be aligned with a relatively large tilt angle. After the reactive liquid crystal on the air interface side is sufficiently raised in this way, it is cooled to the liquid crystal phase temperature, and the reactive liquid crystal is formed from the air interface side to the reactive liquid crystal alignment film side based on the continuous elastic body theory. Hybrid orientation. Furthermore, a hybrid alignment state having a large tilt angle on the air interface side can be fixed by ultraviolet irradiation.
In general, the reactive unsaturated double bond of the UV-polymerizable polymerizable liquid crystal monomer is also polymerized by heat. Therefore, when performing prebaking, it is preferable to perform it below the polymerization temperature of the polymerizable liquid crystal monomer.
In the present invention, the pre-baking temperature is selected from the range of 40 ° C. to 80 ° C. higher than the isotropic phase transition temperature and 70 ° C. to 10 ° C. lower than the polymerization temperature. Can be obtained.

  On the other hand, by adding a leveling agent in the range of 0.01% by mass to 1% by mass with respect to the weight of the reactive liquid crystal and maintaining the reactive liquid crystal composition at the liquid crystal phase temperature, the reactivity on the air interface side is maintained. The liquid crystal can be aligned with a relatively small tilt angle. As described above, the tilt angle on the air interface side can be reduced by increasing the amount of leveling agent added within a predetermined range. By performing ultraviolet irradiation in such a state, a hybrid alignment state with a small tilt angle on the air interface side can be fixed.

  Thus, the tilt angle of the fixed liquid crystal layer on the ferroelectric liquid crystal layer side can be adjusted by appropriately selecting or adjusting the parameters of the leveling agent addition amount, prebaking temperature and time, and the molecular weight of the polymerizable liquid crystal monomer. It can be easily increased and adjusted to the desired value.

  The “liquid crystal phase temperature” means a temperature range in which the reactive liquid crystal composition exhibits a liquid crystal phase. In addition to the temperature range from the liquid crystal phase transition temperature to the isotropic phase transition temperature, the reactive liquid crystal composition has a liquid crystal phase. As long as it shows, it shall also include the temperature range of a supercooled state or a superheated state. The same applies to “isotropic phase temperature” which means a temperature range in which the reactive liquid crystal composition exhibits an isotropic phase.

  In the present invention, a polymerizable liquid crystal monomer having a small molecular weight and a short molecular length can be appropriately selected and mixed to obtain a fixed liquid crystal layer, so that the tilt angle of hybrid alignment can be easily adjusted.

  In addition, the tilt angle of the fixed liquid crystal layer on the reactive liquid crystal alignment film side is preferably 20 ° or less, and more preferably in the range of 5 ° to 15 °. This is because if the tilt angle is too large, it may be difficult to uniformly hybridize the reactive liquid crystal. Further, if the tilt angle is too small, there is a possibility that a reverse domain in which the rising direction of the reactive liquid crystal from the reactive liquid crystal alignment film is locally reversed may occur. If the tilt angle is equal to or greater than a predetermined value, the occurrence of reverse domain is suppressed. That is, as illustrated in FIG. 5, when the pretilt angle of the liquid crystal molecules 5a on the reactive liquid crystal alignment film 4 is 0 °, the optical axis of the liquid crystal molecules is completely horizontal with respect to the substrate. Which of the ends of the molecule rises up is random. For this reason, a disclination line (line defect) 50 corresponding to the boundary of the reverse domain is formed between the liquid crystal molecules whose rising directions are reversed. On the other hand, by adjusting the tilt angle to a predetermined value or more, the liquid crystal molecules applied on the reactive liquid crystal alignment film are in a state where one end has risen in advance, so that the liquid crystal molecules rise in a uniform direction. Become. The phenomenon that the occurrence of reverse domains can be suppressed by setting the tilt angle to a predetermined value or more, and the effect obtained by setting the tilt angle to a predetermined value or more are specific reactive liquid crystals or reactive properties. It is not manifested by the selection of an alignment film for liquid crystal, but based on a technique in which the direction in which reactive liquid crystals are intended to stand up by hybrid alignment is physically aligned.

  When arbitrarily adjusting the tilt angle on the reactive liquid crystal alignment film side of the fixed liquid crystal layer within a predetermined range, the alignment characteristics of the reactive liquid crystal alignment film and the anchoring energy for the reactive liquid crystal are changed, The tilt angle can be suitably adjusted by applying a reactive liquid crystal composition on the alignment film for reactive liquid crystal and then prebaking at a predetermined temperature and time.

  Specifically, by reducing the anchoring energy of the alignment film for reactive liquid crystal, one end of the liquid crystal molecules is drawn into the reactive liquid crystal layer by the surface free energy on the side of the alignment film for reactive liquid crystal. Trying to stand up at a pretilt angle. The anchoring energy is adjusted by selecting the material for the alignment film for reactive liquid crystal as appropriate with a large or small anchoring energy, or by introducing fluorine atoms into the material for the alignment film for reactive liquid crystal. can do.

  Further, by heating (pre-baking) the reactive liquid crystal to room temperature or higher, the molecular motion is activated, so that the molecules can rise at a larger pretilt angle against the anchoring energy. By making the pre-baking time sufficiently long, the rising of the liquid crystal molecules drawn into the reactive liquid crystal layer by the surface free energy on the reactive liquid crystal alignment film side can be sufficiently promoted, and the pretilt angle is further increased. be able to. Therefore, even when prebaking by heating to the same temperature, the pretilt angle can be increased or decreased within a predetermined range by adjusting the time. The prebaking temperature can be selected from the liquid crystal phase temperature or the isotropic phase temperature, but if prebaked at a high temperature, it may be difficult to apply a ferroelectric liquid crystal on the fixed liquid crystal layer. It is preferable to pre-bake at a relatively low temperature among the liquid crystal phase temperatures.

In addition, when the alignment film for reactive liquid crystal is a rubbing alignment film, the distance (gap) between the substrate and the rubbing roll is reduced so that the surface of the coating film such as polyimide or polyamide becomes deeper and closer to horizontal. Since the rubbing groove is formed, the pretilt angle can be further reduced. Further, the pretilt angle can be similarly reduced by increasing the rotational speed of the rubbing roll.
In addition, when the reactive liquid crystal alignment film is a photo alignment film or an oblique deposition alignment film, the pretilt angle can be increased or decreased by adjusting the angle of irradiation light or the deposition angle.

  Thus, the tilt angle of the fixed liquid crystal layer on the reactive liquid crystal alignment film side can be easily selected by appropriately selecting or adjusting the alignment characteristics, anchoring energy, prebaking temperature and time of the alignment film for reactive liquid crystal. Can be increased or decreased and adjusted to the desired value.

In this invention, you may add a photoinitiator, a polymerization inhibitor, etc. to the said reactive liquid crystal as needed.
For example, when polymerizing a polymerizable liquid crystal material by electron beam irradiation, a photopolymerization initiator may not be necessary, but in the case of polymerization by, for example, ultraviolet irradiation, usually photopolymerization is started. An agent is used to promote polymerization. As the photopolymerization initiator, a radical polymerizable initiator can be used. The radical polymerizable initiator is, for example, a compound that generates free radicals by the energy of ultraviolet rays, and is a benzophenone derivative such as benzoin or benzophenone or a derivative thereof such as xanthone or oxanthone derivative; chlorosulfonyl, chloromethyl polynuclear aromatic Halogen-containing compounds such as aromatic compounds, chloromethyl heterocyclic compounds or chloromethylbenzophenones; triazines; fluorenones; haloalkanes; redox couples of photoreducing dyes and reducing agents; organic sulfur compounds; peroxides, etc. Is mentioned. Preferably, Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 907 (all manufactured by Ciba Specialty Chemicals), Darocur (Merck), Adeka 1717 (Asahi Denka Kogyo Co., Ltd.), 2,2′-bis (o Examples include ketones such as -chlorophenyl) -4,5,4'-tetraphenyl-1,2'-biimidazole (manufactured by Kurokin Kasei Co., Ltd.) or biimidazole compounds. Moreover, a photopolymerization initiator as described in JP-A-2005-258428 can be used. These photopolymerization initiators can be used alone or in combination of two or more. When using 2 or more types together, it is good not to inhibit the absorption spectral characteristics. In addition to the photopolymerization initiator, it is also possible to add a sensitizer as long as the object of the present invention is not impaired. The addition amount of such a photopolymerization initiator is generally 0.01% by mass to 20% by mass, preferably 0.1% by mass to 10% by mass, more preferably 0.5% by mass to 5% by mass. % Can be added to the reactive liquid crystal.

  Examples of the polymerization inhibitor include p-benzoquinone, naphthoquinone, p-xyloquinone, p-toluquinone, 2,6-dichloroquinone, 2,5-diacetoxy-p-benzoquinone, 2,5-dicaproxy-p-benzoquinone, 2 , 5-diaeroxy-p-benzoquinone, hydroquinone, pt-butylcatechol, 2,5-dibutylhydroquinone, mono-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, di-t-butyl para Cresol, 2,4,6-tri-t-butylphenol, hydroquinone monomethyl ether, α-naphthol, acetanidin acetate and the like can be used. The addition amount of the polymerization inhibitor is preferably 0.001% by mass to 3% by mass, more preferably 0.01% by mass to 2% by mass with respect to the weight of the reactive liquid crystal. If it is below the above range, it is cured even at a low exposure amount due to light scattering or the like, and if it exceeds this range, the ultraviolet exposure sensitivity is lowered.

  A nonionic or ionic surfactant can be used as a leveling agent to be added in a trace amount when the tilt angle on the ferroelectric liquid crystal layer side is relatively small. Specifically, silicone surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene derivatives, polyoxyethylene / polyoxypropylene / block copolymers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene derivatives Nonionic surfactants such as oxyethylene fatty acid esters and polyoxyethylene alkylamines, or fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates , Alkyl phosphate, polyoxyethylene alkyl sulfate ester salt, naphthalene sulfonic acid formalin condensate, special polycarboxylic sun type polymer surfactant, polyoxyethylene Anionic surfactants such as N'arukirurin ester can be suitably used. The addition amount of the leveling agent is preferably in the range of 0.01% by mass to 1% by mass with respect to the weight of the reactive liquid crystal.

  The thickness of the fixed liquid crystal layer is appropriately adjusted according to the target anisotropy, and can be set, for example, within a range of 1 nm to 1000 nm, and preferably within a range of 3 nm to 100 nm. This is because if the fixed liquid crystal layer is too thick, anisotropy more than necessary occurs, and if the fixed liquid crystal layer is too thin, the predetermined anisotropy may not be obtained.

  The method for forming the fixed liquid crystal layer will be described in detail in the section “B. Manufacturing method of liquid crystal display element”, which will be described later.

(2) Alignment film for reactive liquid crystal As the alignment film for reactive liquid crystal used in the present invention, the above-mentioned reactive liquid crystal can be aligned, and there is an adverse effect in fixing the alignment state of the above-mentioned reactive liquid crystal. There is no particular limitation as long as it does not reach. As the alignment film for reactive liquid crystal, for example, a rubbing-treated alignment film, a photo-alignment-treated photo-alignment film, an oblique deposition alignment film, or the like can be used. Among them, a rubbing-treated alignment film, a photo-alignment film, etc. Is preferred.

  The rubbing-treated alignment film is useful in that a relatively high pretilt angle can be realized. As the alignment film subjected to the rubbing treatment, for example, those described in JP-A-2008-129529 can be used.

  The photo-alignment film irradiates a substrate coated with a photo-excited reaction type material with light with controlled polarization to cause photo-excited reaction (decomposition, isomerization, dimerization) and to give anisotropy to the obtained film. This aligns the liquid crystal molecules on the film. The photo-alignment film is useful in that since the photo-alignment process is a non-contact alignment process, there is no generation of static electricity or dust, and the quantitative alignment process can be controlled. Photoexcitation materials used for photo-alignment films include photoisomerization materials that impart anisotropy to the film by photoisomerization reaction, and anisotropy to the film by photodimerization reaction. And a photodecomposable material that imparts anisotropy to the film by causing a photodecomposition reaction. As the photo-alignment film, for example, those described in JP-A-2006-350322, JP-A-2006-323214, JP-A-2005-258429, and JP-A-2005-258428 can be used.

  The oblique vapor deposition alignment film is formed by an oblique vapor deposition method. The oblique deposition film is useful in that a relatively high pretilt angle can be realized. As the oblique deposition alignment film, for example, those described in International Publication WO2008 / 075732 Pamphlet can be used.

(3) First Electrode Layer The first electrode layer used in the present invention is not particularly limited as long as it is generally used as an electrode of a liquid crystal display element, but the first electrode layer of the first substrate. Preferably, at least one of the second electrode layers of the second substrate is formed of a transparent conductor. Preferred examples of the transparent conductor material include indium oxide, tin oxide, indium tin oxide (ITO), and the like.

  When the liquid crystal display element of the present invention is driven by an active matrix method using TFTs, an entire common electrode formed of the transparent conductor is provided on one of the fixed liquid crystal layer side substrate and the counter substrate, On the other side, a gate electrode and a source electrode are arranged in a matrix, and a TFT element and a pixel electrode are provided in a portion surrounded by the gate electrode and the source electrode.

  Examples of the method for forming the first electrode layer include chemical vapor deposition (CVD), physical vapor deposition (PVD) such as sputtering, ion plating, and vacuum deposition.

(4) 1st board | substrate The 1st board | substrate used for this invention will not be specifically limited if generally used as a board | substrate of a liquid crystal display element, For example, a glass plate, a plastic plate, etc. are mentioned preferably.

(5) Other Configurations In the present invention, partition walls or columnar spacers may be formed on either the fixed liquid crystal layer side substrate or the counter substrate. When partition walls or columnar spacers are formed on the fixed liquid crystal layer side substrate, the partition walls or columnar spacers are formed on the first substrate, and the alignment film for reactive liquid crystal and the fixed liquid crystal layer cover the partition walls or columnar spacers. Is formed.
As the partition walls and columnar spacers, general partition walls and columnar spacers can be applied.
Among them, as described in the section “B. Manufacturing method of liquid crystal display element” described later, it is preferable to apply a ferroelectric liquid crystal on the fixed liquid crystal layer of the fixed liquid crystal layer side substrate. It is preferable that partition walls or columnar spacers are formed on the liquid crystal layer side substrate.

In the present invention, a colored layer may be formed on either the fixed liquid crystal layer side substrate or the counter substrate. When the colored layer is formed, a color filter type liquid crystal display element capable of realizing color display by the colored layer can be obtained.
As the colored layer, a colored layer in a general color filter can be applied.

2. Ferroelectric liquid crystal layer The ferroelectric liquid crystal layer in the present invention is formed between the fixed liquid crystal layer of the fixed liquid crystal layer side substrate and the counter substrate, and includes ferroelectric liquid crystal.

The ferroelectric liquid crystal used in the present invention is not particularly limited as long as it exhibits a chiral smectic C (SmC ^* ) phase. As the phase series of the ferroelectric liquid crystal, for example, a phase change between a nematic (N) phase, a cholesteric (Ch) phase, a chiral smectic C (SmC ^* ) phase, and a nematic (N) phase-chiral smectic C are possible. Phase change with (SmC ^* ) phase, Nematic (N) phase-Smectic A (SmA) phase-Chiral smectic C (SmC ^* ) phase, Nematic (N) phase-Cholesteric (Ch) phase- Examples thereof include those that change phase with a smectic A (SmA) phase-chiral smectic C (SmC ^* ) phase.

In addition, as the ferroelectric liquid crystal, either one showing bistability or one showing monostability can be used. Among these, ferroelectric liquid crystal exhibiting monostability is preferable. When a ferroelectric liquid crystal exhibiting monostability is used, gradation display is possible by continuously changing the director of the liquid crystal (inclination of the molecular axis) by voltage change and analog modulation of the transmitted light intensity. Because it becomes.
In particular, when the liquid crystal display element is driven by a field sequential color system, it is preferable to use a ferroelectric liquid crystal exhibiting monostability. By using a ferroelectric liquid crystal exhibiting monostability, it is possible to drive using an active matrix method using TFTs, and to control gradation by voltage modulation, realizing high-definition and high-quality display. Because it can be done.

  “Showing monostability” means a state in which the state of the ferroelectric liquid crystal when no voltage is applied is stabilized in one state. In the ferroelectric liquid crystal, as illustrated in FIG. 6, the liquid crystal molecules 11 a are tilted from the layer normal z, and rotate along a cone ridge having a bottom surface perpendicular to the layer normal z. In such a cone, the tilt angle of the liquid crystal molecules 11a with respect to the layer normal z is referred to as a tilt angle θ. In this manner, the liquid crystal molecules 11a can operate on the cone between two states inclined by a tilt angle ± θ with respect to the layer normal z. Specifically, showing monostability means a state where the liquid crystal molecules 11a are stabilized in any one state on the cone when no voltage is applied.

  Among ferroelectric liquid crystals exhibiting monostability, half V-shaped switching characteristics in which liquid crystal molecules operate only when a positive or negative voltage is applied, as illustrated in FIGS. 7A and 7B. It is preferable to show this. Using a ferroelectric liquid crystal exhibiting such a half V-shaped switching characteristic, it is possible to take a sufficiently long opening time as a black and white shutter, thereby making it possible to display each color that is temporally switched brighter. This is because a bright color display liquid crystal display element can be realized.

  The “half V-shaped switching characteristic” refers to an electro-optical characteristic in which the amount of transmitted light is asymmetric with respect to an applied voltage. Specifically, among the transmitted light amounts with respect to the applied voltage when a positive and negative voltage of 10 V is applied to the liquid crystal layer, A is the transmitted light amount of the applied voltage when the transmitted light amount is small, and the applied voltage is transmitted when the transmitted light amount is large. When the amount of light is B, B / A is 2 or more.

Such a ferroelectric liquid crystal can be variously selected from generally known liquid crystal materials according to required characteristics. In particular, a ferroelectric liquid crystal that exhibits an SmC ^* phase from the Ch phase without passing through the SmA phase is suitable as a material exhibiting half V-shaped switching characteristics. Specifically, “R2301” manufactured by AZ Electronic Materials, Inc. ". Specific examples of the ferroelectric liquid crystal via the SmA phase include “FELIXM4851-100” manufactured by AZ Electronic Materials.

The ferroelectric liquid crystal layer may contain other compounds in addition to the above ferroelectric liquid crystal. As other compounds, those having an arbitrary function can be used depending on the function required for the liquid crystal display element. Examples of other compounds that can be suitably used include a polymer of a polymerizable monomer. This is because when the polymer of the polymerizable monomer is contained in the ferroelectric liquid crystal layer, the alignment of the ferroelectric liquid crystal is so-called “polymer stabilization” and excellent alignment stability is obtained.
The case where the ferroelectric liquid crystal layer contains a ferroelectric liquid crystal and a polymer of a polymerizable monomer is the same as that described in JP-A-2006-323215.

  The thickness of the ferroelectric liquid crystal layer is preferably in the range of 1.2 μm to 3.0 μm, more preferably in the range of 1.3 μm to 2.5 μm, and still more preferably in the range of 1.4 μm to 2.0 μm. It is. This is because if the thickness of the ferroelectric liquid crystal layer is too thin, the contrast may be lowered, and if the thickness of the ferroelectric liquid crystal layer is too thick, the ferroelectric liquid crystal may be difficult to align.

As a method of sandwiching the ferroelectric liquid crystal between the fixed liquid crystal layer of the fixed liquid crystal layer side substrate and the counter substrate, a method generally used as a manufacturing method of a liquid crystal cell can be used, for example, a vacuum injection method A coating method (dropping method) or the like can be used.
The method for forming the ferroelectric liquid crystal layer is described in detail in the section of “B. Manufacturing method of liquid crystal display element” described later, and thus the description thereof is omitted here.

3. Counter substrate The counter substrate used in the present invention is disposed so as to face the fixed liquid crystal layer of the fixed liquid crystal layer side substrate.

  The counter substrate preferably includes a second substrate, a second electrode layer formed on the second substrate, and a second alignment film formed on the second electrode layer. In this case, the counter substrate is arranged so that the fixed liquid crystal layer of the fixed liquid crystal layer side substrate and the second alignment film of the counter substrate face the fixed liquid crystal layer side substrate, and the fixed liquid crystal layer A ferroelectric liquid crystal layer is formed between the fixed liquid crystal layer of the side substrate and the second alignment film of the counter substrate.

  The second substrate and the second electrode layer can be the same as the first substrate and the first electrode layer of the fixed liquid crystal layer side substrate, and thus description thereof is omitted here. Hereinafter, other configurations of the counter substrate will be described.

(1) Second alignment film The second alignment film used in the present invention is not particularly limited as long as the ferroelectric liquid crystal can be aligned. For example, a rubbing alignment film, A photo-alignment film subjected to photo-alignment treatment, an oblique deposition alignment film, or the like can be used. Among these, a rubbing-process alignment film or photo-alignment film is preferable.
The alignment film subjected to the rubbing treatment, the photo-alignment film subjected to the photo-alignment treatment, and the oblique deposition alignment film are the same as those described in the section of the alignment film for reactive liquid crystal of the fixed liquid crystal layer side substrate. Since there is, explanation here is omitted.

(2) Preferred Embodiment In the present invention, when the ferroelectric liquid crystal exhibits a chiral smectic C (SmC ^* ) phase without passing through a smectic A (SmA) phase in the temperature lowering process, the second alignment film is A rubbing-treated alignment film, a photo-alignment-treated photo-alignment film, or an oblique deposition alignment film is preferable. A ferroelectric liquid crystal that exhibits the SmC ^* phase without passing through the SmA phase is likely to generate two regions (referred to as a double domain) having different layer normal directions. Will be displayed. On the other hand, since the ferroelectric liquid crystal is sandwiched between the fixed liquid crystal layer and the second alignment film as described above, the occurrence of double domains can be suppressed and monodomain alignment can be obtained. Can do. This is considered to be due to the following reasons. That is, it is considered that the polar liquid surface interaction, which is the interaction between the ferroelectric liquid crystal, the surface of the fixed liquid crystal layer and the surface of the second alignment film, is different between the fixed liquid crystal layer and the second alignment film as described above. . Therefore, the fixed liquid crystal layer tends to have a relatively positive polarity between the fixed liquid crystal layer and the second alignment film, and the positive polarity of the spontaneous polarization of the ferroelectric liquid crystal is directed to the second alignment film side. By utilizing this tendency, the direction of spontaneous polarization of liquid crystal molecules can be controlled. Further, since the direction of spontaneous polarization of liquid crystal molecules can be controlled, the ferroelectric liquid crystal monolithic material does not generate a double domain peculiar to the ferroelectric liquid crystal that expresses the SmC ^* phase without passing through the SmA phase. Domain orientation can be obtained.

Further, when the ferroelectric liquid crystal exhibits a chiral smectic C (SmC ^* ) phase without passing through the smectic A (SmA) phase in the temperature lowering process, the counter substrate includes the second substrate and the second substrate. It is also preferable to have a second electrode layer formed thereon. In this case, since the ferroelectric liquid crystal is sandwiched between the fixed liquid crystal layer of the fixed liquid crystal layer side substrate and the second electrode layer of the counter substrate, it is possible to suppress the occurrence of double domains. Domain orientation can be obtained. The fixed liquid crystal layer and the second electrode layer are considered to have different polar surface interactions, which are interactions between the ferroelectric liquid crystal and the surfaces of the fixed liquid crystal layer and the second electrode layer. Therefore, the fixed liquid crystal layer tends to have a relatively positive polarity in the fixed liquid crystal layer and the second electrode layer, and the positive polarity of the spontaneous polarization of the ferroelectric liquid crystal is directed to the second electrode layer side. By utilizing this tendency, the direction of spontaneous polarization of liquid crystal molecules can be controlled. Further, since the direction of spontaneous polarization of liquid crystal molecules can be controlled, the ferroelectric liquid crystal monolithic material does not generate a double domain peculiar to the ferroelectric liquid crystal that expresses the SmC ^* phase without passing through the SmA phase. Domain orientation can be obtained.

Further, when the ferroelectric liquid crystal exhibits a chiral smectic C (SmC ^* ) phase without passing through the smectic A (SmA) phase in the temperature lowering process, the counter substrate includes the second substrate and the second substrate. A second electrode layer formed on the second electrode layer, a non-oriented treatment layer formed on the second electrode layer, containing a photoisomerization-reactive compound having an azobenzene skeleton in the molecule and not subjected to an orientation treatment; It is also preferable to have In this case, since the ferroelectric liquid crystal is sandwiched between the fixed liquid crystal layer of the fixed liquid crystal layer side substrate and the non-aligned treatment layer of the counter substrate, the occurrence of double domains can be suppressed. Domain orientation can be obtained. The fixed liquid crystal layer and the non-oriented treatment layer are considered to have different polar surface interactions, which are the interactions between the ferroelectric liquid crystal and the surfaces of the fixed liquid crystal layer and the non-oriented treatment layer. For this reason, the fixed liquid crystal layer tends to have a relatively positive polarity between the fixed liquid crystal layer and the non-oriented treatment layer, and the positive polarity of the spontaneous polarization of the ferroelectric liquid crystal is directed to the non-oriented treatment layer side. By utilizing this tendency, the direction of spontaneous polarization of liquid crystal molecules can be controlled. Further, since the direction of spontaneous polarization of liquid crystal molecules can be controlled, the ferroelectric liquid crystal monolithic material does not generate a double domain peculiar to the ferroelectric liquid crystal that expresses the SmC ^* phase without passing through the SmA phase. Domain orientation can be obtained.

  In addition, it can confirm that a non-orientation treatment layer is what has not been subjected to the orientation treatment by measuring the polarization ultraviolet-visible absorption spectrum of a non-orientation treatment layer. That is, using a UV-visible spectrophotometer (V7100: manufactured by JASCO Corporation), the non-oriented treatment layer is irradiated with polarized ultraviolet rays, and polarized ultraviolet / visible absorption spectra parallel and perpendicular to the polarization direction of the ultraviolet rays are obtained. taking measurement. If the ratio of the absorption peak of the spectrum in the vertical direction and the horizontal direction is 1.2 or less, it is assumed that the alignment treatment has not been performed.

  The ratio of the absorption peak of the spectrum in the vertical direction and the horizontal direction is preferably 1.2 or less, more preferably 1.1 or less. Depending on the method of applying the material when forming the unoriented layer, the unoriented layer may have a slight anisotropy. The lower limit of the ratio of absorption peaks is not particularly limited.

  Examples of the photoisomerization reactive compound having an azobenzene skeleton in the molecule include, for example, JP 2006-350322 A, JP 2006-323214 A, JP 2005-258429 A, and JP 2005-258428 A. Can be used.

  The thickness of the unoriented treatment layer is preferably in the range of 1 nm to 1000 nm, more preferably in the range of 3 nm to 100 nm. If the thickness of the unaligned layer is thinner than the above range, the direction of spontaneous polarization of the ferroelectric liquid crystal may not be sufficiently controlled. Conversely, if the thickness of the unaligned layer is larger than the above range, it is disadvantageous in terms of cost. It is because it may become.

  For example, JP 2006-350322 A, JP 2006-2006 A include a photoisomerization reactive compound having an azobenzene skeleton in the molecule and a method for forming an unoriented treatment layer that has not been subjected to photo-alignment treatment. In the method for forming a photo-alignment film described in Japanese Patent No. 323214, Japanese Patent Application Laid-Open No. 2005-258429, and Japanese Patent Application Laid-Open No. 2005-258428, the same applies except that light with controlled polarization is not irradiated.

(3) Other Configurations In the counter substrate in the present invention, partition walls or columnar spacers may be formed on the second substrate, and a colored layer may be formed on the second substrate. Note that the partition walls, the columnar spacers, and the colored layers are described in the above-mentioned section of the fixed liquid crystal layer side substrate, and thus the description thereof is omitted here.

4). Polarizing plate The liquid crystal display element of the present invention may have polarizing plates on the outside of the fixed liquid crystal layer side substrate and the counter substrate, respectively. The polarizing plate is not particularly limited as long as it transmits only a specific direction in the wave of light, and a polarizing plate that is generally used as a polarizing plate of a liquid crystal display element can be used.

5). Method for Driving Liquid Crystal Display Element As a method for driving the liquid crystal display element of the present invention, the high-speed response of ferroelectric liquid crystal can be used. A field sequential color system that particularly requires high-speed response is suitable.

  Further, the driving method of the liquid crystal display element of the present invention is not limited to the field sequential method, and may be a color filter method that performs color display using a colored layer.

  As a driving method of the liquid crystal display element of the present invention, an active matrix system using a thin film transistor (TFT) is preferable. This is because by adopting an active matrix system using TFTs, the target pixel can be reliably turned on and off, and a high-quality display becomes possible.

  In the present invention, the fixed liquid crystal layer side substrate may be a TFT substrate and the counter substrate may be a common electrode substrate, the fixed liquid crystal layer side substrate may be a common electrode substrate, and the counter substrate may be a TFT substrate. Among these, the fixed liquid crystal layer side substrate is preferably a TFT substrate, and the counter substrate is preferably a common electrode substrate. Ferroelectric liquid crystals are difficult to align due to their high molecular order, and because TFTs and other projections are formed on the TFT substrate, ferroelectric liquid crystal alignment defects occur near the TFT, causing light leakage (white). Omission) may occur. On the other hand, when the fixed liquid crystal layer side substrate is a TFT substrate, the reactive liquid crystal alignment film and the fixed liquid crystal layer are formed so as to cover the TFT, so that the alignment is simply performed so as to cover the TFT. Compared with the case where a film is formed, it is possible to suppress the occurrence of poor alignment of the ferroelectric liquid crystal at the edge of a projection such as a TFT. This is because the fixed liquid crystal layer is different from general alignment films such as rubbing films and photo-alignment films, and the alignment process is performed to align the reactive liquid crystals during the formation process. The fact that the liquid crystal phase is flowed on the liquid crystal alignment film is considered to have an influence. Therefore, when the fixed liquid crystal layer side substrate is a TFT substrate, it is possible to suppress the alignment failure of the ferroelectric liquid crystal in the vicinity of the TFT and to prevent the occurrence of light leakage (whiteout).

  Further, the driving method of the liquid crystal display element of the present invention may be a segment method.

B. Next, a method for manufacturing a liquid crystal display element of the present invention will be described.
In the method for producing a liquid crystal display element of the present invention, a reactive liquid crystal layer containing a reactive liquid crystal is formed on a first substrate on which a first electrode layer and an alignment film for reactive liquid crystal are sequentially formed. The reactive liquid crystal in the liquid crystal layer is hybrid aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side, and the alignment state of the reactive liquid crystal is fixed to fix the liquid crystal. A fixed liquid crystal layer side substrate preparation step for forming a layer, a ferroelectric liquid crystal coating step for applying a ferroelectric liquid crystal on the fixed liquid crystal layer, and the fixed liquid crystal layer on which the ferroelectric liquid crystal is applied A substrate bonding step for bonding the side substrate and the counter substrate, and a ferroelectric property for aligning the ferroelectric liquid crystal sandwiched between the fixed liquid crystal layer side substrate and the counter substrate without performing an electric field application process. Having a liquid crystal alignment step It is an butterfly.

  According to the present invention, since the reactive liquid crystal is hybrid-aligned so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side, the tilt of the fixed liquid crystal layer on the ferroelectric liquid crystal side is tilted. The corner can be made relatively large. In addition, when the fixed liquid crystal layer is formed on the reactive liquid crystal alignment film, the reactive liquid crystal is hybrid-aligned by the reactive liquid crystal alignment film, for example, by irradiating ultraviolet rays to polymerize the reactive liquid crystal. The alignment state of the reactive liquid crystal can be fixed, the alignment liquid crystal layer can be provided with an alignment regulating force for the ferroelectric liquid crystal, and can be made unaffected by temperature or the like. Furthermore, the reactive liquid crystal is relatively similar in structure to the ferroelectric liquid crystal, and the interaction with the ferroelectric liquid crystal becomes strong, so that the alignment of the ferroelectric liquid crystal can be effectively controlled. According to the present invention, since the ferroelectric liquid crystal is applied on the fixed liquid crystal layer, the alignment regulating force of the fixed liquid crystal layer greatly contributes to the alignment of the ferroelectric liquid crystal, and particularly the initial alignment of the ferroelectric liquid crystal. It is thought to contribute greatly to the condition. Therefore, in the present invention, it is possible to suppress the occurrence of alignment defects such as zigzag defects and improve the contrast.

  In addition, when filling the ferroelectric liquid crystal by the vacuum injection method, the zigzag defect is likely to be partially generated in the liquid crystal display element, whereas when filling the ferroelectric liquid crystal by the coating method, the zigzag defect is the liquid crystal. Since it tends to occur entirely in the display element, it is useful to apply a ferroelectric liquid crystal on the fixed liquid crystal layer in the method of manufacturing a liquid crystal display element having a ferroelectric liquid crystal application step as in the present invention. is there.

  Furthermore, according to the present invention, the ferroelectric liquid crystal can be aligned by the alignment regulating force of the fixed liquid crystal layer only by slowly cooling the ferroelectric liquid crystal without performing an electric field application process. Therefore, since the ferroelectric liquid crystal is aligned without performing an electric field application treatment, the alignment can be maintained even when the temperature is raised to the phase transition temperature or higher, and the occurrence of alignment defects such as zigzag defects can be suppressed.

  Hereinafter, each process in the manufacturing method of the liquid crystal display element of this invention is demonstrated.

1. Immobilized liquid crystal layer side substrate preparation step The immobilized liquid crystal layer side substrate preparation step in the present invention is a reaction containing reactive liquid crystal on a first substrate on which a first electrode layer and an alignment film for reactive liquid crystal are sequentially formed. A reactive liquid crystal layer is formed, and the reactive liquid crystal in the reactive liquid crystal layer is hybrid-aligned so that a tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side, and the reactive liquid crystal This is a step of forming an immobilized liquid crystal layer by fixing the alignment state.

  Since the first substrate, the first electrode layer, the reactive liquid crystal alignment film, and the reactive liquid crystal are described in detail in the section “A. Liquid crystal display element”, the description thereof is omitted here.

  As a method for forming the reactive liquid crystal layer, a method in which the reactive liquid crystal composition containing the reactive liquid crystal is applied on the reactive liquid crystal alignment film is used. Further, instead of applying the reactive liquid crystal composition, a method of forming a dry film or the like in advance and laminating it on the first electrode layer can also be used. From the viewpoint of the simplicity of the production process, a reactive liquid crystal composition is prepared by dissolving a reactive liquid crystal in a solvent, and this is applied to an alignment film for reactive liquid crystal, and a method of removing the solvent is adopted. Is preferred.

  The reactive liquid crystal composition is prepared by dissolving the reactive liquid crystal and, if necessary, a photopolymerization initiator and a polymerization inhibitor in a solvent. When horizontally aligning reactive liquid crystals, it is common to uniformly align reactive liquid crystals horizontally by adding leveling agents such as anionic surfactants and silicone surfactants to reactive liquid crystal compositions. However, in the present invention, the leveling agent is not added, or even when it is added, by adjusting the addition of the leveling agent to a very small amount, the surface free energy of the reactive liquid crystal on the ferroelectric liquid crystal layer side is adjusted. This can be raised sufficiently, and an immobilized liquid crystal layer that is homogeneously hybrid-aligned as a whole can be obtained.

  The solvent used in the reactive liquid crystal composition is not particularly limited as long as it can dissolve the reactive liquid crystal and the like and does not inhibit the alignment ability of the alignment film for reactive liquid crystal. As such a solvent, for example, a solvent described in JP-A-2005-258428 can be used. A solvent may be used independently and may use 2 or more types together.

  Further, if only a single kind of solvent is used, the solubility of the reactive liquid crystal or the like may be insufficient, or the reactive liquid crystal alignment film may be eroded as described above. In this case, this inconvenience can be avoided by using a mixture of two or more solvents. Among the above-mentioned solvents, hydrocarbons and glycol monoether acetate solvents are preferable as the sole solvent, and a mixed system of ethers or ketones and glycol solvent is preferable as the mixed solvent. It is.

  Although the concentration of the reactive liquid crystal composition depends on the solubility of the reactive liquid crystal and the thickness of the immobilized liquid crystal layer, it cannot be defined unconditionally, but is usually 0.1% by mass to 40% by mass, preferably 1% by mass. It adjusts in the range of% -20 mass%. If the concentration of the reactive liquid crystal composition is lower than the above range, the reactive liquid crystal may be difficult to align. Conversely, if the concentration of the reactive liquid crystal composition is higher than the above range, the viscosity of the reactive liquid crystal composition is low. It is because it becomes high and it may become difficult to form a uniform coating film.

  Furthermore, a compound such as that described in JP-A-2005-258428 can be added to the reactive liquid crystal composition as long as the object of the present invention is not impaired. The amount of these compounds added to the reactive liquid crystal is selected within a range that does not impair the object of the present invention. Addition of these compounds improves the curability of the reactive liquid crystal, increases the mechanical strength of the resulting fixed liquid crystal layer, and improves its stability.

  Examples of a method for applying such a reactive liquid crystal composition include spin coating, roll coating, printing, dip coating, die coating, casting, bar coating, blade coating, spray coating, and gravure. Examples thereof include a coating method, a reverse coating method, an extrusion coating method, an ink jet method, a flexographic printing method, and a screen printing method.

  In addition, the solvent is removed after the reactive liquid crystal composition is applied, and the removal of the solvent is performed by, for example, removal under reduced pressure or removal by heating, or a combination thereof.

  In the present invention, the reactive liquid crystal in the reactive liquid crystal layer is hybrid-aligned by the reactive liquid crystal alignment film so that the tilt angle gradually increases in the thickness direction from the reactive liquid crystal alignment film side. It shall be in a state having regularity. That is, a liquid crystal phase is developed in the reactive liquid crystal. This is usually performed by a method such as a method of heat treatment at or below the isotropic phase temperature. Specifically, the reactive liquid crystal layer is heated to the liquid crystal phase temperature to promote the hybrid alignment of the reactive liquid crystal. The reactive liquid crystal applied on the reactive liquid crystal alignment film is heated to the liquid crystal phase temperature, so that the reactive liquid crystal alignment film is horizontally aligned by the anchoring energy with the reactive liquid crystal alignment film, A hybrid alignment state having a predetermined tilt angle can be obtained on the air interface side. In order to promote this hybrid alignment, a magnetic field may be applied to the reactive liquid crystal composition heated to the liquid crystal phase temperature.

The tilt angle of the fixed liquid crystal layer on the air interface side can be adjusted by adjusting the amount of the leveling agent added to the reactive liquid crystal composition (including the case where it is not added), or by using the reactive liquid crystal composition for the reactive liquid crystal. Adjust the temperature and time (including when not prebaked) when prebaking within the range of the liquid crystal phase temperature to the isotropic phase temperature of the reactive liquid crystal after coating on the alignment film, and adjust the molecular weight of the polymerizable liquid crystal monomer Can be controlled.
The method for adjusting the tilt angle has been described in detail in the section “A. Liquid crystal display element”, and thus the description thereof is omitted here.

  The tilt angle of the immobilized liquid crystal layer on the reactive liquid crystal alignment film side is preferably within a predetermined range as described in the above section “A. Liquid crystal display element”.

The tilt angle of the fixed liquid crystal layer on the alignment layer for reactive liquid crystal adjusts the alignment characteristics of the alignment film for reactive liquid crystal and the anchoring energy for the reactive liquid crystal, and is reactive on the alignment film for reactive liquid crystal. It can be controlled by adjusting the temperature and time for pre-baking after applying the liquid crystal composition.
The method for adjusting the tilt angle has been described in detail in the section “A. Liquid crystal display element”, and thus the description thereof is omitted here.

  As described above, the reactive liquid crystal has a polymerizable liquid crystal material, and in order to fix the alignment state of such a polymerizable liquid crystal material, a method of irradiating active radiation that activates polymerization is used. . The active radiation as used herein refers to radiation capable of causing polymerization of the polymerizable liquid crystal material. If necessary, a photopolymerization initiator may be included in the polymerizable liquid crystal material. The actinic radiation is not particularly limited as long as it is a radiation capable of polymerizing the polymerizable liquid crystal material, but usually ultraviolet light or visible light is used from the viewpoint of the ease of the apparatus. The In addition, about irradiation of actinic radiation, it can be made the same as that of description of Unexamined-Japanese-Patent No. 2005-258428.

  Such irradiation with active radiation may be performed under a temperature condition in which the polymerizable liquid crystal material becomes a liquid crystal phase, or may be performed at a temperature lower than the temperature at which the liquid crystal phase is formed. This is because the alignment state of the polymerizable liquid crystal material once in the liquid crystal phase is not disturbed suddenly even if the temperature is lowered thereafter.

As a method for fixing the alignment state of the polymerizable liquid crystal material, in addition to the method of irradiating the active radiation, a method of polymerizing the polymerizable liquid crystal material by heating can also be used. As the reactive liquid crystal used in this case, it is preferable that the polymerizable liquid crystal monomer contained in the reactive liquid crystal is thermally polymerized below the NI transition point of the reactive liquid crystal.
Moreover, you may use together irradiation of actinic radiation, and a heating.

In the fixed liquid crystal layer fixed by irradiation with actinic radiation, if the degree of curing is insufficient by curing with only actinic radiation, a heat treatment (post-baking) may be performed after the exposure to completely terminate the polymerization reaction. preferable.
The post-baking temperature is preferably set within a range of 170 ° C. or higher and 260 ° C. or lower regardless of the type of polymerizable liquid crystal monomer. In order to obtain a substantial reaction rate in production, it is preferable to heat and bak at 170 ° C. or higher. This temperature is also the temperature at which the unsaturated double bond of the polymerizable liquid crystal monomer at one or both ends opens. On the other hand, the higher the heating temperature, the faster the polymerization reaction rate of the polymerizable liquid crystal monomer. However, in the region exceeding 260 ° C., the decomposition reaction of the polymerizable liquid crystal monomer itself occurs, and the deterioration of the fixed liquid crystal layer itself becomes remarkable. In particular, in the case of a polymerizable liquid crystal monomer having a reactive unsaturated double bond at both ends, when heated to a temperature exceeding 260 ° C., the polymerized immobilized liquid crystal layer may be decomposed.

2. Ferroelectric liquid crystal application step The ferroelectric liquid crystal application step in the present invention is a step of applying a ferroelectric liquid crystal on the fixed liquid crystal layer.

  The method for applying the ferroelectric liquid crystal is not particularly limited as long as it can apply a predetermined amount that can be encapsulated. Among them, the ferroelectric liquid crystal is used so that the ferroelectric liquid crystal hardly flows. It is preferable that it is the method which can apply | coat. When the ferroelectric liquid crystal flows in an isotropic phase on the fixed liquid crystal layer, if the flow distance of the ferroelectric liquid crystal is too long, the orientation may be disturbed at the interface where the flowed ferroelectric liquid crystal contacts. Because there is.

  Examples of such a coating method include a discharge method such as an ink jet method and a dispenser method, a coating method such as a bar coating method and a slot die coating method, a printing method such as a flexographic printing method, a gravure printing method, an offset printing method, and a screen printing method. Law. Of these, the discharge method is preferable, and the inkjet method is particularly preferable. If the inkjet method is used, the ferroelectric liquid crystal can be applied in a continuous manner, so that the ferroelectric liquid crystal can be applied so as to shorten the flow distance, and at the contact interface of the flowed ferroelectric liquid crystal. This is because the occurrence of alignment disorder can be prevented.

  Among them, it is preferable to drop the ferroelectric liquid crystal in a straight line with an equal interval. When the ferroelectric liquid crystal is dripped in a straight line at equal intervals, the ferroelectric liquid crystal spreads wet on the fixed liquid crystal layer as compared with the case where the ferroelectric liquid crystal is dropped intermittently in the form of dots. Ferroelectric liquid crystal can be dropped so that the distance becomes shorter. For this reason, it is possible to suppress the alignment property from being lost at the portion where the ferroelectric liquid crystal contacts, and to seal the ferroelectric liquid crystal between the fixed liquid crystal layer side substrate and the counter substrate in a good alignment state.

  In addition, when the ferroelectric liquid crystal is dropped linearly, the ferroelectric liquid crystal is linearly arranged so that the linear direction is substantially parallel or substantially perpendicular to the alignment processing direction of the alignment film for reactive liquid crystal, for example. It can be dripped in.

  When the ferroelectric liquid crystal is formed on the fixed liquid crystal layer, the ferroelectric liquid crystal may be heated or may not be heated. The temperature of the ferroelectric liquid crystal is appropriately selected depending on the ferroelectric liquid crystal coating method.

  For example, when a discharge method is used as a coating method of the ferroelectric liquid crystal, it is preferable that the ferroelectric liquid crystal is heated to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase or a nematic phase, and particularly the ferroelectric property. It is preferable that the liquid crystal is heated to a temperature showing an isotropic phase. This is because if the ferroelectric liquid crystal is not heated, the viscosity of the ferroelectric liquid crystal is too high and the discharge nozzle is clogged, making it very difficult to stably discharge the ferroelectric liquid crystal.

  In the above case, the temperature of the ferroelectric liquid crystal is set to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase or a nematic phase. The specific temperature varies depending on the type of ferroelectric liquid crystal and is appropriately selected. Note that the upper limit of the temperature of the ferroelectric liquid crystal is set to a temperature at which the ferroelectric liquid crystal does not deteriorate. Usually, the temperature of the ferroelectric liquid crystal is set in the vicinity of the nematic phase-isotropic phase transition temperature, or is set to 0 ° C. to 10 ° C. higher than the nematic phase-isotropic phase transition temperature.

  On the other hand, when a coating method or a printing method is used as a method for applying the ferroelectric liquid crystal, it is preferable that the ferroelectric liquid crystal is not heated. When using a coating method or a printing method, it is preferable to use a ferroelectric liquid crystal solution obtained by diluting a ferroelectric liquid crystal with a solvent in order to improve the coating property. For this reason, when the ferroelectric liquid crystal solution is heated, the solvent in the ferroelectric liquid crystal solution is volatilized and it becomes very difficult to apply the ferroelectric liquid crystal.

  Further, when the ferroelectric liquid crystal is applied on the fixed liquid crystal layer, the fixed liquid crystal layer side substrate may or may not be heated. The temperature of the fixed liquid crystal layer side substrate is appropriately selected depending on the application method of the ferroelectric liquid crystal.

  For example, when a discharge method is used as a ferroelectric liquid crystal coating method, the fixed liquid crystal layer side substrate may or may not be heated. When the fixed liquid crystal layer side substrate is heated, the temperature of the fixed liquid crystal layer side substrate is preferably set to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase or a nematic phase. It is preferable to set the temperature at which the liquid crystal exhibits a nematic phase. The specific temperature varies depending on the type of ferroelectric liquid crystal and is appropriately selected. The upper limit of the temperature of the fixed liquid crystal layer side substrate is set to a temperature at which the ferroelectric liquid crystal does not deteriorate.

  On the other hand, when a coating method or a printing method is used as a method for applying the ferroelectric liquid crystal, it is preferable not to heat the fixed liquid crystal layer side substrate. This is because when the fixed liquid crystal layer side substrate is heated, the solvent in the applied ferroelectric liquid crystal solution volatilizes, and the orientation of the ferroelectric liquid crystal may be disturbed.

3. Substrate bonding step The substrate bonding step in the present invention is a step of bonding the fixed liquid crystal layer side substrate coated with the ferroelectric liquid crystal and the counter substrate.

  A general method can be adopted as a method of bonding the fixed liquid crystal layer side substrate and the counter substrate. For example, a sealant is applied to at least one peripheral edge of the fixed liquid crystal layer side substrate or the counter substrate, and the alignment treatment direction of the reactive liquid crystal alignment film and the alignment treatment direction of the second alignment film are substantially parallel. The fixed liquid crystal layer side substrate and the counter substrate are made to face each other, the fixed liquid crystal layer side substrate and the counter substrate are stacked under reduced pressure, the sealant is cured, and the fixed liquid crystal layer side substrate and the counter substrate are bonded together. be able to.

4). Ferroelectric liquid crystal alignment step In the ferroelectric liquid crystal alignment step of the present invention, the ferroelectric liquid crystal sandwiched between the fixed liquid crystal layer side substrate and the counter substrate is aligned without performing an electric field application process. It is a process.

Aligning the ferroelectric liquid crystal specifically means that the ferroelectric liquid crystal is in a chiral smectic C (SmC ^* ) phase. As described above, since the ferroelectric liquid crystal is heated to be in a nematic phase or isotropic phase, for example, the ferroelectric liquid crystal can be cooled to be in the SmC ^* phase. When cooling the heated ferroelectric liquid crystal, the ferroelectric liquid crystal is usually gradually cooled to room temperature. In the present invention, in order to align the ferroelectric liquid crystal, it is not necessary to perform an electric field application treatment, and it is only necessary to cool it slowly.

  When a polymerizable monomer is added to the ferroelectric liquid crystal, the polymerizable monomer is polymerized after aligning the ferroelectric liquid crystal. The polymerization method of the polymerizable monomer is appropriately selected according to the type of the polymerizable monomer. For example, when an ultraviolet curable resin monomer is used as the polymerizable monomer, the polymerizable monomer can be polymerized by ultraviolet irradiation. .

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

The following examples illustrate the present invention in more detail.
[Example 1]
A photosensitive resin material (NN780 manufactured by JSR Corporation) is spin-coated (2000 rpm) on an ITO thin film of a glass substrate (100 mm × 100 mm × 0.7 mm) having an indium tin oxide (ITO) thin film formed on two surfaces. For 10 seconds), vacuum drying, and drying at 90 ° C. for 3 minutes on a hot plate. Thereafter, patterning was performed in a stripe shape having a width of 10 μm and a pitch of 1 mm by a photolithography method, followed by baking at 230 ° C. for 30 minutes. Thus, a partition having a height of 1.5 μm was formed on one substrate on the ITO thin film of the glass substrate.

Next, a cyclopentanone solution (2% by mass) of a photoexcited reaction type material (ROP-103: manufactured by Roric Technology) was applied to both substrates by spin coating (1500 rpm, 15 seconds), and 130 ° C. on a hot plate. Drying was performed for 10 minutes. Thereafter, the film was exposed with polarized ultraviolet light at an angle of 45 ° from 100 ° J for a photo-alignment treatment to obtain a photo-alignment film. The pretilt angle of this photo-alignment film was about 2 °.
Subsequently, a hybrid alignment polymerizable liquid crystal (PLC-7504XL: manufactured by Chisso Corporation) was further laminated on one substrate by spin coating (1500 rpm, 15 seconds), and dried on a hot plate at 60 ° C. for 5 minutes. . Thereafter, the film was exposed to 1000 mJ with ultraviolet light and subjected to a polymerization treatment to obtain a fixed liquid crystal layer having a thickness of 100 nm.

  Next, a ferroelectric liquid crystal material R2301 (manufactured by AZ Electronic Materials) was dropped on the fixed liquid crystal layer in a line shape with a droplet distance of 30 μm by an inkjet method, and the line interval was 1 mm. . A UV curable sealant (LCB610: EHC) was applied to the substrate with a seal dispenser. The substrate was assembled in a state parallel to the polarized UV irradiation direction, and a panel was produced by applying pressure at a temperature 10 ° C. to 20 ° C. higher than the nematic phase-isotropic phase transition temperature in vacuum, and slowly returned to room temperature.

  When the alignment state of the liquid crystal display device thus produced was confirmed with a polarizing microscope, no zigzag defects were observed.

[Example 2]
A liquid crystal was obtained in the same manner as in Example 1 except that the hybrid alignment polymerizable liquid crystal (PLC-7504XL: manufactured by Chisso Corporation) was changed to a hybrid alignment polymerizable liquid crystal (PLC-7504XK: manufactured by Chisso Corporation). A display element was produced.
When the alignment state of the liquid crystal display device thus produced was confirmed with a polarizing microscope, no zigzag defects were observed.

[Example 3]
A liquid crystal was produced in the same manner as in Example 1 except that the hybrid-aligned polymerizable liquid crystal (PLC-7504XL: manufactured by Chisso Corporation) was changed to a hybrid-aligned polymerizable liquid crystal (PLC-7504XH: manufactured by Chisso Corporation). A display element was produced.
When the alignment state of the liquid crystal display device thus produced was confirmed with a polarizing microscope, no zigzag defects were observed.

[Comparative Example 1]
A liquid crystal display element was prepared in the same manner as in Example 1 except that the polymerizable liquid crystal (PLC-7504XL: manufactured by Chisso Corporation) was changed to a polymerizable liquid crystal (ROF-5101: manufactured by Roric Technology). Produced. When this polymerizable liquid crystal was formed to a thickness of 0.5 μm on the photo-alignment film of Example 1, the pretilt angle on the outermost surface (tilt angle on the air interface side) was about 2 °.
When the alignment state of the thus produced liquid crystal display element was confirmed with a polarizing microscope, zigzag defects were observed.

[Comparative Example 2]
A liquid crystal display device was prepared by the same method as in Comparative Example 1 except that a rubbing-treated alignment film was formed as shown below and a fixed liquid crystal layer was not formed instead of forming a photo-alignment film. did. The alignment film subjected to the rubbing treatment was applied with a polyimide material (SE-7492: manufactured by Nissan Chemical Industries, Ltd.) on the substrate by a spin coating method (1500 rpm, 15 seconds), and dried at 200 ° C. for 30 minutes on a hot plate. It was obtained by performing a rubbing treatment with an indentation amount of 0.15 mm. The rubbed alignment film had a pretilt angle of about 15 °.
When the alignment state of the thus produced liquid crystal display element was confirmed with a polarizing microscope, zigzag defects were observed.
Although the comparative example 2 had a relatively high pretilt angle, no zigzag defects were observed in Examples 1 to 3, whereas zigzag defects were observed in Comparative Example 2. This is because the polymerizable liquid crystal is a liquid crystal and the fixed liquid crystal layer has a stronger interaction with the ferroelectric liquid crystal than the rubbed alignment film, so that the ferroelectric liquid crystal follows the pretilt angle of the fixed liquid crystal layer. This is thought to be easier to do. Thereby, it is considered that the alignment of the ferroelectric liquid crystal can be easily controlled in the fixed liquid crystal layer as compared with the alignment film subjected to the rubbing treatment.

[Reference example]
A liquid crystal display device was produced in the same manner as in Example 1 except that the ferroelectric liquid crystal material was applied not on the fixed liquid crystal layer but on the photo-alignment film on the other substrate.
When the alignment state of the thus produced liquid crystal display element was confirmed with a polarizing microscope, zigzag defects were observed.
From Example 1 and the reference example, it was confirmed that the generation of zigzag defects can be effectively suppressed by applying a ferroelectric liquid crystal material on the fixed liquid crystal layer.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element 2 ... 1st board | substrate 3 ... 1st electrode layer 4 ... Reactive liquid crystal aligning film 5 ... Immobilization liquid crystal layer 5a ... Liquid crystal molecule 10 ... Immobilization liquid crystal layer side substrate 11 ... Ferroelectric liquid crystal layer 11a ... Liquid crystal molecule 12 ... Second substrate 13 ... Second electrode layer 14 ... Second alignment film 20 ... Counter substrate

Claims (9)

A first substrate, a first electrode layer formed on the first substrate, a reactive liquid crystal alignment film formed on the first electrode layer, and a hybrid formed on the reactive liquid crystal alignment film An immobilized liquid crystal layer side substrate having an immobilized liquid crystal layer formed by immobilizing aligned reactive liquid crystals;
A counter substrate arranged to face the fixed liquid crystal layer of the fixed liquid crystal layer side substrate;
A ferroelectric liquid crystal layer including a ferroelectric liquid crystal formed between the fixed liquid crystal layer and the counter substrate, and the reactive liquid crystal is formed from the side of the alignment layer for the reactive liquid crystal. A liquid crystal display element, wherein the liquid crystal display element is hybrid-aligned so that a tilt angle gradually increases in a thickness direction toward the liquid crystal layer side.   The liquid crystal display element according to claim 1, wherein the reactive liquid crystal exhibits a nematic phase.   The liquid crystal display element according to claim 1, wherein the reactive liquid crystal contains a polymerizable liquid crystal monomer.   The counter substrate includes a second substrate, a second electrode layer formed on the second substrate, and a second alignment film formed on the second electrode layer, and the fixed liquid crystal layer and 4. The liquid crystal display element according to claim 1, wherein the ferroelectric liquid crystal layer is formed between the second alignment films. A reactive liquid crystal layer containing a reactive liquid crystal is formed on a first substrate on which a first electrode layer and an alignment film for reactive liquid crystal are sequentially formed, and the reactive liquid crystal in the reactive liquid crystal layer is Preparation of a fixed liquid crystal layer side substrate by hybrid alignment so that the tilt angle gradually increases in the thickness direction from the alignment layer side for the reactive liquid crystal, and fixing the alignment state of the reactive liquid crystal to form a fixed liquid crystal layer Process,
A ferroelectric liquid crystal coating step of coating a ferroelectric liquid crystal on the fixed liquid crystal layer;
A substrate bonding step of bonding the fixed liquid crystal layer side substrate coated with the ferroelectric liquid crystal and the counter substrate;
A ferroelectric liquid crystal alignment step for aligning the ferroelectric liquid crystal sandwiched between the fixed liquid crystal layer side substrate and the counter substrate without performing an electric field application process. Manufacturing method.   6. The method for manufacturing a liquid crystal display element according to claim 5, wherein the application method of the ferroelectric liquid crystal is an ink jet method.   The method for producing a liquid crystal display element according to claim 5, wherein the reactive liquid crystal exhibits a nematic phase.   The method for producing a liquid crystal display element according to claim 5, wherein the reactive liquid crystal contains a polymerizable liquid crystal monomer.   The counter substrate includes a second substrate, a second electrode layer formed on the second substrate, and a second alignment film formed on the second electrode layer, and the fixed liquid crystal layer and 9. The method of manufacturing a liquid crystal display element according to claim 5, wherein the ferroelectric liquid crystal is sandwiched between the second alignment films.

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