JPH06301039A - Production of liquid crystal optical element - Google Patents

Abstract

PURPOSE:To provide process for production of the liquid crystal optical element capable of producing the ferroelectric liquid crystal optical element having a large area, reducing the cost thereof and producing the liquid crystal optical element having excellent mechanical strength in the simplified process for production. CONSTITUTION:This process for production of the liquid crystal optical element holding feroelectric liquid crystal flems consists in applying a liquid crystal soln. prepd. by dissolving and dispersing the ferroelectric liquid crystal 9, solid spacers 3 and a non-liquid crystalline resin 10 in a solvent on the surface of the electrodes of a flexible substrate, then evaporating the solvent to cause the phase sepn. of the ferroelectric liquid crystal 9, the solid spacers 3 and the non-liquid crystalline resin 10 to form a ferroelectric liquid crystal film and laminating a counter flexible substrate on the substrate mentioned above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a liquid crystal optical element which is preferably used in the field of optoelectronics as a liquid crystal material such as a liquid crystal display element, a liquid crystal storage element, a liquid crystal acoustic element and a light control glass.

[0002]

2. Description of the Related Art Ferroelectric liquid crystal has been attracting attention as a liquid crystal material for liquid crystal optical elements because it has high-speed response and memory property. However, when a liquid crystal optical element is manufactured by a usual method of injecting a liquid crystal material between glass substrates, it is difficult to increase the area and the yield is low. Therefore, if a flexible substrate (for example, a plastic film) is used as the substrate, a series of continuous processes such as film formation of the liquid crystal, lamination with a counter substrate, and bending alignment can be used. The device can be easily manufactured. However, since the substrate has flexibility, a conduction defect is likely to occur due to pressing or the like, and it is preferable to use some kind of spacer material in order to prevent it.

Japanese Unexamined Patent Publication No. 4-199128 discloses a method of selectively adhering a mixture of a polymer material and a spacer at an arbitrary position through a mask opening to maintain a space between substrates. Since the size of the mask is limited by the size of the mask (screen print), there is a problem that it is not possible to fabricate a device with a size larger than a meter. In addition, since it is necessary to attach or fix the spacer material, there is a problem that the number of steps is increased. Further, the substrate having the spacer portion has a problem that it is difficult to handle because it is necessary to avoid contact of the operator or the manufacturing apparatus with the substrate surface.

Japanese Unexamined Patent Publication (Kokai) No. 4-338724 discloses a method of fixing a spacer by forming a member for fixing the spacer at a predetermined position on the substrate.
There is a problem that the number of processes such as printing the fixing member, spraying spacers and curing the fixing member is increased. There is also a problem that it is difficult to handle the substrate on which the spacer is formed as described above.

Japanese Unexamined Patent Publication (Kokai) No. 2-73219 describes a method in which a thermoplastic resin is mixed with a ferroelectric liquid crystal and the resin is used as a reinforcing material for a panel. However, when a spacer is mixed in the liquid crystal layer. There is a problem in that the mechanical strength is inferior to. Further, if it is attempted to have the same strength as when a spacer is inserted, it is necessary to increase the amount of resin, which causes a problem of lowering the contrast ratio.

[0006]

The present invention is capable of producing a large-area ferroelectric liquid crystal optical element with high yield,
An object of the present invention is to provide a method for manufacturing a liquid crystal optical element, which enables cost reduction and can manufacture a liquid crystal optical element having excellent mechanical strength by a simplified manufacturing process.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the inventors of the present invention dissolved and dispersed a ferroelectric liquid crystal, a solid spacer and a non-liquid crystal resin in a substrate. By applying the liquid crystal solution and drying the solvent,
It has been found that a ferroelectric liquid crystal film having excellent mechanical strength can be formed by a method having a simplified process, and the present invention has been completed based on this finding.

That is, in a method of manufacturing a liquid crystal optical element in which a ferroelectric liquid crystal film is sandwiched between two substrates with electrodes, at least one of which is flexible, a ferroelectric liquid crystal, a solid spacer and a non-liquid crystal resin are used. A liquid crystal solution in which is dissolved or dispersed in a solvent is applied to the surface of at least one of the substrates on which the electrodes are attached, and then the solvent is evaporated, so that the ferroelectric liquid crystal, the solid spacer, and the non-liquid crystal resin are mutually separated. A liquid crystal optical element, characterized in that a ferroelectric liquid crystal film formed in a phase-separated state is formed, and then two substrates thereof are laminated so that the ferroelectric liquid crystal film is sandwiched between these substrates. A manufacturing method is provided.

The ferroelectric liquid crystal used in the method for producing a liquid crystal optical element of the present invention is not particularly limited, but it is preferable to use a ferroelectric polymer liquid crystal for producing a large-screen liquid crystal optical element. . Also, a mixture of ferroelectric low-molecular liquid crystals may be used if necessary. For example, a mixture of a ferroelectric polymer liquid crystal and a ferroelectric low molecular liquid crystal as shown below is preferably used.

[0010]

[Chemical 1]

The solid spacer preferably has a cylindrical shape having a diameter of 1 to 10 μm and a length of 1 to 100 μm or a spherical shape having a diameter of 1 to 10 μm, and the material thereof is silica or a solvent resistant resin. Used for. The mixing amount of the solid spacer is preferably 0.0001 to 1 part by weight with respect to 100 parts by weight of the ferroelectric liquid crystal. If the content is less than 0.0001 parts by weight, the function as a reinforcing material is not exhibited, and if it exceeds 1 part by weight, the contrast ratio of the panel may be deteriorated, and the alignment property and alignment retention property of the liquid crystal layer may be deteriorated. There is.

The non-liquid crystal resin functions as a reinforcing agent and an adhesive for fixing the solid spacer to the substrate, and its type is not particularly limited as long as it is soluble in the solvent used, but polyalkyl acrylate, One or more resins selected from polyalkyl methacrylate, polyvinyl alkyl ether, polyvinyl acetate, polyvinyl butyral, polyvinyl halide, polyvinyl formal, polyvinylidene chloride, polystyrene, poly-α-methylstyrene and polyacrylonitrile, or two or more of these resins. Is preferably used. The amount of the resin mixed is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the ferroelectric liquid crystal. When the content is less than 0.1 parts by weight, the function as a reinforcing material and an adhesive does not appear, and when the content exceeds 10 parts by weight, the contrast ratio of the panel and the orientation of the liquid crystal layer may be deteriorated. is there.

In the method of the present invention, first, a liquid crystal solution is prepared by uniformly dissolving and dispersing a ferroelectric liquid crystal, a solid spacer and a non-liquid crystal resin in a solvent, preferably an organic solvent such as methyl ethone. For dissolution / dispersion, it is preferable to uniformly disperse the solid spacer in the solution using ultrasonic waves or the like.

The subsequent operation will be described with reference to FIGS. 1 to 5, which are cross-sectional explanatory views for explaining the manufacturing method of the present invention.

The liquid crystal solution 4 in which the solid spacer 3 obtained above is uniformly dispersed is applied onto the electrode surface of the flexible substrate 1 having the transparent electrode 2 (see FIG. 1). The method of applying the liquid crystal solution is not particularly limited. Specific examples thereof include a bar coater method, a direct gravure roll method, and a micro gravure roll method. The coating thickness of the liquid crystal solution at this time is set so that the thickness of the ferroelectric liquid crystal film 5 when the solvent is evaporated is about the same as or larger than the diameter of the spacer used (see FIG. 2).

Next, the substrate coated with the liquid crystal solution is heated to evaporate the solvent. As a heating method, for example, a method of blowing hot air, a method of irradiating infrared rays or microwaves, and a heating metal roll such as a heating stainless steel roll 6 is pressed against the liquid crystal coating surface of the liquid crystal solution coating substrate 7 to heat it. Examples thereof include a method (see FIG. 3). FIG. 4 is a partially enlarged view of the ferroelectric liquid crystal film obtained by removing the solvent by heating in FIG. Heating is performed as described above to evaporate the solvent almost completely, and the ferroelectric liquid crystal 9 and the non-liquid crystal resin 10 are added.
And are phase separated. At this time, the phase-separated non-liquid crystal resin fixes the solid spacer 3 on the substrate (see FIG. 4).

Next, another substrate with a transparent electrode is laminated on the liquid crystal coated surface of the substrate so that the electrode surface is in contact with the ferroelectric liquid crystal film (see FIG. 5). As a laminating method, a method of sandwiching between two pressure rolls at room temperature or higher is generally used.

[0018]

EXAMPLES The present invention will now be described in detail based on examples, but the present invention is not limited thereto.

Example 1 2.0 g of a ferroelectric polymer liquid crystal A and 1.0 g of a ferroelectric low molecular weight liquid crystal B shown below were added to a weight average molecular weight of 33,000.
Polymethylmethacrylate (PMMA) of 0.100
g, and a spherical silica spacer having a diameter of 2 μm (Matagoya SW-2.0 manufactured by Catalysts & Chemicals Co., Ltd.) was added 0.001
g was added and dissolved in 6.0 g of methyl ethyl ketone (MEK) to obtain a liquid crystal solution. The liquid crystal solution was put in a reagent bottle and immersed in an ultrasonic cleaner having an output of 0.30 kW for 10 minutes to uniformly disperse the spacers.

[0020]

[Chemical 2] (Iso: isotropic phase, SmA: smectic A phase, SmC
^* : Chiral smectic C phase, Cry: Crystal phase)

Next, a polyether sulfone (PES) film with an ITO transparent electrode was used as a substrate, and a solution was applied to the electrode side by a microgravure method to a thickness of 8 μm (see FIG. 1). Then, the substrate is heated by a stainless roll at 80 ° C. for about 5 seconds (see FIG. 3).
MEK was evaporated, and it was confirmed that a ferroelectric liquid crystal film having a solute film thickness of 2 μm was formed (see FIG. 2).

Another PES substrate with a transparent electrode is placed on the above-mentioned substrate having the ferroelectric liquid crystal film formed thereon, at a temperature of 60 ° C. and a pressure of 2.
Laminated with two rolls of kg / cm ² (see FIG. 5), 4
Bending orientation was performed under an applied voltage of 0 V to fabricate a panel.

The produced panel was subjected to a drop ball test in which 1.8 g of a steel ball was dropped on the panel. The results are shown in Table 1 together with other examples and comparative examples.

Comparative Example 1 The same ferroelectric polymer liquid crystal A as in Example 1 (2.0 g) and ferroelectric low molecular weight liquid crystal B (1.0 g) were added to the same weight average molecular weight of 33.0.
0.100 g of PMA of 00 was mixed and dissolved in 6.0 g of MEK to obtain a liquid crystal solution.

Using the liquid crystal solution and the same substrate as in Example 1, a panel was prepared under the same conditions as in Example 1. The same falling ball test as in Example 1 was performed on the manufactured panel. The results are shown in Table 1.

Example 2 The same ferroelectric polymer liquid crystal A as in Example 1 (2.0 g) and ferroelectric low molecular weight liquid crystal B (1.0 g) were added, and the weight average molecular weight was 52,0.
0.120 g of polystyrene (PS) of 00 was mixed, and a spherical melamine resin spacer with a diameter of 2 μm (Co., Ltd.)
0.010 g of Eposter GP-20 manufactured by Nippon Shokubai Co., Ltd. was added and dissolved in 6.0 g of acetone to obtain a liquid crystal solution. Further, the spacers were uniformly dispersed by an ultrasonic cleaner under the same conditions as in Example 1.

Using the liquid crystal solution and the same substrate as in Example 1, a panel was prepared under the same conditions as in Example 1. The same falling ball test as in Example 1 was performed on the manufactured panel. The results are shown in Table 1.

Comparative Example 2 The same ferroelectric polymer liquid crystal A as in Example 1 (2.0 g) and ferroelectric low molecular weight liquid crystal B (1.0 g) were added, and the weight average molecular weight was 52,0.
0.120 g of polystyrene (PS) of 00 was mixed and dissolved in 6.0 g of acetone to obtain a liquid crystal solution.

Using the liquid crystal solution and the same substrate as in Example 1, a panel was prepared under the same conditions as in Example 1. The same falling ball test as in Example 1 was performed on the manufactured panel. The results are shown in Table 1.

[0030]

[Table 1]

[0031]

According to the manufacturing method of the present invention, it is possible to manufacture a large-area ferroelectric liquid crystal optical element with good yield,
The cost can be reduced, and a liquid crystal optical element having excellent mechanical strength can be manufactured.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view showing a manufacturing method of the present invention.

FIG. 2 is a cross-sectional explanatory view showing the manufacturing method of the present invention.

FIG. 3 is a cross-sectional explanatory view showing the manufacturing method of the present invention.

FIG. 4 is a cross-sectional explanatory view showing the manufacturing method of the present invention.

FIG. 5 is a sectional explanatory view showing the manufacturing method of the present invention.

[Explanation of symbols]

 3 Solid Spacer 9 Ferroelectric Liquid Crystal 10 Non-Liquid Crystal Resin

Claims (4)

[Claims] 1. A method of manufacturing a liquid crystal optical element in which a ferroelectric liquid crystal film is sandwiched between two substrates with electrodes, at least one of which has flexibility, and a ferroelectric liquid crystal, a solid spacer and a non-liquid crystal resin. A liquid crystal solution in which is dissolved or dispersed in a solvent is applied to the surface of at least one of the substrates on which the electrodes are attached, and then the solvent is evaporated, so that the ferroelectric liquid crystal, the solid spacer, and the non-liquid crystal resin are mutually separated. A liquid crystal optical element, characterized in that a ferroelectric liquid crystal film formed in a phase-separated state is formed, and then two substrates thereof are laminated so that the ferroelectric liquid crystal film is sandwiched between these substrates. Production method. 2. The method for producing a liquid crystal optical element according to claim 1, wherein the solid spacer is spherical or cylindrical in shape and made of silica or a solvent resistant resin. 3. The non-liquid crystal resin is polyalkyl acrylate, polyalkyl methacrylate, polyvinyl alkyl ether, polyvinyl acetate, polyvinyl butyral, polyvinyl halide, polyvinyl formal, polyvinylidene chloride, polystyrene, poly-α-methylstyrene and poly. The method for producing a liquid crystal optical element according to claim 1, which is one kind of resin selected from acrylonitrile or a mixture of two or more kinds of these resins. 4. The mixing amount of the solid spacer with respect to 100 parts by weight of the ferroelectric liquid crystal is 0.0001 to 1 part by weight, and the mixing amount of the non-liquid crystal resin is 0.1 to 10 parts by weight.
2. The method for producing a liquid crystal optical element according to 2 or 3.