JPS6374032A - Production of ferroelectric liquid crystal element - Google Patents

Abstract

PURPOSE:To uniformize a cell gap by using a material prepd. by preliminarily dispersing gap materials uniformly into a color filter material. CONSTITUTION:The gap materials 9 to be used to maintain the cell gap of a liquid crystal element are dispersed into a resin for constituting picture elements of a color filter and after the resin is coated on a substrate 1, a colored layer 11 having a pattern shape provided with the gap materials 9 by a photolithographic stage is formed on the substrate 1. More specifically, the gap materials 9 are preliminarily dispersed into the resin having the photosensitivity to constitute the picture element material of the color filter. A coloring material is thereafter patterned by UV rays via a pattern mask and the color filter layer contg. the gap materials 9 is formed by the photolithographic method. The gap materials 9 are otherwise dispersed into a non-photosensitive resin and after the picture element pattern is formed by using such resin, the color filter layer contg. the gap materials 9 is formed by a dyeing stage.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a ferroelectric liquid crystal element such as a liquid crystal display element or a liquid crystal-optical shutter array. The present invention relates to a method for manufacturing a ferroelectric liquid crystal element with improved display and driving characteristics.

[Prior Art] Conventionally, a gap material is used in a liquid crystal color display panel to maintain a gap (cell gap) between a color filter substrate and a counter substrate.

A method for providing the gap material between a pair of parallel substrates is to print a sealant on the outer periphery of the counter substrate when bonding the color filter substrate and the counter substrate, and then apply the gap material to the other color filter substrate. The conventional method was to spread the cell gap by spraying it on the substrate and press-bonding it to the counter substrate.

[Problems to be Solved by the Invention] However, according to the above-mentioned prior art, the gap material is spread over the color filter of the color filter substrate to compress the opposing substrate, so the gap material sinks into the color filter. There were some problems.

Furthermore, in a liquid crystal element, in order to obtain good alignment of ferroelectric liquid crystal, it is necessary to keep the cell gap within the range of Igm±0.11. This requires a high pressure that exceeds the hardness of the color filter itself, which may cause partial destruction of the color filter or cause the gap material to sink into the color filter, making it impossible to maintain a uniform cell gap. However, there was a problem in that orientation defects were generated.

An object of the present invention is to provide a ferroelectric liquid crystal element that can prevent the occurrence of the above-mentioned alignment defects and fully exhibit the high-speed response and memory effect characteristics inherent in ferroelectric liquid crystal elements. be.

[Means to Solve the Problem] Kinoe et al. have focused on the initial orientation of ferroelectric liquid crystals during the cooling process during which they transition from an isotropic phase (high temperature state) to a liquid crystal phase (low temperature state) [1 However, we have discovered a method for manufacturing a ferroelectric liquid crystal element having a structure that allows both the operating characteristics of the element based on the bistability of the ferroelectric liquid crystal and the monodomain property of the liquid crystal layer.

The method for manufacturing a ferroelectric liquid crystal element of the present invention is based on such knowledge, and will be described in more detail.

By ensuring that the thickness of the liquid crystal layer is uniform within the plane of the liquid crystal element, that is, by preventing sudden changes in the thickness of the liquid crystal layer, the initial orientation during the cooling process is maintained in a good state;
It is characterized by forming monodomains with no orientation defects.

That is, the present invention is transparent 11 i1! A gap material is provided between a pair of parallel substrates on which poles are formed, and a ferroelectric liquid crystal is sandwiched between them.
In a method for manufacturing a liquid crystal element having a color filter in which the film thickness of each pixel is set to be the same between at least one transparent electrode and a substrate, the gap material used for maintaining the cell gap of the liquid crystal element is Production of a ferroelectric liquid crystal element characterized by dispersing it in a constituent resin and coating the resin on a substrate, and then forming a pattern-shaped colored layer with a gap material on the substrate by an otolithography process. It's a method.

Particularly suitable liquid crystal materials for use in the present invention are liquid crystals having bistability and ferroelectricity. Specifically, chiral smectic C phase (SmC
”), H phase (Smll”), I phase (Sml”)
, J phase (SmJ”), K phase (SmK”),
G-phase (Sn+G'') or F-phase (SmF'') liquid crystal can be used.

Regarding this ferroelectric liquid crystal, “LE JOURNAL
1
975, Rib (L-69), ``Ferroelectric Liquid Crystals J ('Ferroelec
tric Liquid(:rystals4);
“Applied Physics Letters” (“8p
Plied Physics Letters”）19
1980, No. 36 (+1), ``Submicro Second Bistiple Electro-Optic Switching in Liquid Crystals''('Submic
ro 5econd B15table Electr
oopticSwitching in Liquid
Crystals J) ; “Solid State Physics” 1981 No. 16 (141), “Liquid Crystal J, etc.”
In the present invention, the ferroelectric liquid crystal disclosed in these documents can be used.

Specific examples of ferroelectric liquid crystals include decyloxybenzylidene-p'-amino-2-methylbutylcinnamate (DOBAMB (1:), hexyloxybenzylidene-p'-amino-2-chloropropylcinnamate (1:), !0BACPC), 4-o-(2-methyl)-
Butyl resol silidan-4'-octylaniline (MB
RAS).

When constructing an element using these materials, the element can be supported by a heater or an embedded block, etc., as necessary, in order to maintain the temperature at which the liquid crystal compound enters the chiral smectoid phase. .

Materials for the alignment control film used in the present invention include, for example, polyvinyl alcohol, polyimide, polyamideimide, polyester, polycarbonate, pyrivinyl acetal, polyvinyl chloride, polyvinyl acid, polyamide, polystyrene, cellulose resin, melamine resin, Resins such as area resin, acrylic resin, photosensitive polyimide, photosensitive polyamide, cyclic rubber photoresist, phenol novolac photoresist, or electron beam photoresist (polymethyl methacrylate, epoxidized-1,4-polybutadiene, etc.) ), etc.

Transparent 151 resins used as colored image materials constituting the color filter image used in the present invention include polyamide resins, aminoalkyd resins, polyimide resins, acrylic resins, epoxy resins, silicone resins, and rubber. Examples include photosensitive resins such as urethane resins, vinyl chloride resins, nitrified cotton, and polyester resins.

The pigment materials used as coloring materials for the color filter used in the present invention include azo, anthraquinone, phthalocyanine, gynacritone, inindolinone, dioxazine, perylene, perinone, thioindigo, pyrocholine, Examples include fluorobin type and quinophthalone type.

The gap material used in the present invention is made of glass,
There are alumina, plastic, etc., and shapes such as spheres, cylinders, hexagonal columns, etc. can be used. In particular, as the gap material, alumina beads, SiO□ beads, glass beads, plastic beads, and ceramic beads are preferable.

FIG. 1 is a cross-sectional view showing an example of a ferroelectric liquid crystal device manufactured by the method of the present invention, showing a substrate 1 provided with a patterned blue resin layer 1 having transparent electrodes formed thereon, and a parallel substrate 1 provided thereon. ', one part of the gap material is covered with a colored resin layer 11.
It looks like it's stuck inside! ferroelectric liquid crystal 1
The peripheral edges of the two substrates 1 and 1' are bonded together using a sealing agent 8.

As shown in FIG. 1, the particle size of the gap material used is at least the sum of the cap cost of the color filter and the cell gap ρ6. Therefore, there is an advantage that a gap material having a larger particle size than the gap material used in conventional ferroelectric liquid crystal elements can be used. In other words, it is very difficult to produce a gap material with a high precision of about one particle size, so the larger the particle diameter of the gap material, the easier it is to produce the gap material.

The method for forming a single layer color filter containing a gap material used in the present invention is as follows.

First, the gap material is dispersed in advance into a photosensitive resin that constitutes the image material of the color filter. Thereafter, the coloring material is patterned using ultraviolet rays through a pattern mask, and a photolithography process is performed to form a single layer of a color filter containing a gap material.

In addition, after printing by dispersing a gap material in a non-photosensitive resin, or by dispersing a warming gap material in a resin to be dyed and using this to form a uniform pattern,
This can be done by a method of forming a single layer of color filter containing a gap material through a dyeing process.

[Example] Hereinafter, the present invention will be explained in more detail by showing examples 6. Example 1 Figures 3 (a) to (f) show R (red), G (green), and B (blue) FIG. 3 is a process diagram showing a process of forming three color pixels.

First, on a glass plate of A4 size (210 mm x 297 mm), a blue colored resin material [Heliogen Blue (Its l
iogenBlue) L7080 (Product name, B
ASF Co. 5J, C, 1, No.

74160) and alumina acid spherical gap material (diameter 3
1±0.1 gon) to P8-1000C (trade name, manufactured by Ube Industries, polymer content = IO%, solvent: N-methyl-
A photosensitive colored resin material prepared by dispersing 2-pyrrolidone in a pigment:bolimer=1=2 formulation] was applied to a thickness of 2.0 μm by a spinner coating method to form a colored resin layer 2. (Refer to fjS3 figure (a)) Next, the Hiro colored tree I'I
After pre-baking layer 1 and layer 2 at 80°C for 30 minutes,
Exposure was performed using a high-pressure mercury lamp through a photomask 3 corresponding to the pattern shape to be formed. (See Figure 3(b)) After the exposure, as shown in Figure 3(C), a special developer (N-methyl-2- Developed using ultrasonic waves in a developer containing pyrrolidone as the main component, treated with a special rinse solution (for example, a rinse solution containing isopropyl alcohol as the main component), and then post-baked at 150°C for 130 minutes. A blue patterned colored resin layer 4 containing a patterned gap material was formed. (See FIG. 3(d)) Next, a green colored resin material [Lionol Green 6YK (trade name)] was applied as a second color onto the glass substrate on which the blue colored pattern was formed.

Manufactured by Toyo Ink Co., Ltd., C, 1, No. 74265) and #
, mold gap material (diameter 3 gm ± 0.1 μm) is PA-
1000C (product name, manufactured by Ube Industries, polymer content = lO
%, solvent 2N-methyl-2-pyrrolidone, pigment: polymer-1 = 2 composition)] was prepared in the same manner as above except that a green color containing gap material was used. A patterned colored resin layer 5 was formed at a predetermined position on the substrate.

Furthermore, a red colored resin material [Irgazin Red BPT] was applied as a third color onto the substrate on which the blue and green patterns were formed in this way.
(Product name, manufactured by Ciba-Geigy).

C, 1, No. 71127) and a spherical gap material (diameter 3 pm±(+, 1 l! 1>) of PA-1000C (trade name, manufactured by Ube Industries, Ltd.).

Gap material was prepared in the same manner as above, except that a photosensitive colored resin material prepared by dispersing polymer content in IO%, solvent: N-methyl-2-pyrrolidone, and pigment: polymer (1:2 formulation) was used. A red patterned colored resin layer 6 containing
are formed at predetermined positions on the substrate, R (red), G (green),
A colored pattern of three color stripes of B (blue) was obtained. (See Figure 3(e)) On the color filter pattern obtained in this way,
Transparent J1 similar to that used for the colored resin material as the protective layer 7
A resin material [PA-1000C (trade name, manufactured by Ube Industries, Ltd., polymer content = 10%, solvent 2N-methyl-2-pyrrolidone) was coated with a spinner coating method to a thickness of approximately 1.0 gm.
Formed at Jv. (See FIG. 3(f)) Through the above process, a coplanar color filter substrate containing a gap material has been formed.

The color filter substrate thus formed and the opposing substrate are bonded together to form a cell, and ferroelectric liquid crystal is injected.
After many years, a liquid crystal device was obtained. When this liquid crystal element was observed using a crossed Nicol polarized light wJ microscope, it was confirmed that the internal liquid crystal molecules had no alignment defects.

In addition, in the obtained color filter, the gap material is dispersed and fixed in contact with the glass substrate, so a highly accurate cell gap can be obtained and it can withstand pressure bonding.
It also had excellent heat resistance.

By satisfying the above conditions, alignment defects can be prevented.

Comparative Example 1 A sealing agent was printed on the outer periphery of the liquid crystal cell obtained in Example 1 of the present invention and a counter substrate using a conventional method, and a gap material was sprinkled on the other color filter substrate, and the two were bonded to the counter substrate. Table 1 shows the results of measuring the cell gap of the liquid crystal cell produced by pressure bonding.

The measurement positions were 1 to 50 in FIG. 2.

Table 1 From the above table, the conventional method could not suppress the variation in cell gap within the range of 1.00±O,1OH, but the liquid crystal element formed by the method of the present invention had a variation of 1.00±O.lOH.
The variation in cell gap can be kept within the range of 0.00±0.10 μm.

[Effects of the Invention] As explained above, in the method for manufacturing a ferroelectric liquid crystal element of the present invention, the cell gap is made uniform by using a color filter material in which a gap material is uniformly dispersed in advance.

Furthermore, since the gap material is in direct contact with the substrate, there are no defects due to pressure bonding, and a highly accurate cell gap can be obtained.

Furthermore, in the past, the gap material had a diameter of 1.0±0.1g.
However, since the gap material used in the present invention is mixed into the resin and forms a gap between parallel substrates, It can be easily obtained with a relatively large particle size of 3.0±0.1 μm.

According to the present invention, it is possible to prevent the occurrence of alignment defects by improving the accuracy of the cell gap, and to provide a ferroelectric liquid crystal element that can fully exhibit the characteristics of a ferroelectric liquid crystal.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a ferroelectric liquid crystal device manufactured by the method of the present invention, FIG. 2 is a schematic diagram showing the measurement position of the cell gap of a liquid crystal cell, and FIGS. f)
1 is a process diagram showing a process of forming color pixels of three colors, R (red), G (green), and B (blue). ■, 1'... Substrate 2 Colored resin layer 2a... Photocured portion 3... Photomask 4.5, 6.11... Patterned colored resin layer 7...
Protective layer 8... Sealing agent 9... Gap material 10... Ferroelectric liquid crystal

Claims (3)

[Claims] (1) A gap material is provided between a pair of parallel substrates on which transparent electrodes are formed to sandwich a ferroelectric liquid crystal, and a color filter with the same film thickness for each pixel is placed between at least one of the transparent electrodes and the substrates. In the method for manufacturing a liquid crystal device, a gap material used to maintain the cell gap of the liquid crystal device is dispersed in a resin constituting pixels of a color filter, and after the resin is applied onto a substrate, the gap is removed by a photolithography process. 1. A method for manufacturing a ferroelectric liquid crystal device, comprising forming a colored layer in a pattern shape on a substrate. (2) The method for manufacturing a ferroelectric liquid crystal element according to claim 1, wherein the particle size of the gap material is at least the sum of the film thickness of the color filter and the cell gap. (3) The method for manufacturing a ferroelectric liquid crystal element according to claim 1, wherein the gap material is alumina beads, SiO_2 beads, glass beads, plastic beads, or ceramic beads.