JPH0833544B2 - Liquid crystal element - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid crystal display device, a liquid crystal device such as a liquid crystal-optical shutter array, and more specifically, by improving the initial alignment state of liquid crystal molecules, display and The present invention relates to a ferroelectric liquid crystal device having improved drive characteristics.

[Summary of Disclosure] The present specification and drawings show a ferroelectric liquid crystal device used for a liquid crystal display device, a liquid crystal-optical shutter array, or the like.
By forming the gap agent sandwiched between the substrates by immersing it in the color filter on the substrate, the dispersion of the cell gap is improved and the occurrence of alignment defects is prevented, and the characteristics of the ferroelectric liquid crystal are sufficiently improved. A technique for producing a ferroelectric liquid crystal element that can be exhibited is disclosed.

[Prior Art] Conventionally, in a color liquid crystal display panel, a gap agent is sprinkled on a filter layer formed on a substrate to maintain a space (cell gap) between the filter substrate and the counter substrate, and the filter substrate and the counter substrate are bonded together. The cell gap was obtained by press-bonding with a pressure such that the gap agent does not penetrate into the filter layer.

[Problems to be Solved by the Invention] However, the gap agent dispersed between the substrates becomes less accurate as the particle size becomes smaller, and all of the gap agent is not always in uniform contact with the filter layer. is not. That is, some of them are floating in the liquid crystal and some of them are embedded in the filter. For example, when the gap interval is set to 1 μm, it is actually 1
Only accuracy of about μm ± 0.5 μm was obtained.

Conventionally, it has been considered that the alignment defect of the liquid crystal is caused by the unevenness of the filter surface caused by the gap agent penetrating into the filter. However, as a result of the research conducted by the present inventors, it has been clarified that the alignment defect of the liquid crystal is mainly caused by the above-mentioned variation in the cell gap accuracy rather than the unevenness of the filter surface caused by the gap agent. That is, a highly accurate cell gap is required to eliminate the alignment defect of the liquid crystal.

It is an object of the present invention to provide a ferroelectric liquid crystal device capable of preventing the occurrence of the above-mentioned alignment defects and sufficiently exhibiting the high-speed response and the memory effect characteristic that the ferroelectric liquid crystal device originally has. It is intended.

[Means for Solving Problems] and [Action] The present inventors have paid particular attention to the initial orientation in the temperature decreasing process in which the liquid crystal transitions from the isotropic phase (high temperature state) to the liquid crystal phase (low temperature state), The present inventors have found a liquid crystal device having a structure capable of satisfying both the operating characteristics of the device based on the bistability of liquid crystal and the monodomain property of the liquid crystal layer. The liquid crystal element of the present invention is based on such knowledge. More specifically, the layer thickness of the liquid crystal layer is uniform on the inner surface of the liquid crystal element, that is, it causes a sudden change in the layer thickness of the liquid crystal layer. By eliminating it, the initial orientation in the temperature lowering process is brought into a good state, and a feature is that a monodomain without alignment defects is formed.

That is, the present invention is a pair of substrates, a color filter layer or a protective layer having a predetermined film thickness provided on at least one substrate of the pair of substrates, sandwiched to maintain a distance between the pair of substrates, A liquid crystal device having a gap agent disposed by being pressed into the color filter layer or the protective layer by pressurizing the pair of substrates, and a liquid crystal having a chiral smectic phase when cooled from an isotropic phase.

The liquid crystal material used in the present invention is a liquid crystal that produces a chiral smectic phase when cooled from an isotropic phase, and has bistability and ferroelectricity. Specifically, chiral smectic C phase (SmC ^* phase), H phase (SmH ^* phase), I phase (SmI ^* phase), J phase (SmJ ^* phase), K phase (SmK ^* phase), G phase (SmG) A liquid crystal of ^* phase) or F phase (SmF ^* phase) can be used.

 For this ferroelectric liquid crystal,
De Féjique Luthere ("LE JOURNAL DE PHYSIQUE
 LETTERS ") 1975,36(L-69), "Ferro-elect
Rick Liquid Crystals "(" Ferroelectricl
iquid Crystals ”);“ Applied Physics Les
"Applied Physics Letters" 1980,36
(11), "Sub-micro second bistable
Electro-optic switching in liquid
・ Crystals ("Submicro Second Bistable Electro
optic Switching in Liquid Crystals ”);“ Solids
Ri "1981,16(141), "Liquid crystal" etc.
In the present invention, the ferroelectric liquids disclosed in these are
Crystals can be used.

Specific examples of the ferroelectric liquid crystal compound include desiloxybenzylidene-p′-amino-2-methylbutylcinnamate (DOBAMBC) and hexyloxybenzylidene-p ′.
-Amino-2-chloropropyl cinnamate (HOBACP
C), 4-o- (2-methyl) -butylresorcylidene-4′-octylaniline (MBRA8).

When an element is formed using these materials, the element is supported by a block or the like in which a heater is embedded, if necessary, because the element is held in a temperature state where the liquid crystal compound is in a chiral smectic phase.

Examples of the material of the alignment control film used in the present invention include polyvinyl alcohol, polyimide, polyamideimide, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, and urea resin. Resins such as acrylic resin, photosensitive polyimide, photosensitive polyamide, cyclized rubber photoresist, phenol novolac photoresist or electron beam photoresist (polymethylmethacrylate, epoxidized-1,4-polybutadiene, etc.), etc. It can be selected and formed.

The color filter used in the present invention includes a vapor deposition type, a dyeing type, a resin type, an electrodeposition type, and the like, and may be formed by any method.

Further, as the dye material for the color filter used in the present invention, azo-based, anthraquinone-based, phthalocyanine-based, quinacridone-based, isoindolinone-based, dioxazine-based, perylene-based, perinone-based, thioindigo-based,
Pyrocholine-based, fluororubin-based, quinophthalone-based and the like can be mentioned.

Examples of the material of the gap agent used in the present invention include glass, alumina, plastic and the like, and a spherical shape can be used.

FIG. 1 is a sectional view schematically showing a cell structure of a ferroelectric liquid crystal device according to the present invention. In FIG. 1, a liquid crystal element comprises a pair of parallel substrates 1 arranged vertically, a color filter 2 formed on one substrate, a gap agent 3 and a ferroelectric liquid crystal 4 sandwiched between these substrates. It is composed of a sealant 5 for sealing the periphery.

As shown in the figure, the diameter of the gap agent 3 is the sum of the depth of penetration of the gap agent 3 into the color filter 2, l _F, and the cell gap l _G. Would also use a gapping agent with a large diameter. As described above, it is difficult to make a highly accurate gapping agent with a diameter of around 1 μm, but with such a large diameter, a highly accurate gapping agent can be relatively easily prepared. Further, the bonding pressure of the upper and lower substrates in the present invention varies depending on the material (hardness) of the color filter, but is usually about 30% higher than the pressure bonding in the conventional method. Therefore, the gap agent is pressed with a higher pressure than in the past, and is formed in a state in which the gap agent is embedded in the filter to a certain depth. Therefore, the cell gap can be maintained with extremely high accuracy, and a monodomain without alignment defects can be obtained.

[Examples] FIG. 3 shows an example of forming a color filter on a substrate, and is a diagram showing a process of forming a color filter using a photosensitive coloring resin.

In FIG. 3, a blue coloring resin agent [Heliogen Blue L7080 (trade name, manufactured by BASF, CI No. 7) capable of obtaining desired spectral characteristics is provided on the glass substrate 1.
4160) is PA-1000c (trade name, manufactured by Ube Industries, Ltd., polymer content
10%, solvent = N-methyl-2-pyrrolidone, pigment: polymer = 1: 2 blended) to prepare a photosensitive colored resin agent 2], which was applied to a film thickness of 2.0 μm by a spinner coating method ( See FIG. 3 (a). Next, on this colored resin layer 2
After prebaking at 80 ° C. for 30 minutes, it was exposed with a high pressure mercury lamp through a photomask 10 having a pattern corresponding to the pattern shape to be formed (FIG. 3 (b)).
reference). After completion of the exposure, development is carried out using ultrasonic waves with a dedicated developing solution (developing solution containing N-methyl-2-pyrrolidone as a main component) that dissolves only the unexposed portion of the colored resin layer 2, and a dedicated rinsing solution ( After treatment with a rinse solution containing 1,1,1, -trichloroethane as a main component, post-baking was performed at 150 ° C. for 30 minutes to form a blue colored resin layer 7 having a pattern shape (see FIG. 3 ( See c) and (d)).

Then, a green colored resin material [Lionol Green 6YK (trade name, manufactured by Toyo Ink Co., Ltd., C.
I.No.74265) was dispersed in PA-1000c (trade name, manufactured by Ube Industries, Ltd., polymer content 10%, solvent = N-methyl-2-pyrrolidone, pigment: polymer = 1: 2 blended) to make it photosensitive. The colored resin material 7] was used in the same manner as described above except that the colored resin material 7 was formed at a predetermined position on the substrate.

Further, as a third color, a red colored resin material [Irgazin] is formed on the substrate on which the blue and green patterns are formed.
Red (Irgazin Red) BPT (trade name, Ciba Geigy (Ci
ba-Geigy), CINo.71127) PA-1000c (trade name,
Ube Industries, polymer content 10%, solvent = N-methyl-2
-Pyrrolidone, pigment: polymer = 1: 2 blended) and prepared in the same manner as described above except that a photosensitive colored resin material prepared by dispersing is used to form a red colored resin layer 8 at a predetermined position on the substrate. A colored pattern of three-color stripes of R, R (red), G (green), and B (blue) was obtained (see FIG. 3 (e)).

A sealing agent (DNM-2110, made by Dainippon Paint Co., Ltd.) is printed on the outer periphery of the filter substrate thus obtained, and then a spherical gap agent having a diameter of 2.0 μm (made of glass) is placed on the filter.
Was sprayed. Then, it is bonded to the counter substrate and 1.8 Kg / cm ²
A ferroelectric liquid crystal element was obtained by pressure bonding under pressure and baking at 180 ° C. for 30 minutes.

The ferroelectric liquid crystal device obtained by the above method is 1.
Since it is pressure-bonded with a force of 8 kg / cm ² , it is exactly 1.0 μm into the 2.0 μm filter layer, and the cell gap is 1.0 μm ± 0.
It was possible to obtain 05 μm.

FIG. 2 is a perspective view showing the measurement position of the cell gap in the liquid crystal element, and the measured values of the cell gap at the measurement positions of (1) to (4) in the figure are shown in Table 1 below.

In the above embodiment, the example in which the gap agent is directly sprayed on the color filter has been described. However, as shown in FIG. 3 (f), the protective layer 9 is formed on the three-color coloring pattern, and the gap agent is added to the protective layer 9. You may make it immerse in the protective layer 9.

[Effects of the Invention] As described above, according to the present invention, the cell gap can be kept uniform with high accuracy by inserting a highly accurate gap agent into the filter to a certain depth. it can. Therefore, it is possible to prevent an alignment defect in the initial alignment state of the liquid crystal and to provide a liquid crystal element that can sufficiently exhibit the characteristics of the ferroelectric liquid crystal.

[Brief description of drawings]

FIG. 1 is a sectional view of a ferroelectric liquid crystal device according to the present invention, and FIG.
The drawing shows the cell gap measurement position, and FIG. 3 is a drawing showing the color filter forming process. 1 ... Substrate, 2 ... Color filter, 3 ... Gap agent.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Miki Tamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Nobuyuki Sekimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (1)

[Claims] 1. A pair of substrates, a color filter layer or a protective layer having a predetermined thickness provided on at least one of the pair of substrates, and sandwiched to maintain a space between the pair of substrates, It is characterized in that it has a gap agent disposed by being pressed into the color filter layer or the protective layer by pressurizing the pair of substrates, and a liquid crystal in which a chiral smectic phase is generated by cooling from the isotropic phase. Liquid crystal element.