JPH03220528A - lcd display panel - Google Patents

Abstract

PURPOSE:To make the moisture absorptivity small and to improve the long- period reliability by using fluororesin as a sealing material for sealing the peripheral edge part of a substrate. CONSTITUTION:The liquid crystal display panel which has a medium layer inserted and held between two substrates so that transparent electrode surfaces face each other uses the fluororesin as the sealing material for sealing the substrate peripheral edge part. Consequently, the moisture absorptivity and long-period reliability are improved. Further, the substrate peripheral edge part can be sealed in a short time and the adverse influence of heating in the sealing process upon the liquid crystal can be made small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polymer-dispersed liquid crystal display panel with excellent water resistance.

The liquid crystal display panel of the present invention can be used for various displays, optical shutters, control devices, etc., and can be particularly suitably used as a liquid crystal display panel for large screens.

[Prior art and its problems]

In a conventional method for sealing a liquid crystal display panel, the peripheral edges of two substrates are sealed with a sealant, and after liquid crystal is filled through an injection hole, the injection hole is closed.

This method cannot be used with polymer-dispersed liquid crystal display panels, and the method used was to sandwich the polymer-dispersed liquid crystal between two substrates and then seal the periphery of the substrates with epoxy resin. .

In this case, there was a problem in that the epoxy resin could not be sufficiently cured in order to prevent the liquid crystal inside the cell from deteriorating due to heat. As a result, the sealing becomes insufficient, moisture easily enters the inside, and the performance of the liquid crystal display panel deteriorates, such as a decrease in contrast ratio, during long-term use.

[Means for solving problems]

The present inventors conducted extensive research in order to solve the above problems, and as a result, they arrived at the present invention.

The present invention consists of two substrates on which transparent electrodes are disposed, and a medium layer in which liquid crystal is dispersed in the medium, and the medium layer is
The present invention relates to a liquid crystal display panel which is sandwiched between two substrates so that transparent electrode surfaces face each other, and in which a sealing material for sealing the peripheral edge of the base pile is a fluororesin.

Specific examples of the fluororesin used as the sealing material of the present invention include polytetrafluoroethylene resin, ethylene-47fluoroethylene copolymer resin, vinylidene fluoride resin, trifluorochloride ethylene resin, and vinyl fluoride resin. Examples include resins, tetrafluoroethylene-perfluoroalkoxyethylene copolymer resins, and the like.

Further, adding a filler to the sealing material in a molten state and applying it;
By sealing, moisture resistance can be further improved. Specific examples of fillers include powdered, flaky, fibrous glass, calcium carbonate, tackle, inorganic fillers such as mica, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer resin, etc. , vinylidene fluoride resin, trifluorochlorinated ethylene resin, and other fluororesin powders. The usage ratio of the filler to the polyolefin resin is preferably 5 to 50 parts by weight, particularly 10 to 50 parts by weight per 100 parts by weight of the polyolefin resin.

The medium layer of the present invention is a medium layer in which liquid crystal is dispersed in the medium, and a specific example thereof is a polymer-dispersed liquid crystal, such as N CA P (N CA P ( Nematic Curvilin
ear Aligned Phase: Nematic curve aligned phase) liquid crystal (Special Publication No. 58-501631)
, latex-incorporated liquid crystal (Japanese Patent Application Laid-Open No. 60-252687
), a material in which liquid crystal microdroplets are dispersed in epoxy resin (Japanese Patent Publication No. 61-502128), or a liquid crystal composite film with a network structure prepared by a solvent casting method (Po
lymer Preprints, Japan vol.
, 37. No. 8.2450 (1988) 3, etc.

〔Example〕

The present invention will be explained in further detail with reference to production examples below.

Production Example 1 10% PVA aqueous solution, liquid crystal, dichroic dye (PVA:liquid crystal-1:3.5 (weight ratio), dichroic dye is 3% by weight of liquid crystal
) was mixed well, and this was coated and dried using a doctor blade on a substrate with a transparent electrode, which had been patterned with a predetermined electrode using ITO or the like (thickness: 15 μm). This substrate was bonded to another substrate on which predetermined electrodes had been patterned using ITO or the like in advance so as to match each other at a predetermined position to produce a liquid crystal display panel.

Using a hot melt gun, ethylene-tetrafluoroethylene copolymer resin (Niaflon C0P manufactured by Asahi Glass Co., Ltd.) was applied to the periphery of the bonded substrates to seal the liquid crystal display panel.

The above liquid crystal display panel was subjected to a 500 hour moisture resistance test under the conditions of 50'C and 195% humidity.

The resistance value when 50V is applied is 6.5 x 10' before the test.
Ω was 3.9×10′Ω after the test, and did not change at all.

Production Example 2 A liquid crystal display panel was produced in the same manner as Production Example 1 except that a conventionally known two-component epoxy resin adhesive was used as the sealing material, and it was resistant to humidity for 500 hours at 50°C and 195% humidity. A sex test was conducted.

The resistance value when 50V was applied was 5.4 x 109 before the test.
The resistance after the test was 1.58×10 9 Ω, which was a significant decrease in resistance.

Production Example 3 Ethylene-tetrafluoroethylene copolymer resin (manufactured by Asahi Glass;
Calcium carbonate (Whiten SSB)
A liquid crystal display panel was prepared using a sealing material containing red, average particle size 1.25 μm, specific surface area 1.85 square meters/g, Shiroishi calcium) mixed at a ratio of 75:25 (parts by weight), and heated at 50°C 195%. A 500 hour moisture resistance test was conducted under humid conditions.

The resistance value when 50V was applied was 6.9 x 10' before the test.
Ω, after the test was 5.8×10 9 Ω.

〔Effect of the invention〕

Since the liquid crystal display panel of the present invention uses a fluororesin as a sealing material, it has low hygroscopicity and can improve long-term reliability.

Further, when the sealing material of the present invention is used, the peripheral edge of the substrate can be sealed in a short time, and the adverse effect on the liquid crystal due to heating in the sealing process is small.

Claims (1)

[Claims] (1) Consisting of two substrates on which transparent electrodes were arranged and a medium layer in which liquid crystal was dispersed in the medium, the medium layer was sandwiched between the two substrates so that the transparent electrode surfaces faced each other. A liquid crystal display panel characterized in that a sealing material for sealing a peripheral portion of a substrate is a fluororesin.