Production process of liquid crystal display panel, seal material for liquid crystal cell and liquid crystal display

• US 5,898,041 A
• Filed: 02/28/1996
• Issued: 04/27/1999
• Est. Priority Date: 03/01/1995
• Status: Expired due to Term

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yamada, Satoshi, Matsukawa, Hideki
• Primary Examiner(s): Berman, Susan W.
• Application Number:
  US08/608,109
• Time in Patent Office: 1,154 Days
• Field of Search: 522/103, 522/81, 522/100, 522/83, 522/142, 522/182, 522/183, 252/299.01, 349/153, 349/122, 349/190
• US Class Current: 522/81
• CPC Class Codes: C09J 163/10 Epoxy resins modified by unsaturated compounds
• CPC Class Codes: C09K 2323/055 Epoxy
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G02F 1/1341 Filling or closing of cells
• CPC Class Codes: G02F 1/13415 Drop filling process

Abstract

This invention relates to a liquid crystal display apparatus formed by sealing a liquid crystal between two substrates having electrodes and an alignment film with a seal material, the production process comprising the steps of attaching two substrates in a vacuum, compressing under atmospheric pressure to provide a uniform cell gap, a temporary hardening process of the seal material by ultraviolet ray irradiation and a main hardening process of the seal material by heating, wherein a radically polymerizable curing resin is used in the liquid crystal seal material. The method provides a liquid crystal display panel having a uniform cell gap, without dislocation of the alighnment between substrates, or discharge of uncured component of a seal material to the liquid crystal, capable of having a seal material firmly attached to the substrates even at panel corner portions, and having an excellent straightness and moisture resistance of the seal material.

Claims

1. A seal material for liquid crystal display panels, comprising (meth)acrylate monomers or oligomers derived from an epoxy compound, (meth)acrylic acid ester, a photoinitiator, a thermosetting agent and an inorganic filler, wherein the (meth)acrylic acid ester includes 5 to 10 weight % based on the seal material of (meth)acrylic acid ester having a plurality of (meth)acrylic acid residues per molecule and 2 to 10 weight % based on the seal material of (meth)acrylic acid ester having one (meth)acrylic acid residue per molecule, the seal material being capable of ultraviolet ray curing and thermosetting, wherein the seal material undergoes radical polymerization.

2. A seal material for liquid crystal display panels according to claim 1, wherein (meth)acrylate monomers or oligomers derived from epoxy compound are present in an amount of 40 to 70 weight % based on the seal material and are derived from epoxy compounds selected from the group consisting of bisphenol A and novolak.

3. The seal material for liquid crystal display panels according to claim 1, wherein the photoinitiator is present in an amount of 3 to 5 weight % based on the seal material and is one selected from the group consisting of an acetophenone photoinitiator, a benzoin photoinitiator and a benzophenone photoinitiator.

4. The seal material for liquid crystal display panels according to claim 1, wherein the thermosetting agent is present in an amount of 2 to 5 weight % based on the seal material and is one selected from the group consisting of hydrazide, aromatic amine, acid anhydride and imidazole.

5. The seal material for liquid crystal display panels according to claim 1, wherein the thermosetting agent is a particulate thermosetting agent having an average particle size of 3 μ

m or smaller.

6. The seal material for liquid crystal display panels according to claim 1, further comprising a silane coupling agent present in an amount of 2 to 7 weight % based on the seal material, which is one selected from the group consisting of glycidyl ethoxy silane and glycidyl methoxy silane.

7. The seal material for liquid crystal display panels according to claim 1, wherein the inorganic filler has an average particle size of 1.5 μ

m or smaller, and is present in an amount of 8 to 20 weight % based on the seal material and is one selected from the group consisting of hydrated magnesium silicate, calcium carbonate, aluminum carbonate and silica.