Liquid crystal display element, methods of producing and storing the same, and electronic equipment on which the same is mounted

• US 5,610,742 A
• Filed: 10/11/1994
• Issued: 03/11/1997
• Est. Priority Date: 08/01/1991
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Imazeki, Yoshikatsu, Furukawa, Yoko, Hosogaya, Hiroyuki, Fujisawa, Shinji, Hinata, Shoji, Tsukahara, Akira, Ono, Yoichi
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Dudek, James A.
• Application Number:
  US08/321,453
• Time in Patent Office: 882 Days
• Field of Search: 359/62, 359/63, 359/74, 359/80, 359/81, 359/82, 359/103, 359/99
• US Class Current: 349/122
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133308 Support structures for LCD panels, e.g. frames or bezels
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: Y10S 29/044 Vacuum
• CPC Class Codes: Y10T 29/49718 Repairing
• CPC Class Codes: Y10T 29/49723 including reconditioning of part

Abstract

A liquid crystal display element utilizing flexible gas barrier films decreases poor display performance caused by bubble formation. This decrease is achieved by reducing the permeation of gas and water vapor from the gas barrier films into substrates by devising the structure of the element and the configuration in which the element is mounted. Specifically, edges of the substrates forming the liquid crystal display elements are sealed. Additionally, the gas and water vapor saturation solubilities of the liquid crystal material is controlled to improve resistance to bubble formation. The liquid crystal display elements can also be subjected to and/or stored in a reduced pressure. Electronic equipment incorporating liquid crystal display elements can include a guard plate having a minimum thickness and/or spacing from the display elements.

Claims

1. A method of producing a liquid crystal display element having a pair of flexible substrates sealed to each other by a sealing member with a plurality of spacers therebetween defining a predetermined space between said substrates and a liquid crystal material located in said space, each of said substrates containing a gas barrier film and an orientating film, said orientating film being in contact with said liquid crystal material, said method including the steps of:

performing a gas barrier treatment on said substrates by sealing edges of said substrates; and

placing the liquid crystal display element in a vacuum dryer under reduced pressure for about 24 hours prior to use.

2. The method according to claim 1, further comprising the step of affixing polarizing plates to outer surfaces of said substrates.

3. The method according to claim 2, wherein the step of affixing polarizing plates to outer surfaces of the substrates is performed prior to said gas barrier treatment so that said gas barrier treatment also seals edges of said polarizing plates.

4. The method according to claim 1, wherein said gas barrier treatment includes applying an epoxy system adhesive to the edges of said substrates and hardening said epoxy system adhesive.

5. The method according to claim 1, wherein said gas barrier treatment includes sealing said edges of said substrates using heat.

6. The method according to claim 1, wherein said gas barrier treatment includes immersing the liquid crystal display element in an epoxy system adhesive, thereby forming a film of epoxy system adhesive on the liquid crystal display element;

said method further comprising the step of affixing polarizing plates to outer surfaces of said substrates using said epoxy system adhesive film.

7. The method according to claim 1, wherein said liquid crystal material has an oxygen saturation solubility of at least 10 μ

l/ml.

8. The method according to claim 7, wherein said liquid crystal material has an oxygen saturation solubility of at least 50 μ

l/ml.

9. The method according to claim 1, wherein said liquid crystal material has a nitrogen saturation solubility of at least 10 μ

l/ml.

10. The method according to claim 9, wherein said liquid crystal material has a nitrogen saturation solubility of at least 50 μ

l/ml.

11. The method according to claim 1, wherein said liquid crystal material has a saturation solubility of water vapor of at least 100 ppm.

12. The method according to claim 11, wherein said liquid crystal material has a saturation solubility of water vapor of at least 300 ppm.

13. The method according to claim 1, wherein a degree to which either oxygen, nitrogen, water vapor or a mixture thereof is saturated in the liquid crystal material, immediately after production of said liquid crystal display element, is not more than 0.9.

14. The method according to claim 13, wherein the degree to which either oxygen, nitrogen, water vapor or a mixture thereof is saturated in the liquid crystal material, immediately after production of said liquid crystal display element, is not more than 0.5.

15. The method according to claim 1, wherein 150 to 300 spacers per square millimeter are placed between said substrates.

16. The method according to claim 1, wherein the edges of said substrates are sealed with a material impermeable to gas and water vapor.

17. The method of claim 16, wherein said material is selected from the group consisting of epoxy system adhesive, ethylene-vinyl acetate copolymer, and polyvinyl alcohol.

18. The method according to claim 1, wherein each flexible substrate is made by:

disposing a gas barrier layer on each side of a supporting substrate, each gas barrier layer serving as said gas barrier film; and

placing a hard coat layer on each gas barrier layer, each hard coat layer having a hardness greater than a hardness of a pencil capable of withstanding a bending stress of at least 50.0 MPa.

19. A liquid crystal display element comprising:

a pair of flexible substrates sealed to one another by a sealing member, each of said substrates containing a gas barrier film and an orientating film located on sides of said substrates which oppose one another;

a plurality of spacers disposed between said substrates, said spacers maintaining a predetermined space between said substrates; and

a liquid crystal material sealed in said predetermined space between said substrates, said liquid crystal material having an oxygen saturation solubility of at least 10 μ

l/ml;

wherein edges of said substrates are sealed thereby providing reduced permeation of gas and water vapor into the liquid crystal material.

20. The liquid crystal display element according to claim 19, further comprising polarizing plates affixed to outer surfaces of the substrates.

21. The liquid crystal display element according to claim 19, wherein each substrate comprises:

a supporting substrate;

a gas barrier layer disposed on each side of said supporting substrate and serving as said gas barrier film; and

a hard coat layer having a pencil hardness of not less than H disposed on said gas barrier layers.

22. The liquid crystal display element of claim 21, wherein said hard coat layer is a layer of phenoxy resin.

23. The liquid crystal display element according to claim 19, wherein said liquid crystal material has an oxygen saturation solubility of at least 50 μ

l/ml.

24. The liquid crystal display element according to claim 19, wherein 150 to 300 spacers per square millimeter are located between said substrates.

25. The liquid crystal display element of claim 19, wherein said substrates are sealed by a material impermeable to gas and water vapor located on said edges of said substrates.

26. The liquid crystal display element of claim 25, wherein said material impermeable to gas and water vapor is selected from the group consisting of epoxy system adhesive, ethylene-vinyl acetate copolymers, and polyvinyl alcohol.

27. The liquid crystal display element of claim 19, wherein said substrates are sealed by providing heat seals on said substrate edges.

28. A method of producing a liquid crystal display element having a pair of flexible substrates sealed to each other by a sealing member with a plurality of spacers therebetween defining a predetermined space between said substrates and a liquid crystal material located in said space, each of said substrates containing a gas barrier film and an orientating film, said orientating film being in contact with said liquid crystal material, said method including the steps of:

performing a gas barrier treatment on said substrates by sealing edges of said substrates;

storing the sealed liquid crystal display element in a vacuum dryer under reduced pressure after performing the gas barrier treatment on said substrates; and

removing the sealed liquid crystal display element from storage for assembly onto electronic equipment.

29. A liquid crystal display element comprising:

a pair of flexible substrates sealed to one another by a sealing member, each of said substrates containing a gas barrier film and an orientating film located on sides of said substrates which oppose one another;

a plurality of spacers disposed between said substrates, said spacers maintaining a predetermined space between said substrates; and

a liquid crystal material sealed in said predetermined space between said substrates, said liquid crystal material having a nitrogen saturation solubility of at least 10 μ

l/ml;

wherein edges of said substrates are sealed thereby providing reduced permeation of gas and water vapor into the liquid crystal material.

30. The liquid crystal display element according to claim 29, wherein said liquid crystal material has a nitrogen saturation solubility of at least 50 μ

l/ml.

31. A liquid crystal display element comprising:

a pair of flexible substrates sealed to one another by a sealing member, each of said substrates containing a gas barrier film and an orientating film located on sides of said substrates which oppose one another;

a plurality of spacers disposed between said substrates, said spacers maintaining a predetermined space between said substrates; and

a liquid crystal material sealed in said predetermined space between said substrates, said liquid crystal material having a saturation solubility of water vapor of at least 100 ppm;

wherein edges of said substrates are sealed thereby providing reduced permeation of gas and water vapor into the liquid crystal material.

32. The liquid crystal display element according to claim 31, wherein said liquid crystal material has a saturation solubility of water vapor of at least 300 ppm.

33. A method of producing a liquid crystal display element having a pair of flexible substrates sealed to each other by a sealing member with a plurality of spacers therebetween defining a predetermined space between said substrates and a liquid crystal material located in said space, each of said substrates containing a gas barrier film and an orientating film, said orientating film being in contact with said liquid crystal material, said method including the steps of:

performing a gas barrier treatment on said substrates by sealing edges of said substrates; and

placing the liquid crystal display element in a vacuum dryer under reduced pressure for about 24 hours after assembly of the liquid crystal display element.