Resistance-film type touch panel for use in a liquid crystal display device and liquid crystal display device equipped with the same

• US 6,549,195 B2
• Filed: 12/06/2000
• Issued: 04/15/2003
• Est. Priority Date: 06/08/1998
• Status: Expired due to Fees

• Current Assignee: Kaneka Corporation
• Original Assignee: Kaneka Corporation
• Inventors: Fujii, Sadao, Hikida, Toshihiko
• Primary Examiner(s): Chow, Dennis-Doon
• Assistant Examiner(s): Nelson, Alecia D.
• Application Number:
  US09/732,447
• Publication Number:
  US 20010000961A1
• Time in Patent Office: 860 Days
• Field of Search: 345/173, 345/175, 345/174, 349/162, 349/12
• US Class Current: 345/173
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

The touch panel for use in a liquid crystal display device has a rigid electrode plate composed of a rigid transparent substrate provided with a transparent conductive layer on its upper surface, and a flexible electrode plate composed of a transparent and flexible substrate provided with a transparent conductive layer on its lower surface. On the upper surface of the flexible electrode plate, a polarizer plate is fixed. The flexible transparent substrate includes a transparent film of a transparent amorphous plastic material having a glass transition temperature of 100° C. or higher, and the transparent film has a relative optical elasticity coefficient Cr value of 0.2 to 0.8 defined by the formula: Cr=C/Cpc where C represents an optical elasticity coefficient of the transparent film and Cpc represents an optical elasticity coefficient of a polycarbonate film derived from bisphenol A.

Claims

1. A touch panel comprising:

a rigid electrode plate including a first substrate which is transparent and rigid, and has a first main surface and a second main surface, and a first transparent electrically conductive layer provided on the second main surface of the first substrate;

a flexible electrode plate including a second substrate which is transparent and flexible, and has a first main surface and a second main surface, and a second transparent electrically conductive layer provided on the first main surface of the second substrate, said flexible electrode plate being arranged spaced apart from the rigid electrode plate such that the second transparent conductive layer faces the first transparent conductive layer; and

a polarizer plate fixed on the second main surface of the second substrate;

wherein said flexible electrode has a flexibility sufficient to yield by a pressing force applied pointwise on the polarizer plate to bring the second transparent conductive layer into point contact with the first transparent conductive layer;

the second substrate is made of a transparent film of a transparent amorphous plastic material having a glass transition temperature of 100°

C. or higher, and

the transparent film has a relative optical elasticity coefficient Cr value of 0.2 to 0.8 defined by an equation;

2. The touch panel according to claim 1, wherein said transparent film is constituted as a retardation film.

3. The touch panel according to claim 2, wherein said transparent film has a retardation value of 50 nm to 250 nm.

4. The touch panel according to claim 1, wherein said amorphous plastic is an aromatic polyester containing a structural unit derived from at least one bisphenol selected from the group consisting of 1,1-bis(4-hydroxyphenyl)-(alkyl-substituted)cycloalkane, 1,1-bis(3-substituted-4-hydroxyphenyl)-(alkyl-substituted)cycloalkane and 1,1-bis(3,5-disubstituted-4-hydroxyphenyl)-(alkyl-substituted)cycloalkane.

5. The touch panel according to claim 4, wherein said transparent film is constituted as a retardation film.

6. The touch-panel according to claim 5, wherein said transparent film has a retardation value of 50 nm to 250 nm.

7. The touch panel according to claim 1, wherein said amorphous plastic is a polycarbonate containing a structural unit derived from at least one bisphenol selected from the group consisting of 1,1-bis(4-hydroxyphenyl)-(alkyl-substituted)cycloalkane, 1,1-bis(3-substituted-4-hydroxyphenyl)-(alkyl-substituted)cycloalkane and 1,1-bis(3,5-disubstituted-4-hydroxyphenyl)-(alkyl-substituted)cycloalkane.

8. The touch panel according to claim 7, wherein said transparent film is constituted as a retardation film.

9. The touch panel according to claim 8, wherein said transparent film has a retardation value of 50 nm to 250 nm.

10. The touch panel according to claim 1, wherein said amorphous plastic comprises a mixture of an aromatic polyester containing a structural unit derived from at least one bisphenol selected from the group consisting of 1,1-bis(4-hydroxyphenyl)-(alkyl-substituted)cycloalkane, 1,1-bis(3-substituted-4-hydroxyphenyl)-(alkyl-substituted)cycloalkane and 1,1-bis(3,5-disubstituted-4-hydroxyphenyl)-(alkyl-substituted)cycloalkane, and an aromatic polycarbonate containing a structural unit derived from said at least one bisphenol.

11. The touch panel according to claim 10, wherein said transparent film is constituted as a retardation film.

12. The touch panel according to claim 11, wherein said transparent film has a retardation value of 50 nm to 250 nm.

13. A liquid crystal display device comprising a liquid crystal cell and a touch panel fixed on the liquid crystal cell at a distance, wherein said touch panel is a touch panel according to claim 1.