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

• US 20010000961A1
• Filed: 12/06/2000
• Published: 05/10/2001
• Est. Priority Date: 06/08/1998
• Status: Active Grant

• Current Assignee: Kaneka Corporation
• Original Assignee: Kaneka Corporation
• Inventors: Hikida, Toshihiko, Fujii, Sadao
• Granted Patent: US 6,549,195 B2
• Time in Patent Office: Days
• 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 a 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;

Cr=C/Cpc 

 

(1)

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.

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 1,1bis(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

.