Touch panel and electronic apparatus using the same

• US 20040017363A1
• Filed: 05/23/2003
• Published: 01/29/2004
• Est. Priority Date: 05/07/2001
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakanishi, Akira, Tadokoro, Tetsuya
• Granted Patent: US 7,161,588 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A touch panel comprising: a resin substrate; a first film with one surface provided with a first conductive layer and another surface adhering the resin substrate; a second film provided with a second conductive layer on one surface facing the first conductive layer of the first film; and a third film adhering a surface of the resin substrate opposite to the surface the first film is adhered. The first and third films sandwich the resin substrate via adhesive layers. Warp caused by changes in temperature and humidity during and after the production of the touch panels can be decreased, thereby achieving application of the touch panels to a large-sized display apparatuses.

Claims

1. A touch panel comprising:

a resin substrate;

a first film having a first conductive layer, said first conductive layer on one surface of said first films, another surface of said first film adhering said resin substrate;

a second film having a second conductive layer, said second conductive layer on one surface of said second film facing the first conductive layer of said first film; and

a third film adhering a surface of said resin substrate opposite to the surface adhering said first film.

2. The touch panel of claim 1, wherein an adhesion of said resin substrate and said first film and said resin substrate and said third films are performed via pressure sensitive adhesive layers.

3. The touch panel of claim 2, wherein said pressure sensitive adhesive layer adhering said resin substrate and said first film and said pressure sensitive adhesive layer adhering said resin substrate and said third film have substantially same thickness and are made of same materials.

4. The touch panel of claim 1, wherein a difference in thermal expansion coefficient between said first film and said third film is not more than 1×

10<sup>−

5</sup>/°

C.

5. The touch panel of claim 1, wherein said resin substrate is a resin sheet produced by one of extrusion, casting and injection molding, and said first film and said third film comprise oriented film.

6. The touch panel of claim 1, wherein said first film and said third film have substantially same thickness and are made of same material.

7. The touch panel of claim 1, wherein a difference in thermal expansion coefficient between smallest and largest thermal expansion coefficients among said first, second and third films is not more than 1×

10<sup>−

5</sup>/°

C.

8. The touch panel of claim 1, further comprising a hard coat layer formed on said third film.

9. The touch panel of claim 1, further comprising an pressure sensitive adhesive layer formed on a surface of said third film opposite to the surface adhering said resin substrate.

10. The touch panel of claim 1, wherein said resin substrate, said first conductive layer, said first film, said second conductive layer, said second film and said third film comprise transparent materials.

11. The touch panel of claim 10, further comprising display patterns formed on said third film.

12. The touch panel of claim 10, further comprising an anti-reflection layer formed on said third film.

13. The touch panel of claim 1, wherein entire portions of said first film and said third film corresponding to a visible region adhere to said resin substrate.

14. An electronic apparatus provided with the touch panel of claim 1, wherein said apparatus activates predetermined functions according to a judgement of a control circuit, said judgement based on a predetermined signal obtained by an operation to said touch panel.

15. An electronic apparatus provided with the touch panel of claim 10, wherein said apparatus activates predetermined functions according to a judgement of a control circuit, said judgement based on a predetermined signal obtained by an operation to said touch panel.