Touch panel and an input device equipped therewith

• US 7,071,925 B2
• Filed: 05/31/2002
• Issued: 07/04/2006
• Est. Priority Date: 08/08/2001
• Status: Expired due to Fees

• Current Assignee: Nagano Fujitsu Component Limited
• Original Assignee: Nagano Fujitsu Component Limited
• Inventors: Matsuda, Genichi, Furukawa, Shozo
• Primary Examiner(s): Lefkowitz, Sumati
• Assistant Examiner(s): ENGLISH, ALECIA DIANE
• Application Number:
  US10/157,889
• Publication Number:
  US 20030030626A1
• Time in Patent Office: 1,495 Days
• Field of Search: 345173-178, 178/18.01, 178 1803- 1811
• US Class Current: 345/173
• 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 that includes a polarizing plate, and used as an input device of a display unit of a personal computer, a word processor, an electronic notebook and the like is structured by one or more films that have a low heat contraction coefficient and a low water absorption coefficient, which remarkably suppress occurrence of concave deformations of the polarizing plate after exposure to a high temperature and soaking in water, avoiding short circuits.

Claims

1. A touch panel, having a polarizing plate on an upper surface of a main part of the touch panel, comprising a film pasted on an upper surface of the polarizing plate, the film having a heat contraction rate smaller than 0.3% after being exposed to a temperature of 100 degrees C. for 30 minutes, and a water absorption rate smaller than 0.5% after having been soaked in 23-degree C. water for 24 hours.

2. The touch panel as claimed in claim 1, wherein the film is made from one of:

polyethylene naphthalate,

polynorbornen,

polycycloolefin,

polycarbonate,

polyethersulphone, and

polyarylate.

3. An input device, comprising a touch panel as claimed in claim 2, the touch panel being on a surface of a display unit.

4. The touch panel as claimed in claim 1, further comprising a liquid crystal panel underneath said main part such that said main part is mounted upon said liquid crystal panel, said film pasted on said upper surface of said polarizing plate being formed of a flouroresin film.

5. An input device, comprising a touch panel as claimed in claim 1, the touch panel being on a surface of a display unit.

6. The touch panel as claimed in claim 1, further comprising a liquid crystal panel underneath said main part such that said main part is mounted upon said liquid crystal panel, wherein said film pasted on said upper surface of said polarizing plate is a transparent film.

7. A touch panel as claimed in claim 6, wherein the transparent film is made of one of:

polyethylene napthalate,

polynorbornen,

polycycloolefin,

polycarbonate,

polyethersulphone, and

polyarylate.

8. A touch panel, having a polarizing plate on an upper surface of a main part of the touch panel, the polarizing plate comprising two films and a polarizing film, wherein the two films sandwich the polarizing film, each of the films that sandwich the polarizing film having a heat contraction rate smaller than 0.3% after being exposed to a temperature of 100 degrees C. for 30 minutes, and a water absorption rate smaller than 0.5% after having been soaked in 23-degree C. water for 24 hours.

9. The touch panel as claimed in claim 8, wherein each of the films that sandwich the polarizing film is made from one of:

polyethylene naphthalate,

polynorbornen,

polycycloolefin,

polycarbonate,

polyethersulphone, and

polyarylate.

10. An input device, comprising a touch panel as claimed in claim 9, the touch panel being on a surface of a display unit.

11. An input device, comprising a touch panel as claimed in claim 8, the touch panel being on a surface of a display unit.

12. A touch panel, comprising:

a glass substrate;

a first transparent resistance film formed on an upper surface of the glass substrate;

a further resistance film having an upper surface and a lower surface;

a second transparent resistance film, formed on the lower surface of the further resistance film and pasted along peripheral portions thereof to, while spaced from, the upper surface of the glass substrate having the first transparent resistance film thereon;

a polarizing plate pasted on the upper surface of the further resistance film;

a transparent film pasted on an upper surface of the polarizing plate, having a heat contraction rate smaller than 0.3% after being exposed to a temperature of 100 degrees C. for 30 minutes, and a water absorption rate smaller than 0.5% after having been soaked in 23-degree C. water for 24 hours, and made from one of;

polyethylene napthalate,

polynorbomen,

polycycloolefin,

polycarbonate,

polyethersulphone, and

polyarylate; and

the touch panel being formed on a liquid crystal display panel.

13. A touch panel as claimed in claim 12, further comprising:

a first λ

/4 phase-difference film formed on a bottom surface of the glass substrate and having an absorption axis at a −

45°

direction relatively to the absorption axis of the polarizing plate; and

a second λ

/4 phase-difference film having an absorption axis at a +45°

direction relatively to the absorption axis of the polarizing plate, farmed between the upper surface of the further resistance film and a lower surface of the polarizing plate.