Touch panel

• US 4,990,900 A
• Filed: 06/09/1988
• Issued: 02/05/1991
• Est. Priority Date: 10/01/1987
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Kikuchi, Hiroshi
• Primary Examiner(s): Brier, Jeffrey A.
• Assistant Examiner(s): FATAHI YAR, MAHMOUD
• Application Number:
  US07/204,448
• Time in Patent Office: 971 Days
• Field of Search: 341/22, 341/31, 341/33, 341/34, 340/712, 340/784, 340/719, 250/221, 178/18, 350/350 R, 350/334, 350/339 R, 350/349, 200/5 A
• US Class Current: 345/174
• 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 having a panel body formed by transparent upper and lower electrodes spaced a predetermined distance. The touch panel is mounted on a front surface of a display device to detect a coordinate at a depressed position on the upper electrode. The improvement comprises a transparent insulating liquid material filled between the upper and lower electrodes and a coloring agent containing pigment or dyestuff dispersed in the liquid material. In another aspect, the improvement comprises a transparent insulating liquid material filled between the upper and lower electrodes and an insulating fine powder dispersed in the liquid material.

Claims

1. In a touch panel having a panel body formed by transparent upper and lower electrodes spaced a predetermined distance, said touch panel being mounted on a front surface of a display device to detect a coordinate at a depressed position on said upper electrode;

the improvement comprising a transparent insulating liquid material filled between said upper and lower electrodes and a coloring agent containing pigment or dyestuff dispersed in said liquid material.

2. The touch panel as defined in claim 1, further comprising an insulating fine powder dispensened in said liquid material and wherein said insulating fine powder comprises a transparent spherical powder.

3. The touch panel as defined in claim 2, wherein said insulating fine powder is comprised of spheres having a diameter about equal to a spacing between said upper and said lower electrodes when said upper electrode is not in the depressed position.