Resistive touch pad with multiple regions of sensitivity

• US 20050212773A1
• Filed: 03/25/2004
• Published: 09/29/2005
• Est. Priority Date: 03/25/2004
• Status: Active Grant

• Current Assignee: Toshiba Global Commerce Solutions Holdings Corporation (Toshiba Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Asbill, Roger Lee
• Granted Patent: US 7,289,111 B2
• Time in Patent Office: Days
• 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 pad for a data processing system a first film and an electrically conductive first thin film above the first film, a plurality of electrically non-conductive spacer dots above the first thin film, a second electrically conductive thin film above the plurality of spacer dots, and a second film above the second thin film. The density of spacer dots above the first thin film is non-uniform. In one implementation, the first film is a ceramic, the second film is a flexible polymer, and the first and second thin films are a metal-oxide compound. In one embodiment, the spacer dot density is in a first range over a first portion of the first film and in a second range over a second portion of the first film. The second portion of the first film may define a signature box suitable for receiving a user'"'"'s signature or 6.

Claims

1. A touch pad for a data processing system, comprising:

a first surface and an electrically conductive first thin film above the first film;

a plurality of electrically non-conductive spacer dots above the first thin film;

a second electrically conductive thin film above the plurality of spacer dots;

a second film above the second thin film;

wherein the density of spacer dots above the first thin film is non-uniform.

2. The touch pad of claim 1, wherein the first surface is a ceramic, the second film is a flexible polymer, and the first and second thin films are a metal-oxide compound.

3. The touch pad of claim 1, wherein the spacer dot density is in the range of 0.08 to 0.14 over a first portion of the first film.

4. The touch pad of claim 3, wherein the spacer dot density is in the range of 0.01 to 0.05 over a second portion of the first film.

5. The touch pad of claim 4, wherein the second portion of the first film comprises a signature box suitable for receiving a user'"'"'s signature.

6. The touch pad of claim 4, wherein the first portion of the first film comprises a perimeter surrounding the second portion of the first film.

7. The touch pad of claim 4, wherein a spacer dot diameter in the first portion equals a spacer dot diameter in the second portion and wherein a spacer dot pitch in the first portion differs from a spacer dot pitch in the second portion.

8. A touch pad for a data processing system, comprising:

a first touch pad portion having a first sensitivity determined at least in part by the configuration of a first set of spacer dots within the first portion; and

a second touch pad portion having a second sensitivity determined at least in part by the configuration of a second set of spacer dots within the second portion;

wherein the first sensitivity and the second sensitivity differ due to differences in the first and second spacer dot configurations.

9. The touch pad of claim 8, wherein the first spacer dot configuration and the second spacer dot configuration have different spacer dot densities.

10. The touch pad of claim 9, wherein the first spacer dot density is lower than the second spacer dot density and wherein the first portion of the touch pad comprises a signature block of the touch pad.

11. The touch pad of claim 9, wherein the first space dot density is higher than the second spacer dot density and wherein the first portion of the touch pad comprises a perimeter portion of the touch pad.

12. The touch pad of claim 8, wherein the space dot density in the first portion exceeds the space dot density in the second portion by a factor in the range of 1.6 to 14.

13. The touch pad of claim 12, wherein the spacer dot density in the first portion is in the range of approximately 0.08 to 0.14.

14. The touch pad of claim 8, wherein the spacer dot diameter in the first and second portions is the same and wherein the spacer dot pitch in the first and second portions differs.

15. The touch pad of claim 8, wherein the spacer dot diameter in the first and second portion differs and wherein the spacer dot pitch in the first and second portions is the same.

16. The touch pad of claim 8, wherein the spacer dot diameter in the first and second portions differs and wherein the spacer dot pitch in the first and second portions differs.

17. A touch pad for a data processing system, comprising:

a touch pad film over a first electrically conductive thin film;

a second electrically conductive thin film over a touch pad substrate;

physical means for preventing a force below a first threshold applied to a first portion of the touch pad film from creating electrical contact between the first and second thin films and physical means for preventing a force below a second threshold applied to a second portion of the touch pad film from creating electrical contact between the first and second thin films wherein the first and second thresholds differ due to differences in the physical means in the first and second portions.

18. The touch pad of claim 17, wherein the physical means comprises electrically insulating spacer dots formed on the second thin film.

19. The touch pad of claim 18, wherein a ratio of space dot diameter to space dot pitch in a first portion of the touch pad differs from a ratio of spacer dot diameter to spacer dot pitch in a second portion of the touch pad.

20. Wherein the ratio in the first portion is in the range of approximately 0.01 to 0.05 and the spacer dot density in the second portion is in the range of approximately 0.8 to 0.14.