Linearized touch sensor having protective coating

• US 20070126707A1
• Filed: 12/02/2005
• Published: 06/07/2007
• Est. Priority Date: 12/02/2005
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Jones, Terence
• Application Number:
  US11/293,723
• Publication Number:
  US 20070126707A1
• 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 sensor is disclosed. The sensor includes an electrically resistive layer that covers a touch sensitive area. The sensor further includes an electrically insulative layer that is disposed on the electrically resistive layer. The insulative layer has one or more open areas. Each open area exposes a portion of the resistive layer. The sensor also includes a plurality of electrically conductive segments that are disposed on the insulative layer. Each conductive segment makes electrical contact with the resistive layer through at least one of the open areas in the insulative layer. The conductive segments improve linearity of the touch sensitive area.

Claims

1. A touch sensor comprising:

an electrically resistive layer covering a touch sensitive area;

an electrically insulative layer disposed on the electrically resistive layer, the insulative layer having open areas, each of the open areas exposing a portion of the resistive layer; and

a plurality of electrically conductive segments disposed on the insulative layer, each of the conductive segments making electrical contact with the resistive layer through at least one of the open areas in the insulative layer, wherein the plurality of electrically conductive segments improves linearity of the touch sensitive area.

2. The touch sensor of claim 1, wherein the electrically resistive layer comprises a conductive polymer.

3. The touch sensor of claim 1, wherein the electrically insulative layer is a continuous layer.

4. The touch sensor of claim 1, wherein the electrically insulative layer is a discontinuous layer.

5. The touch sensor of claim 1, wherein the electrically insulative layer is a porous layer.

6. The touch sensor of claim 1, wherein a total area of the one or more open areas is no less than 20% of a total area of the electrically insulative layer.

7. The touch sensor of claim 1, wherein a total area of the one or more open areas is no less than 50% of a total area of the electrically insulative layer.

8. The touch sensor of claim 1, each of the conductive segments makes electrical contact with the resistive layer only through the one or more open areas in the insulative layer.

9. The touch sensor of claim 1, wherein an electric field in the touch sensitive area is linearized to within 10%.

10. The touch sensor of claim 1, wherein an electric field in the touch sensitive area is linearized to within 5%.

11. The touch sensor of claim 1, wherein an electric field in the touch sensitive area is linearized to within 2%.

12. The touch sensor of claim 1, wherein an electric field in the touch sensitive area is linearized to within 1%.

13. The touch sensor of claim 1, wherein an electric field in the touch sensitive area is linearized to within 0.5%.

14. The touch sensor of claim 1 being a capacitive touch sensor.

15. The touch sensor of claim 1 being a resistive touch sensor.

16. A display system comprising the touch sensor of claim 1.

17. A touch sensor comprising:

an electrically resistive layer defining a touch sensitive area;

an electrically insulative layer disposed on the electrically resistive layer; and

a field linearization pattern disposed on the insulative layer and capable of improving a linearity of the touch sensitive area by making electrical contact with the resistive layer through one or more pre-existing openings in the insulative layer.

18. The touch sensor of claim 17, wherein the electrically insulative layer is a continuous layer.

19. The touch sensor of claim 17, wherein the electrically insulative layer is a discontinuous layer.

20. The touch sensor of claim 17, wherein the electrically insulative layer is a porous layer.

21. A touch sensor comprising:

an electrically resistive layer covering a touch sensitive area;

an electrically insulative layer disposed on the resistive layer; and

an electrically conductive linearization pattern disposed on the insulative layer, the linearization pattern making electrical contact with the resistive layer through the insulative layer at a plurality of random locations on the insulative layer, the linearization pattern improving a linearity of the touch sensitive area.

22. The touch sensor of claim 21, wherein each of the plurality of random locations is located at an open area in the insulative layer exposing a portion of the resistive layer.

23. A method for making a touch sensor comprising the steps of:

providing an electrically resistive layer covering a touch sensitive area;

providing an electrically insulative layer on the electrically resistive layer, the insulative layer having one or more open areas exposing the electrically resistive layer; and

providing electrical contact between a field linearization pattern and the electrically resistive layer through at least some of the one or more open areas in the insulative area, the field linearization pattern being configured to improve a linearity of the touch sensitive area.