Projected capacitive touch-sensitive panel

• US 8,237,068 B2
• Filed: 08/07/2009
• Issued: 08/07/2012
• Est. Priority Date: 08/07/2009
• Status: Active Grant

• Current Assignee: OpenPeak LLC (Ni, Wang & Massand, PLLC)
• Original Assignee: OpenPeak Inc.
• Inventors: Szaikowski, Daniel
• Primary Examiner(s): Nguyen, Kevin M
• Application Number:
  US12/537,774
• Publication Number:
  US 20110032193A1
• Time in Patent Office: 1,096 Days
• Field of Search: 345173-183, 178 1903- 1907, 178 2001- 2004, 178/18.08
• US Class Current: 178/18.08
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A touch-sensitive panel is described herein that includes a first sensor layer and a second sensor layer and at least one shield electrode integrated into the first sensor layer and/or the second sensor layer. The at least one shield electrode is operable to cancel parasitic capacitance between at least one sense electrode in the first sensor layer and at least one sense electrode in the second sensor layer. The integrated shield electrode(s) in the first sensor layer and/or the second sensor layer can be used in place of an additional shield layer to combat parasitic capacitance in the touch-sensitive panel, thereby reducing the cost and materials necessary to manufacture the touch-sensitive panel. A touch-screen display that includes such a touch-sensitive panel and a method of operating such a touch-sensitive panel are also described.

Claims

1. A touch-sensitive panel, comprising:

a first sensor layer comprising a first plurality of sense electrodes that are disposed upon and extend in a first direction across a first substrate surface; and

a second sensor layer comprising a second plurality of sense electrodes that are disposed upon and extend in a second direction across a second substrate surface and at least one shield electrode disposed on the second substrate surface;

wherein each sense electrode is operable to generate an electrostatic field used in sensing touch events and wherein the at least one shield electrode is operable to cancel parasitic capacitance between at least one sense electrode in the first plurality of sense electrodes and at least one sense electrode in the second plurality of sense electrodes.

2. The touch-sensitive panel of claim 1, wherein the at least one shield electrode is disposed on the second substrate surface in a manner that reduces internal reflections.

3. The touch-sensitive panel of claim 1, wherein the second sensor layer comprises a plurality of shield electrodes disposed on the second substrate surface, each of the plurality of shield electrodes being disposed between and extending in a substantially parallel manner to a unique pair of the second plurality of sense electrodes.

4. The touch-sensitive panel of claim 3, wherein each of the second plurality of sense electrodes and the plurality of shield electrodes comprises a series of substantially diamond-shaped segments connected together by smaller substantially rectangular-shaped segments.

5. The touch-sensitive panel of claim 3, wherein each of the second plurality of sense electrodes and each of the plurality of shield electrodes has a first end that is disposed on a first side of the second substrate surface and a second end that is disposed on a second side of the second substrate surface and wherein the first end of each of the second plurality of sense electrodes is connected to a corresponding conductive trace operable to drive the sense electrode and wherein the second end of each of the plurality of shield electrodes is connected to a conductive trace operable to drive the shield electrode.

6. The touch-sensitive panel of claim 1, wherein the first sensor layer further comprises at least one shield electrode that is disposed on the first substrate surface and that is operable to cancel parasitic capacitance between at least one sense electrode in the first plurality of sense electrodes and at least one sense electrode in the second plurality of sense electrodes.

7. The touch-sensitive panel of claim 1, wherein the first substrate surface and the second substrate surface comprise surfaces of different substrates.

8. The touch-sensitive panel of claim 1, wherein the first substrate surface and the second substrate surface comprise opposite surfaces of a single substrate.

9. The touch-sensitive panel of claim 1, wherein the first direction is substantially orthogonal to the second direction.

10. The touch-sensitive panel of claim 1, wherein the first substrate surface and the second substrate surface each comprise a surface of a substantially transparent glass substrate.

11. The touch-sensitive panel of claim 1, wherein the first substrate surface and the second substrate surface each comprise a surface of a substantially transparent polyester film.

12. The touch-sensitive panel of claim 1, wherein the first plurality of sense electrodes, the second plurality of sense electrodes, and the at least one shield electrode are each formed from a substantially transparent resistive material.

13. The touch-sensitive panel of claim 12, wherein the substantially transparent resistive material comprises indium tin oxide (ITO).

14. The touch-sensitive panel of claim 13, wherein the ITO comprises non-index-matched ITO.

15. A touch-sensitive panel, comprising:

a first plurality of sense electrodes that are formed from a first layer of substantially transparent resistive material and that extend in a first direction; and

a second plurality of sense electrodes and at least one shield electrode that are formed from a second layer of substantially transparent resistive material and that extend in a second direction;

wherein each sense electrode is operable to generate an electrostatic field used in sensing touch events and wherein the at least one shield electrode is operable to cancel parasitic capacitance between at least one sense electrode in the first plurality of sense electrodes and at least one sense electrode in the second plurality of sense electrodes.

16. A touch-screen display comprising:

a touch-sensitive panel that includes a first sensor layer and a second sensor layer, the first sensor layer comprising a first plurality of sense electrodes that are disposed upon and extend in a first direction across a first substrate surface and the second sensor layer comprising a second plurality of sense electrodes that are disposed upon and extend in a second direction across a second substrate surface and at least one shield electrode disposed on the second substrate surface;

a controller connected to the first plurality of sense electrodes, the second plurality of sense electrodes and the at least one shield electrode, the controller being configured to charge the first and second plurality of sense electrodes to generate an electrostatic field around each sense electrode for use in sensing touch events and to charge the at least one shield electrode in a manner that cancels parasitic capacitance between at least one of the first plurality of sense electrodes and at least one of the second plurality of sense electrodes.

17. The touch-screen display of claim 16, wherein the at least one shield electrode is disposed on the second substrate surface in a manner that reduces internal reflections.

18. The touch-screen display of claim 16, wherein the second sensor layer comprises a plurality of shield electrodes disposed on the second substrate surface, each of the plurality of shield electrodes being disposed between and extending in a substantially parallel manner to a unique pair of the second plurality of sense electrodes.

19. The touch-screen display of claim 18, wherein each of the second plurality of sense electrodes and the plurality of shield electrodes comprises a series of substantially diamond-shaped segments connected together by smaller substantially rectangular-shaped segments.

20. The touch-screen display of claim 18, wherein each of the second plurality of sense electrodes and each of the plurality of shield electrodes has a first end that is disposed on a first side of the second substrate surface and a second end that is disposed on a second side of the second substrate surface and wherein the first end of each of the second plurality of sense electrodes is connected to the controller via a corresponding conductive trace and wherein the second end of each of the plurality of shield electrodes is connected to the controller via a conductive trace.

21. The touch-screen display of claim 16, wherein the first sensor layer further comprises at least one shield electrode that is disposed on the first substrate surface, wherein the controller is further connected to the at least one shield electrode disposed on the first substrate surface and is further configured to charge the at least one shield electrode disposed on the first substrate surface in a manner that cancels parasitic capacitance between at least one of the first plurality of sense electrodes and at least one of the second plurality of sense electrodes.

22. The touch-screen display of claim 16, wherein the first substrate surface and the second substrate surface comprise surfaces of different substrates.

23. The touch-screen display of claim 16, wherein the first substrate surface and the second substrate surface comprise opposite surfaces of a single substrate.

24. The touch-screen display of claim 16, wherein the first direction is substantially orthogonal to the second direction.

25. The touch-screen display of claim 16, wherein the first substrate surface and the second substrate surface each comprise a surface of a substantially transparent glass substrate.

26. The touch-screen display of claim 16, wherein the first substrate surface and the second substrate surface each comprise a surface of a substantially transparent polyester film.

27. The touch-screen display of claim 16, wherein the first plurality of sense electrodes, the second plurality of sense electrodes, and the at least one shield electrode are each formed from a substantially transparent resistive material.

28. The touch-screen display of claim 27, wherein the substantially transparent resistive material comprises indium tin oxide (ITO).

29. The touch-screen display of claim 28, wherein the ITO comprises non-index-matched ITO.

30. A method for operating a touch-sensitive panel comprising:

charging a first plurality of sense electrodes disposed upon and extending in a first direction across a first substrate surface to generate an electrostatic field around each of the first plurality of sense electrodes for use in sensing touch events;

charging a second plurality of sense electrodes disposed upon and extending in a second direction across a second substrate surface to generate an electrostatic field around each of the second plurality of sense electrodes for use in sensing the touch events; and

charging at least one shield electrode disposed upon the second substrate surface in a manner that cancels parasitic capacitance between at least one of the first plurality of sense electrodes and at least one of the second plurality of sense electrodes.

31. A touch-screen display comprising:

a touch-sensitive panel that includes a first plurality of sense electrodes that are formed from a first layer of substantially transparent resistive material and that extend in a first direction and a second plurality of sense electrodes and at least one shield electrode that are formed from a second layer of substantially transparent resistive material and that extend in a second direction;

a controller connected to the first plurality of sense electrodes, the second plurality of sense electrodes and the at least one shield electrode, the controller being configured to charge the first and second plurality of sense electrodes to generate an electrostatic field around each sense electrode for use in sensing touch events and to charge the at least one shield electrode in a manner that cancels parasitic capacitance between at least one of the first plurality of sense electrodes and at least one of the second plurality of sense electrodes.

32. A method for operating a touch-sensitive panel comprising:

charging a first plurality of sense electrodes that are formed from a first layer of substantially transparent resistive material and that extend in a first direction to generate an electrostatic field around each of the first plurality of sense electrodes for use in sensing touch events;

charging a second plurality of sense electrodes that are formed from a second layer of substantially transparent resistive material and that extend in a second direction to generate an electrostatic field around each of the second plurality of sense electrodes for use in sensing the touch events; and

charging at least one shield electrode formed from the second layer of substantially transparent resistive material in a manner that cancels parasitic capacitance between at least one of the first plurality of sense electrodes and at least one of the second plurality of sense electrodes.