Touch sensor having compensated base capacitance

• US 20070046648A1
• Filed: 08/28/2006
• Published: 03/01/2007
• Est. Priority Date: 08/31/2005
• Status: Abandoned Application

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: Lii, Jia-Yih, Lee, Wen-Kai
• Application Number:
  US11/510,817
• Publication Number:
  US 20070046648A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• 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 sensor comprises a plurality of traces in a same sensing layer or in different sensing layers, and the base capacitances of the traces are made uniform by connecting one or more compensation areas to one or more of the traces or selecting the distances between the grounding layer and one or more of the traces. The compensation area and the trace it compensates may or may not in a same layer.

Claims

1. A touch sensor comprising:

a first trace having a first area;

a second trace having a second area; and

a compensation area electrically connected to the second trace such that the first and second traces have a same base capacitance.

2. The touch sensor of claim 1, wherein the compensation area is in a device layer.

3. The touch sensor of claim 1, wherein the compensation area and the second trace both are in a same sensing layer.

4. The touch sensor of claim 1, wherein the first and second traces both are in a same sensing layer.

5. The touch sensor of claim 1, wherein the first and second traces are in two sensing layers, respectively.

6. The touch sensor of claim 1, wherein the first and second traces are perpendicular to each other.

7. A touch sensor comprising:

a first trace having a first area;

a second trace having a second area; and

a first compensation area and a second compensation area electrically connected to the first and second traces, respectively, such that the first and second traces have a same base capacitance.

8. The touch sensor of claim 7, wherein at least one of the first and second compensation areas is in a device layer.

9. The touch sensor of claim 7, wherein the first compensation area and the first trace both are in a same sensing layer.

10. The touch sensor of claim 7, wherein the first and second traces both are in a same sensing layer.

11. The touch sensor of claim 7, wherein the first and second traces are in two sensing layers, respectively.

12. The touch sensor of claim 7, wherein the first and second traces are perpendicular to each other.

13. A touch sensor comprising:

a first trace in a first sensing layer; and

a second trace in a second sensing layer;

wherein the first and second traces have a same base capacitance.

14. The touch sensor of claim 13, wherein the first and second traces are perpendicular to each other.

15. The touch sensor of claim 13, wherein the first and second traces have different areas.

16. The touch sensor of claim 15, further comprising a grounding layer spaced from the first and second traces with a first distance and a second distance, respectively, the first and second distances being not equal.

17. The touch sensor of claim 16, wherein the grounding layer is between the first and second sensing layers.

18. The touch sensor of claim 16, wherein the grounding layer is not between the first and second sensing layers.

20. The touch sensor of claim 13, further comprising a grounding layer between the first and second sensing layers with a same distance to the first and second sensing layers, the first and second traces having a same area.

19. (canceled)