Touch sensor with improved electrode pattern

• US 7,952,567 B2
• Filed: 11/03/2005
• Issued: 05/31/2011
• Est. Priority Date: 04/16/2002
• Status: Active Grant

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Tyco Electronics Corporation (TE Connectivity Limited)
• Inventors: Aroyan, James L., Scharff, Daniel H.
• Primary Examiner(s): Kumar; Srilakshmi K
• Application Number:
  US11/267,759
• Publication Number:
  US 20060119587A1
• Time in Patent Office: 2,035 Days
• Field of Search: 345/173, 345/174, 178/18.01, 178 1805- 1807, 338/15, 200/512, 340/407.1
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04113 Peripheral electrode pattern in resistive digitisers, i.e. electrodes at the periphery of the resistive sheet are shaped in patterns enhancing linearity of induced field
• 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 includes a substrate with a touch region, and a series resistor chain for creating electrical fields across the touch region. The resistor chain comprises a plurality of conductive electrodes that to form overlap resistors therebetween. The electrodes have inner portions that are separated by junctions. The touch sensor also includes insulating regions between the touch region and the resistor chain. The insulating regions are separated by gaps to provide a plurality of conductive pathways to the touch region, thereby minimizing non-linear ripple along the sourcing sides of the substrate. Some of the gaps are junction gaps that are formed between the touch region and junctions. Electrically conductive islands are placed within the junction gaps to provide an electrical node within each junction gap, thereby preventing bunching of equipotential lines within the junction, and minimizing non-linear ripple along the non-sourcing sides of the substrate.

Claims

1. A touch sensor, comprising:

a substrate having a resistive surface bounded by four peripheral edges that terminate at four corners, said resistive surface having a touch region interior to said edges;

a single series resistor chain proximate each peripheral edge for creating electric fields across said touch region, said resistor chain comprising a plurality of conductive electrodes arranged in series with resistive regions of said resistive surface to form overlap resistors therebetween, each electrode including an outer portion in step connection with an inner portion such that said inner portion is closer to said touch region than said outer portion and wherein inner portions of electrodes are parallel to, and separated by said resistive regions from, outer portions of adjacent electrodes, said inner portions of adjacent electrodes being separated by junctions, the series resistor chain electrically connected at a corner of the resistive surface;

a linear array of insulating regions in said resistive surface between said touch region and parallel to said single series resistor chain, said insulating regions being separated by gaps, at least one of said gaps formed between said touch region and at least one junction forming a junction gap; and

an electrically conductive island located within said at least one junction gap.

2. The touch sensor of claim 1, wherein two gaps are formed between said touch region and two adjacent inner portions, and said at least one junction gap is between said two gaps.

3. The touch sensor of claim 1, wherein said substrate is substantially transparent.

4. The touch sensor of claim 1, wherein non-junction gaps are formed between said touch region and at least a majority of said inner portions.

5. The touch sensor of claim 1, wherein junction gaps are formed between said touch region and at least a majority of said junctions.

6. The touch sensor of claim 1, further comprising an electrically conductive island located within at least a plurality of said junction gaps.

7. The touch sensor of claim 1, wherein said resistive surface is fully intact within said gaps.

8. The touch sensor of claim 1, wherein said array of insulating regions is a line where said resistive surface has been removed, said line being parallel to said resistor chain.

9. The touch sensor of claim 1, wherein the electric fields are non-linear.

10. A touch sensor, comprising:

a substrate having a resistive surface bounded by a plurality of peripheral edges, said resistive surface having a touch region interior to said edges;

a single series resistor chain proximate a peripheral edge for creating electric fields across said touch region, said resistor chain comprising a plurality of conductive electrodes arranged in series with resistive regions of said surface to form overlap resistors therebetween, each electrode having an outer portion in step connection with an inner portion such that said inner portion is closer to said touch region than said outer portion and wherein said inner portions of electrodes are parallel to, and separated by resistive regions from, outer portions of adjacent electrodes, and wherein said inner portions of adjacent electrodes being separated by junctions, the series resistor chain electrically connected at a corner of the resistive surface;

a linear array of insulating regions in said resistive surface between said touch region and said resistor chain, said insulating regions being separated by gaps, wherein at least two of said gaps are selected from different ones of;

an empty gap, an island gap having an electrically conductive island, and an electrode gap having an electrically conductive extension from one of said inner portions.

11. The touch sensor of claim 10, wherein said at least two of said gaps are respectively said empty gap and said island gap.

12. The touch sensor of claim 10, wherein said at least two of said gaps are respectively said empty gap and said electrode gap.

13. The touch sensor of claim 10, wherein said at least two of said gaps are respectively said island gap and said electrode gap.

14. The touch sensor of claim 10, wherein said at least two of said gaps comprises three gaps, a first of which is said empty gap, a second of which is said island gap, and a third of which is said electrode gap.

15. The touch sensor of claim 10, wherein said at least two gaps are adjacent to each other.

16. The touch sensor of claim 10, wherein said at least two gaps form junction gaps between said touch region and respective junctions.

17. The touch sensor of claim 10, wherein said at least two gaps form non-junction gaps between said touch region and respective inner portions.

18. The touch sensor of claim 10, wherein said at least two gaps have substantially the same width and substantially different resistances.

19. The touch sensor of claim 10, wherein said at least two gaps have substantially different widths and substantially the same resistances.

20. The touch sensor of claim 10, wherein said gaps have parabolic varying resistances.

21. The touch sensor of claim 10, wherein said resistive surface is fully intact within said gaps.

22. The touch sensor of claim 10, wherein said insulating regions run parallel to said resistor chain.

23. The touch sensor of claim 10, wherein said array of insulating regions is a line where said resistive surface has been removed, said line being parallel to said resistor chain.

24. The touch sensor of claim 10, wherein the electric fields are non-linear.

25. A touch sensor, comprising:

a substrate having a resistive surface at least partially bounded peripherally by edges, said resistive surface having a touch region interior to said edges;

a series resistor chain proximate said edges for creating electric fields across said touch region, said series resistor chain comprising a plurality of conductive electrodes arranged in series with resistive regions of said resistive surface to form overlap resistors therebetween, each electrode including an outer portion in step connection with an inner portion such that said inner portion is closer to said touch region than said outer portion and wherein inner portions of electrodes are parallel to, and separated by said resistive regions from, outer portions of adjacent electrodes, wherein said inner portions of adjacent electrodes are separated by junctions of said resistive surface;

a linear array of insulating regions in said resistive surface, said linear array disposed along said series resistor chain and formed between said touch region and said series resistor chain, said insulating regions being separated from each other by gaps, wherein junction gaps are those of said gaps formed between said touch region and said junctions; and

an electrically conductive island within at least one of said junction gaps.

26. The touch sensor of claim 25, wherein at least two of said gaps formed between said inner portions and said touch region are non-junction gaps, wherein said non-junction gaps are those of said gaps that are not said junction gaps.

27. The touch sensor of claim 26, wherein said non-junction gaps are formed between junction gaps.

28. The touch sensor of claim 26, wherein a majority of said junction gaps have electrically conductive islands therein.

29. The touch sensor of claim 26, wherein at least one non-junction gap has an electrically conductive element therein, and at least one non-junction gap has a conductive element extending from an inner portion of an adjacent electrode.

30. The touch sensor of claim 25, wherein said substrate is substantially transparent.

31. The touch sensor of claim 25, further comprising a dielectric coating disposed over said touch region.

32. The touch sensor of claim 25, wherein said resistive surface is at least partially bounded peripherally by a pair of opposing edges.

33. The touch sensor of claim 25, wherein said resistive surface is bounded peripherally by four edges terminating to form four corners.

34. The touch sensor of claim 25, wherein said resistive surface is fully intact within said gaps.

35. The touch sensor of claim 25, wherein said insulating regions are lines where said resistive surface has been removed, said lines being parallel to said series resistor chain.

36. The touch sensor of claim 25, wherein a plurality of conductive paths per overlap resistor is formed between said touch region and said respective resistor chain.

37. The touch sensor of claim 25, wherein the electric fields are non-linear.