Touch sensor with improved electrode pattern

• US 20060119587A1
• Filed: 11/03/2005
• Published: 06/08/2006
• Est. Priority Date: 04/16/2002
• Status: Active Grant

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Tyco Electronics Corporation (TE Connectivity Ltd. (United Kingdom))
• Inventors: Aroyan, James L., Scharff, Daniel H.
• Granted Patent: US 7,952,567 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• 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 a plurality of peripheral edges, said resistive surface having a touch region interior to said edges;

a 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 inner portion facing said touch region, said inner portions of adjacent electrodes being separated by junctions;

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, at least one of said gaps formed between said touch region and at least one junction; 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 insulating regions run parallel to said resistor chain.

9. 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.

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

11. The touch sensor of claim 1, further comprising a dielectric coating disposed over said touch region.

12. A touch sensor, comprising:

a substrate having a resistive surface at least partially bounded by a pair of opposing peripheral edges, said resistive surface having a touch region interior to said edges;

a series resistor chain proximate each peripheral edge for creating electric fields across said touch region, each 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 inner portion facing said touch region, said inner portions of adjacent electrodes being separated by junctions;

a linear array of insulating regions in said resistive surface adjacent each resistor chain between said touch region and said respective resistor chain, said insulating regions being separated by gaps, said gaps including junction gaps between said touch region and said junctions; and

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

13. The touch sensor of claim 12, wherein at least two gaps are formed between said touch region and at least two adjacent inner portions, and said at least one junction gap is between said at least two gaps.

14. The touch sensor of claim 12, further comprising an electrically conductive island located within at least a plurality of said junction gaps.

15. The touch sensor of claim 12, wherein said resistive surface is fully intact within said gaps.

16. The touch sensor of claim 12, wherein said arrays of insulating regions are lines where said resistive surface has been removed, said lines being parallel to said respective resistor chains.

17. The touch sensor of claim 12, wherein a plurality of conductive paths per overlap resistor is formed between said touch region and said respective resistor chain.

18. The touch sensor of claim 12, wherein the electric fields are non-linear.

19. The touch sensor of claim 12, further comprising a dielectric coating disposed over said touch region.

20. The touch sensor of claim 12, wherein at least one non-junction gap has no electrically conductive element, at least one non-junction gap has an electrically conductive island, and at least one non-junction gap has an electrode extending from an inner portion of an adjacent electrode.

21. The touch sensor of claim 12, wherein said resistive surface is bounded by another pair of opposing peripheral edges, said touch region interior to said other pair of opposing peripheral edges, the touch sensor comprising:

another series resistor chain proximate each of said other pair of peripheral edges for creating electric fields across said touch region, each other resistor chain comprising another plurality of conductive electrodes arranged in series with resistive regions of said surface to form overlap resistors therebetween, each other electrode having another inner portion facing said touch region, said other inner portions of adjacent electrodes being separated by junctions;

another linear array of insulating regions in said resistive surface adjacent each other resistor chain between said touch region and said respective resistor chain, said other insulating regions being separated by gaps, the number of said gaps equaling at least twice the number of overlap resistors in the other resistor chains.

22. The touch sensor of claim 21, wherein said peripheral edges terminate at four corners.

23. The touch sensor of claim 21, wherein the linear array of insulating regions has approximately two gaps per overlap resistor, and the other linear array of insulating regions has approximately three or more gaps per overlap resistor.

24. 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 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 inner portion facing said touch region, said inner portions of adjacent electrodes being separated by junctions;

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.

25. The touch sensor of claim 24, wherein said at least two of said gaps are respectively said empty gap and said island gap.

26. The touch sensor of claim 24, wherein said at least two of said gaps are respectively said empty gap and said electrode gap.

27. The touch sensor of claim 24, wherein said at least two of said gaps are respectively said island gap and said electrode gap.

28. The touch sensor of claim 24, 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.

29. The touch sensor of claim 24, wherein said at least two gaps are adjacent to each other.

30. The touch sensor of claim 24, wherein said at least two gaps form junction gaps between said touch region and respective junctions.

31. The touch sensor of claim 24, wherein said at least two gaps form non-junction gaps between said touch region and respective inner portions.

32. The touch sensor of claim 24, wherein said at least two gaps have substantially the same width and substantially different resistances.

33. The touch sensor of claim 24, wherein said at least two gaps have substantially different widths and substantially the same resistances.

34. The touch sensor of claim 24, wherein said gaps have parabolic varying resistances.

35. The touch sensor of claim 24, wherein said resistive surface is fully intact within said gaps.

36. The touch sensor of claim 24, wherein said insulating regions run parallel to said resistor chain.

37. The touch sensor of claim 24, wherein said array of insulating regions is a line where said resistive surface has been removed, said line being parallel to said resistor chain.

38. The touch sensor of claim 24, wherein each of said electrodes is a Z-shaped electrode.

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

40. The touch sensor of claim 24, further comprising a cover sheet having an electrically conductive coating to provide electrical coupling to said touch region.

41. The touch sensor of claim 24, further comprising a dielectric coating disposed over said touch region.