Interleaved electrodes for touch sensing

• US 20070074914A1
• Filed: 10/05/2005
• Published: 04/05/2007
• Est. Priority Date: 10/05/2005
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Geaghan, Bernard, Badaye, Massoud, Hagermoser, Edward
• Granted Patent: US 7,864,160 B2
• Time in Patent Office: Days
• US Class Current: 178/18.60
• 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 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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 capacitive touch sensing system includes a touch surface and sets of substantially parallel electrodes arranged in relation to the touch surface. Each electrode set includes a primary electrode electrically connected to at least two sub-electrodes. The primary electrode is capable of producing greater capacitive coupling to a touch in proximity with the touch surface in relation to capacitive coupling of the at least two sub-electrodes. The sub-electrodes of the electrode sets are arranged in an interleaved pattern configured to increase an effective area of capacitive coupling associated with each electrode set.

Claims

1. A capacitive touch sensing system, comprising:

a touch surface; and

sets of substantially parallel electrodes arranged in relation to the touch surface, each electrode set comprising a primary electrode capable of producing greater capacitive coupling to a touch in proximity with the touch surface in relation to capacitive coupling of at least two sub-electrodes electrically connected to the primary electrode and disposed on either side of the primary electrode, the sub-electrodes of the electrode sets arranged in an interleaved pattern configured to increase an effective area of capacitive coupling associated with each electrode set.

2. The touch sensing system of claim 1, wherein the interleaved pattern is configured to shape touch response profiles respectively associated with the electrode sets, each touch response profile representative of a relationship between touch signal amplitude and touch position relative to a particular electrode set.

3. The touch sensing system of claim 2, wherein the interleaved pattern is configured to modify a slope of each touch response profile.

4. The touch sensing system of claim 2, wherein widths of the primary electrode and the at least two sub-electrodes of each electrode set are configured to shape the touch response profiles of the electrode sets.

5. The touch sensing system of claim 2, wherein a spacing between the primary electrode and the at least two sub-electrodes of each electrode set is configured to shape the touch response profiles of the electrode sets.

6. The touch sensing system of claim 1, wherein the interleaved pattern is configured to increase a region of linearity of the touch response profiles respectively associated with the electrode sets, each touch response profile representing a relationship between touch signal amplitude and touch position relative to a particular electrode set.

7. The touch sensing system of claim 1, wherein the interleaved pattern is configured to facilitate interpolation among touch signals sensed using the adjacent electrode sets to facilitate touch location determination.

8. The touch sensing system of claim 1, wherein the interleaved pattern is configured to smooth a touch signal transition as the touch is moved from one electrode set to another electrode set.

9. The touch sensing system of claim 1, wherein each electrode set comprises the primary electrode electrically connected to the at least two sub-electrodes at both ends of the primary electrode.

10. The touch sensing system of claim 1, wherein each electrode set comprises the primary electrode electrically connected to the at least two sub-electrodes at one end of the primary electrode.

11. The touch sensing system of claim 1, wherein the electrode sets are electrically connected in accordance with a coding scheme to facilitate touch location determination.

12. The touch sensing system of claim 1, wherein the electrode sets are arranged on a single layer.

13. The touch sensing system of claim 1, wherein the electrode sets are arranged on first and second layers, a longitudinal axis of the electrode sets of the first layer arranged at an angle with respect to a longitudinal axis of the electrode sets of the second layer.

14. The touch sensing system of claim 13, wherein the longitudinal axis of the electrode sets of the first layer is substantially orthogonal to the longitudinal axis of the electrode sets of the second layer.

15. The touch sensing system of claim 1, wherein the interleaved pattern comprises a single level of interleaving.

16. The touch sensing system of claim 1, wherein the interleaved pattern comprises multiple levels of interleaving.

17. The touch sensing system of claim 1, wherein the interleaved pattern comprises a repetitive pattern.

18. The touch sensing system of claim 1, wherein the interleaved pattern comprises at least one sub-electrode near one edge of the touch surface that is electrically connected with a corresponding primary electrode near an opposite edge of the touch surface.

19. The touch sensing system of claim 1, further comprising:

circuitry configured to measure signals sensed using the electrode sets; and

a touch processor coupled to the circuitry and configured to determine a location of the touch in proximity with the touch surface based on the measured signals.

20. The touch sensing system of claim 19, wherein the circuitry is disposed within a touch stylus.

21. The touch sensing system of claim 1, wherein the touch surface and the sets of electrodes arranged in relation to the touch surface form a transparent touch screen.

22. The touch sensing system of claim 21, further comprising a display viewable through the transparent touch screen.

23. A capacitive touch sensing system, comprising:

a touch surface; and

sets of electrically connected and substantially parallel electrodes arranged in relation to the touch surface, each set of electrodes including a primary electrode and at least two sub-electrodes disposed on either side of the primary electrode and having a smaller surface area than the primary electrode, wherein the sub-electrodes of the electrode sets are interleaved.

24. The touch sensing system of claim 23, wherein a width of each primary electrode varies along a longitudinal axis of the primary electrode.

25. The touch sensing system of claim 23, wherein a width of each sub-electrode varies along a longitudinal axis of the sub-electrode.

26. The touch sensing system of claim 23, wherein the electrode sets are disposed on two layers, wherein electrodes on a first layer include geometric elements and electrodes on a second layer include geometric elements complementary with the geometric elements of the first layer electrodes, the complementary geometric elements of the first and second layer electrodes configured to enhance capacitive coupling of the second layer electrodes.

27. The touch sensing system of claim 23, wherein:

the primary electrode of each electrode set comprises a first number of adjacent electrode elements having substantially equal width; and

the at least two sub-electrodes of each electrode set comprises a second number of adjacent electrode elements having substantially equal width.

28. A touch sensing method, comprising:

capacitively sensing a touch on a touch surface using a first set of electrodes, the first set of electrodes including electrically connected and substantially parallel first primary electrode and first sub-electrodes disposed on either side of the first primary electrode;

generating a first touch signal based on the touch sensed using the first electrode set;

capacitively sensing a touch on a touch surface using sets of electrodes adjacent to the first electrode set, each adjacent set of electrodes including electrically connected and substantially parallel adjacent primary electrode and adjacent sub-electrodes disposed on either side of the adjacent primary electrode, the adjacent sub-electrodes interleaved with the first sub-electrodes to increase an area of capacitive coupling of the first and adjacent electrode sets;

generating additional touch signals based on the touch sensed using the adjacent sets of electrodes; and

determining a location of the touch in proximity with the touch surface based on at least one of the first and the additional touch signals.

29. The method of claim 28, wherein determining the location of the touch comprises interpolating among the first and at least one of the additional touch signals.

30. The method of claim 28, wherein the touch is a finger touch.

31. The method of claim 28, wherein the touch is produced by an electrically passive touch implement.

32. The method of claim 28, wherein the touch is produced by an electrically active touch implement.

33. A method for making a touch sensor comprising disposing sets of electrodes on a substrate in accordance with an interleaved pattern configured to increase an effective area of capacitive coupling associated with each set of electrodes, each set of electrodes comprising a primary electrode capable of producing greater capacitive coupling to a touch in relation to capacitive coupling of sub-electrodes electrically connected and substantially parallel to the primary electrode, the primary electrode disposed between at least two of the sub-electrodes.

34. The method of claim 33, wherein the interleaved pattern is configured to shape touch response profiles associated with the electrode sets, each touch response profile representative of a relationship between touch signal amplitude and touch position relative to a particular electrode set.

35. The method of claim 33, wherein disposing the electrode sets on the substrate in accordance with the interleaved pattern comprises disposing the electrode sets in a single layer.

36. The method of claim 33, wherein disposing the electrode sets on the substrate in accordance with the interleaved pattern comprises disposing a first portion of the electrode sets in a first layer and a second portion of the electrode sets in a second layer.

37. The method of claim 33, wherein the primary electrode of each electrode set has a larger surface area than the sub-electrodes of each electrode set.

38. The method of claim 33, further comprising electrically connecting the primary electrode and sub-electrodes of each electrode set at one end of the primary electrode.

39. The method of claim 33, further comprising electrically connecting the primary electrode and sub-electrodes of each electrode set at both ends of the primary electrode.

40. The method of claim 33, wherein disposing the electrode sets on the substrate comprises disposing a plurality of substantially equally spaced and substantially equal width electrode elements on the substrate, wherein the primary electrode of each electrode set includes a first number of adjacent electrode elements and the sub-electrodes of each electrode set include a second number of adjacent electrode elements.

41. A touch sensing system, comprising:

means for capacitively sensing a touch on a touch surface using a first set of electrodes, the first set of electrodes including substantially parallel and electrically connected first primary electrode and first sub-electrodes disposed on either side of the first primary electrode;

means for generating a first touch signal based on the touch sensed using the electrode set;

means for capacitively sensing a touch on a touch surface using sets of electrodes adjacent to the first electrode set, each adjacent set of electrodes including substantially parallel and electrically connected adjacent primary electrode and adjacent sub-electrodes disposed on either side of the adjacent primary electrode, the adjacent sub-electrodes interleaved with the first sub-electrodes to increase an area of capacitive coupling of the first and adjacent electrode sets;

means for generating additional touch signals based on the touch sensed using the adjacent sets of electrodes; and

means for determining a location of the touch in proximity with the touch surface based on at least one of the first and the additional touch signals.