Force imaging input device and system

• US 7,538,760 B2
• Filed: 03/30/2006
• Issued: 05/26/2009
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven P., Huppi, Brian Q.
• Primary Examiner(s): Liang; Regina
• Application Number:
  US11/278,080
• Publication Number:
  US 20070229464A1
• Time in Patent Office: 1,153 Days
• Field of Search: 345173-179, 178/18.01, 178/18.03, 178/18.06
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• 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 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A force imaging touch pad includes first and second sets of conductive traces separated by a spring membrane. When a force is applied, the spring membrane deforms moving the two sets of traces closer together. The resulting change in mutual capacitance is used to generate an image indicative of the amount or intensity of the applied force. A combined location and force imaging touch pad includes two sets of drive traces, one set of sense traces and a spring membrane. In operation, one of the drive traces is used in combination with the set of sense traces to generate an image of where one or more objects touch the touch pad. The second set of drive traces is used in combination with the sense traces and spring membrane to generate an image of the applied force'"'"'s strength or intensity.

Claims

1. A force imaging touch pad, comprising:

a first layer including a first rigid layer and a first plurality of conductive traces oriented in a first direction;

a second layer including a second rigid layer and a second plurality of conductive traces oriented in a second direction, one of the first or second pluralities of conductive traces configured for receiving electrical stimulation signals, and the first and second pluralities of conductive traces crossing over each other to form a plurality of mutual capacitance sensors between the first and second pluralities of conductive traces at each crossover location; and

a deformable dielectric membrane juxtaposed between the first and second layers and deformable to move the first plurality of conductive traces closer to the second plurality of conductive traces when a force is applied to the first layer;

wherein the first and second pluralities of conductive traces are adapted to create a mutual capacitance image when the force is applied to the first layer, the mutual capacitance image indicative of an intensity of the applied force.

2. The force imaging touch pad of claim 1, wherein the first plurality of conductive traces and the second plurality of conductive traces are substantially orthogonal.

3. The force imaging touch pad of claim 1, wherein the deformable dielectric membrane comprises:

a substantially flat membrane having a first surface oriented toward the first layer and a second surface oriented toward the second layer;

a first plurality of raised structures coupled to the first surface of the substantially flat membrane; and

a second plurality of raised structures coupled to the second surface of the substantially flat membrane, wherein the second plurality of raised structures are substantially offset from the first plurality of raised structures.

4. The force imaging touch pad of claim 1, wherein the deformable dielectric membrane comprises:

a substantially flat membrane; and

a plurality of deformable beads affixed to one surface of the substantially flat membrane, wherein the deformable beads are adapted to compress when a force is applied to the first layer toward the second layer.

5. The force imaging touch pad of claim 1, wherein the deformable dielectric membrane comprises one or more thermoplastic springs.

6. The force imaging touch pad of claim 1, wherein the deformable dielectric membrane comprises a dimpled deformable membrane.

7. The force imaging touch pad of claim 5, wherein the thermoplastic springs comprise Polyethylene terephthalate.

8. The force imaging touch pad of claim 1, further comprising a mutual capacitance measurement circuit electrically coupled to the first and second pluralities of conductive traces.

9. A force and location imaging touch pad, comprising:

a first layer including a first plurality of conductive traces oriented in a first direction and a second plurality of conductive traces oriented in a second direction, the first plurality of conductive traces configured for receiving electrical stimulation signals, and the first and second pluralities of conductive traces crossing over each other to form a plurality of mutual capacitance sensors between the first and second pluralities of conductive traces at each crossover location;

a second layer including a third plurality of conductive traces oriented in substantially the first direction, the third plurality of conductive traces configured for receiving electrical stimulation signals, and the second and third pluralities of conductive traces crossing over each other to form a plurality of mutual capacitance sensors between the second and third pluralities of conductive traces at each crossover location;

a base layer;

a first deformable membrane juxtaposed between the first and second layers; and

a second deformable membrane juxtaposed between the second layer and the base layer,

wherein the first and second pluralities of conductive traces are adapted to create a first mutual capacitance image when one or more objects come into close proximity to the first layer, the first mutual capacitance image indicative of where the one or more objects are located relative to the first layer,

wherein the second and third pluralities of conductive traces are adapted to create a second mutual capacitance image when a force is applied to the first layer, the second mutual capacitance image indicative of an intensity of the applied force.

10. The force and location imaging touch pad of claim 9, wherein the first layer comprises a flexible circuit board.

11. The force and location imaging touch pad of claim 9, wherein the first layer comprises one or more layers of thermoplastic resin.

12. The force and location imaging touch pad of claim 9, wherein the first plurality of conductive traces and the second plurality of conductive traces are substantially orthogonal.

13. The force and location imaging touch pad of claim 9, wherein the second layer comprises a flexible circuit board.

14. The force and location imaging touch pad of claim 9, wherein the second layer comprises one or more layers of thermoplastic resin.

15. The force and location imaging touch pad of claim 9, wherein the first deformable membrane comprises a first plurality of raised structures, the second deformable membrane comprises a second plurality of raised structures and the first and second raised structures are substantially spatially offset from one another.

16. The force and location imaging touch pad of claim 15, wherein the first and second pluralities of raised structures comprise thermoplastic resin.

17. The force and location imaging touch pad of claim 9, wherein the first deformable membrane comprises a first plurality deformable beads, the second deformable membrane comprises a second plurality of deformable beads and the first and second pluralities of deformable beads are substantially spatially offset from one another.

18. The force and location imaging touch pad of claim 17, wherein the deformable beads comprise elastomer beads.

19. The force and location imaging touch pad of claim 9, wherein each of the first and second pluralities of raised structures comprises one or more thermoplastic springs.

20. The force and location imaging touch pad of claim 19, wherein the thermoplastic springs comprise Polyethylene terephthalate.

21. The force and location imaging touch pad of claim 9, further comprising a mutual capacitance measurement circuit electrically coupled to the first, second and third pluralities of conductive traces.

22. A force and location imaging touch pad, comprising:

a first surface having a first plurality of conductive traces oriented in a first direction;

a second surface having a second plurality of conductive traces oriented in a second direction, the first and second surfaces juxtaposed to and electrically isolated from one another, the first plurality of conductive traces configured for receiving electrical stimulation signals, and the first and second pluralities of conductive traces crossing over each other to form a plurality of mutual capacitance sensors between the first and second pluralities of conductive traces at each crossover location;

a third surface having a third plurality of conductive traces oriented in substantially the first direction, the third plurality of conductive traces configured for receiving electrical stimulation signals, and the second and third pluralities of conductive traces crossing over each other to form a plurality of mutual capacitance sensors between the second and third pluralities of conductive traces at each crossover location; and

a deformable membrane between the second and third surfaces,

wherein the first and second pluralities of conductive traces are adapted to create a first mutual capacitance image when one or more objects come into close proximity to the first surface, the first mutual capacitance image indicative of where the one or more objects are located relative to the first surface,

wherein the second and third pluralities of conductive traces are adapted to create a second mutual capacitance image when a force is applied to the first surface, the second mutual capacitance image indicative of an intensity of the applied force.

23. The force and location imaging touch pad of claim 22, wherein the first and second surfaces are surfaces of a common layer.

24. The force and location imaging touch pad of claim 23, wherein the common layer comprises a flexible circuit board.

25. The force and location imaging touch pad of claim 23, wherein the common layer comprises one or more layers of thermoplastic resin.

26. The force and location imaging touch pad of claim 22, wherein the first plurality of conductive traces and the second plurality of conductive traces are substantially orthogonal.

27. The force and location imaging touch pad of claim 22, wherein the third surface comprises thermoplastic resin.

28. The force and location imaging touch pad of claim 22, wherein the deformable membrane comprises:

a substantially flat membrane having a first surface oriented toward the first plurality of conductive traces and a second surface oriented toward the third plurality of conductive traces;

a first plurality of raised structures coupled to the first surface of the substantially flat membrane; and

a second plurality of raised structures coupled to the second surface of the substantially flat membrane, wherein the second plurality of raised structures are substantially spatially offset from the first plurality of raised structures.

29. The force and location imaging touch pad of claim 22, wherein the deformable membrane comprises:

a substantially flat membrane; and

a plurality of deformable beads affixed to one surface of the substantially flat membrane, wherein the deformable beads are adapted to compress when a force is applied to the first surface toward the second surface.

30. The force and location imaging touch pad of claim 22, wherein the deformable membrane comprises a dimpled deformable membrane.

31. The force and location imaging touch pad of claim 29, wherein the deformable beads comprise a polymer.

32. The force and location imaging touch pad of claim 22, wherein the deformable membrane comprises one or more thermoplastic springs.

33. The force and location imaging touch pad of claim 32, wherein the thermoplastic springs comprise Polyethylene terephthalate.

34. The force and location imaging touch pad of claim 22, further comprising a mutual capacitance measurement circuit electrically coupled to the first, second and third pluralities of conductive traces.

35. An electronic device, comprising:

a processing unit;

a display unit operatively coupled to the processing unit;

a mutual capacitance measurement circuit operatively coupled to the processing unit; and

a force and location imaging touch pad in accordance with one of claims 9 and 22 and operatively coupled to the mutual capacitance measurement circuit.

36. The electronic device of claim 35, wherein the electronic device comprises a computer system.

37. The electronic device of claim 35, wherein the electronic device comprises a mobile telephone.

38. The electronic device of claim 35, wherein the electronic device comprises a personal digital assistant.

39. A force imaging touch pad, comprising:

a first layer including a first rigid layer and a first plurality of conductive traces oriented in a first direction;

a second layer including a deformable dielectric membrane and a second plurality of conductive traces oriented in a second direction, wherein the deformable dielectric membrane is deformable to move the first plurality of conductive traces closer to the second plurality of conductive traces when a force is applied to the first layer, one of the first and second pluralities of conductive traces is configured for receiving electrical stimulation signals, and the first and second pluralities of conductive traces cross over each other to form a plurality of mutual capacitance sensors between the first and second pluralities of conductive traces at each crossover location; and

a third layer including a second rigid layer, wherein the second layer is disposed between the first and third layers,

wherein the first and second pluralities of conductive traces are adapted to create a mutual capacitance image when a force is applied to the first layer, the mutual capacitance image indicative of an intensity of the applied force.

40. The force imaging touch pad of claim 39, wherein the first plurality of conductive traces and the second plurality of conductive traces are substantially orthogonal.

41. The force imaging touch pad of claim 39, wherein the deformable dielectric membrane comprises:

a substantially flat membrane having the first and second surfaces;

a first plurality of raised structures coupled to the first surface of the substantially flat membrane; and

a second plurality of raised structures coupled to the second surface of the substantially flat membrane, wherein the second plurality of raised structures are substantially offset from the first plurality of raised structures.

42. The force imaging touch pad of claim 39, wherein the deformable dielectric membrane comprises:

a substantially flat membrane having the first and second surfaces; and

a plurality of deformable beads affixed to one surface of the substantially flat membrane, wherein the deformable beads are adapted to compress when a force is applied to the first layer toward the second layer.

43. The force imaging touch pad of claim 39, further comprising a mutual capacitance measurement circuit electrically coupled to the first and second pluralities of conductive traces.

44. The force imaging touch pad of claim 39, wherein the first layer further comprises a third plurality of conductive traces oriented in a third direction, wherein the deformable dielectric membrane is juxtaposed closer to the first plurality of conductive traces than to the third plurality of conductive traces, and further wherein the first and third pluralities of conductive traces are adapted to create a capacitance image when an object is brought into close proximity to the first layer, the capacitance image indicative of a location, relative to of the first layer, where the object is located relative to the first layer.

45. The force imaging touch pad of claim 44, wherein the second and third orientations are substantially the same and the first orientation is substantially orthogonal thereto.

46. A force and location imaging touch pad, comprising:

a first layer including a first plurality of conductive traces oriented in a first direction and a second plurality of conductive traces oriented in a second direction, the first plurality of conductive traces configured for receiving electrical stimulation signals, and the first and second pluralities of conductive traces crossing over each other to form a plurality of mutual capacitance sensors between the first and second pluralities of conductive traces at each crossover location;

a second layer including a deformable dielectric membrane and a third plurality of conductive traces oriented in substantially the first direction, the deformable dielectric membrane having a first surface and a second surface, the first surface juxtaposed to the first layer, the third plurality of conductive traces configured for receiving electrical stimulation signals, and the second and third pluralities of conductive traces crossing over each other to form a plurality of mutual capacitance sensors between the second and third pluralities of conductive traces at each crossover location; and

a base layer juxtaposed to the second surface of the deformable dielectric membrane,

wherein the first and second pluralities of conductive traces are adapted to create a first mutual capacitance image when one or more objects come into close proximity to the first layer, the first mutual capacitance image indicative of where the one or more objects are located relative to the first layer,

wherein the second and third pluralities of conductive traces are adapted to create a second mutual capacitance image when a force is applied to the first layer, the second mutual capacitance image indicative of an intensity of the applied force.

47. The force and location imaging touch pad of claim 46, wherein the first layer comprises a flexible circuit board.

48. The force and location imaging touch pad of claim 46, wherein the first layer comprises one or more layers of thermoplastic resin.

49. The force and location imaging touch pad of claim 46, wherein the first plurality of conductive traces and the second plurality of conductive traces are substantially orthogonal.

50. The force and location imaging touch pad of claim 46, wherein the base layer comprises a flexible circuit board.

51. The force and location imaging touch pad of claim 46, wherein the second layer comprises one or more layers of thermoplastic resin.

52. The force and location imaging touch pad of claim 46, wherein the deformable membrane comprises a first plurality of raised structures juxtaposed to the first surface of the deformable membrane and a second plurality of raised structures juxtaposed to the second surface of the deformable membrane, wherein the first and second pluralities of raised structures are substantially spatially offset from one another.

53. The force and location imaging touch pad of claim 52, wherein the first and second pluralities of raised structures comprise thermoplastic resin.

54. The force and location imaging touch pad of claim 46, wherein the deformable membrane further comprises a first plurality deformable beads.

55. The force and location imaging touch pad of claim 54, wherein the deformable beads comprise elastomer beads.

56. The force and location imaging touch pad of claim 46, further comprising a mutual capacitance measurement circuit electrically coupled to the first, second and third pluralities of conductive traces.

57. A force imaging display, comprising:

a display element;

a first layer including a first rigid layer and a first plurality of substantially transparent conductive traces oriented in a first direction, the first layer adjacent to a first surface of the display element;

a second layer including a second rigid layer and a second plurality of substantially transparent conductive traces oriented in a second direction, the first layer juxtaposed between the second layer and the display element, one of the first and second pluralities of conductive traces configured for receiving electrical stimulation signals, and the first and second pluralities of conductive traces crossing over each other to form a plurality of mutual capacitance sensors between the first and second pluralities of conductive traces at each crossover location; and

a deformable substantially transparent dielectric membrane juxtaposed between the first and second layers and deformable to move the first plurality of conductive traces closer to the second plurality of conductive traces when a force is applied to the second layer,

wherein the first and second pluralities of conductive traces are adapted to create a mutual capacitance image when the force is applied to the second layer, the mutual capacitance image indicative of an intensity of the applied force.

58. The force imaging display of claim 57, wherein the display element comprises a liquid crystal display element.

59. The force imaging display of claim 57, wherein the first and second layers comprise Indium tin oxide traces.

60. The force imaging display of claim 57, wherein the first plurality of substantially transparent conductive traces and the second plurality of substantially transparent conductive traces are substantially orthogonal.

61. The force imaging display of claim 57, wherein the substantially transparent deformable dielectric membrane comprises:

a substantially flat membrane having a first surface oriented toward the first layer and a second surface oriented toward the second layer;

a first plurality of raised structures coupled to the first surface of the substantially flat membrane; and

a second plurality of raised structures coupled to the second surface of the substantially flat membrane, wherein the second plurality of raised structures are substantially offset from the first plurality of raised structures.

62. The force imaging display of claim 57, wherein the substantially transparent deformable dielectric membrane comprises:

a substantially flat membrane; and

a plurality of deformable beads affixed to one surface of the substantially flat membrane, wherein the deformable beads are adapted to compress when a force is applied to the second layer toward the first layer.