CAPACITIVE SENSOR DEVICE

• US 20100292945A1
• Filed: 05/12/2010
• Published: 11/18/2010
• Est. Priority Date: 05/13/2009
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Acker, Phillip, Hargreaves, Kirk, Shahparnia, Shahrooz, Reynolds, Joseph Kurth
• Granted Patent: US 9,804,213 B2
• Time in Patent Office: Days
• US Class Current: 702/65
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• 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 3/041662 using alternate mutual and self-capacitive scanning
• 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: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/960725 Charge-transfer
• CPC Class Codes: H03K 2217/96073 Amplitude comparison
• CPC Class Codes: H03K 2217/960765 Details of shielding arrangements
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion telephones including GPS signal receivers H04M2250/10

Abstract

A capacitive sensor device comprises a first sensor electrode, a second sensor electrode, and a processing system coupled to the first sensor electrode and the second sensor electrode. The processing system is configured to acquire a first capacitive measurement by emitting and receiving a first electrical signal with the first sensor electrode. The processing system is configured to acquire a second capacitive measurement by emitting and receiving a second electrical signal, wherein one of the first and second sensor electrodes performs the emitting and the other of the first and second sensor electrodes performs the receiving, and wherein the first and second capacitive measurements are non-degenerate. The processing system is configured to determine positional information using the first and second capacitive measurements.

Claims

1. A capacitive sensor device comprising:

a first sensor electrode;

a second sensor electrode; and

a processing system coupled to said first sensor electrode and said second sensor electrode, said processing system configured to;

acquire a first capacitive measurement by emitting and receiving a first electrical signal with said first sensor electrode,

acquire a second capacitive measurement by emitting and receiving a second electrical signal, wherein one of said first and second sensor electrodes performs said emitting and the other of said first and second sensor electrodes performs said receiving, wherein said first and second capacitive measurements are non-degenerate, and

determine first positional information using said first and second capacitive measurements.

2. The capacitive sensor device of claim 1, wherein said processing system is configured to determine first positional information using said first and second capacitive measurements by:

making an estimate using said first and second capacitive measurements, wherein said estimate is of a capacitive coupling between said first sensor electrode and one of an input object and said second sensor electrode and wherein said first positional information is based at least in part on said estimate of said capacitive coupling.

3. The capacitive sensor device of claim 2, wherein said capacitive coupling is between said first sensor electrode and said input object, and wherein said processing system is further configured to:

make a second estimate using said first and second capacitive measurements, wherein said second estimate is of a capacitive coupling between said first sensor electrode and said second sensor electrode.

4. The capacitive sensor device of claim 1, wherein said processing system is further configured to:

determine at least one of a size and type of said input object using said first and second capacitive measurements.

5. The capacitive sensor device of claim 1, wherein said processing system is configured to acquire said first capacitive measurement during a first time period and to acquire said second capacitive measurement during a second time period different from said first time period.

6. The capacitive sensor device of claim 5, wherein said second sensor electrode is said one of said first and second sensor electrodes that performs said emitting during said second time period, and wherein said processing system is further configured to:

modulate said second sensor electrode with respect to a system ground during said first time period, such that said second sensor electrode electrically guards said first sensor electrode.

7. The capacitive sensor device of claim 6, wherein said processing system is configured to modulate said second sensor electrode with respect to a system ground during said first time period by:

modulating said second sensor electrode substantially similarly to said first sensor electrode during said first time period.

8. The capacitive sensor device of claim 1, wherein said first sensor electrode is said one of said first and second sensor electrodes that performs said emitting, and wherein said processing system is configured to acquire said first and said second capacitive measurements contemporaneously.

9. The capacitive sensor device of claim 1, wherein said second sensor electrode is said one of said first and second sensor electrodes that performs said emitting, and wherein a surface area of said second sensor electrode is substantially greater than a surface area of said first sensor electrode.

10. The capacitive sensor device of claim 1, wherein said first sensor electrode is aligned along a first axis and said second sensor electrode is aligned along a second axis nonparallel to said first axis.

11. The capacitive sensor device of claim 1, further comprising:

a third sensor electrode coupled to said processing system; and

a fourth sensor electrode coupled to said processing system, wherein said processing system is further configured to;

acquire a third capacitive measurement by emitting and receiving a third electrical signal with said third sensor electrode,

acquire a fourth capacitive measurement by emitting and receiving a fourth electrical signal, wherein one of said third and fourth sensor electrodes performs said emitting and the other of said third and fourth sensor electrodes performs said receiving, wherein said third and fourth capacitive measurement are non-degenerate, and

determine second positional information using said third and fourth capacitive measurements.

12. A method of determining positional information using a capacitive sensor device comprising a first sensor electrode and a second sensor electrode, said method comprising:

emitting and receiving a first electrical signal with said first sensor electrode to acquire a first capacitive measurement;

emitting and receiving a second electrical signal to acquire a second capacitive measurement, wherein one of said first and second sensor electrodes performs said emitting and the other of said first and second sensor electrodes performs said receiving, and wherein said first and second capacitive measurements are non-degenerate;

determining positional information using said first and second capacitive measurements.

13. The method of claim 12, wherein positional information comprises:

at least one of a position, size, and type of an input object.

14. The method of claim 12, wherein said emitting and receiving a first electrical signal with said first sensor electrode to acquire a first capacitive measurement occurs during a first time period, and wherein said emitting and receiving a second electrical signal to acquire a second, capacitive measurement occurs during a second time period, different from said first time period.

15. The method of claim 14, wherein said second sensor electrode is said one of said first and second sensor electrodes that performs said emitting during said second time period, said method further comprising:

modulating said second sensor electrode with respect to a system ground during said first time period, such that said second sensor electrode electrically guards said first sensor electrode.

16. The method of claim 15, wherein said modulating said second sensor electrode with respect to a system ground during said first time period comprises:

modulating said second sensor electrode substantially similarly to said first sensor electrode during said first time period.

17. A capacitive sensor device comprising:

a first plurality of sensor electrodes aligned along a first axis;

a second plurality of sensor electrodes aligned along a second axis non-parallel to said first axis; and

a processing system coupled to said first plurality of sensor electrodes and said second plurality of sensor electrodes, said processing system configured to;

acquire a first plurality of capacitive measurements by emitting electrical signals from a first set of said first plurality of sensor electrodes and receiving said electrical signals from said first set of said first plurality of sensor electrodes with said first set of said first plurality of sensor electrodes, and

acquire a second plurality of capacitive measurements by emitting electrical signals from a first set of said second plurality of sensor electrodes and receiving said electrical signals from said first set of said second plurality of sensor electrodes with a second set of said first plurality of sensor electrodes, wherein said first and second sets of said first plurality of sensor electrodes have at least one sensor electrode in common.

18. The capacitive sensor device of claim 17, wherein said processing system is configured to acquire said first and second pluralities of capacitive measurements simultaneously.

19. The capacitive sensor device of claim 17, wherein said processing system is further configured to:

determine said second set of said first plurality of sensor electrodes using said first plurality of capacitive measurements.

20. The capacitive sensor device of claim 17, further comprising:

an input surface associated with said capacitive sensor device, wherein said processing system is further configured to;

determine a first position estimate of an input object using said first plurality of capacitive measurements, said first position estimate locating said input object relatively farther from said input surface, and

determine a second position estimate of said input object using said second plurality of capacitive measurements, said second position estimate locating said input object relatively closer to said input surface.

21. The capacitive sensor device of claim 17, wherein said processing system is farther configured to:

determine at least one of a size, type, and a capacitive coupling to system ground of an input object using said first and second pluralities of capacitive measurements.

22. A method of sensing using a capacitive sensor device comprising a first plurality of sensor electrodes aligned along a first axis and a second plurality of sensor electrodes aligned along a second axis non-parallel to said first axis, said method comprising:

emitting electrical signals from a first set of said first plurality of sensor electrodes;

receiving said electrical signals from said first set of said first plurality of sensor electrodes with a second set of said first plurality of sensor electrodes to acquire a first plurality of capacitive measurements;

emitting electrical signals from said second set of said first plurality of sensor electrodes, wherein said first and second sets of said first plurality of sensor electrodes have at least one sensor electrode in common; and

receiving second electrical signals from said second set of said first plurality of sensor electrodes with a first set of said second plurality of sensor electrodes to acquire a second plurality of capacitive measurements.

23. The method of claim 22, wherein said emitting electrical signals from said first set of said first plurality of sensor electrodes and emitting said electrical signals from said second set of said first plurality of sensor electrodes occur simultaneously.

24. The method of claim 22, further comprising:

determining said second set of said first plurality of sensor electrodes using said first plurality of capacitive measurements.

25. A capacitive sensor device comprising:

a first plurality of sensor electrodes aligned along a first axis;

a second plurality of sensor electrodes aligned along a second axis non-parallel to said first axis, said second plurality of sensor electrodes forming a matrix pattern with said first plurality of sensor electrodes; and

a processing system coupled to said first plurality of sensor electrodes and said second plurality of sensor electrodes, said processing system configured to;

acquire a first plurality of capacitive measurements by emitting and receiving first electrical signals with said first plurality of sensor electrodes,

make a first estimate of a position of at least one input object using said first plurality of capacitive measurements,

select a first set of said first plurality of sensor electrodes and a first set of said second plurality of sensor electrodes using said first estimate,

acquire a second plurality of capacitive measurements by emitting second electrical signals with one of said first sets of said first and second plurality of sensor electrodes and receiving said second electrical signals with another of said first sets of said first and second plurality of sensor electrodes, and

make a second estimate of said position of said at least one input object using said second plurality of capacitive measurements.

26. The capacitive sensor device of claim 25, wherein said at least one input object comprises two input objects.

27. The capacitive sensor device of claim 25, wherein said second estimate is of finer resolution than said first estimate.

28. The capacitive sensor device of claim 25, wherein said first estimate comprises possible locations of said at least one input object, and said second estimate is a disambiguation of said possible locations.

29. The capacitive sensor device of claim 25, wherein said processing system is further configured to:

determine at least one of a size, a type, and a capacitive coupling to system ground of an input object using said first and second pluralities of capacitive measurements.

30. The capacitive sensor device of claim 25, wherein said processing system is configured to acquire said first plurality of capacitive measurements during a first time period and to acquire said second plurality of capacitive measurements during a second time period different from said first time period, and wherein said processing system is further configured to:

electrically guard said first plurality of sensor electrodes by modulating at least one sensor electrode of said second plurality of sensor electrodes with respect to a system ground during said first time period.

31. A method of sensing using a capacitive sensor device comprising a first plurality of sensor electrodes aligned along a first axis and a second plurality of sensor electrodes aligned along a second axis non-parallel to said first axis, said method comprising:

emitting and receiving first electrical signals with said first plurality of sensor electrodes to acquire a first plurality of capacitive measurements;

making a set of first estimates of positions of at least one input object using said first plurality of capacitive measurements;

determining a first set of said first plurality of sensor electrodes and a first set of said second plurality of sensor electrodes using said first set of estimates of said positions;

emitting second electrical signals with one of said first sets of said first and second plurality of sensor electrodes and receiving said second electrical signals with the other of said first sets of first and second plurality of sensor electrodes to acquire a second plurality of capacitive measurements; and

making a second estimate of said position of said at least one input object using said second plurality of capacitive measurements.

32. The method of claim 31, wherein said making a second estimate of said position of said at least one input object using said second plurality of capacitive measurements comprises:

making an estimate of finer resolution than said first estimate.

33. The method of claim 31, wherein said making said set of first estimate comprises identifying possible locations of said at least one input object, and wherein said making a second estimate comprises disambiguating said possible locations.

34. A capacitive sensor device comprising:

a first plurality of sensor electrodes aligned along a first axis;

a second plurality of sensor electrodes aligned along a second axis non-parallel to said first axis, said second plurality of sensor electrodes forming a matrix pattern with said first plurality of sensor electrodes; and

a processing system coupled to said first plurality of sensor electrodes and said second plurality of sensor electrodes, said processing system configured to;

emit and receive first electrical signals with said first plurality of sensor electrodes during a first time period to acquire a first plurality of capacitive measurements,

electrically guard said first plurality of sensor electrodes by modulating said second plurality of sensor electrodes during said first time period,

emit second electrical signals with said second plurality of sensor electrodes during a second time period different from said first time period,

receive said second electrical signals with said first plurality of sensor electrodes during said second time period to acquire a second plurality of capacitive measurements.

35. The capacitive sensor device of claim 34, wherein said processing system is configured to electrically guard said first plurality of sensor electrodes by modulating said second plurality of sensor electrodes during said first time period by:

modulating substantially all of said second plurality sensor electrodes substantially similarly to at least one of said first plurality of sensor electrodes during said first time period.

36. The capacitive sensor device of claim 34, wherein said processing system is configured to electrically guard said first plurality of sensor electrodes by modulating said second plurality of sensor electrodes during said first time period by:

modulating a subset of said second plurality of sensor electrodes substantially similarly to an amplified version of a modulation of at least one said first plurality of sensor electrodes during said first time period.

37. The capacitive sensor device of claim 34, wherein said processing system is configured to emit second electrical signals with said second plurality of sensor electrodes during a second time period different from said first time period by:

emitting during different portions of said second time period using different sensor electrodes of said second plurality of sensor electrodes;

or

emitting differently modulated electrical signals using different sensor electrodes of said second plurality of sensor electrodes simultaneously.

38. The capacitive sensor device of claim 34, wherein said processing system is further configured to:

determine a position of said input object using at least one of said first and second pluralities of capacitive measurements.

39. The capacitive sensor device of claim 34, wherein said processing system is further configured to:

make a first estimate using said first and second plurality of capacitive measurements, wherein said first estimate is of a capacitive coupling between a first sensor electrode and an input object, and

make a second estimate using said first and second plurality of capacitive measurements, wherein said second estimate is of a capacitive coupling between said first sensor electrode and a second sensor electrode.

40. The capacitive sensor device of claim 34, wherein said processing system is further configured to:

determine at least one of a size, type, and grounding of an input object using said first and second pluralities of capacitive measurements.

41. The capacitive sensor device of claim 34, wherein a surface area of said second plurality of sensor electrodes is substantially greater than a surface area of said first plurality of sensor electrodes.

42. A method of sensing using a capacitive sensor device comprising a first plurality of sensor electrodes aligned along a first axis and a second plurality of sensor electrodes aligned along a second axis non-parallel to said first axis, said method comprising:

emitting and receiving first electrical signals with said first plurality of sensor electrodes during a first time period to acquire a first plurality of capacitive measurements;

modulating sensor electrodes of said second plurality of sensor electrodes during said first time period, to electrically guard said first plurality of sensor electrodes;

emitting second electrical signals with said second plurality of sensor electrodes during a second time period different from said first time period; and

receiving said second electrical signals with said first plurality of sensor electrodes during said second time period to acquire a second plurality of capacitive measurements.

43. The method of claim 42, wherein said modulating sensor electrodes of said second plurality of sensor electrodes during said first time period comprises:

modulating substantially all of said second plurality sensor electrodes substantially similarly to at least one of said first plurality of sensor electrodes during said first time period.

44. The method of claim 42, wherein said modulating sensor electrodes of said second plurality of sensor electrodes during said first time period comprises:

modulating a subset of said second plurality of sensor electrodes substantially similarly to an amplified version of a modulation of at least one said first plurality of sensor electrodes during said first time period.

45. The method of claim 42, wherein said processing system is configured to emit second electrical signals with said second plurality of sensor electrodes during a second time period different from said first time period by:

emitting non-concurrently during said second time period using different sensor electrodes of said second plurality of sensor electrodes or

emitting differently modulated electrical signals using different sensor electrodes of said second plurality of sensor electrodes simultaneously.

46. The method of claim 42, further comprising:

determining a position of an input object using at least one of said first and second pluralities of capacitive measurements.

47. The method of claim 42, further comprising:

making a first estimate using said first and second capacitive measurements, wherein said first estimate is of a capacitive coupling between said first sensor electrode and an input object;

making a second estimate using said first and second capacitive measurements, wherein said second estimate is of a capacitive coupling between said first sensor electrode and said second sensor electrode; and

determining at least one of a size, type, and grounding of an input object using said first and second estimates.

48. A capacitive sensor device comprising:

a transmitting assembly comprising a plurality of transmitting sensor electrodes; and

a receiving assembly comprising;

at least one receiving sensor electrode;

a switching mechanism configured for charging said at least one receiving sensor electrode to a charged voltage; and

a charge measurement mechanism adapted to control said charged voltage applied to an input of said charge measurement mechanism using a reference voltage,

wherein said reference voltage has a substantially constant voltage;

wherein said capacitive sensor device is configured for use with both absolute and transcapacitive measurements.

49. The capacitive sensor device of claim 48, further comprising:

a supply voltage, wherein said reference voltage is proportional to said supply voltage.

50. The capacitive sensor device of claim 48, wherein said plurality of transmitter sensor electrodes is coupled with at least two electric potentials via a plurality of switches.

51. The capacitive sensor device of claim 48, wherein said switching mechanism comprises at least two switches.

52. The capacitive sensor device of claim 48, wherein a first switch of said switching mechanism couples said at least one receiving sensor electrode with a first electric potential during a first time period and a second switch of said switching mechanism couples said at least one receiving sensor electrode with said charge measurement mechanism during a second time period.

53. The capacitive sensor device of claim 52, wherein a third switch of said switching mechanism couples said at least one sensor electrode with a second electric potential.

54. The capacitive sensor device of claim 48, wherein said charge measurement mechanism comprises:

an amplifier;

a reset; and

an integrating feedback capacitance coupled with said amplifier adapted to accumulate charge relative to said reference voltage, wherein said reference voltage has a substantially constant voltage;

wherein said charge measurement mechanism uses said amplifier to control a charge on said integrating feedback capacitance based at least in part, on said reference voltage.

55. The capacitive sensor device of claim 54, wherein said reset comprises a resistor.

56. The capacitive sensor device of claim 54, wherein said reset comprises a switch.

57. The capacitive sensor device of claim 48, wherein a first set of said plurality of transmitter sensor electrodes is configured for emitting a guard signal.

58. The capacitive sensor device of claim 48, comprising a capacitive coupling component configured to perform at least two of the following:

capacitively couple said at least one receiving sensor electrode and an input object, wherein said at least one receiving sensor electrode is modulated with respect to system ground while concurrently at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes electrically guards said at least one receiving sensor electrode;

capacitively couple said at least one transmitter sensor electrode and said at least one receiving sensor electrode, wherein said at least one transmitter sensor electrode is modulated with respect to said at least one receiving sensor electrode while concurrently said receiving sensor electrode is not being modulated;

capacitively couple said at least one receiving sensor electrode and said input object and capacitively couple said at least one receiving sensor electrode and said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes, wherein said at least one receiving sensor electrode is modulated in a first way with respect to said system ground while concurrently said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes is being modulated with respect to said at least one receiving electrode in a first way; and

capacitively couple said at least one receiving sensor electrode and said input object and capacitively couple said at least one receiving sensor electrode and said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes, wherein said at least one receiving sensor electrode is modulated with respect to said system ground while concurrently said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes is modulated with respect to said at least one receiving sensor electrode in a second way.

59. The capacitive sensor device of claim 58, wherein said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes electrically guards said at least one receiving sensor electrode, said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes is driven with a constant voltage potential and one or more transmitter sensor electrodes of said plurality of transmitter sensor electrodes other than said at least one transmitter sensor electrode is alternately driven between two electric potentials.

60. The capacitive sensor device of claim 58, wherein said at least one receiving sensor electrode is modulated with respect to said system ground while concurrently said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes is being modulated with respect to said at least one receiving electrode in a first way comprises at least one of the following:

said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes being driven in an opposite polarity to said at least one receiving sensor electrode; and

said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes and said at least one receiving sensor electrode being driven with different amplitudes.

61. The capacitive sensor device of claim 58, wherein said at least one receiving sensor electrode is modulated with respect to said system ground while concurrently said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes is being modulated with respect to said at least one receiving electrode in a second way comprises at least one of the following:

said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes being driven in an opposite polarity to said at least one receiving sensor electrode; and

said at least one transmitter sensor electrode of said plurality of transmitter sensor electrodes and said at least one receiving sensor electrode being driven with different amplitudes.

62. The capacitive sensor device of claim 48, wherein said at least one receiving sensor electrode comprises:

a first receiving sensor electrode and a second receiving sensor electrode, wherein said input switch is a multiplexer configured for allowing said first receiving sensor electrode and said second sensor electrode to be coupled with said charge measurement mechanism.

63. A capacitive sensor device comprising:

a transmitting assembly comprising a plurality of transmitter sensor electrodes coupled with at least two electric potentials via a plurality of switches; and

a receiving assembly comprising;

at least one receiving sensor electrode;

a switching mechanism configured for charging said at least one receiving sensor electrode to a charged voltage; and

a charge measurement mechanism adapted to control said charged voltage applied to an input of said charge measurement mechanism using a reference voltage, wherein said reference voltage has a substantially constant voltage, and wherein said charge measurement mechanism comprises;

an amplifier;

a reset; and

an integrating feedback capacitance coupled with said amplifier adapted to accumulate charge relative to said reference voltage, wherein said reference voltage has a substantially constant voltage;

wherein said charge measurement mechanism uses said amplifier to control a charge on said integrating feedback capacitance based at least in part on said reference voltage;

wherein said capacitive sensor device is configured for use with both absolute and transcapacitive measurements.

64. The capacitive sensor device of claim 63, further comprising:

a supply voltage, wherein said reference voltage is proportional to said supply voltage.

65. The capacitive sensor device of claim 63, wherein said switching mechanism comprises at least two switches.

66. The capacitive sensor device of claim 63, wherein a first switch of said switching mechanism couples said at least one receiving sensor electrode with a first electric potential during a first time period and a second switch of said switching mechanism couples said at least one receiving sensor electrode with said charge measurement mechanism during a second time period.

67. The capacitive sensor device of claim 66, wherein a third switch of said switching mechanism couples said at least one sensor electrode with a second electric potential.

68. The capacitive sensor device of claim 63, wherein said reset comprises a resistor.

69. The capacitive sensor device of claim 63, wherein said reset comprises a switch.