Touch detection for a digitizer

• US 8,400,427 B2
• Filed: 03/05/2012
• Issued: 03/19/2013
• Est. Priority Date: 02/10/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: N-Trig Ltd (Microsoft Corporation)
• Inventors: Perski, Haim, Morag, Meir
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US13/411,795
• Publication Number:
  US 20120162131A1
• Time in Patent Office: 379 Days
• Field of Search: 345173-183, 178 1801- 1807, 178 1901- 1907
• US Class Current: 345/174
• 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 3/02 Input arrangements using manually operated switches, e.g. using keyboards or dials
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04162 for exchanging data with external devices, e.g. smart pens, via the digitiser sensing hardware
• 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 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0442 using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
• 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 3/046 by electromagnetic means
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

A detector for providing position detection of objects over a sensor with a first and second set of conductor lines forming a grid with a plurality of junctions there between at which the conductor lines do not contact, includes a signal generator providing a signal to at least one conductor line of the first set of conductor lines, and circuitry detecting output arising from one or both of an electromagnetic stylus and one or more fingers when present. The output arising from each of the one or more fingers is detected from at least one conductor line of the second set of conductor lines in response to the signal provided to the at least one conductor line of the first set of conductor lines. The circuitry detects positions of one or both the electromagnetic stylus and each of the one or more fingers when present responsive to the output detected.

Claims

1. A detector for providing position detection of objects over a sensor, the sensor including a first and second set of conductor lines forming a grid with a plurality of junctions there between at which the conductor lines do not contact, the detector comprising:

a signal generator providing a signal to at least one conductor line of the first set of conductor lines; and

circuitry detecting output arising from one or both of an electromagnetic stylus and one or more fingers when present,

wherein the output arising from each of the one or more fingers is detected from at least one conductor line of the second set of conductor lines in response to the signal provided to the at least one conductor line of the first set of conductor lines, and

wherein the circuitry detects positions of one or both the electromagnetic stylus and each of the one or more fingers when present responsive to the output detected.

2. The detector of claim 1, wherein the circuitry is operable to detect positions of each of the electromagnetic stylus and the one or more fingers, all interacting with the sensor at the same time.

3. The detector of claim 1, wherein the output arising from the electromagnetic stylus and the one or more fingers is detected from same conductor lines.

4. The detector of claim 1, wherein the circuitry is operable to detect output from transparent conductor lines.

5. The detector of claim 1, wherein the circuitry is operable to detect output from conductor lines formed from indium tin oxide (ITO), wherein the conductor lines are the first and second set of conductor lines forming the grid.

6. The detector of claim 1, wherein position detection of the one or more fingers is capacitive based detection.

7. The detector of claim 1, wherein the circuitry is operable to detect position of the electromagnetic stylus and positions of the one or more fingers independently.

8. The detector of claim 1, wherein the circuitry is operable to detect position of the electromagnetic stylus and positions of the one or more fingers at different times.

9. The detector of claim 1, wherein the circuitry is operable to also detect output from the first set of conductor lines.

10. The detector of claim 9, wherein the circuitry is operable to detect output from first and second set of conductor lines simultaneously.

11. The detector of claim 1, wherein the circuitry is operable to detect simultaneous inputs from the electromagnetic stylus and the one or more fingers.

12. The detector of claim 1, wherein the circuitry is operable to switch from applying the signal to the first set of conductor lines and detecting output on the first set of conductor lines.

13. The detector of claim 1, wherein the circuitry is operable to apply the signal to each one of a plurality of conductor lines in the first set of conductor lines, one line at a time.

14. The detector of claim 13, wherein the circuitry is operable to detect output in the second set of conductor lines, in response to each signal applied to the plurality of conductor lines in the first set of conductor lines.

15. The detector of claim 14, wherein the circuitry is operable to detect output in the second set of conductor lines, indicative of capacitive coupling change induced by the one or more fingers over junctions formed between a conductor line of the first set of conductor lines and conductor lines of the second set of conductor lines.

16. The detector of claim 1, wherein the signal generator includes an oscillator.

17. The detector of claim 16, wherein the oscillator is configured to oscillate with respect to a reference voltage level, thereby to permit a capacitive current flow between each of the one or more fingers and at least one conductor line from the first and second set of conductor lines.

18. The detector of claim 1, wherein the signal generated is an AC signal.

19. The detector of claim 1, wherein the signal generator is operable to generate a signal for exciting circuitry in the electromagnetic stylus.

20. The detector of claim 19, wherein the signal for exciting circuitry in the electromagnetic stylus is applied to at least one conductor line of the first or second set of conductor lines.

21. The detector of claim 1, wherein the electromagnetic stylus is internally powered using a battery.

22. The detector of claim 1, wherein the circuitry identifies when a tip of the electromagnetic stylus contacts the sensor responsive to the output arising from the electromagnetic stylus in at least one conductor line.

23. The detector of claim 22, wherein the circuitry detects a frequency of energy emitted by the electromagnetic stylus and identifies contact of the tip on the sensor responsive to detecting a defined change in the frequency of energy emitted by the electromagnetic stylus.

24. The detector of claim 1, wherein the circuitry is operative to distinguish between positions of multiple electromagnetic styluses present over the sensor at the same time.

25. The detector of claim 1, wherein the circuitry is operable to detect an oscillating signal transferred via the junctions to conductor lines in the second set of conductor lines, the transference being indicative of capacitive coupling change induced by positioning of the one or more fingers over the sensor at the respective junctions.

26. The detector of claim 1, further comprising a tabulation of leakage signal values caused by capacitance values for each junction.

27. The detector of claim 1, further comprising a tabulation of signal values detected at each junction while both the electromagnetic stylus and the one or more fingers are removed from the sensor.

28. The detector of claim 26, wherein the circuitry is operable to use the leakage signal values to correct readings at each conductor.

29. The detector of claim 28, wherein the circuitry is operable to update the tabulation upon startup of the detector.

30. The detector of claim 28, wherein the circuitry is operable to update the tabulation during operation of the detector.

31. The detector of claim 1, wherein the circuitry is operable to use interpolation to increase accuracy of the position detection.

32. The detector of claim 1, wherein the circuitry is operable to determine an amount of parasitic current transfer for each junction and subtract the amount from the outputs detected.

33. A method for providing position detection of objects over a sensor, the sensor including a first and second set of conductor lines forming a grid with a plurality of junctions there between at which the conductor lines do not contact, the method comprising:

providing a signal to at least one line conductor line of the first set of conductor lines;

detecting output arising from one or both of an electromagnetic stylus and one or more fingers when present,

wherein the output arising from each of the one or more fingers is detected from at least one conductor line of the second set of conductor lines in response to the signal provided to the at least one conductor line of the first set of conductor lines; and

detecting positions of one or both the electromagnetic stylus and each of the one or more fingers responsive to the output detected.

34. The method of claim 33, comprising detecting positions of each of the electromagnetic stylus and the one or more fingers, all interacting with the sensor at the same time.

35. The method of claim 33, wherein the output arising from the electromagnetic stylus and the one or more fingers is detected from same conductor lines.

36. The method of claim 33, wherein position detection of the one or more fingers is capacitive based detection.

37. The method of claim 33, wherein position of the electromagnetic and positions of the one or more fingers is detected independently.

38. The method of claim 33, wherein position of the electromagnetic stylus and positions of the one or more fingers is detected at different times.

39. The method of claim 33, comprising detecting output also from the first set of conductor lines.

40. The method of claim 39, comprising detecting output from first and second set of conductor lines simultaneously.

41. The method of claim 33, comprising detecting simultaneous inputs from the electromagnetic stylus or the one or more fingers.

42. The method of claim 33, comprising switching from applying the signal to the first set of conductor lines and detecting output on the first set of conductor lines.

43. The method of claim 33, comprising applying the signal to each one of a plurality of conductor lines in the first set of conductor lines, one line at a time.

44. The method of claim 43, comprising detecting output in the second set of conductor lines, in response to each signal applied to the plurality of conductor lines in the first set of conductor lines.

45. The method of claim 44, detecting output in the second set of conductor lines indicative of capacitive coupling change induced by the one or more fingers over junctions formed between a conductor line of the first set of conductor lines and conductor lines of the second set of conductor lines.

46. The method of claim 33, wherein the signal provided is an oscillating signal.

47. The method of claim 46, wherein the signal is configured to oscillate with respect to a reference voltage level, thereby to permit a capacitive current flow between each of the one or more fingers and at least one conductor line from the first and second set of conductor lines.

48. The method of claim 33, wherein the signal provided is an AC signal.

49. The method of claim 33, comprising providing a signal for exciting circuitry in the electromagnetic stylus.

50. The method of claim 49, wherein the signal for exciting circuitry in the electromagnetic stylus is applied to at least one conductor line of the first or second set of conductor lines.

51. The method of claim 33, wherein the electromagnetic stylus is internally powered using a battery.

52. The method of claim 33, comprising identifying when a tip of the electromagnetic stylus contacts the sensor responsive to the output arising from the electromagnetic stylus in at least one conductor line.

53. The method of claim 52, comprising detecting a frequency of energy emitted by the electromagnetic stylus and identifying contact of the tip on the sensor responsive to detecting a defined change in the frequency of energy emitted by the electromagnetic stylus.

54. The method of claim 33, comprising distinguishing between positions of multiple electromagnetic styluses.

55. The method of claim 33, comprising detecting an oscillating signal transferred via the junctions to conductor lines in the second set of conductor lines, the transference being indicative of capacitive coupling change induced by positioning of the one or more fingers over the sensor at the respective junctions.

56. The method of claim 33, comprising determining a tabulation of signal values detected at each junction while both the electromagnetic stylus and the one or more fingers are removed from the sensor.

57. The method of claim 33, comprising determining a tabulation of leakage signals values caused by capacitance values for each junction.

58. The method of claim 57, comprising correcting readings at each conductor responsive to the leakage signals tabulated.

59. The method of claim 58, comprising updating the tabulation upon startup of the position detection of the objects over the sensor.

60. The method of claim 58, wherein updating the tabulation during operation of the position detection of the objects over the sensor.

61. The method of claim 33, comprising performing interpolation to increase accuracy of the position detection.

62. The method of claim 33, comprising determining an amount of parasitic current transfer for each junction and subtracting the amount from the outputs detected.