Fingertip touch recognition for a digitizer

• US 20070285404A1
• Filed: 06/13/2007
• Published: 12/13/2007
• Est. Priority Date: 06/13/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: N-Trig Ltd (Microsoft Corporation)
• Inventors: Rimon, Ori, Kerner, Ariel
• Granted Patent: US 8,059,102 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• 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

Abstract

A method for verifying a fingertip touch input to a digitizer, the method comprises detecting a pattern of signals obtained from conductive lines of a digitizer sensor, comparing the pattern to a pre-determined fingertip characteristic, and recognizing a fingertip touch input based on the comparison.

Claims

1. A method for verifying a fingertip touch input to a digitizer, the method comprising:

detecting a pattern of signals obtained from conductive lines of a digitizer sensor;

comparing the pattern to a pre-determined fingertip characteristic; and

recognizing a fingertip touch input based on the comparison.

2. The method according to claim 1, wherein the conductive lines are parallel conductive lines.

3. The method according to claim 1, wherein the conductive lines include two orthogonal sets of parallel conductive lines forming a grid.

4. The method according to claim 3, wherein the two orthogonal sets are electrically separated from each other.

5. The method according to claim 2, wherein the parallel conductive lines are equally spaced.

6. The method according to claim 2, wherein the parallel conductive lines are spaced 4 mm apart.

7. The method according to claim 2, wherein pairs of the parallel conductive lines are input to differential amplifiers.

8. The method according to claim 7, wherein the pattern is a pattern of differential amplifier outputs.

9. The method according to claim 7, wherein the pairs of the parallel conductive lines are non-adjacent conductive lines.

10. The method according to claim 1, wherein the pattern is a pattern of signal amplitudes.

11. The method according to claim 1, wherein the pattern is a pattern of signal amplitudes above a pre-defined amplitude threshold.

12. The method according to claim 1, wherein the pattern is a pattern of signal amplitude gradients.

13. The method according to claim 1, wherein the pattern is a pattern of signal amplitude gradients above a pre-defined gradient threshold.

14. The method according to claim 1, wherein the pattern includes a pattern of signal amplitudes and a pattern of signal amplitude gradients.

15. The method according to claim 1 comprising determining a number of gaps in the pattern of signals.

16. The method according to claim 15 comprising defining a maximum number of gaps below which the pattern of signals qualifies for verifying fingertip touch.

17. The method according to claim 1, wherein the pattern of signals is detected using a capacitive touch method.

18. The method according to claim 12, wherein the signal amplitude gradients are spatial high-pass filtered signals of the pattern of signals.

19. The method according to claim 18, wherein the pattern is a contour pattern.

20. The method according to claim 17 comprising:

determining a ratio of a dimension of an area from which the digitizer sensor is detected; and

defining a range of the ratio that qualifies for verifying fingertip touch.

21. The method according to claim 20 comprising:

determining an area from which a signal on the digitizer sensor is detected; and

determining a range of the area that qualifies for verifying fingertip touch.

22. The method according to claim 1, wherein the digitizer sensor is transparent.

23. The method according to claim 1, wherein the detecting includes multi-touch detection.

24. A system for verifying a fingertip input to a digitizer comprising:

a digitizer sensor comprising a plurality of conductive lines; and

a controller operative to verify a fingertip touch input based detection of a pattern of outputs from the plurality of conductive lines.

25. The system according to claim 24, wherein the plurality of conductive lines include parallel conductive lines.

26. The system according to claim 24, wherein the plurality of conductive lines includes two orthogonal sets of parallel conductive lines forming a grid.

27. The system according to claim 26, wherein the two orthogonal sets are electrically separated from each other.

28. The system according to claim 24, wherein the plurality of conductive lines is equally spaced.

29. The system according to claim 24, wherein the plurality of conductive lines is spaced 4 mm apart.

30. The system according to claim 24, wherein pairs of the parallel conductive lines are input to differential amplifiers.

31. The method according to claim 30, wherein the pattern is a pattern of differential amplifier outputs.

32. The method according to claim 30, wherein the pairs of the parallel conductive lines are non-adjacent conductive lines.

33. The system according to claim 24, wherein the controller is operative to determine a pattern of signal amplitudes from the output.

34. The system according to claim 24, wherein the controller is operative to determine a pattern of signal amplitudes from the output above a pre-defined amplitude threshold.

35. The system according to claim 24, wherein the controller is operative to determine a pattern of signal amplitude gradients from the output.

36. The system according to claim 24, wherein the controller is operative to determine a pattern signal amplitude gradients from the output above a pre-defined gradient threshold.

37. The system according to claim 24, wherein the controller is operative to determine a number of gaps in the pattern of signals.

38. The system according to claim 37, wherein the controller is operative to reject an input signal corresponding to a pattern with gaps above a pre-defined maximum number of gaps.

39. The system according to claim 24, wherein the pattern of outputs is detected using a capacitive touch method.

40. The system according to claim 35, wherein the signal amplitude gradients are high-pass filtered signal of the output.

41. The system according to claim 40, wherein the pattern is a contour pattern.

42. The system according to claim 39, wherein the controller is operative to determine a ratio of dimensions of an area from which the output is detected and to determine if the ratio is within a pre-defined range of ratios qualifying for verifying fingertip touch.

43. The system according to claim 42, wherein the controller is operative to determine if the area is within a pre-defined range of areas qualifying for verifying fingertip touch and to determine if the dimension is within a pre-defined range of dimensions qualifying for verifying fingertip touch.

44. The system according to claim 24, wherein the digitizer sensor is transparent.

45. The system according to claim 24, wherein the controller is operative to detect multi-touch input.

46. The system according to claim 24, comprising a host computer, wherein the host computer is in communication with the controller.

47. The system according to claim 46, wherein the controller transmits input verified as fingertip input to the host computer.