System and method for detection with a digitizer sensor

• US 8,232,977 B2
• Filed: 11/13/2008
• Issued: 07/31/2012
• Est. Priority Date: 11/14/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: N-Trig Ltd (Microsoft Corporation)
• Inventors: Zachut, Rafi, Morag, Meir, Kaplan, Amir
• Primary Examiner(s): Wang, Quan-Zhen
• Assistant Examiner(s): DALRYMPLE, TROY S
• Application Number:
  US12/269,971
• Publication Number:
  US 20090127005A1
• Time in Patent Office: 1,356 Days
• Field of Search: 345173-183
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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 detection on a digitizer sensor, the method comprises simultaneously transmitting orthogonal signals having the same frequency on at least two conductors of a digitizer sensor; sampling a signal on at least one other conductor crossing the at least two conductors, wherein the signal is responsive to capacitive coupling at cross-junctions formed between the at least two conductors and at least one other conductor; decomposing the sampled signal into orthogonal components; and analyzing the orthogonal components to detect user interaction at each cross junction.

Claims

1. A method for detection on a digitizer sensor, the method comprising:

simultaneously transmitting orthogonal signals having a same frequency on at least two conductors of a digitizer sensor;

sampling a signal on at least one other conductor crossing the at least two conductors, wherein the signal is responsive to capacitive coupling at cross-junctions formed between the at least two conductors and the at least one other conductor;

decomposing the signal that is sampled into orthogonal components; and

analyzing the orthogonal components to detect user interaction at each cross junction.

2. The method according to claim 1, comprising detecting a position of the user interaction on the digitizer sensor.

3. The method according to claim 1, wherein the orthogonal signals are orthogonal in phase.

4. The method according to claim 3, wherein the decomposing is performed by orthogonal phase detectors.

5. The method according to claim 1 comprising:

estimating a phase shift of the orthogonal signals transmitted over a length of the at least two conductors; and

shifting the phase of the signal that is sampled by the estimated phase shift.

6. The method according to claim 5 wherein the length of the at least two conductors comprises the length of said conductors between an input generator and cross-junctions with the at least one other conductor.

7. The method according to claim 5 wherein the estimated phase shift is the phase shift at a central point along the length of the at least two conductors.

8. The method according to claim 7, wherein the shifting is operative to provide maximum compensation of phase shift in a central area of the digitizer sensor and compensation of half the overall phase shift across the length of the at least two conductors at their endpoints.

9. The method according to claim 1, wherein the digitizer sensor is a grid based digitizer sensor and wherein the at least two conductors are conductive lines associated with a first axis of the grid based sensor and the at least one other conductor is a conductive line associated with a second axis of the grid based sensor orthogonal to the first axis.

10. The method according to claim 1, wherein the user interaction is detected by comparing an amplitude level of one of the orthogonal components and a signal level in the absence of the user interaction.

11. The method according to claim 1, wherein the user interaction is selected from a group including fingertip, hand and conductive object.

12. The method according to claim 1, wherein the user interaction is selected from a group including touch user interaction and hover user interaction.

13. The method according to claim 1, wherein the orthogonal signals transmitted to the at least two conductors are pulsed signals.

14. The method according to claim 1, wherein the orthogonal signals transmitted to the at least two conductors are AC signals.

15. A digitizer system comprising:

a digitizer sensor comprising a first set of conductors and a second set of conductors that cross with the first set of conductors at cross junctions;

a signal generator configured for providing first and second triggering signals at a pre-defined frequency to two conductors from the first set of conductors, wherein the first and second triggering signals are orthogonal signals;

a controller configured for sampling an output signal from at least one conductor from the second set of conductors; and

a processor configured for decomposing the output signal sampled from the at least one conductor from the second set of conductors into orthogonal components and for detecting user interactions on the cross junctions of the of the digitizer sensor based on the orthogonal components of the output signal sampled.

16. The system according to claim 15, wherein the output signal on the at least one conductor from second set of conductors is evoked from capacitive coupling at the cross junctions.

17. The system according to claim 15, wherein the processor is configured for detecting a position of the user interaction on the digitizer sensor.

18. The system according to claim 15 wherein the first and second triggering signals are orthogonal in phase.

19. The system according to claim 18, wherein the processor includes orthogonal phase detectors.

20. The system according to claim 15, wherein the processor includes a phase shift corrector configured for correcting phase of the output signal by a pre-determined phase shift of the triggering signal along a length of the two conductors.

21. The system according to claim 15, wherein the digitizer sensor is a grid based digitizer sensor and wherein the first set of conductors are conductive lines associated with a first axis of the grid based sensor and the second set of conductors are conductive lines associated with a second axis of the grid based sensor orthogonal to the first axis.

22. The system according to claim 15, wherein the user interaction is detected by comparing an amplitude level of one of the orthogonal components of the output signal and a signal level in the absence of user interaction.

23. The system according to claim 15, wherein the user interaction is selected from a group including fingertip, hand and conductive object.

24. The system according to claim 15, wherein the user interaction is selected from a group including touch user interaction and hover user interaction.

25. The system according to claim 15, wherein the first and second triggering signals are pulsed signals.

26. The system according to claim 15, wherein the first and second triggering signals are AC signals.

27. A method for user interaction detection on a digitizer, the method comprising:

simultaneously transmitting orthogonal signals having the same frequency on at least two conductors of a digitizer sensor;

sampling a signal on at least one other conductor crossing the at least two conductors, wherein the signal is responsive to capacitive coupling at cross-junctions formed between the at least two conductors and at least one other conductor; and

determine multiple user interaction positions on the digitizer sensor from the sampled signal.

28. The method according to claim 27, wherein the orthogonal signals are orthogonal in phase.

29. The method according to claim 27, comprising:

decomposing the sampled signal into orthogonal components; and

analyzing the orthogonal components to determine the multiple user interaction positions.

30. The method according to claim 27, wherein the user interaction is selected from a group including fingertip, hand and conductive object.

31. The method according to claim 27, wherein the user interaction is selected from a group including touch user interaction and hover user interaction.

32. The method according to claim 27, wherein the digitizer sensor is a grid based digitizer sensor and wherein the at least two conductors are conductive lines associated with a first axis of the grid based sensor and the at least one other conductor is a conductive line associated with a second axis of the grid based sensor orthogonal to the first axis.