SYSTEM AND METHOD FOR DETECTION WITH A DIGITIZER SENSOR

• US 20090127005A1
• Filed: 11/13/2008
• Published: 05/21/2009
• 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: Kaplan, Amir, Morag, Meir, ZACHUT, Rafi
• Granted Patent: US 8,232,977 B2
• Time in Patent Office: Days
• US Class Current: 178/18.30
• 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 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.

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 transmitted signal over a length of the at least two conductors; and

shifting the phase of the sampled signal by the determined phase shift.

6. The method according to claim 5 wherein the length comprises the length of said conductors between an input generator and said crossing.

7. The method according to claim 5 wherein the determined 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 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 signal 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 signal transmitted to the at least two conductors is pulsed signal.

14. The method according to claim 1, wherein the signal transmitted to the at least two conductors is an AC signal.

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 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 sampled output signal.

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

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

18. The system according to claim 15 wherein the first and second 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 at least 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 signal components 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 signal transmitted to the two conductors is pulsed signal.

26. The system according to claim 15, wherein the signal transmitted to the two conductors is an AC signal.

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;

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 system 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.