METHOD AND DEVICE FOR POSITION DETECTION

• US 20120068953A1
• Filed: 11/30/2011
• Published: 03/22/2012
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Chang, Chin-Fu, Lee, Cheng-Han, Tang, Chi-Hao, Ho, Shun-Lung
• Granted Patent: US 8,471,826 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• 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 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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 3/047 using sets of wires, e.g. crossed wires

Abstract

The method and device for position detection are disclosed. Corresponding to a first touch related sensing information, a second touch related sensing information is acquired for determining at least one position. Each position is used separately for determining the position of a centroid according to the first touch related sensing information or the second touch related sensing information.

Claims

1. A method for position detection, comprising:

obtaining a second touch related sensing information corresponding to a first touch related sensing information; and

calculating at least one centroid position based on the second touch related sensing information, a value of each centroid position corresponding to a centroid calculation result obtained after subtracting a base value from all values in a first calculation range of the first touch related sensing information, where the base value is determined according to at least one value of the first touch related sensing information.

2. The method of claim 1, wherein values of the first touch related sensing information correspond to signals of a plurality of sensors.

3. The method of claim 1, wherein values of the first touch related sensing information correspond to signals of a single sensor at a plurality of time points.

4. The method of claim 1, wherein the base value is the value immediately preceding the first calculation range or the average of the value immediately preceding and the value immediately following the first calculation range.

5. The method of claim 1, wherein the base value is the first value of the first calculation range or the average of the first value and the last value of the first calculation range.

6. The method of claim 1, wherein the base value is the average of all the values of the first calculation range.

7. The method of claim 1, wherein each value of the first touch related sensing information is a dual difference, each dual difference being the difference between a pair of differences of the second touch related sensing information.

8. The method of claim 1, wherein calculating the at least one centroid position based on the second touch related sensing information includes:

converting the second touch related sensing information into the first touch related sensing information, each first value of the first touch related sensing information corresponding to a second value of the second touch related sensing information, wherein the first value is an accumulation of the second value with all the values preceding or following the second value;

determining at least one position based on the second touch related sensing information;

determining the corresponding first calculation range in the first touch related sensing information based on each position;

determining the corresponding base value based on each first calculation range;

generating a set of calculation values by subtracting the corresponding base value from all the values in each first calculation range; and

calculating at least one centroid position based on each set of calculation values.

9. The method of claim 1, wherein calculating the at least one centroid position based on the second touch related sensing information includes:

determining at least one position based on the second touch related sensing information;

determining a corresponding second calculation range in the second touch related sensing information based on each position; and

calculating one of the at least one centroid position based on each second calculation range.

10. The method of claim 9, wherein the second calculation range includes i values before and j+1 values after a corresponding position D_n.

11. The method of claim 10, wherein the centroid position

12. The method of claim 10, wherein the centroid position

13. The method of claim 9, wherein determining at least one position based on the second touch related sensing information includes determining based on at least one zero-crossing in the second touch related sensing information, wherein each zero-crossing is between a pair of positive and negative values of the second touch related sensing information.

14. The method of claim 9, wherein each value of the second touch related sensing information is a dual difference, each dual difference being generated based on signals of three sensors from a plurality of sensors or signals of one sensor at three of a plurality of time points.

15. A device for position detection, comprising:

a touch sensitive device including a plurality of sensors; and

a controller for scanning signals of the sensors and generating a second touch related sensing information corresponding to a first touch related sensing information, and calculating at least one centroid position based on the second touch related sensing information, a value of each centroid position corresponding to a centroid calculation result obtained after subtracting a base value from all values in a first calculation range of the first touch related sensing information, where the base value is determined according to at least one value of the first touch related sensing information.

16. The device of claim 15, wherein the base value is the value immediately preceding the first calculation range or the average of the value immediately preceding and the value immediately following the first calculation range.

17. The device of claim 15, wherein the base value is the first value of the first calculation range or the average of the first value and the last value of the first calculation range.

18. The device of claim 15, wherein the base value is the average of all the values of the first calculation range.

19. The device of claim 15, wherein each value of the first touch related sensing information is a dual difference, each dual difference being the difference between a pair of differences of the second touch related sensing information.

20. The device of claim 15, wherein the controller calculating the at least one centroid position based on the second touch related sensing information includes:

converting the second touch related sensing information into the first touch related sensing information, each first value of the first touch related sensing information corresponding to a second value of the second touch related sensing information, wherein the first value is an accumulation of the second value with all the values preceding or following the second value;

determining at least one position based on the second touch related sensing information;

determining the corresponding first calculation range in the first touch related sensing information based on each position;

determining the corresponding base value based on each first calculation range;

generating a set of calculation values by subtracting the corresponding base value from all the values in each first calculation range; and

calculating at least one centroid position based on each set of calculation values.

21. The device of claim 15, wherein the controller calculating the at least one centroid position based on the second touch related sensing information includes:

determining at least one position based on the second touch related sensing information;

determining a corresponding second calculation range in the second touch related sensing information based on each position; and

calculating one of the at least one centroid position based on each second calculation range.

22. The device of claim 21, wherein the second calculation range includes i values before and j+1 values after a corresponding position D_n.

23. The device of claim 22, wherein the centroid position

24. The device of claim 22, wherein the centroid position

25. The device of claim 21, wherein determining at least one position based on the second touch related sensing information includes determining based on at least one zero-crossing in the second touch related sensing information, wherein each zero-crossing is between a pair of positive and negative values of the second touch related sensing information.

26. The device of claim 21, wherein each value of the second touch related sensing information is a dual difference, each dual difference being generated based on signals of three sensors from a plurality of sensors or signals of one sensor at three of a plurality of time points.

27. A method for determining centroid positions from touch related sensing information, comprising:

obtaining a touch related sensing information that includes a plurality of continuous differences;

determining the position of at least a zero-crossing according to the touch related sensing information for determining at least a position;

determining a calculation range in the touch related sensing information based on each determined position; and

calculating a centroid position based on each calculation range.

28. The method of claim 27, wherein the touch related sensing information has odd number of zero-crossings, each zero-crossing being between a pair of positive and negative values of the touch related sensing information.

29. The method of claim 27, wherein each determined position corresponding to a single touch is determined based on a difference closest to a zero-crossing.

30. The method of claim 27, wherein the calculation range includes i differences before and j+1 differences after a corresponding determined position D_n.

31. The method of claim 30, wherein the centroid position

32. The method of claim 30, wherein the centroid position

33. The method of claim 27, wherein the touch related sensing information is converted from a plurality of continuous dual differences, wherein each dual difference corresponds to the difference between a pair of differences of the touch related sensing information.

34. The method of claim 27, wherein the touch related sensing information is converted from a plurality of continuous dual differences, wherein each difference corresponds to one of these dual differences, and is an accumulation of the corresponding dual difference with all the values before or after the corresponding dual difference.

35. The method of claim 27, wherein each difference corresponds to the difference between signals of a pair of sensors in a plurality of sensors or the difference between signals of a single sensor at a pair of time points in a plurality of time points.

36. A device for determining centroid positions from touch related sensing information, comprising a controller and a host, which performs at least the following operations:

obtaining a touch related sensing information that includes a plurality of continuous differences;

determining at least a position based on the touch related sensing information;

determining a calculation range in the differential touch related sensing information based on each position; and

calculating a centroid position based on each calculation range.

37. The device of claim 36, wherein the touch related sensing information has odd number of zero-crossings, each zero-crossing being between a pair of positive and negative values of the touch related sensing information.

38. The device of claim 37, wherein the controller or the host further performs at least the following operations:

determining the position of at least one zero-crossing, wherein the at least one position is determined by the position of the at least one zero-crossing.

39. The device of claim 38, wherein each position corresponding to a single touch is determined based on a difference closest to a zero-crossing.

40. The device of claim 36, wherein the calculation range includes i differences before and j+1 differences after a corresponding position D_n.

41. The device of claim 40, wherein the centroid position

42. The device of claim 40, wherein the centroid position

43. The device of claim 36, wherein the touch related sensing information is converted from a plurality of continuous dual differences, wherein each dual difference corresponds to the difference between a pair of differences of the touch related sensing information.

44. The device of claim 36, wherein the touch related sensing information is converted from a plurality of continuous dual differences, wherein each difference corresponds to one of these dual differences, and is an accumulation of the corresponding dual difference with all the values before or after the corresponding dual difference.

45. The device of claim 36, wherein each difference corresponds to the difference between signals of a pair of sensors in a plurality of sensors or the difference between signals of a single sensor at a pair of time points in a plurality of time points.