Predictive Touch Surface Scanning

• US 20140285469A1
• Filed: 05/12/2014
• Published: 09/25/2014
• Est. Priority Date: 07/28/2009
• Status: Active Grant

• Current Assignee: Parade Technologies, Ltd.
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Wright, David G., Kolokowsky, Steven, Grivna, Edward L.
• Granted Patent: US 9,417,728 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• 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 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A method for locating a conductive object at a touch-sensing surface may include detecting a first resolved location for the conductive object at the touch-sensing surface based on a first scan of the touch-sensing surface, predicting a location for the conductive object, and determining a second resolved location for the conductive object by performing a second scan of a subset of sensor electrodes of the touch-sensing surface, wherein the subset of sensor electrodes is selected based on the predicted location of the conductive object.

Claims

1-20. -20. (canceled)

21. A method comprising:

identifying a first area of a touch-sensing surface to perform a local scan to track a first conductive object detected, or predicted to be detected, proximate to the touch-sensing surface, wherein the first area is less than a full area of the touch-sensing surface;

performing the local scan of the first area to track the first conductive object; and

performing a second scan of a second area of the touch-sensing surface with at least one of a reduced scan rate or a reduced resolution to detect any additional conductive objects proximate to the touch-sensing surface within the second area.

22. The method of claim 21, wherein the performing the second scan comprises scanning a plurality of unit cells within the second area in a scanning pattern, wherein each of the plurality of unit cells is an intersection between a pair of electrodes of the touch-sensing surface, wherein the scanning the plurality of unit cells in the scanning pattern comprises scanning a plurality of subsets of the plurality of unit cells at different points in time, wherein each of the plurality of subsets is less than a total number of the plurality of unit cells in the second area.

23. The method of claim 22, wherein the scanning pattern is a striped pattern.

24. The method of claim 22, wherein the scanning pattern is a checkerboard pattern.

25. The method of claim 21, wherein the touch-sensing surface comprises a plurality of electrodes arranged as rows and columns, and wherein the performing the second scan comprises measuring mutual capacitances of a plurality of unit cells, wherein each of the plurality of unit cells is an intersection of a pair of one of the rows and one of the columns.

26. The method of claim 25, wherein the measuring the mutual capacitances comprises measuring the mutual capacitances of the plurality of unit cells in a scanning pattern in which a first subset of intersections of the plurality of unit cells is scanned, and wherein the first subset of intersections is less than a total number of unit cells corresponding to the second area.

27. The method of claim 26, wherein the scanning pattern is a striped pattern for which the first subset of intersections comprises alternating ones of the rows and alternating ones of the columns.

28. The method of claim 26, wherein the scanning pattern is a striped pattern for which the first subset of intersections comprises every third one of the rows and every third one of the columns.

29. The method of claim 26, wherein the scanning pattern is a checkerboard pattern for which the first subset of intersections comprises alternating diagonal intersections.

30. The method of claim 29, further comprising performing a third scan in the scanning pattern comprising additional mutual capacitances of the plurality of unit cells in the scanning pattern in which a second subset of intersections of the plurality of unit cells is scanned, and wherein the second subset of intersections comprise the intersections of the plurality of unit cells not scanned in the second scan.

31. The method of claim 21, further comprising:

performing a set of one or more subsequent local scans to track the first conductive object when no additional conductive objects are detected proximate to the touch-sensing surface based on the second scan; and

after a timeout, performing a third scan of the second area with the at least one of the reduced scan rate or the reduced resolution to detect any additional conductive objects proximate to the touch-sensing surface within the second area, wherein the performing the third scan comprises measuring mutual capacitances of intersections within the second area not measured in the second scan.

32. The method of claim 21, further comprising, based on the second scan:

detecting a second conductive object proximate to the touch-sensing surface within the second area;

performing a first set of one or more subsequent local scans to track the first conductive object; and

performing a second set of one or more subsequent local scans to track the second conductive object.

33. A device comprising:

a touch-sensing surface comprising a plurality of electrodes;

a capacitance sensing circuit coupled to the plurality of electrodes to measure mutual capacitances of intersections between pairs of the plurality of electrodes; and

processing logic coupled to the capacitance sensing circuit, wherein the processing logic is to;

identify a first area of the touch-sensing surface to perform a local scan to track a first conductive object detected, or predicted to be detected, proximate to the touch-sensing surface, wherein the first area is less than a full area of the touch-sensing surface;

perform the local scan of the first area to track the first conductive object; and

perform a second scan of a second area of the touch-sensing surface with at least one of a reduced scan rate or a reduced resolution to detect any additional conductive objects proximate to the touch-sensing surface within the second area.

34. The device of claim 33, wherein the processing logic is further to measure mutual capacitances of a plurality of unit cells within the second area in a scanning pattern in which a plurality of subsets of the plurality of unit cells is scanned at different points in time, wherein each of the plurality of unit cells is an intersection between a pair of electrodes of the touch-sensing surface, and wherein each of the plurality of subsets is less than a total number of the plurality of unit cells in the second area.

35. The device of claim 34, wherein the scanning pattern is at least one of a striped pattern or a checkerboard pattern.

36. The device of claim 33, wherein the touch-sensing surface comprises a plurality of electrodes arranged as rows and columns, and wherein the processing logic is further to measure mutual capacitances of a plurality of unit cells, wherein each of the plurality of unit cells is an intersection of a pair of one of the rows and one of the columns.

37. A non-transitory computer-readable storage medium to store instructions that when executed by a processing device performs operations comprising:

identifying a first area of a touch-sensing surface to perform a local scan to track a first conductive object detected, or predicted to be detected, proximate to the touch-sensing surface, wherein the first area is less than a full area of the touch-sensing surface;

performing the local scan of the first area to track the first conductive object; and

performing a second scan of a second area of the touch-sensing surface with at least one of a reduced scan rate or a reduced resolution to detect any additional conductive objects proximate to the touch-sensing surface within the second area.

38. The non-transitory computer-readable storage medium of claim 37, wherein the performing the second scan comprises scanning a plurality of unit cells within the second area in a scanning pattern, wherein each of the plurality of unit cells is an intersection between a pair of electrodes of the touch-sensing surface, wherein the scanning the plurality of unit cells in the scanning pattern comprises scanning a plurality of subsets of the plurality of until cells at different points in time, wherein each of the plurality of subsets is less than a total number of the plurality of unit cells in the second area.

39. The non-transitory computer-readable storage medium of claim 37, wherein the touch-sensing surface comprises a plurality of electrodes arranged as rows and columns, and wherein the performing the second scan comprises measuring mutual capacitances of a plurality of unit cells, wherein each of the plurality of unit cells is an intersection of a pair of one of the rows and one of the columns, and wherein the measuring the mutual capacitances comprises measuring the mutual capacitances of the plurality of unit cells in a scanning pattern in which a first subset of intersections of the plurality of unit cells is scanned, and wherein the first subset of intersections is less than a total number of unit cells corresponding to the second area.

40. The non-transitory computer-readable storage medium of claim 37, wherein the operations further comprise:

performing a set of one or more subsequent local scans to track the first conductive object when no additional conductive objects are detected proximate to the touch-sensing surface based on the second scan; and

after a timeout, performing a third scan of the second area with the at least one of the reduced scan rate or the reduced resolution to detect any additional conductive objects proximate to the touch-sensing surface within the second area, wherein the performing the third scan comprises measuring mutual capacitances of intersections within the second area not measured in the second scan.