Dynamic Mode Switching for Fast Touch Response

• US 20110025629A1
• Filed: 07/27/2010
• Published: 02/03/2011
• Est. Priority Date: 07/28/2009
• Status: Active Grant

• Current Assignee: Parade Technologies, Ltd.
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Baumbach, Jason, Grivna, Edward, Peng, Tao, Bordui, David, Zhang, Weibiao, Chen, MingChan
• Granted Patent: US 9,069,405 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• CPC Class Codes: G06F 3/041662 using alternate mutual and self-capacitive scanning
• CPC Class Codes: G06F 3/044 by capacitive means
• 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 of operating a touch-sensing surface may include determining a presence of at least one conductive object at the touch-sensing surface by performing a search measurement of a first set of sensor elements of the touch-sensing surface, and in response to determining the presence of the at least one conductive object, determining a location of the at least one conductive object by performing a tracking measurement of a second set of sensor elements of the touch-sensing surface.

Claims

1. A method of operating a touch-sensing surface, the method comprising:

determining a presence of at least one conductive object proximate to the touch-sensing surface by performing a search measurement of a first set of sensor elements of the touch-sensing surface; and

in response to determining the presence of the at least one conductive object, determining a location of the at least one conductive object by performing a tracking measurement of a second set of sensor elements of the touch-sensing surface.

2. The method of claim 1, wherein performing a search measurement of the first set of sensor elements comprises measuring a capacitance for each of the sensor elements of the touch-sensing surface.

3. The method of claim 1, wherein performing the search measurement comprises measuring a self capacitance for each sensor element in the first set of sensor elements.

4. The method of claim 1, wherein the second set of sensor elements includes row sensor elements and column sensor elements.

5. The method of claim 1, wherein performing the tracking measurement comprises measuring a mutual capacitance between at least one pair of sensor elements.

6. The method of claim 1, wherein performing the tracking measurement comprises:

based on a plurality of possible locations of the conductive object identified by the search measurement, performing a resolve scan to identify at least one of the plurality of possible locations as an actual location of the conductive object.

7. The method of claim 1, wherein the second set of sensor elements includes sensor elements adjacent to a location of the at least one conductive object at the touch-sensing surface.

8. The method of claim 1, wherein each of the sensor elements of the second set of sensor elements intersects another sensor element within a threshold distance from a location of a conductive object at the touch-sensing surface.

9. The method of claim 1, wherein each of the sensor elements in the first set of sensor elements is a row sensor element of the touch-sensing surface.

10. The method of claim 1, wherein each of the sensor elements in the first set of sensor elements is a column sensor element of the touch-sensing surface.

11. The method of claim 1, wherein the first set of sensor elements includes a plurality of sensor elements, and wherein performing the search measurement comprises measuring a self capacitance of the plurality of sensor elements at a single sense channel.

12. The method of claim 1, wherein the first set of sensor elements includes at least one measured sensor element and a plurality of non-measured sensor elements, and wherein performing the search measurement comprises driving each of the non-measured sensor elements with a shield drive signal.

13. The method of claim 1, wherein the first set of sensor elements is divided into a plurality of zones, wherein each of the plurality of zones includes a set of sensor elements from the first set of sensor elements, and wherein performing the search measurement comprises scanning each of the plurality of zones according to a predetermined sequence.

14. The method of claim 13, wherein sensor elements of a first zone of the plurality of zones are interleaved with sensor elements of a second zone of the plurality of zones.

15. A touch sensor controller, comprising:

processing logic;

a plurality of inputs configured to couple the processing logic with each of a plurality of sensor elements of a touch-sensing surface; and

a capacitance sensor coupled with the plurality of inputs, wherein the capacitance sensor is configured to perform a search measurement of a first set of sensor elements of the touch-sensing surface to determine a presence of one or more conductive objects at the touch-sensing surface, and in response to determining the presence of the at least one conductive object, perform a tracking measurement of a second set of sensor elements of the touch-sensing surface.

16. The touch sensor controller of claim 15, wherein the first set of sensor elements is different from the second set of sensor elements.

17. The touch sensor controller of claim 15, wherein the first set of sensor elements includes all of the sensor elements of the touch-sensing surface.

18. The touch sensor controller of claim 15, wherein the capacitance sensor is further configured to perform the search measurement by measuring a self capacitance for each sensor element of the first set of sensor elements.

19. The touch sensor controller of claim 15, wherein the capacitance sensor is configured to perform the tracking measurement by measuring a mutual capacitance between each of a plurality of row sensor elements in the second set of sensor elements and each of a plurality of column sensor elements in the second set of sensor elements.

20. The touch sensor controller of claim 15, wherein the capacitance sensor is further configured to identify a plurality of possible locations of the one or more conductive objects by performing the search measurement, and to perform a resolve scan to identify at least one of the plurality of possible locations as an actual location of the one or more conductive objects.

21. The touch sensor controller of claim 15, wherein the capacitance sensor is further configured to select the second set of sensor elements to include sensor elements adjacent to a location of the one or more conductive objects at the touch-sensing surface.

22. The touch sensor controller of claim 15, wherein the capacitance sensor is further configured to select the second set of sensor elements to include sensor elements intersecting another sensor element within a threshold distance from a location of the one or more conductive objects at the touch-sensing surface.

23. The touch sensor controller of claim 15, wherein each of the sensor elements in the first set of sensor elements is a row sensor element of the touch-sensing surface.

24. The touch sensor controller of claim 15, wherein each of the sensor elements in the first set of sensor elements is a column sensor element of the touch-sensing surface.

25. The touch sensor controller of claim 15, wherein the capacitance sensor is further configured to perform the search scan by measuring a self capacitance of a plurality of sensor elements of the first set of sensor elements, wherein the self capacitance is measured at a single sense channel.

26. The touch sensor controller of claim 15, wherein the capacitance sensor is further configured to perform the search scan by driving each of a plurality of non-measured sensor elements of the first set of sensor elements with a shield drive signal.

27. A touch-sensor controller, comprising:

a plurality of inputs configured to couple with each of a plurality of sensor elements of a touch-sensing surface; and

a capacitance sensor coupled with the plurality of inputs, wherein the capacitance sensor is configured to perform a self-capacitance measurement of at least one of the plurality of sensor elements to determine a presence of one or more conductive objects at the touch-sensing surface, and wherein the capacitance sensor is further configured to perform a mutual capacitance measurement between at least one pair of the plurality of sensor elements.

28. The touch-sensor controller of claim 27, wherein the capacitance sensor is further configured to determine the location of the one or more conductive objects at the touch-sensing surface based on the mutual capacitance measurement.

29. The touch-sensor controller of claim 27, wherein the capacitance sensor is further configured to perform the self-capacitance measurement on each of the sensor elements of the touch-sensing surface.

30. The touch-sensor controller of claim 27, wherein the capacitance sensor is configured to perform the mutual capacitance measurement between each of a plurality of row sensor elements and each of a plurality of column sensor elements of the touch-sensing surface.

31. The touch-sensor controller of claim 27, wherein the capacitance sensor is further configured to identify a plurality of possible locations of the one or more conductive objects based on the self-capacitance measurement, and to identify at least one of a plurality of possible locations as an actual location of the one or more conductive objects based on the mutual capacitance measurement.

32. The touch-sensor controller of claim 27, wherein the capacitance sensor is further configured perform the mutual capacitance measurement on sensor elements adjacent to a location of the one or more conductive objects at the touch-sensing surface.

33. The touch-sensor controller of claim 27, wherein the capacitance sensor is further configured to perform the mutual capacitance measurement on a set of sensor elements including sensor elements intersecting another sensor element within a threshold distance from a location of the one or more conductive objects at the touch-sensing surface.