Multi-touch auto scanning

• US 8,823,660 B2
• Filed: 12/29/2011
• Issued: 09/02/2014
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Krah, Christoph Horst, Vu, Minh-Dieu Thi, Wilson, Thomas James
• Primary Examiner(s): NGUYEN, JENNIFER T
• Application Number:
  US13/340,153
• Publication Number:
  US 20120157167A1
• Time in Patent Office: 978 Days
• Field of Search: 345173-178, 178 1801- 1806
• US Class Current: 345/173
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• 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 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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 system and method for autonomously scanning a sensor panel device is disclosed. A sensor panel processor can be disabled after a first predetermined amount of time has elapsed without the sensor panel device sensing any events. One or more system clocks can also be disabled to conserve power. While the processor and one or more system clocks are disabled, the sensor panel device can periodically autonomously scan the sensor panel for touch activity. If one or more results from the autonomous scans exceed a threshold, the sensor panel device re-enables the processor and one or more clocks to actively scan the sensor panel. If the threshold is not exceeded, the sensor panel device continues to periodically autonomously scan the sensor panel without intervention from the processor. The sensor panel device can periodically perform calibration functions to account for any drift that may be present in the system.

Claims

1. A touch surface device, comprising:

a sensor panel having at least one sense node that provides an output signal indicative of an occurrence or absence of an event occurring at the panel;

a processor operatively connected to the panel, the processor capable of processing the output signal of the panel; and

auto-scan logic circuitry operatively connected to the sensor panel and the processor, the auto-scan logic circuitry capable of determining the occurrence or absence of an event occurring at the panel without intervention from the processor.

2. The touch device of claim 1, wherein the auto-scan logic circuitry enters an auto-scan mode when no event is sensed on the panel for a predetermined amount of time.

3. The touch device of claim 1, wherein the auto-scan logic comprises a sniff timer, the sniff timer initiating a scan of the sensor panel for determining an occurrence or absence of an event occurring at the panel when the sniff timer reaches a first predetermined amount of time.

4. The touch device of claim 3, wherein the auto-scan logic further comprises a calibration timer, the calibration timer initiating a scan automatically when the calibration timer reaches a second predetermined amount of time which is longer than first predetermined amount of time.

5. The touch device of claim 4, wherein the calibration timer initiates a calibration sequence that accounts for drift present in the sensor panel.

6. The touch device of claim 3, wherein the auto-scan logic comprises a power management timer, the power management timer sending a start-up signal to one or more voltage drivers prior to the sniff timer reaching the predetermined amount of time.

7. The touch device of claim 1, wherein the auto-scan logic comprises a clock manager that is capable of disabling and enabling one or more clocks incorporated in the touch surface device.

8. The touch device of claim 1, further comprising a computing system that incorporates the touch panel device.

9. The touch panel device of claim 8, further comprising a mobile telephone that incorporates the computing system.

10. The touch panel device of claim 8, further comprising a digital audio player that incorporates the computing system.

11. An apparatus for generating an image of an event at a sensitive surface, comprising:

auto-scan logic circuitry couplable to a sensor panel, the auto-scan logic circuitry capable of performing, without intervention from a sensor processor, an auto-scan sequence after a first predetermined amount of time has been exceeded,

wherein the apparatus performs an auto-scan sequence only if the first predetermined amount of time has been exceeded and a calibration time has not been exceeded.

12. The apparatus of claim 11, wherein the auto-scan sequence comprises:

scanning the sensor panel for determining an occurrence or absence of an event at the panel,

generating values representative of the occurrence or absence of events; and

comparing the values representative of events with a predetermined threshold.

13. The apparatus of claim 12, wherein the auto-scan sequence includes measuring stray capacitance.

14. The apparatus of claim 12, wherein an event comprises a touching of an object against a surface of the touch panel.

15. The apparatus of claim 11, wherein the auto-scan logic comprises:

a sniff timer that initiates the auto-scan sequence after the first predetermined amount time has been exceeded; and

a calibration timer that initiates a calibration sequence after a second predetermined amount of time has been exceeded.

16. The apparatus of claim 15, wherein the calibration sequence comprises calibrating the apparatus for drift present in the panel.

17. The apparatus of claim 15, wherein the calibration sequence comprises an active scan of the panel, the active scan including processing performed by the sensor processor.

18. The apparatus of claim 11, wherein the auto-scan logic circuitry forms part of a single multi-touch subsystem for processing events.

19. The apparatus of claim 11, further comprising a computing system that incorporates the apparatus.

20. The touch panel device of claim 19, further comprising a mobile telephone that incorporates the computing system.

21. The touch panel device of claim 19, further comprising a digital audio player that incorporates the computing system.

22. A method for scanning a sensor panel, comprising:

initiating an auto-scan mode after one or more touch events have not been sensed on a sensor panel for a first predetermined amount of time, the auto-scan mode comprising;

a) disabling a sensor panel processor;

b) performing a sniff scan when a second predetermined amount of time has been exceeded; and

c) performing a calibration scan when a third predetermined amount of time has been exceeded.

23. The method of claim 22, wherein performing the sniff scan comprises:

scanning the panel for an occurrence or absence of an event at the panel;

generating one or more values representative of events occurring at distinct locations at the panel and

comparing the one or more values with a threshold and enabling the sensor panel processor if the one or more values exceed the threshold.

24. The method of claim 23, wherein the generating values step includes measuring a stray capacitance value of one or more touch sensors in the sensor panel.

25. The method of claim 23, wherein the step of generating the values includes measuring a mutual capacitance value of one or more touch sensors in the sensor panel.

26. The method of claim 23, wherein the auto-scan mode further includes activating a voltage driver operatively connected to the sensor panel prior to the second predetermined amount of time being exceeded.

27. The method of claim 23, further comprising programming the threshold into a memory storage unit.

28. The method of claim 27, wherein the memory storage unit comprises a programmable register.

29. The method of claim 22, wherein the calibration scan comprises:

activating the sensor panel processor;

scanning the sensor panel for an occurrence or absence of an event at the panel; and

performing a calibration to account for drift present in the sensor panel.

30. The method of claim 29, wherein the calibration scan further comprises turning on a high frequency oscillator.

31. The method of claim 22, wherein the sniff scan comprises obtaining an image of the sensor panel and comparing the image with a threshold.

32. The method of claim 22, wherein the initiating step further includes setting an auto-scan enable bit.

33. The method of claim 22, wherein the performing a sniff scan further includes resetting a sniff timer.

34. An apparatus for sensing an event on a sensor panel, comprising:

means for providing an output signal indicative of an occurrence or absence of an event on a panel;

means for switching to an auto-scan mode after having not sensed a touch event on the sensor panel for a first predetermined amount of time, the switching to the auto-scan mode comprising disabling a processor of the sensor panel; and

means for switching to a sniff mode after a second predetermined amount of time has been exceeded, the switching to the sniff mode comprising performing a sniff scan.

35. The apparatus of claim 34, further including means for performing a calibration mode after a second third predetermined amount of time has been exceeded.

36. A mobile telephone comprising:

a sensor panel having at least one sense node that provides an output signal indicative of an occurrence or absence of an event occurring at the panel;

a processor operatively connected to the panel, the processor capable of processing the output signal of the panel; and

auto-scan logic circuitry operatively connected to the sensor panel and the processor, the auto-scan logic circuitry capable of determining the occurrence or absence of an event occurring at the panel without intervention from the processor.

37. The mobile telephone of claim 36, wherein the auto-scan logic circuitry enters an auto-scan mode when no event is sensed on the panel for a predetermined amount of time.

38. The mobile telephone of claim 36 wherein the auto-scan logic comprises a sniff timer, the sniff timer initiating a scan of the sensor panel, for determining an occurrence or absence of an event occurring at the panel, when the sniff timer reaches a first predetermined amount of time.

39. The mobile telephone of claim 38, wherein the auto-scan logic further comprises a calibration timer, the calibration timer initiating a scan automatically when the calibration timer reaches a second predetermined amount of time which is longer than first predetermined amount of time.

40. The mobile telephone of claim 38, wherein the calibration timer initiates a calibration sequence that accounts for drift present in the sensor panel.

41. The mobile telephone of claim 36, wherein the auto-scan logic comprises a power management timer, the power management timer sending a start-up signal to one or more voltage drivers prior to the sniff timer reaching the predetermined amount of time.

42. The mobile telephone of claim 36, wherein the auto-scan logic comprises a clock manager capable of disabling and enabling one or more clocks incorporated in the mobile telephone.

43. A multi-event sensitive device comprising:

a sensor panel having a plurality of sense nodes that provide output signals indicative of an occurrence or absence of an event occurring at the panel;

auto-scan logic circuitry operatively connected to the sensor panel, the auto-scan logic circuitry capable of determining the occurrence or absence of an event occurring at the panel in an auto-scan mode, the auto-scan logic comprising noise management circuitry configured to differentiate between an occurrence of an event and noise present in the device; and

a processor operatively connected to the auto-scan logic, the processor configured to be disabled when the auto-scan mode is activated and the processor configured to be enabled when the auto-scan mode is deactivated.

44. The multi-event sensitive device of claim 43, wherein determining the occurrence or absence of an event occurring at the panel comprises measuring a change in stray capacitance in the sensor panel.

45. The multi-event sensitive device of claim 43, wherein determining the occurrence or absence of an event occurring at the panel comprises measuring a change in mutual capacitance in the sensor panel.