MULTI-TOUCH AUTO SCANNING

• US 20160283038A1
• Filed: 06/07/2016
• Published: 09/29/2016
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: KRAH, Christoph H., VU, Minh-Dieu Thi, WILSON, Thomas James
• Granted Patent: US 10,712,866 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 system for scanning a sensor panel, comprising:

auto-scan logic configured to place the system in an auto-scan mode after a first predetermined amount of time elapses without any events being detected on the sensor panel; and

a calibration timer configured for periodically returning the system to an active scan mode and initiating a calibration scan upon expiration of a calibration time.

2. The system of claim 1, wherein the calibration timer is further configured for returning the system to the active scan mode when no events are detected during the calibration time.

3. The system of claim 1, wherein the system is configured for resetting the calibration timer when the system is placed in the auto-scan mode.

4. The system of claim 1, wherein the calibration scan comprises waking up a high frequency oscillator and activating a system clock and a processor to perform the calibration scan of the sensor panel.

5. The system of claim 4, wherein the calibration scan further comprises calibrating the sensor panel.

6. The system of claim 1, further comprising a sniff timer configured for periodically triggering a scan of the sensor panel while the system remains in the auto-scan mode.

7. The system of claim 6, wherein the calibration timer is a longer duration than the sniff timer.

8. The system of claim 1, further comprising logic configured for resetting the calibration timer if an interrupt is received.

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

initiating an auto-scan mode after a first predetermined amount of time elapses without any events being detected on the sensor panel; and

periodically returning to an active scan mode and initiating a calibration scan upon expiration of a calibration timer.

10. The method of claim 9, further comprising returning to the active scan mode when no events are detected during a pendency of the calibration timer.

11. The method of claim 9, further comprising resetting the calibration timer when the auto-scan mode is initiated.

12. The method of claim 9, wherein the calibration scan comprises waking up a high frequency oscillator and activating a system clock and a processor to perform the calibration scan of the sensor panel.

13. The method of claim 12, wherein the calibration scan further comprises calibrating the sensor panel.

14. The method of claim 9, further comprising periodically triggering a scan of the sensor panel while the system remains in the auto-scan mode upon expiration of a sniff timer.

15. The method of claim 14, wherein the calibration timer is a longer duration than the sniff timer.

16. The method of claim 9, further comprising resetting the calibration timer if an interrupt is received.

17. An apparatus for scanning a sensor panel, comprising:

means for initiating an auto-scan mode after a first predetermined amount of time elapses without any events being detected on the sensor panel; and

means for periodically returning to an active scan mode and initiating a calibration scan upon expiration of a calibration timer.

18. The apparatus of claim 17, further comprising means for returning to the active scan mode when no events are detected during a pendency of the calibration timer.

19. The apparatus of claim 17, further comprising means for resetting the calibration timer when the auto-scan mode is initiated.

20. The apparatus of claim 17, further comprising means for waking up a high frequency oscillator and activating a system clock and a processor to perform the calibration scan of the sensor panel.