FLEXIBLE SCAN PLAN USING COARSE MUTUAL CAPACITANCE AND FULLY-GUARDED MEASUREMENTS

• US 20170090619A1
• Filed: 03/31/2016
• Published: 03/30/2017
• Est. Priority Date: 09/30/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: VERMA, Shwetabh, YOUSEFPOR, Marduke
• Granted Patent: US 10,365,773 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/041662 using alternate mutual and self-capacitive scanning
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A touch controller for flexible scanning operation is disclosed. The touch controller can include circuitry configured to perform coarse detection scans, select a fine scan type based on results from the coarse detection scans, and perform a fine scan corresponding to the selected fine scan type. A fine mutual capacitance scan can be performed when conditions corresponding to a poorly grounded or ungrounded object or user are detected based on the coarse detection scans. A fine fully-bootstrapped self-capacitance scan can be performed when conditions corresponding to a well-grounded object or user are detected based on the coarse detection scans. A touch processor can be configured to sense touch events from the fine scan.

Claims

1. An apparatus comprising:

sense circuitry configured to;

perform a plurality of coarse detection scans; and

perform a fine scan corresponding to a fine scan type, wherein the fine scan is a higher resolution scan than a coarse detection scan of the plurality of coarse detection scans of a corresponding coarse scan type; and

a processor capable of;

selecting the fine scan type from one of a fine mutual capacitance scan or a fine self-capacitance scan based on results from the plurality of coarse detection scans; and

detecting a touch event based on the fine scan.

2. The apparatus of claim 1, wherein the plurality of coarse detection scans includes a banked mutual capacitance scan and a banked self-capacitance scan.

3. The apparatus of claim 2, wherein the banked self-capacitance scan includes detecting self-capacitances of a first plurality of banks of electrodes of a touch sensor panel.

4. The apparatus of claim 3, wherein the first plurality of banks of electrodes includes one or more first banks of first electrodes with a first position characteristic, one or more second banks of second electrodes with a second position characteristic, one or more third banks of third electrodes with a third position characteristic, and one or more fourth banks of fourth electrodes with a fourth position characteristic.

5. The apparatus of claim 2, wherein the banked mutual capacitance scan includes:

a first scan step sensing a second plurality of banks of electrodes to measure mutual capacitances formed between first groups of electrodes with a first position characteristic and fourth groups of electrodes with a fourth position characteristic for the second plurality of banks; and

a second scan step sensing a third plurality of banks of electrodes to measure mutual capacitances formed between second groups of electrodes with a second position characteristic and third groups of electrodes with a third position characteristic for the third plurality of banks.

6. The apparatus of claim 1, wherein selecting the fine scan type based on the results from the plurality of coarse detection scans comprises:

calculating one or more first parameters and one or more second parameters from the results of the plurality of coarse detection scans; and

selecting the fine scan type based on a comparison of the one or more first parameters and the one or more second parameters.

7. The apparatus of claim 6, wherein the one or more first parameters are one or more first attenuation factors corresponding to a first coarse detection scan of the plurality of detection scans and the one or more second parameters are one or more second attenuation factors corresponding a second coarse detection scan of the plurality of coarse detection scans.

8. The apparatus of claim 7, the processor further capable of:

in accordance with a determination that the one or more first attenuation factors are greater than the one or more second attenuation factors, selecting the fine scan type based on a corresponding scan type of the first coarse detection scan of the plurality of detection scans; and

in accordance with a determination that the one or more second attenuation factors are greater than the one or more first attenuation factors, selecting the fine scan type based on a corresponding scan type of the second coarse detection scan of the plurality of detection scans.

9. The apparatus of claim 1, the processor further capable of compensating results of the fine scan according to one or more scaling parameters.

10. A system comprising:

a touch sensor panel including a plurality of electrodes; and

a touch controller configured to;

during a first time period of a touch frame, perform a first self-capacitance scan of the touch sensor panel;

during a second time period of the touch frame, perform a first step of a first mutual capacitance scan of the touch sensor panel;

during a third time period of the touch frame, perform a second step of a first mutual capacitance scan of the touch sensor panel;

determine based on the first self-capacitance scan and the first mutual capacitance scan whether to perform a second self-capacitance scan or a second mutual capacitance scan;

in accordance with a determination to perform the second self-capacitance scan, perform the second self-capacitance scan, including one or more self-capacitance scan steps, during fourth time period; and

in accordance with a determination to perform the second mutual capacitance scan, perform the second mutual capacitance scan, including one or more mutual capacitance scan steps, during the fourth time period.

11. A method comprising:

performing a plurality of coarse detection scans;

selecting a fine scan type from one of a fine mutual capacitance scan or a fine self-capacitance scan based on results from the plurality of coarse detection scans; and

performing a fine scan corresponding to the fine scan type, wherein the fine scan is a higher resolution scan than a coarse detection scan of the plurality of coarse detection scans of a corresponding coarse scan type.

12. The method of claim 11, wherein the plurality of coarse detection scans includes a banked mutual capacitance scan and a banked self-capacitance scan.

13. The method of claim 12, wherein the banked self-capacitance scan includes detecting self-capacitances of a first plurality of banks of electrodes of a touch sensor panel.

14. The method of claim 13, wherein the banked self-capacitance scan detects self-capacitances for the touch sensor panel in one scan step.

15. The method of claim 13, wherein each electrode of the touch sensor panel is driven during the banked self-capacitance scan.

16. The method of claim 13, wherein the first plurality of banks of electrodes includes one or more first banks of first electrodes with a first position characteristic, one or more second banks of second electrodes with a second position characteristic, one or more third banks of third electrodes with a third position characteristic, and one or more fourth banks of fourth electrodes with a fourth position characteristic.

17. The method of claim 11, wherein selecting the fine scan type based on the results from the plurality of coarse detection scans comprises:

calculating one or more first parameters and one or more second parameters from the results of the plurality of coarse detection scans; and

selecting the fine scan type based on a comparison of the one or more first parameters and the one or more second parameters.

18. The method of claim 17, wherein the one or more first parameters are one or more first attenuation factors corresponding to a first coarse detection scan of the plurality of detection scans and the one or more second parameters are one or more second attenuation factors corresponding a second coarse detection scan of the plurality of coarse detection scans.

19. The method of claim 18, the method further comprising:

in accordance with a determination that the one or more first attenuation factors are greater than the one or more second attenuation factors, selecting the fine scan type based on a corresponding scan type of the first coarse detection scan of the plurality of detection scans; and

in accordance with a determination that the one or more second attenuation factors are greater than the one or more first attenuation factors, selecting the fine scan type based on a corresponding scan type of the second coarse detection scan of the plurality of detection scans.

20. The method of claim 11, the method further comprising compensating results of the fine scan according to one or more scaling parameters generated based on the results of the plurality of coarse detection scans.

21. A non-transitory computer readable storage medium, the computer readable medium containing instructions that, when executed by a processor, can perform a method comprising:

performing a plurality of coarse detection scans;

selecting a fine scan type from one of a fine mutual capacitance scan or a fine self-capacitance scan based on results from the plurality of coarse detection scans; and

performing a fine scan corresponding to the fine scan type, wherein the fine scan is a higher resolution scan than a coarse detection scan of the plurality of coarse detection scans of a corresponding coarse scan type.

22. The non-transitory computer readable storage medium of claim 21, wherein selecting the fine scan type based on the results from the plurality of coarse detection scans comprises:

calculating one or more first parameters and one or more second parameters from the results of the plurality of coarse detection scans; and

selecting the fine scan type based on a comparison of the one or more first parameters and the one or more second parameters.

23. The non-transitory computer readable storage medium of claim 22, wherein the one or more first parameters are one or more first attenuation factors corresponding to a first coarse detection scan of the plurality of detection scans and the one or more second parameters are one or more second attenuation factors corresponding a second coarse detection scan of the plurality of coarse detection scans.

24. The non-transitory computer readable storage medium of claim 23, further comprising:

in accordance with a determination that the one or more first attenuation factors are greater than the one or more second attenuation factors, selecting the fine scan type based on a corresponding scan type of the first coarse detection scan of the plurality of detection scans; and

in accordance with a determination that the one or more second attenuation factors are greater than the one or more first attenuation factors, selecting the fine scan type based on a corresponding scan type of the second coarse detection scan of the plurality of detection scans.

25. The non-transitory computer readable storage medium of claim 21, further comprising compensating results of the fine scan according to one or more scaling parameters generated based on attenuation factors calculated based on the results of the plurality of coarse detection scans.