Acquiring multiple capacitive partial profiles with orthogonal sensor electrodes

• US 9,501,169 B2
• Filed: 06/27/2014
• Issued: 11/22/2016
• Est. Priority Date: 06/27/2014
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Losh, Jonathan
• Primary Examiner(s): Davis, David D
• Application Number:
  US14/318,219
• Publication Number:
  US 20150378495A1
• Time in Patent Office: 879 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

Embodiments include a method, input device, and processing system for driving a plurality of sensor electrodes for capacitive sensing. The method includes acquiring a first capacitive partial profile by driving a capacitive sensing signal onto a first sensor electrode of a first plurality of sensor electrodes while driving a second sensor electrode of the first plurality of sensor electrodes with a substantially constant voltage. The method further includes acquiring a second capacitive partial profile by driving the capacitive sensing signal onto the second sensor electrode while driving the first sensor electrode with the substantially constant voltage, and determining a first capacitive profile based on at least the acquired first and second capacitive partial profiles.

Claims

1. A processing system, comprising:

a sensor module comprising sensor circuitry coupled to a plurality of sensor electrodes, the sensor module configured to;

simultaneously drive, during a first time period, a capacitive sensing signal onto a first sensor electrode of a first plurality of sensor electrodes and a substantially constant voltage onto a second sensor electrode of the first plurality of sensor electrodes;

acquire, during the first time period, a first capacitive partial profile based on the capacitive sensing signal driven onto the first sensor electrode;

simultaneously drive, during a second time period, the capacitive sensing signal onto the second sensor electrode and the substantially constant voltage onto the first sensor electrode, wherein the first and second time periods are non-overlapping;

acquire, during the second time period, a second capacitive partial profile based on the capacitive sensing signal driven onto the second sensor electrode; and

drive, during at least one of the first and second time periods, one or more sensor electrodes of a second plurality of sensor electrodes with the substantially constant voltage, the second plurality of sensor electrodes disposed substantially orthogonal to the first plurality of sensor electrodes; and

a determination module configured to determine a first capacitive profile based on at least the first and second capacitive partial profiles.

2. The processing system of claim 1, wherein acquiring the second capacitive partial profile comprises driving the capacitive sensing signal onto a third sensor electrode of the first plurality of sensor electrodes, and wherein the second sensor electrode and the third sensor electrode are simultaneously driven with the capacitive sensing signal while the first sensor electrode is driven with the substantially constant voltage, the first sensor electrode located substantially between the second and third sensor electrodes.

3. The processing system of claim 1, wherein the sensor module is further configured to:

simultaneously drive, during the first time period, the capacitive sensing signal onto a first subset of the first plurality of sensor electrodes that includes the first sensor electrode, and the substantially constant voltage onto a second subset of the first plurality of sensor electrodes that includes the second sensor electrode;

acquire, during the first time period, the first capacitive partial profile based on the capacitive sensing signal driven onto the first subset;

simultaneously drive, during the second time period, the capacitive sensing signal onto the second subset and the substantially constant voltage onto the first subset; and

acquire, during the second time period, the second capacitive partial profile based on the capacitive sensing signal driven onto the second subset,

wherein the first plurality of sensor electrodes are arranged in parallel, and wherein sensor electrodes of the first subset are disposed in an alternating arrangement with sensor electrodes of the second subset.

4. The processing system of claim 3, wherein the sensor electrodes are selected for inclusion in the first and second subsets based on a capacitive baseline image.

5. The processing system of claim 1, wherein the sensor module is further configured to:

acquire a third capacitive partial profile by driving the capacitive sensing signal onto a fourth sensor electrode of the second plurality of sensor electrodes, while driving a fifth sensor electrode of the second plurality of sensor electrodes with the substantially constant voltage; and

acquire a fourth capacitive partial profile by driving a capacitive sensing signal onto the fifth sensor electrode while driving the fourth sensor electrode with the substantially constant voltage; and

wherein the determination module is further configured to determine a second capacitive profile for the sensing region based on at least the third and fourth capacitive partial profiles.

6. The processing system of claim 1, wherein the sensing module is further configured to determine a second capacitive baseline image based on a comparison of a first capacitive baseline image with the first capacitive profile.

7. The processing system of claim 6, wherein the first capacitive baseline image is obtained using transcapacitive sensing.

8. A method for driving a plurality of sensor electrodes for capacitive sensing, the method comprising:

acquiring, during a first time period, a first capacitive partial profile by driving a capacitive sensing signal onto a first sensor electrode of a first plurality of sensor electrodes, while driving a second sensor electrode of the first plurality of sensor electrodes with a substantially constant voltage;

acquiring, during a second time period, a second capacitive partial profile by driving the capacitive sensing signal onto the second sensor electrode while driving the first sensor electrode with the substantially constant voltage, wherein the first and second time periods do not overlap;

driving, during at least one of the first and second time periods, one or more sensor electrodes of a second plurality of sensor electrodes with the substantially constant voltage, the second plurality of sensor electrodes disposed substantially orthogonal to the first plurality of sensor electrodes; and

determining a first capacitive profile based on at least the first and second capacitive partial profiles.

9. The method of claim 8, wherein acquiring the second capacitive partial profile comprises driving the capacitive sensing signal onto a third sensor electrode of the first plurality of sensor electrodes, wherein the second sensor electrode and the third sensor electrode are simultaneously driven with the capacitive sensing signal while the first sensor electrode is driven with a substantially constant voltage, the first sensor electrode located substantially between the second and third sensor electrodes.

10. The method of claim 8, further comprising:

acquiring the first capacitive partial profile by driving the capacitive sensing signal onto a first subset of the first plurality of sensor electrodes that includes the first sensor electrode, while driving a second subset of the first plurality of sensor electrodes that includes the second sensor electrode with the substantially constant voltage;

acquiring the second capacitive partial profile by driving the second subset of sensor electrodes with the capacitive sensing signal while driving the first subset with the substantially constant voltage,

wherein the first plurality of sensor electrodes are arranged in parallel, and wherein sensor electrodes of the first subset are disposed in an alternating arrangement with sensor electrodes of the second subset.

11. The method of claim 10, further comprising selecting the sensor electrodes for inclusion in the first and second subsets based on a capacitive baseline image.

12. The method of claim 8, further comprising:

acquiring a third capacitive partial profile by driving the capacitive sensing signal onto a fourth sensor electrode of the second plurality of sensor electrodes, while driving a fifth sensor electrode of the second plurality of sensor electrodes with the substantially constant voltage;

acquiring a fourth capacitive partial profile by driving a capacitive sensing signal onto the fifth sensor electrode while driving the fourth sensor electrode with the substantially constant voltage; and

determining a second capacitive profile based on at least the third and fourth capacitive partial profiles.

13. The method of claim 8, further comprising determining a second capacitive baseline image based on a comparison of a first capacitive baseline image with the first capacitive profile.

14. The method of claim 13, wherein the first capacitive baseline image is obtained using transcapacitive sensing.

15. An input device comprising:

a plurality of sensor electrodes, including a first plurality of sensor electrodes arranged along a first sensing axis; and

a processing system coupled to the plurality of sensor electrodes and configured to;

acquire, during a first time period, a first capacitive partial profile by driving a capacitive sensing signal onto a first sensor electrode of the first plurality of sensor electrodes, while driving a second sensor electrode of the first plurality of sensor electrodes with a substantially constant voltage;

acquire, during a second time period, a second capacitive partial profile by driving the capacitive sensing signal onto the second sensor electrode while driving the first sensor electrode with the substantially constant voltage, wherein the first and second time periods do not overlap; and

determine a first capacitive profile based on at least the first and second capacitive partial profiles.

16. The input device of claim 15, wherein acquiring the second capacitive partial profile comprises driving the capacitive sensing signal onto a third sensor electrode of the first plurality of sensor electrodes, and wherein the second sensor electrode and the third sensor electrode are simultaneously driven with the capacitive sensing signal while the first sensor electrode is driven with the substantially constant voltage.

17. The input device of claim 15, wherein the processing system is further configured to:

acquire the first capacitive partial profile by driving the capacitive sensing signal onto a first subset of the first plurality of sensor electrodes that includes the first sensor electrode, while a second subset of the first plurality of sensor electrodes that includes the second sensor electrode is driven with the substantially constant voltage; and

acquire the second capacitive partial profile by driving the capacitive sensing signal onto the second subset while the first subset is driven with the substantially constant voltage,

wherein the first plurality of sensor electrodes are arranged in parallel, and wherein sensor electrodes of the first subset are disposed in an alternating arrangement with sensor electrodes of the second subset.

18. The input device of claim 17, wherein the sensor electrodes are selected for inclusion in the first and second subsets based on a capacitive baseline image.

19. The input device of claim 15, wherein the processing system is further configured to:

acquire a third capacitive partial profile by driving the capacitive sensing signal onto a fourth sensor electrode of a second plurality of sensor electrodes arranged along a second sensing axis, the second sensing axis substantially orthogonal to the first sensing axis, while driving a fifth sensor electrode of the second plurality of sensor electrodes with the substantially constant voltage;

acquire a fourth capacitive partial profile by driving a capacitive sensing signal onto the fifth sensor electrode while driving the fourth sensor electrode with the substantially constant voltage; and

determine a second capacitive profile for the sensing region based on at least the third and fourth capacitive partial profiles.

20. The input device of claim 15, wherein the processing system is further configured to determine a second capacitive baseline image based on a comparison of a first capacitive baseline image with the first capacitive profile.

21. The input device of claim 20, wherein the first capacitive baseline image is obtained using transcapacitive sensing.