Combining trans-capacitance data with absolute-capacitance data for touch force estimates

• US 10,108,303 B2
• Filed: 03/31/2016
• Issued: 10/23/2018
• Est. Priority Date: 03/31/2016
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Shepelev, Petr, Wingard, Andrew
• Primary Examiner(s): Bibbins, Latanya
• Application Number:
  US15/088,026
• Publication Number:
  US 20170285797A1
• Time in Patent Office: 936 Days
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/041662 using alternate mutual and self-capacitive scanning
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

Techniques for obtaining force-based data of an input device are provided. The techniques include driving sensor electrodes in transcapacitive mode and in absolute capacitive mode, obtaining profiles for each of the modes, scaling the transcapacitive profile, and subtracting the scaled transcapacitive profile from the profile for absolute capacitive sensing. The result of this subtraction is force-based data that indicates the degree of force with that input object applies to the input device.

Claims

1. A method for obtaining force-based data associated with a touch event, the method comprising:

driving a plurality of sensor electrodes in transcapacitive mode to obtain a plurality of transcapacitive measurements;

driving the plurality of sensor electrodes in absolute capacitive mode to obtain a plurality of absolute capacitive measurements; and

determining the force-based data based on differences between the plurality of transcapacitive measurements and the plurality of absolute capacitive measurements.

2. The method of claim 1, wherein:

the plurality of sensor electrodes comprises at least one display electrode, wherein the display electrode is configured for both display updating and capacitive sensing.

3. The method of claim 1, wherein during a touch event, an input object causes at least one sensor electrode of the plurality of sensor electrodes to move closer to a conductor within an input device that includes the plurality of sensor electrodes.

4. The method of claim 1, wherein determining the force-based data comprises:

collapsing the plurality of transcapacitive measurements to obtain a plurality of composite transcapacitive measurements.

5. The method of claim 4, wherein collapsing the plurality of transcapacitive measurements comprises:

combining transcapacitive measurements of the plurality of transcapacitive measurements, each such transcapacitive measurement corresponding to the same sensor electrode, to form a composite transcapacitive measurement of the plurality of composite transcapacitive measurements.

6. The method of claim 4, further comprising:

scaling the plurality of composite transcapacitive measurements to obtain a plurality of scaled composite transcapacitive measurements.

7. The method of claim 6, wherein determining the force-based data comprises:

subtracting the scaled composite transcapacitive measurements from the plurality of absolute capacitive measurements to obtain the force-based data.

8. A processing system for obtaining force-based data associated with a touch event, the processing system comprising:

sensing circuitry configured to;

drive a plurality of sensor electrodes in transcapacitive mode to obtain a plurality of transcapacitive measurements, and

drive the plurality of sensor electrodes in absolute capacitive mode to obtain a plurality of absolute capacitive measurements; and

a determination processor configured to;

determine the force-based data based on differences between the plurality of transcapacitive measurements and the plurality of absolute capacitive measurements.

9. The processing system of claim 8, wherein:

the plurality of sensor electrodes comprises at least one display electrode, wherein the display electrode is configured for both display updating and capacitive sensing.

10. The processing system of claim 8, wherein during a touch event, at least one sensor electrode of the plurality of sensor electrodes is configured to move closer to a conductor within an input device that includes the plurality of sensor electrodes in response to touch applied by an input object.

11. The processing system of claim 8, wherein the determination processor is configured to determine the force-based data by:

collapsing the plurality of transcapacitive measurements to obtain a plurality of composite transcapacitive measurements.

12. The processing system of claim 11, wherein the determination processor is configured to collapse the plurality of transcapacitive measurements by:

combining transcapacitive measurements of the plurality of transcapacitive measurements, each such transcapacitive measurement corresponding to the same sensor electrode, to form a composite transcapacitive measurement of the plurality of composite transcapacitive measurements.

13. The processing system of claim 11, wherein the determination processor is further configured to:

scale the plurality of composite transcapacitive measurements to obtain a plurality of scaled composite transcapacitive measurements.

14. The processing system of claim 13, wherein the determination processor is configured to determine the force-based data by:

subtracting the scaled composite transcapacitive measurements from the plurality of absolute capacitive measurements to obtain the force-based data.

15. An input device for obtaining force-based data associated with a touch event, the input device comprising:

a plurality of sensor electrodes; and

a processing system comprising;

sensing circuitry configured to;

drive a plurality of sensor electrodes in transcapacitive mode to obtain a plurality of transcapacitive measurements, and

drive the plurality of sensor electrodes in absolute capacitive mode to obtain a plurality of absolute capacitive measurements; and

a determination processor configured to;

determine the force-based data based on differences between the plurality of transcapacitive measurements and the plurality of absolute capacitive measurements.

16. The input device of claim 15, wherein:

the plurality of sensor electrodes comprises at least one display electrode, wherein the display electrode is configured for both display updating and capacitive sensing.

17. The input device of claim 15, wherein during a touch event, at least one sensor electrode of the plurality of sensor electrodes is configured to move closer to a conductor within an input device that includes the plurality of sensor electrodes in response to touch applied by an input object.

18. The input device of claim 15, wherein the determination processor is configured to determine the force-based data by:

collapsing the plurality of transcapacitive measurements to obtain a plurality of composite transcapacitive measurements.

19. The input device of claim 18, wherein the determination processor is configured to collapse the plurality of transcapacitive measurements by:

combining transcapacitive measurements of the plurality of transcapacitive measurements, each such transcapacitive measurement corresponding to the same sensor electrode, to form a composite transcapacitive measurement of the plurality of composite transcapacitive measurements.

20. The input device of claim 18, wherein the determination processor is further configured to:

scale the plurality of composite transcapacitive measurements to obtain a plurality of scaled composite transcapacitive measurements.