Virtual Sensor Mirroring for Circular Touch Panels

• US 20160291737A1
• Filed: 04/04/2016
• Published: 10/06/2016
• Est. Priority Date: 04/02/2015
• Status: Active Grant

• Current Assignee: Parade Technologies, Ltd.
• Original Assignee: Parade Technologies, Ltd.
• Inventors: Hirakawa, Naoki
• Granted Patent: US 10,025,439 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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

A touch sensing system includes a capacitive sense array. Each sensor has a unique location type. The system includes a capacitance measurement circuit coupled to the array, which measures capacitance changes at each sensor. The system also includes a memory device that stores three or more adjustment parameters. Each parameter corresponds to one or more location types, and is used in computing virtual sensor values. The system receives measured capacitance changes corresponding to a touch on the array and identifies a first sensor whose measured capacitance change is a local maximum. The system determines a location type of the first sensor. According to the location type, the adjustment parameters corresponding to the location type, and the measured capacitance changes, the system computes virtual sensor measurements. The system then computes a centroid of the touch using the measured capacitance changes and the virtual sensor measurements.

Claims

1. A touch sensing system, comprising:

a two-dimensional capacitive sense array including a plurality of capacitive sensors, wherein each capacitive sensor in the capacitive sense array is associated with a unique location type;

a capacitance measurement circuit coupled to the capacitive sense array and configured to measure capacitance changes at each capacitive sensor of the capacitive sense array;

a memory device storing three or more adjustment parameters, wherein each adjustment parameter corresponds to one or more of the location types;

a processing unit coupled to the capacitance measurement circuit, wherein the processing unit is configured for;

receiving measured capacitance changes corresponding to a touch on the capacitive sense array;

identifying a first sensor whose measured capacitance change is a local maximum within the capacitance sense array;

determining a first location type of the first sensor;

in accordance with the first location type, the adjustment parameters corresponding to the first location type, and the measured capacitance changes, computing a plurality of virtual sensor measurements; and

computing a centroid of the touch using a plurality of the measured capacitance changes and the plurality of virtual sensor measurements.

2. The touch sensing system of claim 1, wherein the location types are core, inner edge, outer edge, outer corner, and inner corner.

3. The touch sensing system of claim 1, wherein the two-dimensional capacitive sense array is non-rectangular.

4. The touch sensing system of claim 1, wherein the adjustment parameters include a first adjustment parameter for inner edges, a second adjustment parameter for outer edges, and a plurality of additional adjustment parameters for corners.

5. The touch sensing system of claim 4, wherein the plurality of additional adjustment parameters for corners include an inner corner adjustment parameter, an outer corner adjustment parameter, an edge corner adjustment parameter, and corner adjustment parameter.

6. A method of computing touch centroids for capacitive sense arrays, comprising:

at a touch sensing system, wherein the touch sensing system includes a two-dimensional capacitive sense array having a plurality of capacitive sensors and each capacitive sensor in the capacitive sense array is associated with a unique location type;

storing three or more adjustment parameters, wherein each adjustment parameter corresponds to one or more of the location types;

measuring capacitance changes corresponding to a touch on the capacitive sense array;

identifying a first sensor whose measured capacitance change is a local maximum within the capacitance sense array;

determining a first location type of the first sensor;

in accordance with the first location type, the adjustment parameters corresponding to the first location type, and the measured capacitance changes, computing a plurality of virtual sensor measurements; and

computing a centroid of the touch using a plurality of the measured capacitance changes and the plurality of virtual sensor measurements.

7. The method of claim 6, wherein the location types are core, inner edge, outer edge, outer corner, and inner corner.

8. The method of claim 6, wherein the two-dimensional capacitive sense array is non-rectangular.

9. The method of claim 6, wherein the adjustment parameters include a first adjustment parameter for inner edges, a second adjustment parameter for outer edges, and a plurality of additional adjustment parameters for corners.

10. The method of claim 9, wherein the plurality of additional adjustment parameters for corners include an inner corner adjustment parameter, an outer corner adjustment parameter, an edge corner adjustment parameter, and corner adjustment parameter.

11. A non-transitory computer readable storage medium, storing one or more programs configured for execution by one or more processors of a touch sensing system, wherein the touch sensing system includes a two-dimensional capacitive sense array having a plurality of capacitive sensors and each capacitive sensor in the capacitive sense array is associated with a unique location type, the one or more programs including instructions for:

storing three or more adjustment parameters, wherein each adjustment parameter corresponds to one or more of the location types;

measuring capacitance changes corresponding to a touch on the capacitive sense array;

identifying a first sensor whose measured capacitance change is a local maximum within the capacitance sense array;

determining a first location type of the first sensor;

in accordance with the first location type, the adjustment parameters corresponding to the first location type, and the measured capacitance changes, computing a plurality of virtual sensor measurements; and

computing a centroid of the touch using a plurality of the measured capacitance changes and the plurality of virtual sensor measurements.

12. The computer readable storage medium of claim 11, wherein the location types are core, inner edge, outer edge, outer corner, and inner corner.

13. The computer readable storage medium of claim 11, wherein the two-dimensional capacitive sense array is non-rectangular.

14. The computer readable storage medium of claim 11, wherein the adjustment parameters include a first adjustment parameter for inner edges, a second adjustment parameter for outer edges, and a plurality of additional adjustment parameters for corners.

15. The computer readable storage medium of claim 14, wherein the plurality of additional adjustment parameters for corners include an inner corner adjustment parameter, an outer corner adjustment parameter, an edge corner adjustment parameter, and corner adjustment parameter.