CIRCULAR SINGLE-LAYER TOUCH SENSORS

• US 20110031041A1
• Filed: 12/22/2009
• Published: 02/10/2011
• Est. Priority Date: 08/07/2009
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Worfolk, Patrick, Bulea, Mihai M.
• Granted Patent: US 8,440,920 B2
• Time in Patent Office: Days
• US Class Current: 178/18.06
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0448 Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.

Abstract

A two-dimensional capacitive sensor device comprises a sensor substrate with a plurality of wedge shaped sensor cells arranged in a single-layer circular pattern proximal to the substrate. The plurality of wedge shaped sensor cells are arranged in a rotationally symmetric pattern about a center of the single-layer circular pattern. A sensor cell of the plurality of wedge shaped sensor cells comprises a first sensor electrode and a second sensor electrode separated by a border. The first and second sensor electrodes are configured for detecting changes in capacitance caused by one or more input objects. The first and second sensor electrodes become substantially thinner in width approaching the center of the single-layer circular pattern than at a distance further from the center. A sensor circuitry is communicatively coupled with the sensor electrodes of the sensor cell and the sensor circuitry is configured to interpret the changes in capacitance.

Claims

1. A two-dimensional capacitive sensor device comprising:

a sensor substrate;

a plurality of wedge shaped sensor cells arranged in a single-layer circular pattern proximal to said substrate, said plurality of wedge shaped sensor cells arranged in a rotationally symmetric pattern about a center of said single-layer circular pattern,

wherein a sensor cell of said plurality of wedge shaped sensor cells comprises a first sensor electrode and a second sensor electrode separated by a border, said first and second sensor electrodes configured for detecting changes in capacitance caused by one or more input objects, and said first and second sensor electrodes becoming substantially thinner in width approaching said center of said single-layer circular pattern than at a distance further from said center; and

sensor circuitry communicatively coupled with said sensor electrodes of said sensor cell of said plurality of wedge shaped sensor cells and configured to interpret said changes in capacitance.

2. The two-dimensional capacitive sensor device of claim 1, wherein sensor cells of said plurality of wedge shaped sensor cells comprise at least three sensor electrodes per sensor cell.

3. The two-dimensional capacitive sensor device of claim 1, wherein all sensor electrodes of said single-layer circular pattern are of substantially the same surface area.

4. The two-dimensional capacitive sensor device of claim 1, wherein a width ratio of sensor electrodes within said sensor cell varies in a radial direction relative to said center of said single-layer circular pattern.

5. The two-dimensional capacitive sensor device of claim 1, wherein a width ratio of sensor electrodes within said sensor cell is substantially equal to another sensor cell within said plurality of wedge shaped sensor cells at a constant radial distance relative to said center of said single-layer circular pattern.

6. The two-dimensional capacitive sensor device of claim 1, wherein all other sensor cells of said plurality of wedge shaped sensor cells are either rotations or rotated reflections of said sensor cell.

7. The two-dimensional capacitive sensor device of claim 1, wherein connections between said sensing circuitry and said sensor electrodes of said sensor cell of said plurality of wedge shaped sensor cells are disposed around a circumferential edge of said single-layer circular pattern.

8. A two-dimensional capacitive sensor pattern comprising:

a sensor substrate; and

a plurality of wedge shaped sensor cells arranged in a single-layer circular pattern proximal to said substrate, said plurality of wedge shaped sensor cells arranged in a rotationally symmetric pattern about a center of said single-layer circular pattern, and

wherein a sensor cell of said plurality of wedge shaped sensor cells comprises at least a first sensor electrode and a second sensor electrode of different shapes that are separated by a shared piecewise linear electrode border, said first and second sensor electrodes configured for detecting changes in capacitance caused by one or more input objects.

9. The two-dimensional capacitive sensor pattern of claim 8, wherein sensor cells of said plurality of wedge shaped sensor cells comprise at least three sensor electrodes per sensor cell.

10. The two-dimensional capacitive sensor pattern of claim 8, wherein all sensor electrodes of said single-layer circular become substantially thinner in width approaching said center of said single-layer circular pattern than at a distance further from said center

11. The two-dimensional capacitive sensor pattern of claim 8, wherein all sensor electrodes of said single-layer circular pattern are of substantially the same surface area.

12. The two-dimensional capacitive sensor pattern of claim 8, wherein a width ratio of sensor electrodes within said sensor cell varies in a radial direction relative to the center of said single-layer circular pattern.

13. The two-dimensional capacitive sensor pattern of claim 8, wherein a width ratio of sensor electrodes within said sensor cell is substantially equal to another sensor cell within said plurality of wedge shaped sensor cells at a constant radial distance relative to the center of said single-layer circular pattern.

14. The two-dimensional capacitive sensor pattern of claim 8, wherein all other sensor cells of said plurality of wedge shaped sensor cells are either rotations or rotated reflections of said sensor cell.

15. The two-dimensional capacitive sensor pattern of claim 8, wherein connections between sensing circuitry and sensor electrodes of said plurality of wedge shaped sensor cells are disposed around a circumferential edge of said single-layer circular pattern.

16. A method of creating a circular sensor pattern of a two-dimensional capacitive sensor pattern with a plurality of wedge shaped sensor cells, said method comprising:

forming a first wedge shaped sensor cell proximal to a sensor substrate, said first wedge shaped sensor cell comprising at least a first sensor electrode and a second sensor electrode of different shapes separated by a shared piecewise linear electrode border, said first sensor electrode having a different shape than said second sensor electrode; and

forming an additional N−

1 wedge shaped sensor cells proximal to said sensor substrate such that said first wedge shaped sensor cell and said additional N−

1 wedge shaped sensor cells are arranged to form a single-layer circular pattern, wherein each of said N−

1 wedge shaped sensor cells comprises a rotation or reflected rotation of said first wedge shaped sensor cell.

17. The method as recited in claim 16, wherein said forming a first wedge shaped sensor cell proximal to a sensor substrate comprises:

forming said first wedge shaped sensor cell with at least three sensor electrodes.

18. The method as recited in claim 16, wherein said forming a first wedge shaped sensor cell proximal to a sensor substrate comprises:

forming sensor electrodes of said first wedge shaped sensor cell to be of substantially the same surface area.

19. The method as recited in claim 16, wherein said forming a first wedge shaped sensor cell proximal to a sensor substrate comprises:

forming sensor electrodes of said first wedge shaped sensor cell such that a width ratio of said sensor electrodes within said first wedge shaped sensor cell varies in a radial direction relative to the center of said single-layer circular pattern.

20. The method as recited in claim 16, wherein said forming an additional N−

1 wedge shaped sensor cells proximal to said sensor substrate such that said first wedge shaped sensor cell and said additional N−

1 wedge shaped sensor cells are arranged to form a single-layer circular pattern comprises;

forming said N wedge shaped sensor cells such that a width ratio of sensor electrodes within each of said wedge shaped sensor cells is substantially equal at a constant radial distance relative to the center of said single-layer circular pattern.