REDUCING FLOATING GROUND EFFECTS IN PIXELATED SELF-CAPACITANCE TOUCH SCREENS

• US 20150378465A1
• Filed: 06/27/2014
• Published: 12/31/2015
• Est. Priority Date: 06/27/2014
• Status: Active Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: LIN, Albert, SHIH, David H.C.
• Granted Patent: US 10,289,251 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/96031 Combination of touch switch and LC display

Abstract

A touch controller is disclosed. In some examples, the touch controller can include sense circuitry configured to be coupled to a first touch pixel and a second touch pixel on a touch sensor panel. In some examples, the sense circuitry can be configured to drive and sense the first touch pixel during a first time period while coupling the second touch pixel to a reference voltage. In some examples, the sense circuitry can be configured to drive and sense the second touch pixel during a second time period while coupling the first touch pixel to the reference voltage. In some examples, the reference voltage can be a system ground of the touch controller. In some examples, the sense circuitry can be configured to drive and sense pluralities of touch pixels in a similar manner.

Claims

1. A touch controller comprising:

sense circuitry configured to be coupled to a first touch pixel and a second touch pixel on a touch sensor panel, the sense circuitry configured to;

during a first time period, drive and sense the first touch pixel and couple the second touch pixel to a reference voltage; and

during a second time period, drive and sense the second touch pixel and couple the first touch pixel to the reference voltage.

2. The touch controller of claim 1, wherein the reference voltage comprises a system ground of the touch controller.

3. The touch controller of claim 1, wherein the sense circuitry is configured to be coupled to a first plurality of touch pixels and a second plurality of touch pixels, the first plurality of touch pixels including the first touch pixel and the second plurality of touch pixels including the second touch pixel, the sense circuitry configured to:

during the first time period, drive and sense the first plurality of touch pixels and couple the second plurality of touch pixels to the reference voltage; and

during the second time period, drive and sense the second plurality of touch pixels and couple the first plurality of touch pixels to the reference voltage.

4. The touch controller of claim 3, wherein first plurality of touch pixels and the second plurality of touch pixels are alternately arranged in a checkerboard pattern on the touch sensor panel.

5. The touch controller of claim 4, wherein:

the sense circuitry is configured to be coupled to the first plurality of touch pixels using a first set of routing on the touch sensor panel,

the sense circuitry is configured to be coupled to the second plurality of touch pixels using a second set of routing on the touch sensor panel, and

the first set of routing and the second set of routing are alternately disposed between columns of touch pixels on the touch sensor panel.

6. The touch controller of claim 3, wherein one or more distances between touch pixels in the first plurality of touch pixels are substantially the same as one or more distances between touch pixels in the second plurality of touch pixels.

7. The touch controller of claim 3, wherein the sense circuitry is configured to drive and sense multiple other pluralities of touch pixels on the touch sensor panel during other respective time periods, the multiple other pluralities of touch pixels being different than the first and second pluralities of touch pixels, and the other respective time periods being different than the first and second time periods.

8. The touch controller of claim 1, further comprising:

logic configured to dynamically determine the first touch pixel and the second touch pixel to be driven and sensed by the sense circuitry.

9. The touch controller of claim 8, wherein the logic is configured to:

determine a size of an object interacting with the touch sensor panel; and

determine the first touch pixel and the second touch pixel based on the determined size of the object.

10. The touch controller of claim 8, wherein the logic is configured to:

determine a location of an object interacting with the touch sensor panel; and

determine the first touch pixel and the second touch pixel based on the determined location of the object.

11. The touch controller of claim 9, wherein the logic is configured to:

prior to determining the size of the object, initiate an initial scan of the touch sensor panel in which the first touch pixel and the second touch pixel are driven and sensed simultaneously; and

determine the size of the object based on the initial scan.

12. The touch controller of claim 10, wherein the logic is configured to:

prior to determining the location of the object, initiate an initial scan of the touch sensor panel in which the first touch pixel and the second touch pixel are driven and sensed simultaneously; and

determine the location of the object based on the initial scan.

13. A method of operating a touch sensor panel, the method comprising:

during a first time period;

driving and sensing a first touch pixel on the touch sensor panel, and

coupling a second touch pixel on the touch sensor panel to a reference voltage; and

during a second time period;

driving and sensing the second touch pixel, and

coupling the first touch pixel to the reference voltage.

14. The method of claim 13, wherein coupling the first touch pixel and the second touch pixel, respectively, to the reference voltage comprises coupling the first touch pixel and the second touch pixel, respectively, to a system ground of the touch sensor panel.

15. The method of claim 13, wherein a first plurality of touch pixels includes the first touch pixel and a second plurality of touch pixels includes the second touch pixel, the method further comprising:

during the first time period;

driving and sensing the first plurality of touch pixels, and

coupling the second plurality of touch pixels to the reference voltage; and

during the second time period;

driving and sensing the second plurality of touch pixels, and

coupling the first plurality of touch pixels to the reference voltage.

16. The method of claim 15, wherein first plurality of touch pixels and the second plurality of touch pixels are alternately arranged in a checkerboard pattern on the touch sensor panel.

17. The method of claim 16, further comprising:

coupling the first plurality of touch pixels to sense circuitry using a first set of routing on the touch sensor panel; and

coupling the second plurality of touch pixels to the sense circuitry using a second set of routing on the touch sensor panel,

wherein the first set of routing and the second set of routing are alternately disposed between columns of touch pixels on the touch sensor panel.

18. The method of claim 15, wherein one or more distances between touch pixels in the first plurality of touch pixels are substantially the same as one or more distances between touch pixels in the second plurality of touch pixels.

19. The method of claim 15, further comprising:

driving and sensing multiple other pluralities of touch pixels on the touch sensor panel during other respective time periods, the multiple other pluralities of touch pixels being different than the first and second pluralities of touch pixels, and the other respective time periods being different than the first and second time periods.

20. The method of claim 13, further comprising:

dynamically determining the first touch pixel and the second touch pixel to be driven and sensed.

21. The method of claim 20, wherein dynamically determining the first touch pixel and the second touch pixel comprises:

determining a size of an object interacting with the touch sensor panel; and

determining the first touch pixel and the second touch pixel based on the determined size of the object.

22. The method of claim 20, wherein dynamically determining the first touch pixel and the second touch pixel comprises:

determining a location of an object interacting with the touch sensor panel; and

determining the first touch pixel and the second touch pixel based on the determined location of the object.

23. The method of claim 21, further comprising:

prior to determining the size of the object, initiating an initial scan of the touch sensor panel in which the first touch pixel and the second touch pixel are driven and sensed simultaneously; and

determining the size of the object based on the initial scan.

24. The method of claim 22, further comprising:

prior to determining the location of the object, initiating an initial scan of the touch sensor panel in which the first touch pixel and the second touch pixel are driven and sensed simultaneously; and

determining the location of the object based on the initial scan.