WIDE DYNAMIC RANGE CAPACITIVE SENSING

• US 20150324062A1
• Filed: 06/30/2015
• Published: 11/12/2015
• Est. Priority Date: 04/30/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: ELIAS, John Greer, HOTELLING, Steven P.
• Granted Patent: US 9,569,053 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04101 2.5D-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 and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• 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 3/0418 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
• CPC Class Codes: H03K 17/955 using a capacitive detector

Abstract

A touch sensor panel configured to detect objects touching the panel as well as objects that are at a varying proximity to the touch sensor panel. The touch sensor panel includes circuitry that can configure the panel in a mutual capacitance (near field) architecture or a self-capacitance (far field and super far field) architecture. The touch sensor panel can also include circuitry that works to minimize an effect that a parasitic capacitance can have on the ability of the touch sensor panel to reliably detect touch and proximity events.

Claims

1. A method for determining an object sensing mode of a touch sensor panel, comprising:

at an electronic device with one or more processors and memory,

operating the touch sensor panel in a first object sensing mode having a first resolution,

if a first touch or proximity event is detected in the first object sensing mode, switching the touch sensor panel to operate in a second object sensing mode having a second resolution, and

if no second touch or proximity event is detected in the second object sensing mode, switching the touch sensor panel back to operate in the first object sensing mode.

2. The method of claim 1, further comprising:

if a second touch or proximity event is detected in the second object sensing mode, switching the touch sensor panel to operate in a third object sensing mode having a third resolution.

3. The method of claim 2, further comprising:

if no third touch or proximity event is detected in the third object sensing mode, switching the touch sensor panel back to operate in the second object sensing mode.

4. The method of claim 1, wherein the first and second resolutions are different levels of x-y location resolution.

5. The method of claim 1, wherein the first and second resolutions are different levels of z proximity resolution.

6. The method of claim 1, wherein the first, second and third object sensing modes are selected from the group consisting of a super-far field mode, a far field mode, and a near field mode.

7. The method of claim 1, wherein switching the touch sensor panel to operate between the first and second object sensing modes comprises switching between a mutual capacitance touch detection architecture and a self-capacitance touch detection architecture.

8. The method of claim 1, wherein detecting the first or second touch or proximity event comprises:

setting a gain of one or more sense amplifiers in the touch sensor panel;

determining whether the touch or proximity event is detected; and

if no touch or proximity event is detected, adjusting the gain of the one or more sense amplifiers and re-determining whether the touch or proximity event is detected.

9. An apparatus for determining an object sensing mode of a touch sensor panel, comprising:

switching circuitry configured to switch the touch sensor panel between a plurality of object sensing modes; and

a processor communicatively coupled to the switching circuitry and capable of configuring the switching circuitry to operate the touch sensor panel in a first object sensing mode having a first resolution,

if a first touch or proximity event is detected in the first object sensing mode, configuring the switching circuit to operate the touch sensor panel in a second object sensing mode having a second resolution, and

if no second touch or proximity event is detected in the second object sensing mode, configuring the switching circuitry to operate the touch sensor panel in the first object sensing mode.

10. The apparatus of claim 9, wherein the processor is further capable of configuring the switching circuitry to operate the touch sensor panel in a third object sensing mode having a third resolution, if a second touch or proximity event is detected in the second object sensing mode.

11. The apparatus of claim 10, wherein the processor is further capable of switching the touch sensor panel back to operate in the second object sensing mode, if no third touch or proximity event is detected in the third object sensing mode.

12. The apparatus of claim 9, wherein the first and second resolutions are different levels of x-y location resolution.

13. The apparatus of claim 9, wherein the first and second resolutions are different levels of z proximity resolution.

14. The apparatus of claim of claim 9, wherein the first, second and third object sensing modes are selected from the group consisting of a super-far field mode, a far field mode, and a near field mode.

15. The apparatus of claim 9, wherein switching the touch sensor panel to operate between the first and second object sensing modes comprises switching between a mutual capacitance touch detection architecture and a self-capacitance touch detection architecture.

16. The apparatus of claim 9, wherein the processor is further capable of:

setting a gain of one or more sense amplifiers in the touch sensor panel;

determining whether the touch or proximity event is detected; and

if no touch or proximity event is detected, adjusting the gain of the one or more sense amplifiers and re-determining whether the touch or proximity event is detected.

17. A non-transitory computer readable storage medium having stored thereon a set of instructions for determining an object sensing mode of a touch sensor panel that when executed by a processor causes the processor to:

operate the touch sensor panel in a first object sensing mode having a first resolution;

if a first touch or proximity event is detected in the first object sensing mode, switch the touch sensor panel to operate in a second object sensing mode having a second resolution; and

if no second touch or proximity event is detected in the second object sensing mode, switch the touch sensor panel back to operate in the first object sensing mode.

18. The non-transitory computer readable storage medium of claim 17, wherein the processor is further caused to switch the touch sensor panel to operate in a third object sensing mode having a third resolution, if a second touch or proximity event is detected in the second object sensing mode.

19. The non-transitory computer readable storage medium of claim 18, wherein the processor is further caused to switch the touch sensor panel back to operate in the second object sensing mode, if not third touch or proximity event is detected in the third object sensing mode.

20. The non-transitory computer readable storage medium of claim 17, wherein the first and second resolutions are different levels of x-y location resolution.

21. The non-transitory computer readable storage medium of claim 17, wherein the first and second resolutions are different levels of z proximity resolution.

22. The non-transitory computer readable storage medium of claim 17, wherein the first, second and third object sensing modes are selected from the group consisting of a super-far field mode, a far field mode and a near field mode.

23. The non-transitory computer readable storage medium of claim 17, wherein switching the touch sensor panel to operate between the first and second object sensing modes comprises switching between a mutual capacitance touch detection architecture and a self-capacitance architecture.

24. The non-transitory computer readable storage medium of claim 17, wherein detecting the first or second touch or proximity event comprises:

setting a gain of one or more sense amplifiers in the touch sensor panel;

determining whether the touch or proximity event is detected; and

if no touch or proximity event is detected, adjusting the gain of the one or more sense amplifiers and re-determining whether the touch or proximity event is detected.