Wide dynamic range capacitive sensing
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.
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 and a first gain,
if no 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 a second gain greater than the first gain, and
if no second touch or proximity event is detected in the second object sensing mode and the second gain is not a maximum gain, switching the touch sensor panel to operate in the second object sensing mode having a third gain greater than the second gain.
2. The method of claim 1 , further comprising:
if no 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 to operate in the first 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. 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 and a first gain,
if no 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 a second gain greater than the first gain, and
if no second touch or proximity event is detected in the second object sensing mode and the second gain is not a maximum gain, configuring the switching circuitry to operate the touch sensor panel in the second object sensing mode having a third gain greater than the second gain.
9. The apparatus of claim 8 , 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 no second touch or proximity event is detected in the second object sensing mode.
10. The apparatus of claim 9 , wherein the processor is further capable of switching the touch sensor panel to operate in the first object sensing mode, if no third touch or proximity event is detected in the third object sensing mode.
11. The apparatus of claim 8 , wherein the first and second resolutions are different levels of x-y location resolution.
12. The apparatus of claim 8 , wherein the first and second resolutions are different levels of z proximity resolution.
13. The apparatus of claim 8 , 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.
14. The apparatus of claim 8 , 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.
15. 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 and a first gain;
if no 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 a second gain greater than the first gain; and
if no second touch or proximity event is detected in the second object sensing mode and the second gain is not a maximum gain, switch the touch sensor panel to operate in the second object sensing mode having a third gain greater than the second gain.
16. The non-transitory computer readable storage medium of claim 15 , 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 no second touch or proximity event is detected in the second object sensing mode.
17. The non-transitory computer readable storage medium of claim 16 , wherein the processor is further caused to switch the touch sensor panel back to operate in the first object sensing mode, if no third touch or proximity event is detected in the third object sensing mode.
18. The non-transitory computer readable storage medium of claim 15 , wherein the first and second resolutions are different levels of x-y location resolution.
19. The non-transitory computer readable storage medium of claim 15 , wherein the first and second resolutions are different levels of z proximity resolution.
20. The non-transitory computer readable storage medium of claim 15 , 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.
21. The non-transitory computer readable storage medium of claim 15 , 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.