SYSTEM AND METHOD FOR DETECTING GROUNDING STATE OF A TOUCH ENABLED COMPUTING DEVICE

• US 20170177138A1
• Filed: 12/22/2015
• Published: 06/22/2017
• Est. Priority Date: 12/22/2015
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: ORLOVSKY, Michael, WINEBRAND, Amil, HARAN, On
• Granted Patent: US 10,423,268 B2
• Time in Patent Office: Days
• 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 3/04186 Touch location disambiguation
• 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 method includes sampling output from sensor having electrode junctions integrated on a device including a display, detecting capacitance between the device ground and a user (C_BD) based on the output sampled and a pre-defined model, and defining one of two grounding states of the device based on the capacitance detected. Output is processed based on the grounding state defined and touch coordinates are determined based on the output processed. The touch coordinates are reported to a controller of the display.

Claims

1. A method comprising:

sampling output from sensor having electrode junctions integrated on a device including a display;

detecting capacitance between the device ground and a user (C_BD) based on the output sampled and a pre-defined model;

defining one of two grounding states of the device based on the capacitance detected;

processing the output based on the grounding state defined;

determining touch coordinates based on the output processed; and

reporting the touch coordinates to a controller of the display.

2. The device of claim 1, wherein the model is a physical model for C_BD capacitive estimation based on a number of touched junctions and a relative effect, and wherein the number of touched junction and the relative effect is detected from the output sampled.

3. The method of claim 1, wherein the C_BD is detected per frame of output sampled.

4. The method of claim 1, wherein the one of two grounding states is defined based on accumulated averages of C_BD.

5. The method of claim 4, wherein the two grounding states is grounded and ungrounded.

6. The method of claim 5, comprising switching from the grounded state to the ungrounded state based on a first threshold and switching from the ungrounded state to the grounded state based on a second threshold, wherein the first threshold is other than the second threshold.

7. The method of claim 4, comprising performing processing for palm rejection and wherein parameters of a palm rejection processing scheme is adjusted based on the defined grounding state.

8. The method of claim 4, comprising performing processing for finger separation and wherein parameters of a finger separation processing scheme is adjusted based on the defined grounding state.

9. The method of claim 4, comprising performing processing for finger separation and wherein the processing for finger separation is disabled based on defining an ungrounded state.

10. The method of claim 1, wherein C_BD is modeled as total capacitance between the user and the device ground minus touch capacitance between the user and the sensor.

11. A device comprising:

a display;

a controller configured to control the display;

a sensor having electrode junctions, the sensor configured to sense touch input; and

a circuit in communication with the sensor, the circuit configured to;

sample output from the sensor;

detect capacitance between the device ground and a user touching the sensor (C_BD) based on the output sampled and a pre-defined model;

define one of two grounding states of the device based on the capacitance detected;

process the output based on the grounding state defined;

determine touch coordinates based on the output processed; and

report the touch coordinates to the controller.

12. The device of claim 11, wherein the model is a physical model for C_BD capacitive estimation based on a number of touched junctions and a relative effect, and wherein the number of touched junction and the relative effect is detected from the output sampled.

13. The device of claim 11, wherein the C_BD is detected per frame of output sampled.

14. The device of claim 11, wherein the circuit includes a grounding state machine configured to define the grounding state based on accumulated averages of C_BD.

15. The device of claim 14, wherein the grounding state machine defines a grounded state or an ungrounded state.

16. The device of claim 15, wherein the grounding state machine stores a first threshold on C_BD defined to switch from a grounded state to an ungrounded state and a second threshold on C_BD defined to switch from the ungrounded state to the grounded state, wherein the first threshold is other than the second threshold.

17. The device of claim 14, wherein the circuit is configured to perform processing for palm rejection and wherein parameters of a palm rejection processing scheme is adjusted based on the defined grounding state.

18. The device of claim 14, wherein the circuit is configured to perform processing for finger separation and wherein parameters of a finger separation processing scheme is adjusted based on the defined grounding state.

19. The device of claim 14, wherein the circuit is configured to perform processing for finger separation and wherein the processing for finger separation is disabled based on defining an ungrounded state.

20. The device of claim 11, wherein CBD is modeled as total capacitance between the user and the device ground minus touch capacitance between the user and the sensor.