MULTI-TOUCH DETECTION

• US 20160195993A1
• Filed: 03/14/2016
• Published: 07/07/2016
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: MOORE, Jonathan, ZACHUT, Rafi, PERSKI, Haim
• Granted Patent: US 11,016,627 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/047 using sets of wires, e.g. crossed wires
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

A method for multi-touch detection in a touch input device comprising a grid based sensor, the method comprises sampling outputs from a grid based sensor over a first stage of detection, selecting sensor lines based on the sampled outputs, scanning the selected sensor lines along one axis of the grid based sensor over a second stage of detection, and determining positions of user interaction based on outputs sampled in response to scanning the selected sensor lines during the second stage of detection.

Claims

1. A method comprising:

operating a sensor for capacitive based detection of user interactions, the sensor including sensor lines arranged along a first axis and along a second axis to form a grid;

sampling first outputs of the sensor responsive to simultaneously triggering a first set of the sensor lines with a same signal over a first stage of detection;

selecting a second set of the sensor lines that indicate a presence of the user interactions based on the first outputs sampled;

scanning based on a multi-touch detection method only the second set over a second stage of detection to receive second outputs; and

determining positions of the user interactions from the second outputs.

2. The method according to claim 1, wherein the second set is selected by comparing amplitudes of the first outputs to a threshold value.

3. The method according to claim 1, wherein the first stage and the second stage are performed over a single refresh cycle of the sensor.

4. The method according to claim 1, wherein the first stage has a shorter duration than the second stage.

5. The method according to claim 1, wherein the first set is only along the first axis or only along the second axis.

6. The method according to claim 1, wherein the first outputs sampled are sampled simultaneously.

7. The method according to claim 1, wherein the first outputs sampled are difference signals between pairs of sensor lines of the sensor.

8. The method according to claim 1, wherein the second set is selected in response to detecting that magnitudes of the first outputs are below a threshold value.

9. The method according to claim 8, wherein the threshold value is determined in relation to a baseline level determined in an absence of a finger touch.

10. The method according to claim 1, wherein the second set selected includes at least one sensor line along the first axis and at least one other sensor line along the second axis.

11. The method according to claim 1, comprising:

selecting at least one additional sensor line, that is contiguous to the second set; and

including the at least one additional sensor line in the second set.

12. The method according to claim 1, comprising

restricting a size of the second set.

13. The method according to claim 12, wherein the size of the second set is restricted by selecting sensor lines providing a strongest indication the user interactions.

14. The method according to claim 12, comprising transmitting the positions determined to a host computer associated with the sensor.

15. The method according to claim 1, wherein the user interactions interact with the sensor by touching the sensor or by hovering over the sensor.

16. The method according to claim 1, wherein the user interactions are fingertips.

17. A device comprising:

a sensor including sensor lines arranged along a first axis and along a second axis to form a grid; and

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

sample first outputs of the sensor responsive to simultaneously triggering a plurality first set of the sensor lines of the sensor with a same signal over a first stage of detection;

select a second set of the sensor lines of the sensor that indicate a presence of the user interactions from based on the first outputs sampled;

scan based on a multi-touch detection method only the second set one sensor line at a time over a second stage of detection to receive second outputs;

sample second outputs responsive to the scanning over the second stage of detection; and

determine positions of the user interactions on the sensor from the second outputs sampled over the second stage of detection.

18. The device according to claim 17, wherein the first stage and the second stage are performed over a single refresh cycle of the sensor.

19. The device according to claim 17, wherein the first set is only along the first axis or only along the second axis.

20. The device according to claim 17, wherein the first outputs sampled are difference signals between pairs of sensor lines of the sensor.