Method and apparatus for detecting simultaneous touch events on a bending-wave touchscreen

• US 9,696,856 B2
• Filed: 09/29/2009
• Issued: 07/04/2017
• Est. Priority Date: 09/29/2009
• Status: Active Grant

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Elo Touch Solutions, Inc.
• Inventors: D'Souza, Henry M.
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): PARKER, JEFFREY ALAN
• Application Number:
  US12/569,608
• Publication Number:
  US 20110074544A1
• Time in Patent Office: 2,835 Days
• Field of Search: 345173, 345174, 345156
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/0433 in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member

Abstract

A method of detecting touch events on a touch panel includes identifying sets of coordinate locations based on at least one signal from at least one sensor. The at least one signal is responsive to at least one touch event, and the coordinate locations represent matches with respect to template fingerprints. Consecutive ones of the sets of coordinate locations are compared based on a first distance threshold to form streams of spatially continuous coordinate locations that satisfy the first distance threshold. A touch event is identified corresponding to one of the streams of spatially continuous coordinate locations, the stream having a minimum number of spatially continuous coordinate locations.

Claims

1. A method for determining touch events on a touch panel, the method comprising:

identifying initial coordinate locations representative of the touch events based at least on template fingerprints, wherein a template fingerprint of the template fingerprints is an acoustic profile of a signal that represents a sound recognized when a coordinate location on the touch panel is touched, wherein the template fingerprint is established prior to the touch events, and wherein one of the initial coordinate locations corresponds to a primary touch event;

identifying subsequent coordinate locations representative of the touch events based at least on the template fingerprints;

gathering coordinate locations that are within a distance threshold to form groups of coordinate locations;

identifying one or more secondary touch events that correspond to one or more of the groups with a predetermined number of coordinate locations identified within a predetermined period of time; and

identifying a secondary touch event of the one or more secondary touch events based at least on a ratio between a score associated with the primary touch event and a score associated with the secondary touch event.

2. The method of claim 1, wherein the identifying the initial coordinate locations comprises:

identifying the primary touch event as one of the initial coordinate locations that has a highest degree of correlation with one of the template fingerprints, the highest degree of correlation exceeding a predetermined degree of correlation;

eliminating one or more of the initial coordinate locations that are within a predetermined distance of the primary touch event; and

identifying additional initial coordinate locations representative of the touch events until a maximum number of coordinate locations is identified.

3. The method of claim 1, wherein the identifying the subsequent coordinate locations comprises:

identifying a best match that corresponds to one of the subsequent coordinate locations with a highest degree of correlation with one of the template fingerprints;

eliminating one or more of the subsequent coordinate locations that are within a predetermined distance of the best match; and

identifying additional subsequent coordinate locations representative of the touch events until a maximum number of coordinate locations is identified.

4. The method of claim 1, wherein the initial and subsequent coordinate locations are identified from one or more signals from one or more sensors.

5. The method of claim 1, wherein the identifying the secondary touch event comprises:

assigning a score to each of the initial and subsequent coordinate locations based at least on a degree of correlation with one of the template fingerprints;

calculating a primary average score by averaging the scores associated with the initial and subsequent coordinate locations in a group that includes the primary touch event; and

calculating a secondary average score by averaging the scores associated with the initial and subsequent coordinate locations in a group corresponding to the secondary touch event.

6. The method of claim 1, further comprising;

identifying one or more new coordinate locations after identification of the primary touch event and the one or more secondary touch events.

7. The method of claim 1, wherein the predetermined number of coordinate locations is at least three.

12. The method of claim 1, further comprising:

eliminating one or more of the groups when one or more of the subsequent coordinate locations are excluded from the one or more of the groups.

13. The method of claim 1, further comprising:

reporting the initial coordinate location corresponding to the primary touch event to an operating system with substantially no delay.

14. The method of claim 1, further comprising:

associating, prior to the touch events, a coordinate position on the touch panel with one or more sensor signals generated when a known coordinate location is sensed;

processing the one or more sensor signals; and

storing a first result as a first template fingerprint of the template fingerprints.

15. The method of claim 14, further comprising:

processing the one or more sensor signals differently; and

storing a second result as a second template fingerprint, wherein the first template fingerprint and the second template fingerprint represent the coordinate position on the touch panel.

16. The method of claim 15, further comprising:

constructing a new template fingerprint based at least on the first template fingerprint and the second template fingerprint when the initial coordinate locations representative of the touch events are identified.

17. The method of claim 1, wherein the template fingerprints are based at least on a phase difference.

8. A touch system, comprising:

a touch panel;

one or more sensors configured to generate one or more signals responsive to touch events on the touch panel; and

a processor module configured to;

identify initial coordinate locations representative of the touch events based at least on template fingerprints, wherein a template fingerprint of the template fingerprints is an acoustic profile of a signal that represents a sound recognized when a coordinate location on the touch panel is touched, wherein the template fingerprint is established prior to the touch events, wherein one of the initial coordinate locations corresponds to a primary touch event;

identify subsequent coordinate locations representative of the touch events based at least on the template fingerprints;

gather coordinate locations that are within a distance threshold to form groups of coordinate locations;

identify one or more secondary touch events that correspond to one or more of the groups with a predetermined number of coordinate locations identified within a predetermined period of time; and

identify a secondary touch event of the one or more secondary touch events based at least on a ratio between a score associated with the primary touch event and a score associated with the secondary touch event.

9. The touch system of claim 8, wherein the processor module is further configured to construct a fingerprint from the one or more signals based at least on a phase difference.

10. The touch system of claim 8, wherein the processor module is configured to identify the primary touch event as one of the initial coordinate locations that has a highest degree of correlation with one of the template fingerprints, the highest degree of correlation exceeding a predetermined degree of correlation.

11. The touch system of claim 8, wherein the processor module is further configured to eliminate initial and subsequent coordinate locations that are within a predetermined distance of the touch events.

18. The touch system of claim 8, further comprising:

a memory, wherein the processor module is further configured to;

associate, prior to the touch events, a coordinate position on the touch panel with one or more sensor signals generated when a known coordinate location is sensed;

process the one or more sensor signals; and

store a first result as a first template fingerprint of the template fingerprints in the memory.

19. The touch system of claim 18, wherein the processor module is further configured to:

process the one or more sensor signals differently; and

store a second result as a second template fingerprint in the memory, wherein the first template fingerprint and the second template fingerprint represent the coordinate position on the touch panel.

20. The touch system of claim 19, wherein the processor module is further configured to:

construct a new template fingerprint based at least on the first template fingerprint and the second template fingerprint when the initial coordinate locations representative of the touch events are identified.