SYSTEMS AND METHODS FOR ASSESSING LOCATIONS OF MULTIPLE TOUCH INPUTS

• US 20090284495A1
• Filed: 05/13/2009
• Published: 11/19/2009
• Est. Priority Date: 05/14/2008
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Cordeiro, Craig A., GEAGHAN, Bernard O.
• Granted Patent: US 8,493,355 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 2203/04108 Touchless 2D- 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 without distance measurement in the Z direction
• CPC Class Codes: G06F 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• CPC Class Codes: G06F 3/041662 using alternate mutual and self-capacitive scanning
• 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
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

Matrix-based touch input systems assess touch locations of two or more temporally overlapping touch inputs by forming valid x-y coordinate pairs from independently determined x- and y-coordinates. Valid x-y pairs are formed based on comparing one or more signal parameters such as signal magnitude, signal strength, signal width, and signal rates of change. In matrix capacitive systems where capacitance-to-ground signals are used to determine the x- and y-coordinates, the determined coordinates may be formed into valid x-y pairs using mutual capacitance measurements. When resolving more than two temporally overlapping touches, information gained by resolving a valid x-y coordinate pair of at least one of the touches may be used to resolve the remaining touches.

Claims

1. For use in a matrix capacitive touch screen system that includes a sensor having a plurality of x-electrodes for providing x-signals based on capacitance-to-ground measurements and indicative of x-coordinates of touch inputs, and a plurality of y-electrodes for providing y-signals based on capacitance-to-ground measurements and indicative of y-coordinates of touch inputs, a method for assessing touch locations of two or more temporally overlapping touch inputs, the method comprising:

responsive to capacitance-to-ground x-signals, determining valid x-coordinates of the two or more temporally overlapping touch inputs;

responsive to capacitance-to-ground y-signals, determining valid y-coordinates of the two or more temporally overlapping touch inputs; and

forming valid x-y pairs from the determined x- and y-coordinates, the valid x-y pairs being indicative of the touch locations.

2. The method of claim 1, wherein forming valid x-y pairs includes comparing timing sequences of capacitance-to-ground x-signals to timing sequences of capacitance-to-ground y-signals.

3. The method of claim 1, wherein forming valid x-y pairs includes comparing magnitudes of capacitance-to-ground x-signals to magnitudes of capacitance-to-ground y-signals.

4. The method of claim 1, wherein forming valid x-y pairs includes comparing rates of change of at least one parameter of capacitance-to-ground x-signals to rates of change of the at least one parameter of capacitance-to-ground y-signals.

5. The method of claim 4, wherein the at least one parameter includes signal strength.

6. The method of claim 4, wherein the at least one parameter includes signal width.

7. The method of claim 1, wherein forming valid x-y pairs includes measuring mutual capacitance signals between x-electrodes located proximate to the determined x-coordinates and y-electrodes located proximate to the determined y-coordinates.

8. The method of claim 1, further comprising sensing capacitance-to-ground x-signals and capacitance-to-ground y-signals associated with pre-touch hovering of at least one of the touch inputs.

9. The method of claim 8, wherein forming valid x-y pairs includes using the sensed pre-touch hovering signals.

10. The method of claim 1, wherein forming valid x-y pairs includes comparing possible coordinate pairs to allowed touch areas.

11. A matrix capacitive touch screen system comprising:

a sensor including a plurality of x-electrodes for providing x-signals based on capacitance-to-ground measurements and indicative of x-coordinates of touch input locations, and a plurality of y-electrodes for providing y-signals based on capacitance-to-ground measurements and indicative of y-coordinates of touch input locations;

a controller including logic circuitry and coupled to the x-electrodes to receive the x-signals and coupled to the y-electrodes to receive the y-signals, the controller configured to determine one or more x-coordinates from the x-signals and one or more y-coordinates from the y-signals, and responsive to two or more temporally overlapping touch inputs applied to the touch sensor to form valid x-y pairs from the determined x-coordinates and determined y-coordinates, the valid x-y pairs being indicative of locations of the two or more temporally overlapping touch inputs.

12. The touch screen system of claim 11, further comprising a processor to receive the valid x-y pairs from the controller and to execute operations of one or more applications in response thereto.

13. The touch screen system of claim 12, wherein the controller is further configured to receive information from the processor related to application-specific allowed touch areas, and to use the received information to form the valid x-y pairs.

14. The touch screen system of claim 11 implemented in a multiplayer game.

15. The touch screen system of claim 11 implemented in a mobile device.

16. For use in a matrix touch screen system that includes a sensor providing x-signals indicative of x-coordinates of touch inputs and y-signals indicative of y-coordinates of touch inputs, a method for assessing touch locations of three or more temporally overlapping touch inputs comprising:

determining valid x-coordinates of the three or more temporally overlapping touch inputs from received x-signals;

determining valid y-coordinates of the three or more temporally overlapping touch inputs from received y-signals;

forming a first valid x-y pair from the determined x-coordinates and determined y-coordinates, the first valid x-y pair being indicative of touch location of a first one of the three or more temporally overlapping touch inputs, the remaining touch inputs being unresolved; and

responsive to the first valid x-y pair, forming additional valid x-y pairs for one or more of the remaining unresolved touch inputs.

17. The method of claim 16, further comprising delaying forming additional valid x-y pairs until sufficient additional x-signals or y-signals are received to allow one or more of the remaining unresolved touch inputs to be validated.

18. The method of claim 16, further comprising reporting valid x-y pairs as touch locations to a processor executing operations of an application based on the touch locations.

19. The method of claim 18, further comprising reporting x- and y-coordinates of the remaining unresolved touch inputs to the processor and, responsive thereto, receiving information from the processor related to application-specific allowed touch areas.

20. The method of claim 16, wherein the sensor is a matrix capacitive sensor.

21. The method of claim 16, wherein the sensor is an IR sensor.

22. The method of claim 16, wherein the sensor is a SAW sensor.

23. For use in a matrix capacitive touch screen system that includes a sensor and a display, the sensor having a plurality of x-electrodes for providing x-signals based on capacitance-to-ground measurements and indicative of x-coordinates of touch inputs, and a plurality of y-electrodes for providing y-signals based on capacitance-to-ground measurements and indicative of y-coordinates of touch inputs, a method comprising:

detecting two temporally overlapping touch inputs to the sensor;

responsive to capacitance-to-ground x-signals, determining valid x-coordinates of the two temporally overlapping touch inputs;

responsive to capacitance-to-ground y-signals, determining valid y-coordinates of the two temporally overlapping touch inputs;

defining a bounding box having vertices at intersections of the determined x- and y-coordinates, the bounding box associated with an area indicated on the display; and

adjusting the area indicated on the display in response to detecting relative motion of the two overlapping touch inputs.

24. A matrix capacitive touch screen system comprising:

a display;

a sensor including a plurality of x-electrodes for providing x-signals based on capacitance-to-ground measurements and indicative of x-coordinates of touch input locations, and a plurality of y-electrodes for providing y-signals based on capacitance-to-ground measurements and indicative of y-coordinates of touch input locations;

a controller including logic circuitry and coupled to the x-electrodes to receive the x-signals and coupled to the y-electrodes to receive the y-signals, the controller configured to determine valid x-coordinates of touch inputs from received x-signals and to determine valid y-coordinates of touch inputs from received y-signals, wherein in response to detecting two temporally overlapping touch inputs the controller defines a bounding box having vertices at intersections of the determined x- and y-coordinates, adjusts the bounding box based on detecting subsequent relative motion between the two touch inputs, and transmits information related to the bounding box for indication on the display.

25. For use in a matrix touch screen having a plurality of nodes at the intersections of x- and y-sensor bars, each node being driven by electronics such that it yields a signal strength, a method for assessing touch locations of two or more temporally overlapping touch inputs comprising:

for nodes having signal strength above a defined touch-event threshold;

(1) associating the node having the highest signal strength with a first touch;

(2) associating nodes adjacent the node with the highest signal strength with the first touch;

(3) among nodes not associated with the first touch, associating the node having the highest signal strength with a second touch; and

,

(4) associating nodes adjacent to the node associated with the second touch with the second touch.

26. The method of claim 25, wherein adjacent at least comprises nodes one node away from a given node.

27. The method of claim 26, further comprising:

(2b) associating unassociated nodes adjacent to nodes associated with the first touch with a reserve area;

and wherein step (3) additionally excludes nodes included in the reserve area from consideration for the second touch.