Architecture and method for multi-aspect touchscreen scanning

• US 20100149110A1
• Filed: 12/12/2008
• Published: 06/17/2010
• Est. Priority Date: 12/12/2008
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Gray, Patrick T.
• Granted Patent: US 8,711,121 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• 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 2203/04808 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 3/041661 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 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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

Architecture and method for multi-aspect touchscreen scanning. This architectures employs a single type of circuitry capable to perform both signal generation and signal detection for performing both zone scanning and cross point within a touchscreen to identify a user'"'"'s interaction with the touchscreen and to discriminate actual touch locations on the touchscreen (including multiple, concurrent user touch locations on the touchscreen). This signal generation/detection circuitry can be implemented multiple times within the architecture (e.g., one for providing/detecting signals of conductors aligned in a first direction across the touchscreen, and another for providing/detecting signals of conductors aligned in a second direction across the touchscreen). Moreover, a combination of both zone scanning and cross point within the touchscreen allows for a very accurate discrimination between false/phantom touch locations and actual/real touch locations made by a user interacting with the touchscreen.

Claims

1. An apparatus, comprising:

a touchscreen including a plurality of first conductors aligned in a first direction and a plurality of second conductors aligned in a second direction;

a first amplification circuitry that, based on an input signal, generates an output signal and a feedback signal, wherein the feedback signal is coupled to a first conductor of the plurality of first conductors; and

a second amplification circuitry that produces a response signal based on a difference between the input signal and the output signal, wherein the response signal corresponds to a user'"'"'s interaction with the touchscreen.

2. The apparatus of claim 1, further comprising:

a grounding circuitry that grounds all conductors of the plurality of first conductors except the first conductor to which the feedback signal is coupled.

3. The apparatus of claim 1, wherein:

the first amplification circuitry includes a first input and a second input;

the input signal is coupled to the first input; and

the feedback signal is coupled to the second input.

4. The apparatus of claim 1, further comprising:

a multiplexor (MUX) that successively couples the feedback signal to each conductor of the plurality of first conductors.

5. The apparatus of claim 1, further comprising:

a third amplification circuitry that, based on at least one additional input signal, generates at least one additional output signal and at least one additional feedback signal, wherein the at least one additional feedback signal is coupled to a first conductor of the plurality of second conductors;

a fourth amplification circuitry that produces at least one additional response signal based on at least one additional difference between the at least one additional input signal and the at least one additional output signal, wherein the at least one additional response signal also corresponding to the user'"'"'s interaction with the touchscreen; and

a signal response processing module that processes the response signal and the at least one additional response signal to identify a location of the user'"'"'s interaction with the touchscreen.

6. The apparatus of claim 5, further comprising:

a grounding circuitry that;

grounds all conductors of the plurality of first conductors except the first conductor of the plurality of first conductors to which the feedback signal is coupled; and

grounds all conductors of the plurality of second conductors except the first conductor of the plurality of second conductors to which the at least one additional feedback signal is coupled.

7. The apparatus of claim 5, further comprising:

a first multiplexor (MUX) that successively couples the feedback signal to each conductor of the plurality of first conductors; and

a second MUX that successively couples the at least one additional feedback signal to each conductor of the plurality of second conductors.

8. The apparatus of claim 1, further comprising:

a grounding circuitry that grounds all conductors of the plurality of first conductors except the first conductor of the plurality of first conductors to which the feedback signal is coupled; and

wherein;

a ground potential level to which the grounding circuitry performs grounding is an actual ground potential level or a circuit common voltage potential.

9. The apparatus of claim 8, further comprising:

a multiplexor (MUX) that successively couples the feedback signal to each conductor of the plurality of first conductors; and

wherein;

except during a time period in which the MUX couples the feedback signal to the first conductor of the plurality of first conductors, the MUX couples the first conductor of the plurality of first conductors to the grounding circuitry.

10. A method, comprising:

performing first zone scanning of a plurality of first conductors aligned in a first direction in a touchscreen;

performing second zone scanning of a plurality of second conductors aligned in a second direction in the touchscreen;

based on the first zone scanning and the second zone scanning, identifying a plurality of possible multi-touch locations corresponding to a user'"'"'s interaction with the touchscreen; and

performing cross point scanning of at least one of the plurality of possible multi-touch locations, based on the plurality of possible multi-touch locations identified, to identify at least one actual touch location corresponding to the user'"'"'s interaction with the touchscreen.

11. The method of claim 10, wherein:

the performing cross point scanning of at least one of the plurality of possible multi-touch locations, based on the plurality of possible multi-touch locations identified, to identify at least one actual touch location corresponding to the user'"'"'s interaction with the touchscreen further comprises;

performing a coarse cross point scanning of the plurality of possible multi-touch locations to identify a first plurality of actual touch locations corresponding to the user'"'"'s interaction with the touchscreen; and

performing a fine cross point scanning of the first plurality of actual touch locations to identify a second plurality of actual touch locations corresponding to the user'"'"'s interaction with the touchscreen.

12. The method of claim 11, wherein:

the performing cross point scanning of at least one of the plurality of possible multi-touch locations includes interpolating at least two possible multi-touch locations of the plurality of possible multi-touch locations.

13. The method of claim 11, wherein:

the performing the fine cross point scanning of the first plurality of actual touch locations includes interpolating at least two actual touch locations of the first plurality of actual touch locations.

14. The method of claim 10, wherein:

the first zone scanning includes coupling a signal to a first conductor of the plurality of first conductors and detecting a change in the signal caused by the user'"'"'s interaction with the touchscreen.

15. The method of claim 10, wherein:

the cross point scanning includes coupling a first signal to a first conductor of the plurality of first conductors and detecting a second signal in a second conductor of the plurality of second conductors caused by the user'"'"'s interaction with the touchscreen; and

an intersection of the first conductor and the second conductor corresponds to the at least one actual touch location corresponding to the user'"'"'s interaction with the touchscreen.

16. The method of claim 10, further comprising:

identifying a plurality of possible touch locations corresponding to the user'"'"'s interaction with the touchscreen within each of the plurality of possible multi-touch locations; and

performing cross point scanning of each of the plurality of possible touch locations within each of the plurality of possible multi-touch locations to identify a plurality of actual touch locations within each corresponding possible multi-touch location of the plurality of possible multi-touch locations.

17. The method of claim 16, wherein:

the plurality of possible touch locations include actual touch locations and false touch locations within each of the plurality of possible multi-touch locations.

18. The method of claim 10, wherein:

the performing first zone scanning includes coupling an amplifier feedback signal to a first conductor within the plurality of first conductors.

19. The method of claim 18, further comprising:

detecting the user'"'"'s interaction with the touchscreen by evaluating a characteristic of the amplifier feedback signal that is coupled to the first conductor within the plurality of first conductors.

20. The method of claim 10, further comprising:

employing an amplification circuitry to generate an amplifier feedback signal from an input signal;

coupling the amplifier feedback signal to a first conductor within the plurality of first conductors;

subtracting the input signal from the amplifier feedback signal to produce a touch response signal; and

evaluating a magnitude of the touch response signal to determine if a user is interacting with the first conductor within the plurality of first conductors.

21. An apparatus, comprising:

a first signal generation/detection circuitry that performs first zone scanning of a plurality of first conductors aligned in a first direction in a touchscreen; and

a second signal generation/detection circuitry that performs second zone scanning of a plurality of second conductors aligned in a second direction in the touchscreen; and

wherein;

based on the first zone scanning and the second zone scanning, the first signal generation/detection circuitry and the second signal generation/detection circuitry cooperatively identify a plurality of possible multi-touch locations corresponding to a user'"'"'s interaction with the touchscreen; and

the first signal generation/detection circuitry and the second signal generation/detection circuitry cooperatively perform cross point scanning of at least one of the plurality of possible multi-touch locations, based on the plurality of possible multi-touch locations identified, to identify at least one actual touch location corresponding to the user'"'"'s interaction with the touchscreen.

22. The apparatus of claim 21, wherein:

when performing the cross point scanning, the first signal generation/detection circuitry and the second signal generation/detection circuitry cooperatively perform;

a coarse cross point scanning of the plurality of possible multi-touch locations to identify a first plurality of actual touch locations corresponding to the user'"'"'s interaction with the touchscreen; and

a fine cross point scanning of the first plurality of actual touch locations to identify a second plurality of actual touch locations corresponding to the user'"'"'s interaction with the touchscreen.

23. The apparatus of claim 22, wherein:

the coarse cross point scanning of the plurality of possible multi-touch locations includes interpolating at least two possible multi-touch locations of the plurality of possible multi-touch locations.

24. The apparatus of claim 22, wherein:

the fine cross point scanning of the first plurality of actual touch locations includes interpolating at least two actual touch locations of the first plurality of actual touch locations.

25. The apparatus of claim 21, wherein:

the first zone scanning includes coupling a signal to a first conductor of the plurality of first conductors and detecting a change in the signal caused by the user'"'"'s interaction with the touchscreen.

26. The apparatus of claim 21, wherein:

the cross point scanning includes coupling a first signal to a first conductor of the plurality of first conductors and detecting a second signal in a second conductor of the plurality of second conductors caused by the user'"'"'s interaction with the touchscreen; and

an intersection of the first conductor and the second conductor corresponds to the at least one actual touch location corresponding to the user'"'"'s interaction with the touchscreen.

27. The apparatus of claim 21, wherein:

the first signal generation/detection circuitry and the second signal generation/detection circuitry cooperatively;

identify a plurality of possible touch locations corresponding to the user'"'"'s interaction with the touchscreen within each of the plurality of possible multi-touch locations; and

perform cross point scanning of each of the plurality of possible touch locations within each of the plurality of possible multi-touch locations to identify a plurality of actual touch locations within each corresponding possible multi-touch location of the plurality of possible multi-touch locations.

28. The apparatus of claim 27, wherein:

the plurality of possible touch locations include actual touch locations and false touch locations within each of the plurality of possible multi-touch locations.