Architecture and method for multi-aspect touchscreen scanning

• US 8,711,121 B2
• Filed: 12/12/2008
• Issued: 04/29/2014
• 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.
• Primary Examiner(s): Lefkowitz, Sumati
• Assistant Examiner(s): Tung, David
• Application Number:
  US12/333,473
• Publication Number:
  US 20100149110A1
• Time in Patent Office: 1,964 Days
• Field of Search: 345173-178
• 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 2203/04808 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 conductor pattern including a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a second direction different from the first direction;

a first circuit for detecting first response signals produced by each of the plurality of first conductors to identify a first identified conductor of the plurality of first conductors;

a second circuit for detecting second response signals produced by each of the plurality of second conductors to identify a second identified conductor of the plurality of second conductors, an intersection between the first identified conductor and the second identified conductor corresponding to a possible location of a user'"'"'s interaction with the conductor pattern; and

a signal processing circuit for receiving a select response signal from the second identified conductor produced in response to a select input signal applied to the first identified conductor, the select input signal being applied to the first identified conductor after the possible location is identified, the select response signal being used to determine whether the possible location is an actual location of the user'"'"'s interaction with the conductor pattern.

2. The apparatus of claim 1, wherein:

the first circuit includes a first signal generating circuit for generating and sequentially applying first input signals to the plurality of first conductors and for generating the select input signal;

the first circuit includes a first signal detecting circuit for detecting the first response signals produced in response to the first input signals;

the second circuit includes a second signal generating circuit for generating and sequentially applying second input signals to the plurality of second conductors; and

the second circuit includes a second signal detecting circuit for detecting the second response signals produced in response to the second input signals and for detecting the select response signal and providing the select response signal to the signal processing circuit.

3. The apparatus of claim 1, further comprising:

a first signal selecting circuit for selectively connecting the first circuit to the plurality of first conductors; and

a second signal selecting circuit for selectively connecting the second circuit to the plurality of second conductors.

4. The apparatus of claim 1, wherein the first circuit includes the second circuit and further comprising:

a signal selecting circuit for selectively connecting the first circuit to the plurality of first conductors and the plurality of second conductors.

5. The apparatus of claim 1, wherein:

the first circuit further detects first signal components in the first response signals and provides the first signal components to the signal processing circuit;

the second circuit detects second signal components in the second response signals and provides the second signal components to the signal processing circuit; and

the signal processing circuit identifies the first identified conductor using the first signal components and the second identified conductor using the second signal components.

6. The apparatus of claim 1, wherein:

the first circuit applies the select input signal to the first identified conductor during a cross-point scanning operation; and

the first circuit skips a predetermined number of the plurality of first conductors during the cross-point scanning operation.

7. The apparatus of claim 1, wherein the first circuit includes:

a first amplification circuitry that, based on a generated signal and a detection signal corresponding to one of the first response signals, generates an output signal and a feedback signal, wherein the feedback signal is coupled to at least one first conductor of the plurality of first conductors; and

a second amplification circuitry that produces a difference signal based on a difference between the generated signal and the output signal, wherein the difference signal corresponds to signal components within the detection signal.

8. The apparatus of claim 7, further comprising:

a signal selecting circuit for selectively coupling the feedback signal to the at least one first conductor and for coupling other ones of the plurality of first conductors except for the at least one first conductor to a predetermined electric potential.

9. The apparatus of claim 7, wherein the second circuit includes:

a third amplification circuitry that, based on an additional generated signal and an additional detection signal corresponding to one of the second response signals, generates an additional output signal and an additional feedback signal, wherein the additional feedback signal is coupled to at least one of the plurality of second conductors; and

a fourth amplification circuitry that produces an additional difference signal based on a difference between the additional generated signal and the additional output signal, wherein the additional difference signal corresponds to signal components within the additional detection signal.

10. The apparatus of claim 9, further comprising:

an additional signal selecting circuit for selectively coupling the additional feedback signal to the at least one second conductor and for coupling other ones of the plurality of second conductors except for the at least one second conductor to a predetermined electric potential.

11. The apparatus of claim 9, wherein the signal processing circuit is coupled to the second amplification circuitry and the fourth amplification circuitry to receive the signal components and identify the possible location based on the signal components.

12. The apparatus of claim 11, further comprising:

a signal selecting circuit for selectively coupling the signal components corresponding to one of the difference signal and the additional difference signal to the signal processing circuit.

13. The apparatus of claim 1, wherein the signal processing circuit further receives at least one additional select response signal associated with at least one additional possible location of the user'"'"'s interaction with the conductor pattern and determines at least one actual location of the user'"'"'s interaction with the conductor pattern from the possible location and the at least one additional possible location.

14. The apparatus of claim 13, wherein:

at least one of the possible location and the at least one additional possible location corresponds to a phantom location; and

the signal processing circuit further prevents the phantom location from being considered one of the at least one actual location.

15. A method, comprising:

detecting, by a first circuit, first response signals produced by each of a plurality of first conductors of a conductor pattern to identify a first identified conductor of the plurality of first conductors, the plurality of first conductors being disposed in a first direction;

detecting, by a second circuit, second response signals produced by each of a plurality of second conductors of the conductor pattern to identify a second identified conductor of the plurality of second conductors, the plurality of second conductors being disposed in a second direction different from the first direction;

identifying, by a signal processing circuit, an intersection between the first identified conductor and the second identified conductor as corresponding to a possible location of a user'"'"'s interaction with the conductor pattern; and

after identifying the possible location, receiving, by the signal processing circuit, a select response signal from the second identified conductor produced in response to a select input signal applied to the first identified conductor to determine whether the possible location is an actual location of the user'"'"'s interaction with the conductor pattern.

16. The method of claim 15, further comprising:

generating and sequentially applying first input signals to the plurality of first conductors, the first response signals being produced in response to the first input signals; and

generating and sequentially applying second input signals to the plurality of second conductors, the second response signals being produced in response to the second input signals.

17. The method of claim 15, further comprising:

selectively connecting the first circuit to the plurality of first conductors; and

selectively connecting the second circuit to the plurality of second conductors.

18. The method of claim 15, wherein the first circuit includes the second circuit and further comprising:

selectively connecting the first circuit to the plurality of first conductors and the plurality of second conductors.

19. The method of claim 15, further comprising:

detecting, by the first circuit, first signal components in the first response signals;

providing the first signal components to the signal processing circuit;

detecting, by the second circuit, second signal components in the second response signals;

providing the second signal components to the signal processing circuit;

identifying, by the signal processing circuit, the first identified conductor using the first signal components; and

identifying, by the signal processing circuit, the second identified conductor using the second signal components.

20. The method of claim 15, further comprising:

applying, by the first circuit, the select input signal to the first identified conductor during a cross-point scanning operation; and

skipping, by the first circuit, a predetermined number of the plurality of first conductors during the cross-point scanning operation.

21. The method of claim 15, further comprising:

receiving, by the signal processing circuit, at least one additional select response signal associated with at least one additional possible location of the user'"'"'s interaction with the conductor pattern; and

determining, by the signal processing circuit, at least one actual location of the user'"'"'s interaction with the conductor pattern from the possible location and the at least one additional possible location.

22. The method of claim 21, wherein at least one of the possible location and the at least one additional possible location corresponds to a phantom location, and further comprising:

preventing, by the signal processing circuit, the phantom location from being considered one of the at least one actual location.

23. The method of claim 21, wherein the possible location and the at least one additional possible location are possible multi-touch locations, and further comprising:

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

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

24. The method of claim 23, wherein:

the performing coarse cross point scanning of at least one of the possible multi-touch locations includes resolving at least two possible multi-touch locations of the as the first plurality of actual locations.

25. The method of claim 23, 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.

26. The method of claim 15, further comprising:

detecting the user'"'"'s interaction with the conductor pattern by evaluating respective characteristics of the first and second response signals.

27. A processor programmed to execute a process for detecting a user'"'"'s interaction with a panel, the process comprising:

detecting first response signals produced by each of a plurality of first conductors of a conductor pattern to identify a first identified conductor of the plurality of first conductors, the plurality of first conductors being disposed in a first direction;

detecting second response signals produced by each of a plurality of second conductors of the conductor pattern to identify a second identified conductor of the plurality of second conductors, the plurality of second conductors being disposed in a second direction different from the first direction;

identifying an intersection between the first identified conductor and the second identified conductor as corresponding to a possible location of a user'"'"'s interaction with the conductor pattern; and

after identifying the possible location, receiving a select response signal from the second identified conductor produced in response to a select input signal applied to the first identified conductor to determine whether the possible location is an actual location of the user'"'"'s interaction with the conductor pattern.