Projective Capacitive Touch Apparatus, and Method for Identifying Distinctive Positions

• US 20100039405A1
• Filed: 12/31/2008
• Published: 02/18/2010
• Est. Priority Date: 08/13/2008
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Chia, Pang-Chiang, Liao, Shih-Yi, Jou, Ming-Jong, Chen, Hsiang-Yi, Hsieh, Yao-Jen, Chou, Heng-Sheng
• Granted Patent: US 8,179,408 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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

Abstract

A projective capacitive touch apparatus and a method for identifying multi-touched positions are provided. The multi-touched positions are touched on a projective capacitive touch panel. The method comprises the following steps: generating a first set of reference values according to the first touch position; generating a plurality of second sets of reference values according to a second touch position, and filtering out at least one ghost second set of reference values from the second sets of reference values. Furthermore, the plurality of second sets of reference values comprise a real second set of reference value and at least one ghost second set of reference values, while the ghost second set of reference values comprises parts of the first set of reference values.

Claims

1. A method for identifying distinctive positions, the distinctive positions being defined on a projective capacitive touch panel, the method comprising the steps of:

(1) generating a first set of reference values according to a first touched position;

(2) generating a plurality of second sets of reference values according to a second touched position, wherein;

the plurality of the second sets of reference values comprise a real second set of reference values and at least one ghost second set of reference values; and

the at least one ghost second set of reference values comprises parts of the first set of reference values; and

(3) filtering out the at least one ghost second set of reference values.

2. The method as claimed in claim 1, wherein the step (1) is to generate a first set of coordinate values according to the first touched position, and the step (2) is to generate a plurality of second sets of coordinate values according to the second touched position.

3. The method as claimed in claim 2, wherein:

the step (1) is to generate a first set of two-dimensional coordinate values according to the first touched position;

the step (2) is to generate three second sets of two-dimensional coordinate values according to the second touched position;

the three second sets of two-dimensional coordinate values comprise a real second set of two-dimensional coordinate values and two ghost second sets of two-dimensional coordinate values; and

each of the ghost second sets of two-dimensional coordinate values comprises one different one-dimensional coordinate value of the first set of two-dimensional coordinate values.

4. The method as claimed in claim 1, after the step (2), further comprising the step of determining that the difference between the real second set of reference values and the first set of reference values is greater than a threshold value.

5. The method as claimed in claim 1, wherein the step (1) comprises the step of determining the first touched position in a first scanning cycle.

6. The method as claimed in claim 5, wherein the step (2) comprises the step of determining the second touched position in a second scanning cycle.

7. The method as claimed in claim 1, further comprising the step of generating a first set of continuous reference value sequence according to a first motion trajectory generated by movement of the first touched position.

8. The method as claimed in claim 1, further comprising the step of generating a second set of continuous reference value sequence according to a second motion trajectory generated by movement of the second touched position.

9. A projective capacitive touch apparatus, comprising:

a projective capacitive touch panel, being adapted to generate a reference signal according to a touched position;

a controller, being connected to the projective capacitive touch panel and adapted to generate a first set of reference values according to a first reference signal generated from a first touched position and to generate a plurality of second sets of reference values according to a second reference signal generated from a second touched position, wherein;

the plurality of the second sets of reference values comprise a real second set of reference values and at least one ghost second set of reference values; and

the at least one ghost second set of reference values comprises parts of the first set of reference values; and

a processor for filtering out the at least one ghost second set of reference values.

10. The projective capacitive touch apparatus as claimed in claim 9, wherein the controller is configured to generate a first set of coordinate values and a plurality of second sets of coordinate values according to the first touched position and the second touched position respectively.

11. The projective capacitive touch apparatus as claimed in claim 10, wherein:

the controller is configured to generate a first set of two-dimensional coordinate values and three second sets of two-dimensional coordinate values according to the first touched position and the second touched position respectively;

the three second sets of two-dimensional coordinate values comprise a real second set of two-dimensional coordinate values and two ghost second sets of two-dimensional coordinate values; and

each of the ghost second sets of two-dimensional coordinate values comprises one different one-dimensional coordinate value of the first set of two-dimensional coordinate values.

12. The projective capacitive touch apparatus as claimed in claim 9, wherein the processor is further configured to determine that the difference between the real second set of reference values and the first set of reference values is greater than a threshold value.

13. The projective capacitive touch apparatus as claimed in claim 9, wherein the controller is configured to determine the first touched position in a first scanning cycle.

14. The projective capacitive touch apparatus as claimed in claim 9, wherein the controller is configured to determine the second touched position in a second scanning cycle.

15. The projective capacitive touch apparatus as claimed in claim 9, wherein the controller further generates a first set of continuous reference value sequence according to a first motion trajectory generated by movement of the first touched position.

16. The projective capacitive touch apparatus as claimed in claim 9, wherein the controller further generates a second set of continuous reference value sequence according to a second motion trajectory generated by movement of the second touched position.

17. The projective capacitive touch apparatus as claimed in claim 13, wherein the first scanning cycle is smaller than 0.0125 second.

18. The projective capacitive touch apparatus as claimed in claim 14, wherein the second scanning cycle is smaller than 0.0125 second.

19. A projective capacitive touch apparatus, comprising:

a generating means for generating a first set of reference values according to a first touched position and a plurality of second sets of reference values according to a second touched position, wherein;

the plurality of second sets of reference values comprise a real second set of reference values and at least one ghost second set of reference values; and

the at least one ghost second set of reference values comprise parts of the first set of reference values; and

a filtering means for filtering out the at least one ghost second set of reference values.

20. The projective capacitive touch apparatus as claimed in claim 19, wherein the generating means is to generate a first set of coordinate values and a plurality of second sets of coordinate values according to the first touched position and the second touched position respectively.

21. The projective capacitive touch apparatus as claimed in claim 20, wherein:

the generating means is to generate a first set of two-dimensional coordinate values and three second sets of two-dimensional coordinate values according to the first touched position and the second touched position respectively;

the three second sets of two-dimensional coordinate values comprise a real second set of two-dimensional coordinate values and two ghost second sets of two-dimensional coordinate values; and

each of the ghost second sets of two-dimensional coordinate values comprises one different one-dimensional coordinate value of the first set of two-dimensional coordinate values.

22. The projective capacitive touch apparatus as claimed in claim 19, wherein the generating means is further configured to determine that the difference between the real second set of reference values and the first set of reference values is greater than a threshold value.

23. The projective capacitive touch apparatus as claimed in claim 19, wherein the generating means is configured to determine the first touched position in a first scanning cycle.

24. The projective capacitive touch apparatus as claimed in claim 23, wherein the generating means is configured to determine the second touched position in a second scanning cycle.

25. The projective capacitive touch apparatus as claimed in claim 19, wherein the generating means is to further generate a first set of continuous reference value sequence according to a first motion trajectory generated by movement of the first touched position.

26. The projective capacitive touch apparatus as claimed in claim 19, wherein the generating means is to further generate a second set of continuous reference value sequence according to a second motion trajectory generated by movement of the second touched position.

27. The projective capacitive touch apparatus as claimed in claim 23, wherein the first scanning cycle is smaller than 0.0125 second.

28. The projective capacitive touch apparatus as claimed in claim 24, wherein the second scanning cycle is smaller than 0.0125 second.