WAVEFORM DIVIDING METHOD FOR A CAPACITIVE TOUCH CONTROL DEVICE

• US 20120262193A1
• Filed: 04/12/2012
• Published: 10/18/2012
• Est. Priority Date: 04/14/2011
• Status: Active Grant

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: WU, Tsung-Hsien, Huang, Kuo-Ming
• Granted Patent: US 9,024,644 B2
• Time in Patent Office: Days
• US Class Current: 324/679
• 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 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A waveform dividing method for a capacitive touch control device saves a first waveform in a direction, and then saves a multi-touch waveform in the direction when another object further touches the capacitive touch control device. If the multi-touch waveform is identified as having waveform overlapping, a second waveform is extracted from the difference between the multi-touch waveform and the first waveform. By calculating with the second waveform, accurate positioning of the objects on the capacitive touch control device can be achieved.

Claims

1. A waveform dividing method for a capacitive touch control device, comprising steps of:

A.) saving and updating a first waveform in a direction caused by a first object when the first object touches the capacitive touch control device;

B.) saving a multi-touch waveform in the direction when the first object is stationary on the capacitive touch control device and a second object further touches the capacitive touch control device, wherein the multi-touch waveform is established by the first waveform and a second waveform in the direction caused by the second object;

C.) identifying whether the multi-touch waveform has waveform overlapping resulted from the first waveform and the second waveform; and

D.) extracting the second waveform from the multi-touch waveform and the first waveform if the multi-touch waveform is identified as having waveform overlapping.

2. The waveform dividing method of claim 1, further comprising a step of calculating a starting point and an end point of the first waveform.

3. The waveform dividing method of claim 2, further comprising a step of calculating a starting point and an end point of the second waveform.

4. The waveform dividing method of claim 1, wherein the step C comprises a step of identifying the multi-touch waveform as having waveform overlapping if the first waveform and the second waveform are connected or indistinguishable from each other.

5. The waveform dividing method of claim 1, wherein the step C comprises a step of identifying the multi-touch waveform as having waveform overlapping if the multi-touch waveform does not have a valley or if the multi-touch waveform has a valley whose sensed value exceeds a threshold value.

6. The waveform dividing method of claim 1, wherein the step C comprises a step of defining an overlapping area on the capacitive touch control device according to a position of the first waveform, to facilitate determination of whether the multi-touch waveform has waveform overlapping.

7. The waveform dividing method of claim 1, wherein the step C comprises steps of:

identifying the number of objects according to a sensed result in the direction; and

identifying the number of objects according to a sensed result in a second direction.

8. A waveform dividing method for a capacitive touch control device, comprising steps of:

A.) saving a first waveform in a direction caused by a first object when the first object touches the capacitive touch control device;

B.) identifying waveform overlapping in a multi-touch waveform established by the first waveform and a second waveform in the direction caused by a second object;

C.) extracting the second waveform from a difference between the multi-touch waveform and the first waveform; and

D.) calculating with the second waveform to produce a position information in the direction for the second object.

9. The waveform dividing method of claim 8, further comprising a step of calculating a starting point and an end point of the first waveform.

10. The waveform dividing method of claim 9, further comprising a step of calculating a starting point and an end point of a waveform of the second object.

11. The waveform dividing method of claim 8, wherein the step B comprises a step of identifying the multi-touch waveform as having waveform overlapping in the direction, if the first waveform and the second waveform are connected or indistinguishable from each other.

12. The waveform dividing method of claim 8, wherein the step B comprises a step of identifying the multi-touch waveform as having waveform overlapping in the direction, if the multi-touch waveform does not have a valley or if the multi-touch waveform has a valley whose sensed value exceeds a threshold value.

13. The waveform dividing method of claim 8, wherein the step B comprises a step of defining an overlapping area on the capacitive touch control device according to a position of the first waveform, to facilitate determination of whether the multi-touch waveform has waveform overlapping.

14. The waveform dividing method of claim 8, wherein the step B comprises steps of:

identifying the number of objects according to a sensed result in the direction; and

identifying the number of objects according to a sensed result in a second direction.

15. A waveform dividing method for a capacitive touch control device, comprising steps of:

A.) saving a first waveform in a direction;

B.) identifying waveform overlapping in a multi-touch waveform established by the first waveform and a second waveform in the direction;

C.) reconstructing the second waveform from a difference between the multi-touch waveform and the first waveform; and

D.) calculating with the second waveform to produce a position information.

16. The waveform dividing method of claim 15, further comprising a step of calculating a starting point and an end point of the first waveform.

17. The waveform dividing method of claim 16, further comprising a step of calculating a starting point and an end point of the second waveform.

18. The waveform dividing method of claim 15, wherein the step B comprises a step of identifying the multi-touch waveform as having waveform overlapping in the direction, if the first waveform and the second waveform are connected or indistinguishable from each other.

19. The waveform dividing method of claim 15, wherein the step B comprises a step of identifying the multi-touch waveform as having waveform overlapping in the direction, if the multi-touch waveform does not have a valley or if the multi-touch waveform has a valley whose sensed value exceeds a threshold value.

20. The waveform dividing method of claim 15, wherein the step B comprises a step of defining an overlapping area on the capacitive touch control device according to a position of the first waveform, to facilitate determination of whether the multi-touch waveform has waveform overlapping.

21. The waveform dividing method of claim 15, wherein the step B comprises steps of:

identifying the number of objects as a first number according to a sensed result in the direction;

identifying the number of objects as a second number according to a sensed result in a second direction; and

comparing the first number and the second number.