POSITION APPARATUS FOR TOUCH DEVICE AND POSITION METHOD THEREOF

• US 20100252336A1
• Filed: 09/03/2009
• Published: 10/07/2010
• Est. Priority Date: 04/07/2009
• Status: Active Grant

• Current Assignee: Ite Tech (ITE Technologies Incorporated)
• Original Assignee: Ite Tech (ITE Technologies Incorporated)
• Inventors: Huang, Shun-Ken, Lu, Cheng-Long
• Granted Patent: US 8,420,958 B2
• Time in Patent Office: Days
• US Class Current: 178/18.60
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• 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 position apparatus of a touch device and a position method thereof are provided, wherein the touch device includes a plurality of scan lines. In the position method, a plurality of capacitances in the scan lines are sensed. Next, a plurality of capacitances respectively sensed in an i^th scan line of the scan lines and a subset of the scan lines neighboring with the i^th scan line are selected. When the capacitance sensed in the i^th scan line is larger than each of the capacitances sensed in the subset of the scan lines, the capacitance sensed in the i^th scan line is determined as a peak capacitance. Finally, a touch position is calculated according to the peak capacitance and the capacitances sensed in the subset of the scan lines.

Claims

1. A position method of a touch device, wherein the touch device has a plurality of scan lines, the position method comprising:

sensing a plurality of capacitances in the scan lines

selecting the capacitances respectively sensed in an i^th scan line of the scan lines and a subset of the scan lines neighboring with the i^th scan line;

determining the capacitance sensed in the i^th scan line is a peak capacitance when the capacitance sensed in the i^th scan line is larger than each of the capacitances sensed in the subset of the scan lines; and

calculating a touch position according to the peak capacitance and the capacitances sensed in the subset of the scan lines.

2. The position method as claimed in claim 1, wherein the step of calculating the touch position according to the peak capacitance and the capacitances sensed in the subset of the scan lines further comprises:

respectively calculating an i^th length, an (i+1)^th length, and an (i−

1)^th length according to the peak capacitance, an (i+1)^th capacitance sensed in the subset of the scan lines, and an (i−

1)^th capacitance sensed in the subset of the scan lines; and

calculating a first weighted sum of the i^th length and a sub-length as the touch position when the i^th length is smaller than a weighted value of the sub-length and a reference coefficient, wherein the sub-length is a maximum of the (i−

1)^th length and the (i+1)^th length.

3. The position method as claimed in claim 2, wherein the reference coefficient is related to an area of a touch tool.

4. The position method as claimed in claim 3, wherein the reference coefficient is larger than 1, and the reference coefficient is inversely proportional to the area of the touch tool.

5. The position method as claimed in claim 2, wherein the first weighted sum is W1=(√

{square root over (C<sub>i±

1</sub>)}×

P<sub>i±

1</sub>+√

{square root over (C_i)}×

P_i)/(√

{square root over (C<sub>i±

1</sub>)}+√

{square root over (C_i)}), where √

{square root over (C<sub>i±

1</sub>)} is the sub-length, √

{square root over (C<sub>i−

1</sub>)}, √

{square root over (C_i)}, and √

{square root over (C_i+1)} are respectively the (i−

1)^th length, the i^th length, and the (i+1)^th length, and P<sub>i−

1</sub>, P_i, and P_i+1 are respectively indices of positions where the scan lines corresponding to the (i−

1)^th capacitance C<sub>i−

1</sub>, the peak capacitance C_i, and the (i+1)^th capacitance C_i+1 are located in the touch device.

6. The position method as claimed in claim 2, wherein the step of calculating the touch position according to the peak capacitance and the capacitances sensed in the subset of the scan lines further comprises:

calculating a second weighted sum of the (i−

1)^th length, the i^th length, and the (i+1)^th length as the touch position when the i^th length is larger than or equal to the weighted value of the sub-length and the reference coefficient.

7. The position method as claimed in claim 6, wherein the second weighted sum is W2=(√

{square root over (C<sub>i−

1</sub>)}×

P<sub>i−

1</sub>+√

{square root over (C_i)}×

P_i+√

{square root over (C_i+1)}×

P_i+1)/(√

{square root over (C<sub>i−

1</sub>)}+√

{square root over (C_i)}+√

{square root over (C_i+1)}), wherein √

{square root over (C<sub>i−

1</sub>)}, √

{square root over (C_i)}, and √

{square root over (C_i+1)} are respectively the (i−

1)^th length, the i^th length, and the (i+1)^th length, and P<sub>i−

1</sub>, P_i, and P_i+1 are respectively indices of positions where the scan lines corresponding to the (i−

1)^th capacitance C<sub>i−

1</sub>, the peak capacitance C_i, and the (i+1)^th capacitance C_i+1 are located in the touch device.

8. The position method as claimed in claim 1, wherein the step of selecting the capacitances respectively sensed in the i^th scan line of the scan lines and the subset of the scan lines neighboring with the i^th scan line further comprises:

determining whether the i^th scan line is in a touch state upon the capacitance sensed in the i^th scan line and a touch threshold; and

when the i^th scan line is in the touch state, proceeding to the step of determining the capacitance in the i^th scan line is the peak capacitance when the capacitance sensed in the i^th scan line is larger than each of the capacitances sensed in the subset of the scan lines.

9. The position method as claimed in claim 1, wherein the step of calculating the touch position according to the peak capacitance and the capacitances sensed in the subset of the scan lines further comprises:

calculating a first weighted sum of the peak capacitance and a sub-capacitance as the touch position when the i^th capacitance is smaller than a weighted value of a sub-capacitance and a reference coefficient, wherein the sub-capacitance is a maximum of the (i−

1)^th capacitance and the (i+1)^th capacitance.

10. The position method as claimed in claim 9, wherein the first weighted sum is W1=(C_i±

1×

P<sub>i±

1</sub>+C_i×

P_i)/(C<sub>i±

1</sub>+C_i), where C<sub>i±

1</sub> is the sub-capacitance, and P<sub>i−

1</sub>, P_i, and P_i+1 are respectively indices of positions where the scan lines corresponding to the (i−

1)^th capacitance C<sub>i−

1</sub>, the peak capacitance C_i, and the (i+1)^th capacitance C_i+1 are located in the touch device.

11. The position method as claimed in claim 9, wherein the step of calculating the touch position according to the peak capacitance and the capacitances sensed in the subset of the scan lines further comprises:

calculating a second weighted sum of the peak capacitance, the i^th capacitance, and the (i+1)^th capacitance as the touch position when the i^th capacitance is larger than or equal to the weighted value of the sub-capacitance and the reference coefficient.

12. The position method as claimed in claim 11, wherein the second weighted sum is W2=(C_i−

1×

P<sub>i−

1</sub>+C_i×

P_i+C_i+1×

P_i+1)/(C<sub>i−

1</sub>+C_i+C_i+1), and P<sub>i−

1</sub>, P_i, and P_i+1 are respectively indices of positions where the scan lines corresponding to the (i−

1)^th capacitance C<sub>i−

1</sub>, the peak capacitance C_i, and the (i+1)^th capacitance C_i+1 are located in the touch device.

13. A position apparatus of a touch device, wherein the touch device has a plurality of scan lines, the position apparatus comprising:

a multiplexer coupled to the touch device for selecting capacitances respectively sensed in an i^th scan line of the scan lines and a subset of the scan lines neighboring with the i^th scan line; and

a processing unit, comprising;

a peak detector coupled to the multiplexer and determining the capacitance sensed in the i^th scan line is a peak capacitance when the capacitance sensed in the i^th scan line is larger than each of the capacitances sensed in the subset of the scan lines; and

a position detector coupled to the multiplexer and the peak detector and calculating a touch position according to the peak capacitance and the capacitances sensed in the subset of the scan lines when the capacitance sensed in the i^th scan line is the peak capacitance.

14. The position apparatus as claimed in claim 13, wherein the position detector respectively calculates an i^th length, an (i+1)^th length, and an (i−

1)^th length according to the peak capacitance, an (i+1)^th capacitance sensed in the subset of the scan lines, and an (i−

1)^th capacitance sensed in the subset of the scan lines, and the position detector calculates a first weighted sum of the i^th length and a sub-length as the touch position when the i^th length is smaller than a weighted value of the sub-length and a reference coefficient, wherein the sub-length is a maximum of the (i−

1)^th length and the (i+1)^th length.

15. The position apparatus as claimed in claim 14, wherein the reference coefficient is related to an area of a touch tool.

16. The position apparatus as claimed in claim 15, wherein the reference coefficient is larger than 1, and the reference coefficient is inversely proportional to the area of the touch tool.

17. The position apparatus as claimed in claim 14, wherein the first weighted sum is W1=(√

{square root over (C<sub>i±

1</sub>)}×

P<sub>i±

1</sub>+√

{square root over (C_i)}×

P_i)/(√

{square root over (C<sub>i±

1</sub>)}+√

{square root over (C_i)}), wherein √

{square root over (C<sub>i±

1</sub>)} is the sub-length, √

{square root over (C<sub>i−

1</sub>)}, √

{square root over (C_i+1)}, and √

{square root over (C_i)} are respectively the (i−

1)^th length, the (i+1)^th length, and the i^th length, and P<sub>i−

1</sub>, P_i, and P_i+1 are respectively indices of positions where the scan lines corresponding to the (i−

1)^th capacitance C<sub>i−

1</sub>, the peak capacitance C_i, and the (i+1)^th capacitance C_i+1 are located in the touch device.

18. The position apparatus as claimed in claim 14, wherein the position detector calculates a second weighted sum of the (i−

1)^th length, the i^th length, and the (i+1)^th length as the touch position when the i^th length is larger than or equal to the weighted value of the sub-length and the reference coefficient.

19. The position apparatus as claimed in claim 18, wherein the second weighted sum is W2=(√

{square root over (C<sub>i−

1</sub>)}×

P<sub>i−

1</sub>+√

{square root over (C_i)}×

P_i+√

{square root over (C_i+1×

P_i+1)})/(√

{square root over (C<sub>i−

1</sub>)}+√

{square root over (C_i)}+√

{square root over (C_i+1)}), wherein √

{square root over (C<sub>i−

1</sub>)}, √

{square root over (C_i)}, and √

{square root over (C_i+1)} are respectively the (i−

1)^th length, the i^th length, and the (i+1)^th length, and P<sub>i−

1</sub>, P_i, and P_i+1 are respectively indices of positions where the scan lines corresponding to the (i−

1)^th capacitance C<sub>i−

1</sub>, the peak capacitance C_i, and the (i+1)^th capacitance C_i+1 are located in the touch device.

20. The position apparatus as claimed in claim 13, wherein the processing unit further comprises a touch detector, the touch detector is coupled between the multiplexer and the peak detector for determining whether the i^th scan line is in a touch state upon the capacitance sensed in the i^th scan line and a touch threshold, and the peak detector determines whether the capacitance in the i^th scan line is the peak capacitance or not when the i^th scan line is in the touch state.

21. The position apparatus as claimed in claim 13, wherein the position detector calculates a first weighted sum of the peak capacitance and a sub-capacitance as the touch position when the i^th capacitance is smaller than a weighted value of the sub-capacitance and a reference coefficient, wherein the sub-capacitance is a maximum of the (i−

1)^th capacitance and the (i+1)^th capacitance.

22. The position apparatus as claimed in claim 21, wherein the first weighted sum is W1=(C_i±

1×

P<sub>i±

1</sub>+C_i×

P_i)/(C<sub>i±

1</sub>+C_i), wherein C<sub>i±

1</sub> is the sub-capacitance, and P<sub>i−

1</sub>, P_i, and P_i+1 are respectively indices of positions where the scan lines corresponding to the (i−

1)^th capacitance C<sub>i−

1</sub>, the peak capacitance C_i, and the (i+1)^th capacitance C_i+1 are located in the touch device.

23. The position apparatus as claimed in claim 21, wherein the position detector calculates a second weighted sum of the (i−

1)^th capacitance, the peak capacitance, and the (i+1)^th capacitance as the touch position when the i^th capacitance is larger than or equal to the weighted value of the sub-capacitance and the reference coefficient.

24. The position apparatus as claimed in claim 23, wherein the second weighted sum is W2=(C_i−

1×

P<sub>i−

1</sub>+C_i×

P_i+C_i+1×

P_i+1)/(C<sub>i−

1</sub>+C_i+C_i+1), wherein P<sub>i−

1</sub>, P_i, and P_i+1 are respectively indices of positions where the scan lines corresponding to the (i−

1)^th capacitance C<sub>i−

1</sub>, the peak capacitance C_i, and the (i+1)^th capacitance C_i+1 are located in the touch device.

25. The position apparatus as claimed in claim 13, further comprising:

a converting unit coupled between the multiplexer and the processing unit for converting the capacitances in an analog format to the capacitances in a digital format.