Position apparatus for touch device and position method thereof

• US 8,420,958 B2
• Filed: 09/03/2009
• Issued: 04/16/2013
• Est. Priority Date: 04/07/2009
• Status: Expired due to Fees

• Current Assignee: Ite Tech (ITE Technologies Incorporated)
• Original Assignee: Ite Tech (ITE Technologies Incorporated)
• Inventors: Lu, Cheng-Long, Huang, Shun-Ken
• Primary Examiner(s): Chow, Van
• Application Number:
  US12/553,972
• Publication Number:
  US 20100252336A1
• Time in Patent Office: 1,321 Days
• Field of Search: None
• US Class Current: 178/18.06
• 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, comprising;

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.

2. The position method as claimed in claim 1, wherein the reference coefficient is related to an area of a touch tool.

3. The position method as claimed in claim 2, wherein the reference coefficient is larger than 1, and the reference coefficient is inversely proportional to the area of the touch tool.

4. The position method as claimed in claim 1, 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<sub>i±

1</sub>)} 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.

5. 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 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.

6. The position method as claimed in claim 5, 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.

7. 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, comprising;

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.

8. The position method as claimed in claim 7, 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.

9. The position method as claimed in claim 7, 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.

10. The position method as claimed in claim 9, 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.

11. 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,

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 length.

12. The position apparatus as claimed in claim 11, wherein the reference coefficient is related to an area of a touch tool.

13. The position apparatus as claimed in claim 12, wherein the reference coefficient is larger than 1, and the reference coefficient is inversely proportional to the area of the touch tool.

14. The position apparatus as claimed in claim 11, 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.

15. The position apparatus as claimed in claim 11, wherein the position detector calculates a second weighted sum of the (i−

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

16. The position apparatus as claimed in claim 15, 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.