Touch point detecting device and the touch point detecting method thereof

• US 9,256,313 B2
• Filed: 08/17/2011
• Issued: 02/09/2016
• Est. Priority Date: 05/28/2011
• Status: Active Grant

• Current Assignee: TPK Touch Solutions (Xiamen) Inc. (TPK Holding Co., Ltd.)
• Original Assignee: TPK Touch Solutions (Xiamen) Inc. (TPK Holding Co., Ltd.)
• Inventors: Liu, Yong
• Primary Examiner(s): Hicks, Charles
• Assistant Examiner(s): Truong, Nguyen H
• Application Number:
  US13/211,331
• Publication Number:
  US 20120299842A1
• Time in Patent Office: 1,637 Days
• Field of Search: 345/173, 178 1801- 2004
• US Class Current: 1/1
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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

A touch point detecting device is provided. The touch point detecting device comprises a plurality of electrodes and a scanning unit connected to said electrodes and scanning said electrodes with at least two variable excitation signal frequencies. A touch point detecting method is also provided. By means of the touch point detecting device, the electrode border as well as the integrated circuit package of the processor is reduced without reducing the detection accuracy of touch points.

Claims

1. A touch point detecting device, comprising:

a plurality of electrodes;

a scanning unit connected to said electrodes and configured to scan at least one of said electrodes with at least two variable excitation signal frequencies; and

a processor configured to calculate a first baseline output value difference and a second baseline output value difference in a calibration step, to detect at least two variable output values generated on said corresponding electrode where at least one touch point occurs, to calculate an output value difference of said at least two corresponding output values when said at least one touch point occurs, and to calculate a distance between said at least one touch point and one of a first end or a second end of said electrode where said at least one touch point occurs according to said at least two variable output values;

wherein the scanning unit is configured to scan each of said electrodes with said at least two variable excitation signal frequencies under the circumstances that said at least one touch point occurs at the first end of said electrode and occurs at the second end of said electrode, respectively, in the calibration step,

wherein the processor is configured to further detect at least two variable output values generated on the first end of said corresponding electrode and detects at least two variable output values generated on the second end of said corresponding electrode in the calibration step, and

wherein the first baseline output value difference is calculated according to said at least two corresponding variable output values occurred at the first end of said electrode, whereas the second baseline output value difference is calculated according to said at least two corresponding variable output values occurred at the second end of said electrode.

2. The touch point detecting device of claim 1, wherein said electrodes are disposed in a first direction.

3. The touch point detecting device of claim 1, wherein said electrodes comprise a plurality of first electrodes disposed in a first direction and a plurality of second electrodes disposed in a second direction.

4. The touch point detecting device of claim 3, wherein said first direction intersects with said second direction.

5. The touch point detecting device of claim 1, wherein said electrodes are polygon.

6. The touch point detecting device of claim 1, wherein said electrodes comprise a plurality of separated conductive units and a plurality of conductive lines connecting said conductive units.

7. The touch point detecting device of claim 1, wherein said scanning unit is set within said processor.

8. The touch point detecting device of claim 1, wherein said scanning unit is set outside said processor.

9. The touch point detecting device of claim 1, wherein said electrodes are made of transparent conductive material.

10. The touch point detecting device of claim 1, wherein said electrodes are made of metal.

11. The touch point detecting device of claim 1, wherein the electrodes extend along a first direction, and are arranged in parallel along a second direction, and wherein only the first ends of the electrodes are connected to the scanning unit.

12. A touch point detecting method, comprising the steps of

a) performing a calibration step, which comprises:

a1) scanning each of a plurality of electrodes with at least two variable excitation signal frequencies;

a2) detecting at least two output values generated on said corresponding electrode;

a3) calculating a first output value difference of said corresponding output values when said at least one touch point occurs at a first end of said electrode;

a4) recording said first output value difference from the step a3) as a first baseline output value difference;

a5) repeating steps a1) and a2) herein;

a6) calculating a second output value difference of said corresponding output values when said at least one touch point occurs at a second end of said corresponding electrode; and

a7) recording said second output value difference from the step a6) as a second baseline output value difference;

b) scanning at least one of said electrodes with said at least two variable excitation signal frequencies;

c) detecting at least two output values generated on said corresponding electrode where at least one touch point occurs;

d) calculating a third output value difference of said at least two corresponding output values when said at least one touch point occurs;

e) calculating a distance between said at least one touch point and one of the first end and the second end of said electrode where said at least one touch point occurs according to said at least two variable output values; and

f) outputting a position of said at least one touch point.

13. The touch point detecting method of claim 12, wherein said step b) and step c) further comprise:

b1) scanning said electrodes with a first excitation signal frequency of said at least two variable excitation signal frequencies;

c1) detecting a first output value generated on said electrode where said at least one touch point occurs;

c2) detecting said electrode generating said first output value;

b2) scanning said electrode generating said first output value with a second excitation signal frequency of said at least two variable excitation signal frequencies; and

c3) detecting a second output value.

14. The touch point detecting method of claim 12, wherein said step b) and step c) further comprise:

b1) scanning said electrodes with a first excitation signal frequency of said at least two variable excitation signal frequencies;

c1) detecting a first output value generated on said electrode where said at least one touch point occurs;

b2) scanning said electrode with a second excitation signal frequency of said at least two variable excitation signal frequencies; and

c2) detecting a second output value generated on said electrode where said at least one touch point occurs.

15. The touch point detecting method of claim 13 or 14, wherein said electrodes are scanned one at a time.

16. The touch point detecting method of claim 13 or 14, wherein said electrodes are scanned synchronously.

17. The touch point detecting method of claim 12, wherein the step e) is to calculate said position of said at least one touch point on said electrode in a first direction.

18. The touch point detecting method of claim 12, wherein in the step e), the distance is calculated based on a proportional relation formed by said third output value difference, said first baseline output value difference and said second, baseline output value difference and a distance between the first end and the second end of the detected electrode.

19. The touch point detecting method of claim 12, wherein before the step f), the method further comprises the step of calculating said position of said at least one touch point on said electrode in a second direction according to said third output value difference, said first baseline output value difference and said second, baseline output value difference.

20. The touch point detecting method of claim 19, wherein said position of said at least one touch point on said electrode in the second direction is calculated by a means of interpolation.