COORDINATES ALGORITHM AND POSITION SENSING SYSTEM OF TOUCH PANEL

• US 20100321328A1
• Filed: 12/29/2009
• Published: 12/23/2010
• Est. Priority Date: 06/17/2009
• Status: Abandoned Application

• Current Assignee: Novatek Microelectronics Corporation (Novatek Microelectronics Corp Limited)
• Original Assignee: Novatek Microelectronics Corporation (Novatek Microelectronics Corp Limited)
• Inventors: Chen, Chun-Hung, CHANG, Hui-Hung, Huang, Chun-Ching, Wu, Meng-Hsiu
• Application Number:
  US12/649,104
• Publication Number:
  US 20100321328A1
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• 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 sensing system of a touch panel including a sensing unit and a decision unit is provided. When the touch panel is touched, the sensing unit obtains the sensing capacitances of p x-directional sensing lines and q y-directional sensing lines, wherein the sensing capacitances generated by these sensing lines exceed a threshold. The decision unit takes the central coordinates of the sensing lines with peak sensing capacitances as an x base coordinate and a y base coordinate, and adjusts the x base coordinate and the y base coordinate according to the ratios of the sensing capacitances of the other sensing lines to the peak sensing capacitance respectively to obtain an interpolated x coordinate and an interpolated y coordinate.

Claims

1. A coordinate algorithm of a touch panel, comprising:

determining the range of the x coordinates of a plurality of x-directional sensing lines and the range of the y coordinates of a plurality of y-directional sensing lines of the touch panel on the basis of a default resolution;

obtaining the sensing capacitances of p x-directional sensing lines and q y-directional sensing lines when the touch panel is touched, wherein the sensing capacitances generated by these sensing lines exceed a threshold, and both p and q are a positive integer;

taking the x central coordinate of the x-directional sensing lines with peak sensing capacitances as an x base coordinate, and adjusting the x base coordinate according to the ratios of the sensing capacitances of the other (p−

1) x-directional sensing lines to the peak sensing capacitance to obtain an interpolated x coordinate; and

taking the y central coordinate of the y-directional sensing lines with peak sensing capacitances as a y base coordinate, and adjusting the y base coordinate according to the ratios of the sensing capacitances of the other (q−

1) y-directional sensing lines to the peak sensing capacitance to obtain an interpolated y coordinate.

2. The coordinate algorithm of a touch panel according to claim 1, wherein an M-order x coordinate is interpolated between two neighboring x-directional sensing lines, an N-order y coordinate is interpolated between two neighboring y-directional sensing lines, and both M and N are a positive integer.

3. The coordinate algorithm of a touch panel according to claim 1, wherein if two x-directional sensing lines have the peak sensing capacitance and the sensing capacitance of the x-directional sensing line between the two x-directional sensing lines is slightly smaller than the peak sensing capacitance, then the x central coordinate of the x-directional sensing lines with a slightly smaller sensing capacitance is taken as the x base coordinate, and if two y-directional sensing lines have the peak sensing capacitance and the sensing capacitance of the y-directional sensing line between the two y-directional sensing lines is slightly smaller than the peak sensing capacitance, then the y central coordinate of the y-directional sensing lines with a slightly smaller sensing capacitance is taken as the y base coordinate.

4. The coordinate algorithm of a touch panel according to claim 1, if only one single x-directional sensing line generates sensing capacitances exceeding the threshold, then the x central coordinate of the x-directional sensing lines is taken as the x base coordinate, and the x base coordinate is adjusted according to the ratios of the sensing capacitances of the x-directional sensing lines to a maximum sensing capacitance to obtain the interpolated x coordinate.

5. The coordinate algorithm of a touch panel according to claim 1, if only one single y-directional sensing line generates sensing capacitances exceeding the threshold, then the y central coordinate of the y-directional sensing lines is taken as the y base coordinate, and the y base coordinate is adjusted according to the ratios of the sensing capacitances of the y-directional sensing lines to a maximum sensing capacitance to obtain the interpolated y coordinate.

6. The coordinate algorithm of a touch panel according to claim 1, wherein when the touch panel is touched, if only the interpolated x coordinate is obtained but not the interpolated y coordinate or only the interpolated y coordinate is obtained but not the interpolated x coordinate, then only the obtained interpolated x coordinate or the obtained interpolated y coordinate is regarded as invalid, otherwise, both the interpolated x coordinate and the interpolated y coordinate are regarded as valid.

7. The coordinate algorithm of a touch panel according to claim 6, further comprising:

obtaining a plurality of interpolated x coordinates and a plurality of interpolated y coordinates when the touch point of the touch panel shifts continuously; and

performing edge correction to the interpolated x coordinates and the interpolated y coordinates to obtain a plurality of corrected x coordinates and a plurality of corrected y coordinates if the interpolated x coordinates and the interpolated y coordinates are regarded as valid.

8. The coordinate algorithm of a touch panel according to claim 7, wherein one of the interpolated x coordinates and its previous interpolated x coordinate are taken average to obtain the corresponding corrected x coordinates, and one of the interpolated y coordinates and its previous interpolated y coordinate are taken average to obtain the corresponding corrected y coordinate.

9. The coordinate algorithm of a touch panel according to claim 7, wherein the interpolated x coordinates obtained within a fixed time are taken average to obtain the corresponding corrected x coordinate, and the interpolated y coordinates obtained within the fixed time are taken average to obtain the corresponding corrected y coordinate.

10. The coordinate algorithm of a touch panel according to claim 6, further comprising:

obtaining a plurality of interpolated x coordinate and a plurality of interpolated y coordinate when the touch point of the touch panel shifts continuously; and

performing touch motion recognition to the interpolated x coordinates and the interpolated y coordinates to obtain corresponding touch motion information if the interpolated x coordinates and the interpolated y coordinates are regarded as valid.

11. A position sensing system of a touch panel, comprising:

a sensing unit used for obtaining the sensing capacitances of p x-directional sensing lines and q y-directional sensing lines when the touch panel is touched, wherein the sensing capacitances generated by these sensing lines exceed a threshold, and both p and q are a positive integer; and

a decision unit used for taking the central coordinates of the sensing lines with peak sensing capacitances as an x base coordinate and a y base coordinate, and adjusting the x base coordinate and the y base coordinate according to the ratios of the sensing capacitances of the other sensing lines to the peak sensing capacitance respectively to obtain an interpolated x coordinate and an interpolated y coordinate.

12. The position sensing system of a touch panel according to claim 11, wherein the sensing unit determines the range of the x coordinate of each x-directional sensing line and the range of the y coordinate of each y-directional sensing line of the touch panel on the basis of a default resolution.

13. The position sensing system of a touch panel according to claim 12, wherein the sensing unit differentiates an M-order x coordinate between two neighboring x-directional sensing lines and differentiates an N-order y coordinate between two neighboring y-directional sensing lines, and both M and N are a positive integer.

14. The position sensing system of a touch panel according to claim 11, wherein the decision unit takes the x central coordinate of the x-directional sensing lines with peak sensing capacitances as the x base coordinate, and adjusts the x base coordinate according to the ratios of the sensing capacitances of the other (p−

1) x-directional sensing lines to the peak sensing capacitance to obtain the interpolated x coordinate, and further takes the y central coordinate of the y-directional sensing lines with peak sensing capacitances as the y base coordinate and adjusts the y base coordinate according to the ratios of the sensing capacitances of the other (q−

1) y-directional sensing lines to the peak sensing capacitance to obtain the interpolated y coordinate.

15. The position sensing system of a touch panel according to claim 14, if two x-directional sensing lines have the peak sensing capacitance and the sensing capacitance of the x-directional sensing line between the two x-directional sensing lines is slightly smaller than the peak sensing capacitance, then the decision unit takes the x central coordinate of the x-directional sensing lines with a slightly smaller sensing capacitance as the x base coordinate, and if two y-directional sensing lines have the peak sensing capacitances and the sensing capacitance of the y-directional sensing line between the two y-directional sensing lines is slightly smaller than the peak sensing capacitance, then the decision unit takes the y central coordinate of the y-directional sensing lines with a slightly smaller sensing capacitance as the y base coordinate.

16. The position sensing system of a touch panel according to claim 14, wherein if only one single x-directional sensing line generates sensing capacitances exceeding the threshold, then the decision unit takes the x central coordinate of the x-directional sensing lines as the x base coordinate, and adjusts the x base coordinate according to the ratios of the sensing capacitances of the x-directional sensing lines to a maximum sensing capacitance to obtain the interpolated x coordinate.

17. The position sensing system of a touch panel according to claim 14, wherein if only one single y-directional sensing line generates sensing capacitances exceeding the threshold, then the decision unit takes the y central coordinate of the y-directional sensing lines as the y base coordinate, and adjusts the y base coordinate according to the ratios of the sensing capacitances of the y-directional sensing lines to a maximum sensing capacitance to obtain the interpolated y coordinate.

18. The position sensing system of a touch panel according to claim 14, wherein when the touch panel is touched, if the decision unit only obtains the interpolated x coordinate but not the interpolated y coordinate or only obtains the interpolated y coordinate but not the interpolated x coordinate, then the decision unit only regards the obtained interpolated x coordinate or the obtained interpolated y coordinate as invalid, otherwise, the decision unit regards both the interpolated x coordinate and the interpolated y coordinate as valid.

19. The position sensing system of a touch panel according to claim 18, wherein the decision unit obtains a plurality of interpolated x coordinate and a plurality of interpolated y coordinate when the touch point of the touch panel shifts continuously, and the position sensing system further comprises:

an edge correction unit used for performing edge correction to the interpolated x coordinates and the interpolated y coordinates to obtain a plurality of corrected x coordinates and a plurality of corrected y coordinates both when both the interpolated x coordinates and the interpolated y coordinates are regarded as valid.

20. The position sensing system of a touch panel according to claim 19, wherein the edge correction unit takes average of one of the interpolated x coordinates and its previous interpolated x coordinate to obtain the corresponding corrected x coordinate, and takes average of one of the interpolated y coordinates and its previous interpolated y coordinate to obtain the corresponding corrected y coordinate.

21. The position sensing system of a touch panel according to claim 19, wherein the edge correction unit takes average of the interpolated x coordinates obtained within a fixed time to obtain the corresponding corrected x coordinate, and takes average of the interpolated y coordinates obtained within the fixed time to obtain the corresponding corrected y coordinate.

22. The position sensing system of a touch panel according to claim 18, wherein the decision unit obtains a plurality of interpolated x coordinate and a plurality of interpolated y coordinate when the touch point of the touch panel shifts continuously, and the position sensing system further comprises:

a touch motion recognition circuit used for performing touch motion recognition to the interpolated x coordinates and the interpolated y coordinates to obtain corresponding touch motion information when both the interpolated x coordinates and the interpolated y coordinates are regarded as valid.

23. A position sensing system of a touch panel, comprising:

a sensing unit used for obtaining the sensing capacitances of p sensing lines when the touch panel is touched, wherein the sensing capacitances generated by the p sensing lines exceed a threshold, and p is a positive integer; and

a decision unit used for taking the central coordinate of the sensing lines with peak sensing capacitances as a base coordinate, and adjusting the base coordinate according to the ratios of the sensing capacitances of the other sensing lines to the peak sensing capacitance respectively to obtain an interpolated coordinate.

24. The position sensing system of a touch panel according to claim 23, wherein the decision unit takes the central coordinate of the sensing lines with peak sensing capacitances as the base coordinate, and adjusts the base coordinate according to the ratios of the sensing capacitances of the other (p−

1) sensing lines to the peak sensing capacitance to obtain the interpolated coordinate.