TOUCH SCREEN AND METHOD FOR POSITIONING COORDINATE

• US 20100033449A1
• Filed: 08/03/2009
• Published: 02/11/2010
• Est. Priority Date: 08/05/2008
• Status: Active Grant

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: Hsi, Ming Chieh, CHIU, Yen-Chen
• Granted Patent: US 8,462,127 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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

The present invention relates to a touch screen and a method for positioning a coordinate. The touch screen includes a sensor array layer and a microprocessor. The sensor array layer includes M×N capacitive sensors, wherein M rows of the capacitive sensors are disposed along a first axis, and N columns of the capacitive sensors are disposed along a second axis. The microprocessor includes a plurality of pins correspondingly coupled to the capacitive sensors. When the touch screen is touched to change at least one of sensing values of the capacitive sensors in the sensor array layer, the microprocessor performs an interpolation calculation to determine a touched coordinate according to the sensing values sensed by the capacitive sensors.

Claims

1. A touch screen, comprising:

a sensor array layer, which comprises M×

N capacitive sensors, wherein M rows of the capacitive sensors are disposed along a first axis, and N columns of the capacitive sensors are disposed along a second axis; and

a microprocessor, which comprises a plurality of pins correspondingly coupled to the capacitive sensors, wherein when the touch screen is touched to change at least one of sensing values of the capacitive sensors in the sensor array layer, the microprocessor performs an interpolation calculation to determine a touched coordinate according to the sensing values sensed by the capacitive sensors.

2. The touch screen according to claim 1, further comprising:

an electronic component layer; and

a grounding layer disposed between the sensor array layer and the electronic component layer.

3. The touch screen according to claim 1, further comprising:

a first silicon oxide layer; and

a second silicon oxide layer, wherein the sensor array layer is disposed between the first silicon oxide layer and the second silicon oxide layer.

4. The touch screen according to claim 1, wherein a coordinate of one of the capacitive sensors located in the i^th row and the j^th column is represented as (i, j).

5. The touch screen according to claim 4, wherein when the touch screen is touched to change the sensing value of the capacitive sensor located in the i^th column and the j^th row and the sensing value of the capacitive sensor located in the (i+1)^th column and the j^th row in the sensor array layer:

the microprocessor acquires the sensing value of the capacitive sensor located in the i^th column and the j^th row, and the sensing value of the capacitive sensor located in the (i+1)^th column and the j^th row, and performs the following interpolation calculation to obtain a first axial coordinate of the touched coordinate;

$\mathrm{the}<br><br><br><br>\mathrm{first}<br><br><br><br>\mathrm{axial}<br><br><br><br>\mathrm{coordinate}=\frac{K\times <br><br>i+L\times <br><br>\left(i+1\right)}{K+L}\times <br><br>S$

wherein K represents the sensing value of the capacitive sensor at the i^th column and the j^th row, L represents the sensing value of the capacitive sensor at the (i+1)^th column and the j^th row, and S represents an interval coordinate number between the capacitive sensors.

6. The touch screen according to claim 4, wherein when the touch screen is touched to change the sensing value of the capacitive sensor located in the i^th column and the j^th row, and the sensing value of the capacitive sensor located in the j^th column and the (j+1)^th row in the sensor array layer:

the microprocessor acquires the sensing value of the capacitive sensor located in the i^th column and the j^th row, and the sensing value of the capacitive sensor located in the i^th column and the (j+1)^th row, and performs the following interpolation calculation to obtain a second axial coordinate of the touched coordinate;

$\mathrm{the}<br><br><br><br>\mathrm{second}<br><br><br><br>\mathrm{axial}<br><br><br><br>\mathrm{coordinate}=\frac{K\times <br><br>j+L\times <br><br>\left(j+1\right)}{K+L}\times <br><br>S$

wherein K represents the sensing value of the capacitive sensor located in the i^th column and the j^th row, L represents the sensing value of the capacitive sensor located in the (i+1)^th column and the j^th row, and S represents a coordinate interval number between the capacitive sensors.

7. The touch screen according to claim 1, wherein a coordinate (x, y) of the capacitive sensor located at the i^th column and the j^th row is represented as (i+N×

j, M×

i+j).

8. The touch screen according to claim 7, wherein the microprocessor further performs a coordinate transferring calculation according to:

$x<br><br><br><br>0=\frac{-x+N\times <br><br>y}{M\times <br><br>N-1}$ $y<br><br><br><br>0=\frac{M\times <br><br>x-y}{M\times <br><br>N-1}$

wherein (x0, y0) is a transferred coordinate of the capacitive sensor.

9. The touch screen according to claim 1, further comprising:

M×

N sensing lines respectively electrically connected to the M×

N capacitive sensors and the microprocessor,

wherein the microprocessor assigns corresponding M×

N gains to the M×

N capacitive sensors according to a layout resistance of each of the sensing lines.

10. The touch screen according to claim 1, further comprising:

M×

N sensing lines respectively electrically connected to the M×

N capacitive sensors and the microprocessor,

wherein the microprocessor assigns corresponding M×

N threshold values to the M×

N capacitive sensors according to a layout resistance of each of the sensing lines, and judges whether the (I, J)^th capacitive sensor is touched or not according to whether the sensing value of the (I, J)^th capacitive sensor is greater than the threshold value of the (I, J)^th capacitive sensor.

11. The touch screen according to claim 1, further comprising:

M×

N sensing lines respectively electrically connected to the M×

N capacitive sensors and the microprocessor,

wherein the microprocessor assigns corresponding M×

N threshold values to the M×

N capacitive sensors according to a layout resistance of each of the sensing lines, and judges whether the (I, J)^th capacitive sensor is touched or not according to whether the sensing value of the (I, J)^th capacitive sensor minus a base value of the (I, J)^th capacitive sensor is greater than the threshold value of the (I, J)^th capacitive sensor.

12. A coordinate positioning method, comprising:

providing a touch screen;

providing a sensor array layer, comprising M×

N capacitive sensors, in the touch screen, wherein M rows of the capacitive sensors are disposed along a first axis, and N columns of the capacitive sensors are disposed along a second axis;

providing a plurality of reference coordinates, each comprising a first axial coordinate and a second axial coordinate, to the capacitive sensors; and

determining, when the touch screen is touched to change at least one of sensing values of the capacitive sensors in the sensor array layer, a touched coordinate by performing an interpolation calculation according to the sensing values sensed by the capacitive sensors and the first axial coordinate and the second axial coordinate of the corresponding reference coordinate.

13. The method according to claim 12, wherein a coordinate of one of the capacitive sensors located in the i^th row and the j^th column is represented as (i, j).

14. The method according to claim 13, wherein when the touch screen is touched to change the sensing value of the capacitive sensor located in the i^th column and the j^th row and the sensing value of the capacitive sensor located in the (i+1)^th column and the j^th row in the sensor array layer:

the sensing value of the capacitive sensor located in the i^th column and the j^th row, and the sensing value of the capacitive sensor located in the (i+1)^th column and the j^th row are acquired, and the following interpolation calculation is performed to obtain the first axial coordinate of the touched coordinate;

$\mathrm{the}<br><br><br><br>\mathrm{first}<br><br><br><br>\mathrm{axial}<br><br><br><br>\mathrm{coordinate}=\frac{K\times <br><br>i+L\times <br><br>\left(i+1\right)}{K+L}\times <br><br>S$

wherein K represents the sensing value of the capacitive sensor at the i^th column and the j^th row, L represents the sensing value of the capacitive sensor at the (i+1)^th column and the j^th row, and S represents a coordinate interval number between the capacitive sensors.

15. The method according to claim 13, wherein when the touch screen is touched to change the sensing value of the capacitive sensor located in the i^th column and the j^th row, and the sensing value of the capacitive sensor located in the i^th column and the (j+1)^th row in the sensor array layer:

the sensing value of the capacitive sensor located in the i^th column and the j^th row, and the sensing value of the capacitive sensor located in the i^th column and the (j+1)^th row are acquired, and the following interpolation calculation is performed to obtain the second axial coordinate of the touched coordinate;

$\mathrm{the}<br><br><br><br>\mathrm{second}<br><br><br><br>\mathrm{axial}<br><br><br><br>\mathrm{coordinate}=\frac{K\times <br><br>j+L\times <br><br>\left(j+1\right)}{K+L}\times <br><br>S$

wherein K represents the sensing value of the capacitive sensor at the i^th column and the j^th row, L represents the sensing value of the capacitive sensor at the (i+1)^th column and the j^th row, and S represents a coordinate interval number between the capacitive sensors.

16. The method according to claim 12, wherein a coordinate (x, y) of the capacitive sensor located at the i^th column and the j^th row is represented as (i+N×

j, M×

i+j).

17. The method according to claim 16, further comprising:

performing a coordinate transferring calculation according to;

$x<br><br><br><br>0=\frac{-x+N\times <br><br>y}{M\times <br><br>N-1}$ $y<br><br><br><br>0=\frac{M\times <br><br>x-y}{M\times <br><br>N-1}$

wherein (x0, y0) is a transferred coordinate of the capacitive sensor.

18. The method according to claim 12, further comprising:

providing M×

N sensing lines respectively electrically connected to the M×

N capacitive sensors and a microprocessor; and

assigning corresponding M×

N gains to the M×

N capacitive sensors according to a layout resistance of each of the sensing lines.

19. The method according to claim 12, further comprising:

providing M×

N sensing lines respectively electrically connected to the M×

N capacitive sensors and a microprocessor;

assigning corresponding M×

N threshold values to the M×

N capacitive sensors according to a layout resistance of each of the sensing lines; and

judging whether the (I, J)^th capacitive sensor is touched or not according to whether the sensing value of the (I, J)^th capacitive sensor is greater than the threshold value of the (I, J)^th capacitive sensor.

20. The method according to claim 12, further comprising:

providing M×

N sensing lines respectively electrically connected to the M×

N capacitive sensors and a microprocessor;

assigning corresponding M×

N threshold values to the M×

N capacitive sensors according to a layout resistance of each of the sensing lines; and

judging whether the (I, J)^th capacitive sensor is touched or not according to whether the sensing value of the (I, J)^th capacitive sensor minus a base value of the (I, J)^th capacitive sensor is greater than the threshold value of the (I, J)^th capacitive sensor.