Touch panel device having high touch sensitivity and touch positioning method thereof

• US 8,395,596 B2
• Filed: 12/17/2009
• Issued: 03/12/2013
• Est. Priority Date: 08/11/2009
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Yang, Jun-Wei, Yang, Chia-Feng, Hsu, Yu-Min, Cheng, Yung-Tse
• Primary Examiner(s): GIESY, ADAM
• Application Number:
  US12/641,297
• Publication Number:
  US 20110037708A1
• Time in Patent Office: 1,181 Days
• Field of Search: 345/174, 178/18.06
• US Class Current: 345/174
• 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 panel device having high touch sensitivity includes sensing capacitors, switches, storage capacitors, a differential amplifier and a signal processing unit. During a sense period, the switches are periodically turned on alternately for periodically transferring the charges of the sensing capacitors to the storage capacitors. The differential amplifier is put in use for amplifying the voltage difference of two corresponding storage capacitors for generating a touch readout signal. The signal processing unit performs an OR operation on two touch readout signals generated during different sense periods based on different sensing capacitor combinations regarding same panel touch position for providing a touch position signal.

Claims

1. A touch panel device comprising:

a touch panel;

a first sensing capacitor disposed in the touch panel;

a first switch, electrically connected to the first sensing capacitor, for controlling an electrical connection between the first sensing capacitor and a power source;

s second switch, electrically connected to the first sensing capacitor;

a first storage capacitor, electrically connected to the second switch, for accumulating charges transferred from the first sensing capacitor so as to generate a first voltage when the second switch is turned on;

a third switch, electrically connected to the first storage capacitor, for controlling an operation of discharging the charges accumulated in the first storage capacitor;

a second sensing capacitor disposed in the touch panel;

a fourth switch, electrically connected to the second sensing capacitor, for controlling an electrical connection between the second sensing capacitor and the power source;

s fifth switch, electrically connected to the second sensing capacitor;

a second storage capacitor, electrically connected to the fifth switch, for accumulating charges transferred from the second sensing capacitor so as to generate a second voltage when the fifth switch is turned on;

a sixth switch, electrically connected to the second storage capacitor, for controlling an operation of discharging the charges accumulated in the second storage capacitor; and

a differential amplifier, electrically connected to the first storage capacitor and the second storage capacitor, for generating a touch readout signal through performing a differential amplification operation on the first and second voltages.

2. The touch panel device of claim 1, wherein:

the first switch and the second switch are working based on an alternating turn-on operation; and

the fourth switch and the fifth switch are working based on an alternating turn-on operation.

3. The touch panel device of claim 1, wherein:

the first switch and the second switch are periodically turned on alternately during a sense period so that the first storage capacitor accumulates the charges periodically transferred from the first sensing capacitor; and

the fourth switch and the fifth switch are periodically turned on alternately during the sense period so that the second storage capacitor accumulates the charges periodically transferred from the second sensing capacitor.

4. The touch panel device of claim 1, wherein:

the third switch is turned on during a reset period for discharging the charges accumulated in the first storage capacitor; and

the sixth switch is turned on during the reset period for discharging the charges accumulated in the second storage capacitor.

5. The touch panel device of claim 1, wherein:

the second switch and the third switch are turned on during a reset period for discharging the charges stored in the first sensing capacitor and the first storage capacitor; and

the fifth switch and the sixth switch are turned on during the reset period for discharging the charges stored in the second sensing capacitor and the second storage capacitor.

6. The touch panel device of claim 1, further comprising:

a third sensing capacitor disposed in the touch panel;

a seventh switch, electrically connected to the third sensing capacitor, for controlling an electrical connection between the third sensing capacitor and the power source;

a fourth sensing capacitor disposed in the touch panel;

an eighth switch, electrically connected to the fourth sensing capacitor, for controlling an electrical connection between the fourth sensing capacitor and the power source; and

a multiplexer comprising a first input end electrically connected to the first sensing capacitor, a second input end electrically connected to the second sensing capacitor, a third input end electrically connected to the third sensing capacitor, a fourth input end electrically connected to the fourth sensing capacitor, a first output end electrically connected to the second switch, and a second output end electrically connected to the fifth switch, wherein the charges stored in the first or third sensing capacitor are transferred to the first storage capacitor via the first output end of the multiplexer when the second switch is turned on, and the charges stored in the second or fourth sensing capacitor are transferred to the second storage capacitor via the second output end of the multiplexer when the fifth switch is turned on.

7. The touch panel device of claim 6, wherein the seventh switch and the second switch are periodically turned on alternately during a sense period so that the first storage capacitor periodically accumulates the charges transferred from the third sensing capacitor when the multiplexer electrically connects the third sensing capacitor and the second switch.

8. The touch panel device of claim 6, wherein the eighth switch and the fifth switch are periodically turned on alternately during a sense period so that the second storage capacitor periodically accumulates the charges transferred from the fourth sensing capacitor when the multiplexer electrically connects the fourth sensing capacitor and the fifth switch.

9. The touch panel device of claim 6, wherein the second switch and the third switch are turned on during a reset period for discharging the charges stored in the third sensing capacitor and the first storage capacitor when the multiplexer electrically connects the third sensing capacitor and the second switch.

10. The touch panel device of claim 6, wherein the fifth switch and the sixth switch are turned on during a reset period for discharging the charges stored in the fourth sensing capacitor and the second storage capacitor when the multiplexer electrically connects the fourth sensing capacitor and the fifth switch.

11. The touch panel device of claim 6, wherein the second sensing capacitor is adjacent to the first sensing capacitor.

12. The touch panel device of claim 6, wherein the fourth sensing capacitor is adjacent to the third sensing capacitor.

13. The touch panel device of claim 1, further comprising:

a signal processing unit, electrically connected to the differential amplifier, for generating a plurality of digital readout signals through performing analog/digital conversion operations on the touch readout signals generated during different sense periods, and for generating at least one touch position signal according to the digital readout signals; and

a memory unit, electrically connected to the signal processing unit, for storing the digital readout signals.

14. A touch panel device comprising:

a touch panel;

a first sensing capacitor disposed in the touch panel;

a second sensing capacitor disposed in the touch panel;

a third sensing capacitor disposed in the touch panel;

a fourth sensing capacitor disposed in the touch panel;

a first differential amplifier comprising a first input end electrically connected to the first sensing capacitor, a second input end, and an output end for outputting a first touch readout signal;

a second differential amplifier comprising a first input end, a second input end electrically connected to the fourth sensing capacitor, and an output end for outputting a second touch readout signal;

a first switch comprising a first end electrically connected to the second sensing capacitor and a second end electrically connected to the second input end of the first differential amplifier;

a second switch comprising a first end electrically connected to the third sensing capacitor and a second end electrically connected to the second input end of the first differential amplifier;

a third switch comprising a first end electrically connected to the second sensing capacitor and a second end electrically connected to the first input end of the second differential amplifier; and

a fourth switch comprising a first end electrically connected to the third sensing capacitor and a second end electrically connected to the first input end of the second differential amplifier.

15. The touch panel device of claim 14, further comprising:

a fifth switch, electrically connected to the first sensing capacitor, for controlling an electrical connection between the first sensing capacitor and a power source;

a sixth switch electrically connected between the first sensing capacitor and the first input end of the first differential amplifier;

a first storage capacitor, electrically connected to the sixth switch, for accumulating charges transferred from the first sensing capacitor when the sixth switch is turned on;

a seventh switch, electrically connected to the first storage capacitor, for controlling an operation of discharging the charges accumulated in the first storage capacitor;

an eighth switch, electrically connected to the second sensing capacitor, for controlling an electrical connection between the second sensing capacitor and the power source;

a ninth switch comprising a first end electrically connected to the second sensing capacitor and a second end electrically connected to the first ends of the first and third switches;

a second storage capacitor, electrically connected to the second end of the ninth switch, for accumulating charges transferred from the second sensing capacitor when the ninth switch is turned on;

a tenth switch, electrically connected to the second storage capacitor, for controlling an operation of discharging the charges accumulated in the second storage capacitor;

an eleventh switch, electrically connected to the third sensing capacitor, for controlling an electrical connection between the third sensing capacitor and the power source;

a twelfth switch comprising a first end electrically connected to the third sensing capacitor and a second end electrically connected to the first ends of the second and fourth switches;

a third storage capacitor, electrically connected to the second end of the twelfth switch, for accumulating charges transferred from the third sensing capacitor when the twelfth switch is turned on;

a thirteenth switch, electrically connected to the third storage capacitor, for controlling an operation of discharging the charges accumulated in the third storage capacitor;

a fourteenth switch, electrically connected to the fourth sensing capacitor, for controlling an electrical connection between the fourth sensing capacitor and the power source;

a fifteenth switch electrically connected between the fourth sensing capacitor and the second input end of the second differential amplifier;

a fourth storage capacitor, electrically connected to the fifteenth switch, for accumulating charges transferred from the fourth sensing capacitor when the fifteenth switch is turned on; and

a sixteenth switch, electrically connected to the fourth storage capacitor, for controlling an operation of discharging the charges accumulated in the fourth storage capacitor.

16. The touch panel device of claim 14, further comprising:

a signal processing unit, electrically connected to the first differential amplifier and the second differential amplifier, for generating a plurality of digital readout signals through performing analog/digital conversion operations on the first and second touch readout signals generated during different sense periods, and for generating at least one touch position signal according to the digital readout signals; and

a memory unit, electrically connected to the signal processing unit, for storing the digital readout signals.

17. The touch panel device of claim 14, wherein the second sensing capacitor is adjacent to the first sensing capacitor.

18. The touch panel device of claim 14, wherein the fourth sensing capacitor is adjacent to the third sensing capacitor.

19. The touch panel device of claim 14, wherein the third sensing capacitor is adjacent to the second sensing capacitor.

20. A touch positioning method for use in a touch panel device, the touch panel device having plural sensing elements disposed at plural panel positions, the touch positioning method comprising:

generating a plurality of first touch readout signals through sequentially scanning plural sets of two adjacent sensing elements;

generating a plurality of second touch readout signals through sequentially scanning plural sets of two sensing elements spaced out at least one sensing element;

generating a plurality of third touch readout signals through performing an OR operation on the first and second readout signals corresponding to each panel position of the touch panel device;

performing a touch position analyzing operation on the third touch readout signals for generating at least one touch position signal; and

outputting the at least one touch position signal.

21. The touch positioning method of claim 20, further comprising:

storing the first touch readout signals; and

storing the second touch readout signals.