Self-adjusting photosensitive touch circuit and display device thereof

• US 8,928,629 B2
• Filed: 03/21/2012
• Issued: 01/06/2015
• Est. Priority Date: 10/20/2011
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Chung, Yueh-Hung, Hsu, Ya-Ling
• Primary Examiner(s): Davis, David D
• Application Number:
  US13/425,507
• Publication Number:
  US 20130100077A1
• Time in Patent Office: 1,021 Days
• Field of Search: None
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

The present invention relates to a self-adjusting photosensitive touch circuit, which includes a light-sensing component, a variable capacitor and a switch component. The light-sensing component is for sensing a touch status and receives a first control signal. The light-sensing component is enabled by a level of the first control signal. The variable capacitor is electrically coupled to the light-sensing component. A capacitance of the variable capacitor is altered along with a voltage difference between two terminals of the variable capacitor. The switch component is electrically coupled to the variable capacitor, and receives a second control signal. The switch component is enabled by a level of the second control signal. Therefore, a range of the gate voltage difference of the light-sensing component can be increased, so as to improve the sensitivity and accuracy of the light-sensing component. Moreover, the present invention also relates to a display device thereof.

Claims

1. A self-adjusting photosensitive touch circuit comprising:

a light-sensing component, for sensing a touch status, and receiving a first control signal, wherein the light-sensing component is enabled by a level of the first control signal, the light-sensing component comprises a first terminal, a second terminal and a third terminal, the first terminal of the light-sensing component receives the first control signal, and the third terminal of the light-sensing component receives a third control signal;

a variable capacitor, electrically coupled to the light-sensing component, wherein a capacitance of the variable capacitor is altered along with a voltage difference between two terminals of the variable capacitor; and

a switch component, electrically coupled to the variable capacitor, and configured for receiving a second control signal, wherein the switch component is enabled by a level of the second control signal, the switch component comprises a first terminal, a second terminal, and a third terminal, the first terminal of the switch component receives the second control signal, and the second terminal of the switch component is electrically coupled to the second terminal of the light-sensing component; and

an integrator, electrically coupled to the third terminal of the switch component, to output a touch signal corresponding to the touch status.

2. The circuit as claimed in claim 1, wherein the variable capacitor comprises a first terminal and a second terminal, the first terminal thereof is electrically coupled to the second terminal of the light-sensing component, and the second terminal thereof receives a reference voltage.

3. The circuit as claimed in claim 2, wherein when the first control signal is in the high level, the third control signal is in the high level, and rising edges of the first control signal and the third control signal are behind a rising edge of the second control signal.

4. The circuit as claimed in claim 3, wherein when the second control signal is in the high level, a voltage of the second terminal of the variable capacitor increases to a first voltage value;

and when the second control signal is in the low level and the first control signal and the third control signal are in the high level, the voltage of the second terminal of the variable capacitor increases to a second voltage value.

5. The circuit as claimed in claim 1, wherein the variable capacitor comprises a first terminal and a second terminal, the first terminal of the variable capacitor receives a reference voltage, and the second terminal of the variable capacitor is electrically coupled to the second terminal of the light-sensing component.

6. The circuit as claimed in claim 5, wherein when the first control signal is in the high level, the third control signal is in the low level, falling edges of the first control signal and the third control signal are behind a rising edge of the second control signal.

7. The circuit as claimed in claim 6, wherein when the second control signal is in the high level, a voltage of the first terminal of the variable capacitor decreases to a first voltage value;

and when the second control signal and the third control signal are in the low level and the first control signal is in the high level, the voltage of the first terminal of the variable capacitor decreases to a second voltage value.

8. The circuit as claimed in claim 1, wherein when light irradiation intensity received by the light-sensing component is higher, the capacitance of the variable capacitor is greater.

9. A self-adjusting photosensitive touch circuit comprising:

a light-sensing component, for sensing a touch status, and receiving a first control signal, wherein the light-sensing component is enabled by a level of the first control signal, the light-sensing component comprises a first terminal, a second terminal and a third terminal, the first terminal of the light-sensing component receives the first control signal, and the third terminal of the light-sensing component receives a third control signal;

a variable capacitor, electrically coupled to the light-sensing component, wherein a capacitance of the variable capacitor is altered along with a voltage difference between two terminals of the variable capacitor, the variable capacitor comprises a first terminal and a second terminal, the first terminal of the variable capacitor is electrically coupled to the second terminal of the light-sensing component, and the second terminal of the variable capacitor receives a reference voltage; and

a switch component, electrically coupled to the variable capacitor, and configured for receiving a second control signal, wherein the switch component is enabled by a level of the second control signal;

wherein when the first control signal is in the high level, the third control signal is in the high level, and rising edges of the first control signal and the third control signal are behind a rising edge of the second control signal;

when the second control signal is in the high level, a voltage of the second terminal of the variable capacitor increases to a first voltage value; and

when the second control signal is in the low level and the first control signal and the third control signal are in the high level, the voltage of the second terminal of the variable capacitor increases to a second voltage value.

10. The circuit as claimed in claim 9, wherein the switch component comprises a first terminal, a second terminal, and a third terminal, the first terminal of the switch component receives the second control signal, and the second terminal of the switch component is electrically coupled to the second terminal of the light-sensing component.

11. The circuit as claimed in claim 10, further comprising an integrator, electrically coupled to the third terminal of the switch component, to output a touch signal corresponding to the touch status.

12. The circuit as claimed in claim 9, wherein when light irradiation intensity received by the light-sensing component is higher, the capacitance of the variable capacitor is greater.

13. A self-adjusting photosensitive touch circuit comprising:

a light-sensing component, for sensing a touch status, and receiving a first control signal, wherein the light-sensing component is enabled by a level of the first control signal, the light-sensing component comprises a first terminal, a second terminal and a third terminal, the first terminal of the light-sensing component receives the first control signal, and the third terminal of the light-sensing component receives a third control signal;

a variable capacitor, electrically coupled to the light-sensing component, wherein a capacitance of the variable capacitor is altered along with a voltage difference between two terminals of the variable capacitor, the variable capacitor comprises a first terminal and a second terminal, the first terminal of the variable capacitor receives a reference voltage, and the second terminal of the variable capacitor is electrically coupled to the second terminal of the light-sensing component; and

a switch component, electrically coupled to the variable capacitor, and configured for receiving a second control signal, wherein the switch component is enabled by a level of the second control signal;

wherein when the first control signal is in the high level, the third control signal is in the low level, falling edges of the first control signal and the third control signal are behind a rising edge of the second control signal;

when the second control signal is in the high level, a voltage of the first terminal of the variable capacitor decreases to a first voltage value; and

when the second control signal and the third control signal are in the low level and the first control signal is in the high level, the voltage of the first terminal of the variable capacitor decreases to a second voltage value.

14. The circuit as claimed in claim 13, wherein the switch component comprises a first terminal, a second terminal, and a third terminal, the first terminal of the switch component receives the second control signal, and the second terminal of the switch component is electrically coupled to the second terminal of the light-sensing component.

15. The circuit as claimed in claim 14, further comprising an integrator, electrically coupled to the third terminal of the switch component, to output a touch signal corresponding to the touch status.

16. The circuit as claimed in claim 13, wherein when light irradiation intensity received by the light-sensing component is higher, the capacitance of the variable capacitor is greater.