Pixel Unit, Method for Sensing Touch of an Object, and Display Apparatus Incorporating the Same

• US 20090058831A1
• Filed: 05/13/2008
• Published: 03/05/2009
• Est. Priority Date: 09/05/2007
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Tsai, Kun-Hua, Hung, Chi-Mao, Chen, Chi-Wen, Chang, Meng-Hsiang, Shih, Li-Wei, Chen, Chien-Jen
• Granted Patent: US 9,176,629 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A pixel unit, method for sensing touch of an object, and a display apparatus incorporating the same are provided. The display apparatus includes a data line. The pixel unit includes a first switch circuit electrically connected to the data line and a sensing circuit electrically connected to the first switch circuit. The sensing circuit generates a signal in response to the touch of the object, while the signal is transmitted through the data line with the first switch circuit turned on. In addition, the display apparatus further includes a readout line. The pixel unit further includes a second switch circuit electrically connected to the readout line. The sensing circuit is electrically connected to the second switch circuit. In a first time period, the sensing circuit receives a reference voltage via the first switch circuit. Then the signal generated by the touch of the object is transmitted through the readout line via the second switch circuit in a second time period.

Claims

1. A pixel unit for use in a display apparatus with a data line, comprising:

a switch circuit electrically connected to the data line; and

a sensing circuit, electrically connected to the switch circuit, for generating a signal in response to touch of an object;

wherein the signal is transmitted through the data line with the switch circuit being turned on.

2. The pixel unit of claim 1, wherein the switch circuit comprises a transistor having:

a first electrode, electrically connected to the data line, for transmitting the signal to the data line; and

a second electrode, electrically connected to the sensing circuit, for receiving the signal.

3. The pixel unit of claim 2, wherein the display apparatus comprises a scan line, and the transistor further has a gate, electrically connected to the scan line, for controlling whether to turn on the transistor.

4. The pixel unit of claim 2, wherein the transistor comprises an n-type transistor.

5. The pixel unit of claim 2, wherein the transistor comprises a p-type transistor.

6. The pixel unit of claim 1, wherein the sensing circuit has a variable capacitor, a capacitance value of the variable capacitor is changed in response to the touch of the object, and the sensing circuit generates the signal in response to the capacitance value of the variable capacitor.

7. The pixel unit of claim 6, wherein the variable capacitor has:

a first electrode, electrically connected to the switch circuit, for transmitting the signal to the switch circuit; and

a second electrode electrically connected to a power source, wherein the power source is a reference value for the sensing circuit to generate the signal.

8. The pixel unit of claim 1, wherein the display apparatus is a display apparatus with a touch screen function.

9. A display apparatus, comprising:

a data line;

a driving circuit; and

a pixel unit for receiving pixel data transmitted by the driving circuit, comprising;

a switch circuit electrically connected to the data line; and

a sensing circuit, electrically connected to the switch circuit, for generating a signal in response to touch of an object;

wherein the signal is transmitted through the data line with the switch circuit being turned on.

10. The display apparatus of claim 9, wherein the switch circuit comprises a transistor having:

a first electrode, electrically connected to the data line, for transmitting the signal to the data line; and

a second electrode, electrically connected to the sensing circuit, for receiving the signal.

11. The display apparatus of claim 10, wherein the display apparatus comprises a scan line, and the transistor further has a gate, electrically connected to the scan line, for controlling whether to turn on the transistor.

12. The display apparatus of claim 10, further comprising a sensing signal determination circuit, electrically connected to the data line, for receiving the signal from the data line.

13. The display apparatus of claim 12, wherein the sensing signal determination circuit comprises a comparator.

14. The display apparatus of claim 12, wherein the sensing signal determination circuit comprises an integrator.

15. The display apparatus of claim 12, further comprising a control unit, electrically connected to the sensing signal determination circuit and the driving circuit, for controlling transmission of the signal and the pixel data.

16. The display apparatus of claim 10, wherein the transistor comprises an n-type transistor.

17. The display apparatus of claim 10, wherein the transistor comprises a p-type transistor.

18. The display apparatus of claim 9, wherein the sensing circuit has a variable capacitor, a capacitance value of the variable capacitor is changed in response to the touch of the object, and the sensing circuit generates the signal in response to the capacitance value of the variable capacitor.

19. The display apparatus of claim 18, wherein the variable capacitor has:

a first electrode, electrically connected to the switch circuit, for transmitting the signal to the switch circuit; and

a second electrode electrically connected to a power source, wherein the power source is a reference value for the sensing circuit to generate the signal.

20. The display apparatus of claim 9, wherein the display apparatus is a display apparatus with a touch screen function.

21. A display apparatus for sensing touch of an object, comprising:

a plurality of data lines;

a plurality of scan lines; and

a plurality of pixel units, each of the pixel units comprising a variable capacitor electrically connected to the switch circuit and a switch circuit;

wherein the variable capacitors of the pixel units generate a plurality of signals in response to the touch of the object, the scan lines are orderly electrically connected to the pixel units to orderly turn on the switch circuits of the pixel units, and the signals are transmitted through the data lines by orderly turning on the switch circuits of the pixel units.

22. The display apparatus of claim 21, further comprising a plurality of sensing signal determination circuits, orderly electrically connected to the data lines, for receiving the signals from the data lines respectively.

23. The display apparatus of claim 22, wherein each of the sensing signal determination circuits comprises a comparator.

24. The display apparatus of claim 22, wherein each of the sensing signal determination circuits comprises an integrator.

25. The display apparatus of claim 21, wherein the switch circuit is a transistor, and a gate of the transistor is electrically connected to one of the scan lines.

26. The display apparatus of claim 25, wherein the transistor is an n-type transistor.

27. The display apparatus of claim 25, wherein the transistor is a p-type transistor.

28. A method for sensing touch of an object on a pixel unit, the pixel unit comprising a first switch circuit, a second switch circuit, and a variable capacitor, the method comprising the following steps of:

turning on the first switch circuit in a first time period and inputting a reference voltage through a data line by the first switch circuit;

generating a signal in response to the touch of the object according to the reference voltage; and

turning on the second switch circuit in a second time period and transmitting the signal through a readout line by the second switch circuit.

29. The method of claim 28, wherein the reference voltage is a maximum voltage of all signals in the pixel unit.

30. A pixel unit for use in a display apparatus for sensing touch of an object, the display apparatus comprising a data line and a readout line, the pixel unit comprising:

a first switch circuit electrically connected to the data line;

a second switch circuit electrically connected to the readout line; and

a variable capacitor electrically connected to the first switch circuit and the second switch circuit;

wherein the variable capacitor receives a reference voltage from a data line by the first switch circuit in a first time period and generates a signal in response to the touch of the object according to the reference voltage, and the signal is transmitted through the readout line by the second switch circuit in a second time period.

31. The pixel unit of claim 30, wherein the reference voltage is a maximum voltage of all signals in the pixel unit.

32. The pixel unit of claim 30, wherein the first switch circuit is a transistor having:

a first electrode, electrically connected to the data line, for receiving the reference voltage; and

a second electrode, electrically connected to the variable capacitor, for transmitting the reference voltage to the variable capacitor.

33. The pixel unit of claim 30, wherein the second switch circuit is a transistor having:

a first electrode, electrically connected to the variable capacitor, for receiving the signal; and

a second electrode, electrically connected to the readout line, for transmitting the signal through the readout line.

34. The pixel unit of claim 30, wherein the display apparatus is a display apparatus with a touch screen function.

35. A display apparatus, comprising:

a data line;

a driving circuit;

a readout line; and

a pixel unit for receiving pixel data transmitted by the driving circuit, comprising;

a first switch circuit electrically connected to the data line;

a second switch circuit electrically connected to the readout line; and

a variable capacitor electrically connected to the first switch circuit and the second switch circuit;

wherein the variable capacitor receives a reference voltage from a data line by the first switch circuit in a first time period and generates a signal in response to the touch of the object according to the reference voltage, and the signal is transmitted through the readout line by the second switch circuit in a second time period.

36. The display apparatus of claim 35, wherein the reference voltage is a maximum voltage of all signals in the pixel unit.

37. The display apparatus of claim 35, wherein the first switch circuit is a transistor having:

a first electrode, electrically connected to the data line, for receiving the reference voltage; and

a second electrode, electrically connected to the variable capacitor, for transmitting the reference voltage to the variable capacitor.

38. The display apparatus of claim 35, wherein the second switch circuit is a transistor having:

a first electrode, electrically connected to the variable capacitor, for receiving the signal; and

a second electrode, electrically connected to the readout line, for transmitting the signal through the readout line.