METHOD AND APPARATUS COMPENSATING PARASITIC CAPACITANCE IN TOUCH PANEL

• US 20110242050A1
• Filed: 03/31/2011
• Published: 10/06/2011
• Est. Priority Date: 04/06/2010
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: BAEK, Jong-hak, BYUN, San-ho, CHOI, Yoon-kyung
• Application Number:
  US13/076,686
• Publication Number:
  US 20110242050A1
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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

A touch controller and touch display device incorporating same are described. The touch controller includes a parasitic capacitance compensation unit that receives a common electrode voltage to generate a quantity of charge capable of compensating for a quantity of charge associated with a parasitic capacitance between a sensing channel and a common electrode in a touch panel capable of capacitive sensing of a touch input.

Claims

1. A touch controller comprising:

a parasitic capacitance compensation unit that receives a common electrode voltage to generate a quantity of charge capable of compensating for a quantity of charge associated with a parasitic capacitance between a sensing channel and a common electrode in a touch panel capable of capacitive sensing of a touch input.

2. The touch panel of claim 1, wherein the parasitic capacitance compensation unit receives an excitation pulse in parallel with the common electrode voltage.

3. The touch panel of claim 2, wherein the parasitic capacitance compensation unit comprises a differential op amplifier that receives the common electrode voltage and the excitation pulse via an inversion input terminal.

4. The touch panel of claim 3, wherein the excitation pulse and the common electrode voltage are summed and applied to the differential op amplifier.

5. The touch panel of claim 4, wherein the quantity of charge associated with the parasitic capacitance is proportional to a voltage difference between the excitation pulse and the common electrode voltage.

6. The touch panel of claim 3, further comprising:

a negative capacitor connected to an output of the differential op amplifier and compensating for the parasitic capacitance.

7. The touch panel of claim 6, wherein a capacitance of the negative capacitor ranges from between about 1.7 times the parasitic capacitance to about 2.3 times the parasitic capacitance.

8. The touch panel of claim 1, further comprising:

a signal conversion unit that receives a touch signal, the touch signal being generated by sensing a variation in a sensing unit disposed in the sensing channel in the touch panel;

a filtering unit that filters the touch signal; and

an analog-digital conversion unit that converts the touch signal from an analog signal into a corresponding digital signal.

9. A touch display device compensating for parasitic capacitance, the touch display device comprising:

a touch panel comprising a plurality of sensing channels that perform a touch screen operation of sensing a variation in a sensing unit disposed in the plurality of sensing channels, and outputting a touch signal of the sensing unit, the touch signal being generated during the touch screen operation; and

a touch controller comprising a signal conversion unit that receives the variation signal, converts the variation signal into a voltage, and outputs the voltage,

wherein the touch controller comprises;

a parasitic capacitance compensation unit that receives a common electrode voltage to generate a quantity of charge capable of compensating for a quantity of charge associated with a parasitic capacitance between a sensing channel and a common electrode in the touch panel.

10. The touch display device of claim 9, wherein the parasitic capacitance compensation unit that receives an excitation pulse in parallel with the common electrode voltage.

11. The touch display device of claim 10, wherein the parasitic capacitance compensation unit comprises a differential op amplifier that receives the common electrode voltage and the excitation pulse via an inversion input terminal.

12. The touch display device of claim 11, wherein the excitation pulse and the common electrode voltage are summed and applied to the differential op amplifier.

13. The touch display device of claim 12, wherein the quantity of charge associated with the parasitic capacitance is proportional to a voltage difference between the excitation pulse and the common electrode voltage.

14. The touch display device of claim 11, further comprising:

a negative capacitor connected to an output of the differential op amplifier and compensating for the parasitic capacitance.

15. The touch display device of claim 14, wherein a capacitance of the negative capacitor ranges from about 1.7 times the parasitic capacitance to about 4 times the parasitic capacitance.

16. The touch display device of claim 9, wherein the touch controller further comprises:

a filtering unit that filters the touch signal; and

an analog-digital conversion unit that converts the touch signal from an analog signal into a corresponding digital signal.

17. The touch display device of claim 9, wherein the touch panel comprises an ON-cell type touch panel unified with the display panel in a common body.

18. The touch display device of claim 9, wherein the touch panel comprises an overlay touch panel.

19. The touch display device of claim 9, wherein the common electrode of the touch display device does not include a common electrode protection layer.

20. A method compensating for parasitic capacitance in a touch system, the method comprising:

sensing variation in capacitance for a plurality of sensing units disposed in a plurality of sensing channels in response to a touch input, and outputting a touch signal corresponding to the variation;

receiving, amplifying, and outputting the touch signal, wherein the receiving, amplifying, and outputting of the touch signal is performed by a touch controller; and

receiving a common electrode voltage to generate a quantity of charge capable of compensating for a quantity of charge associated with a parasitic capacitance between the plurality of sensing channels and a common electrode, wherein the receiving of the common electrode voltage is performed by a parasitic capacitance compensation unit of the touch controller.

21. The method of claim 20, wherein the parasitic capacitor compensation unit receives an excitation pulse in parallel with the common electrode voltage.

22. The method of claim 21, wherein the parasitic capacitor compensation unit comprises a differential op amplifier that receives the common electrode voltage and the excitation pulse via an inversion input terminal.

23. The method of claim 22, wherein the excitation pulse and the common electrode voltage are summed and applied to the differential op amplifier.

24. The method of claim 23, wherein the quantity of charge associated with the parasitic capacitance is proportional to a voltage difference between the excitation pulse and the common electrode voltage.

25. The method of claim 22, wherein the touch system comprises:

a negative capacitor connected to an output of the differential op amplifier and compensating for the parasitic capacitance.

26. The method of claim 25, wherein capacitance of the negative capacitor ranges from between about 1.7 times the parasitic capacitance to about 2.3 times the parasitic capacitance.

27. The method of claim 20, further comprising:

filtering the touch signal following amplifying of the touch signal; and

converting the touch signal following filtering of the touch signal from an analog form to a corresponding digital form.

28. The method of claim 20, wherein the touch panel of the touch system comprises an ON-cell type touch panel unified with a display panel in a common body.

29. The method of claim 20, wherein the touch panel of the touch system comprises an overlay touch panel.