Touch sensitive display device with modulated ground voltage, driving circuit, control circuit, and operating method of the touch sensitive display device

• US 9,760,213 B2
• Filed: 12/30/2015
• Issued: 09/12/2017
• Est. Priority Date: 10/13/2015
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, SungChul, Jang, HyungUk, Bae, SangHyuck, Han, Sungsu, Ju, Suyun, Jung, DoYoung
• Primary Examiner(s): LANDIS, LISA S
• Application Number:
  US14/984,657
• Publication Number:
  US 20170102825A1
• Time in Patent Office: 622 Days
• Field of Search: 345173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

Exemplary embodiments of the present invention relate to a touch technology, and more specifically, to a signal control circuit, a power control circuit, a drive circuit, a timing controller, a touch system, and a touch sensitive display device and a driving method thereof that can simply swing various voltages in a display device for a touch mode period by using a modulated ground voltage obtained by swinging a ground voltage, thereby effectively providing touch driving and preventing unnecessary parasitic capacitance from being generated not only in an active area but also in all other areas.

Claims

1. A touch sensitive display device comprising:

a display panel that comprises a plurality of common electrodes, the common electrodes driven for touch sensing and image display;

a driving circuit to supply a touch driving signal to at least a first common electrode of the common electrodes;

ground wiring; and

a circuit to provide a modulated ground voltage to the ground wiring, the touch driving signal having a same phase as the modulated ground voltage, and pulses of the touch driving signal have a DC voltage offset relative to pulses of the modulated ground voltage.

2. The touch sensitive display device of claim 1, further comprising:

a power control circuit to generate at least one of a modulated common electrode voltage and a modulated power supply voltage based on the modulated ground voltage.

3. The touch sensitive display device of claim 2, wherein the at least one of the modulated common electrode voltage and the modulated power supply voltage has a same phase as the modulated ground voltage.

4. The touch sensitive display device of claim 3, wherein the at least one of the modulated common electrode voltage and the modulated power supply voltage has a same amplitude as the modulated ground voltage.

5. The touch sensitive display device of claim 2, wherein the power control circuit includes a first power input terminal to receive the modulated ground voltage and a second power input terminal to receive a modulated power supply voltage, the modulated power supply voltage having a same phase as the modulated ground voltage.

6. The touch sensitive display device of claim 1, wherein the display panel comprises a data line coupled to at least one pixel, and the driving circuit also supplies a data line load free driving signal to the data line, the data line load free driving signal having a same phase as the modulated ground voltage.

7. The touch sensitive display device of claim 1, wherein the display panel comprises a gate line coupled to at least one pixel, and the display device further comprises:

a gate driving circuit that supplies a gate line load free driving signal to the gate line, the gate line load free driving signal having a same phase as the modulated ground voltage.

8. The touch sensitive display device of claim 1, wherein the driving circuit supplies a common electrode load free driving signal to at least one second common electrode of the common electrodes while the touch driving signal is supplied to the first common electrode, the common electrode load free driving signal having a same phase as the modulated ground voltage.

9. The touch sensitive display device of claim 1, wherein the circuit to provide a modulated ground voltage comprises:

a multiplexer having a first input to receive the modulated ground voltage, a second input to receive a DC ground voltage, and an output coupled to the ground wiring, the multiplexer selecting between the modulated ground voltage at the first input and the direct current (DC) ground voltage at the second input.

10. The touch sensitive display device of claim 1, wherein the circuit to provide a modulated ground voltage further includes circuitry to adjust an amplitude of the modulated ground voltage.

11. The touch sensitive display device of claim 1, wherein the display panel is driven in a touch mode period and a display mode period in a time division manner, wherein the driving circuit provides the touch driving signal to the first common electrode during the touch mode period for touch sensing and provides a DC common electrode voltage to the first common electrode during the display mode period for image display.

12. The touch sensitive display device of claim 1, wherein the display panel is driven in a touch mode and a display mode that overlap with each other, and while the touch mode and the display mode overlap, the touch driving signal supplied to the first common electrode is a modulated common electrode voltage operating as a display voltage for image display.

13. The touch sensitive display device of claim 12, wherein the display panel comprises a pixel electrode, and a pixel voltage in the pixel electrode has a same phase as the modulated ground voltage.

31. The display device of claim 1, wherein the touch driving signal is supplied to the first common electrode for touch sensing, and wherein the circuit provides the modulated ground voltage to the ground wiring for touch sensing, and the modulated ground voltage is a pulse modulation signal.

32. The display device of claim 1, wherein the touch driving signal is supplied to the first common electrode for touch sensing, and wherein the display panel comprises a signal line disposed in a non-display area of the display panel, and a display voltage pulse applied to the signal line has a same phase as the modulated ground voltage.

14. A method of operating a touch sensitive display device that comprises display panel including a plurality of common electrodes, the common electrodes driven for touch sensing and image display, the method comprising:

supplying a touch driving signal to at least a first common electrode of the common electrodes; and

providing a modulated ground voltage to ground wiring of the touch sensitive display device, the touch driving signal having a same phase as the modulated ground voltage, and pulses of the touch driving signal have a DC voltage offset relative to pulses of the modulated ground voltage.

15. The method of claim 14, further comprising:

generating at least one of a modulated common electrode voltage and a modulated power supply voltage based on the modulated ground voltage.

16. The method of claim 15, wherein the at least one of the modulated common electrode voltage and the modulated power supply voltage has a same phase as the modulated ground voltage.

17. The method of claim 16, wherein the at least one of the modulated common electrode voltage and the modulated power supply voltage has a same amplitude as the modulated ground voltage.

18. The method of claim 14, further comprising:

supplying a data line load free driving signal to a data line coupled to at least one pixel, the data line load free driving signal having a same phase as the modulated ground voltage.

19. The method of claim 14, further comprising:

supplying a gate line load free driving signal to a gate line coupled to at least one pixel, the gate line load free driving signal having a same phase as the modulated ground voltage.

20. The method of claim 14, further comprising:

supplying a common electrode load free driving signal to at least one second common electrode of the common electrodes while the touch driving signal is supplied to the first common electrode,

the common electrode load free driving signal having a same phase as the modulated ground voltage.

21. The method of claim 14, further comprising:

adjusting an amplitude of the modulated ground voltage.

22. The method of claim 14, wherein the display panel is driven in a touch mode period and a display mode period in a time division manner, wherein the touch driving signal is provided to the first common electrode during the touch mode period for touch sensing, and further comprising:

providing a DC common electrode voltage to the first common electrode during the display mode period for image display.

23. The method of claim 14, wherein the display panel is driven in a touch mode and a display mode that overlap with each other, and while the touch mode and the display mode overlap, the touch driving signal supplied to the first common electrode is a modulated common electrode voltage operating as a display voltage for image display.

24. A driving circuit for a touch sensitive display device that comprises a display panel, the display panel comprising plurality of common electrodes driven for touch sensing and image display, the driving circuit comprising:

a first circuit to supply a touch driving signal to at least a first common electrode of the common electrodes,

wherein the touch driving signal has a same phase as a modulated ground voltage provided to ground wiring of the touch sensitive display device, and pulses of the touch driving signal have a DC voltage offset relative to pulses of the modulated ground voltage.

25. The driving circuit of claim 24, further comprising:

a second circuit to provide the modulated ground voltage to the ground wiring of the touch sensitive display device.

26. The driving circuit of claim 24, wherein the display panel comprises a data line coupled to at least one pixel, and the first circuit also supplies a data line load free driving signal to the data line, the data line load free driving signal having a same phase as the modulated ground voltage.

27. The driving circuit of claim 24, wherein the first circuit supplies a common electrode load free driving signal to at least one second common electrode of the common electrodes while the touch driving signal is supplied to the first common electrode, the common electrode load free driving signal having a same phase as the modulated ground voltage.

28. A control circuit for a touch sensitive display device that comprises a display panel, the display panel comprising plurality of common electrodes driven for touch sensing and image display, the control circuit comprising:

a first circuit to provide a modulated ground voltage to ground wiring of the touch sensitive display device,

wherein the modulated ground voltage has a same phase as a touch driving signal provided to at least a first common electrode of the common electrodes, and pulses of the modulated ground voltage have has a DC voltage offset relative to pulses of the touch driving signal.

29. The control circuit of claim 28, further comprising:

a second circuit to generate the modulated ground voltage,

wherein the first circuit to provide the modulated ground voltage to the ground wiring comprises a multiplexer having a first input to receive the modulated ground voltage, a second input to receive a DC ground voltage, and an output coupled to the ground wiring, the multiplexer selecting between the modulated ground voltage at the first input and the direct current (DC) ground voltage at the second input.

30. The control circuit of claim 28, further comprising:

a second circuit to adjust an amplitude of the modulated ground voltage.