Display device and driving method thereof

• US 9,965,071 B2
• Filed: 02/04/2016
• Issued: 05/08/2018
• Est. Priority Date: 12/31/2014
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kang, Seong Kyu, Kim, Hoon Bae, Lee, Sung Yub
• Primary Examiner(s): Sitta, Grant
• Application Number:
  US15/016,250
• Publication Number:
  US 20160188065A1
• Time in Patent Office: 824 Days
• Field of Search: 345173, 345 76
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally

Abstract

In a touch display device, a controller generates a touch sync signal for controlling timing of a touch sensing period and a display period in each of a plurality of frames. A touch panel has a plurality of touch electrodes in a display area to generate touch sensing signals indicating whether or not a touch occurs during the touch sensing period. A touch sensing circuit supplies a touch drive signal to the plurality of touch electrodes during the touch sensing period and detects if the touch occurred based on the touch sensing signals received from the plurality of touch electrodes. A touch assistance line surrounds the display area and is disposed in the non-display area of the touch panel. A touch assistance signal supply circuit generates a touch assistance signal on the touch assistance line. The touch assistance signal mimics the touch drive signal during the touch sensing period.

Claims

1. A touch display device, comprising:

a controller to generate a touch sync signal for controlling timing of a touch sensing period and a display period in each of a plurality of frames;

a touch panel having a display area and a non-display area surrounding the display area, the touch panel having a plurality of touch electrodes in the display area to generate touch sensing signals indicating whether or not a touch occurred during the touch sensing period;

a touch sensing circuit to supply an alternating touch drive signal to one or more of the plurality of touch electrodes during the touch sensing period and to detect if the touch occurred based on the touch sensing signals received from the one or more of the plurality of touch electrodes;

a touch assistance signal supply circuit to generate an alternating touch assistance signal during the touch sensing period, the alternating touch assistance signal mimicking the alternating touch drive signal during the touch sensing period; and

a voltage supply line disposed in the non-display area of the touch panel, the voltage supply line disposed outside outer edges of the display area and the voltage supply line at least partially surrounding the plurality of touch electrodes, the voltage supply line supplying a DC voltage during the display period to drive gate pulses onto gate lines of display pixels of the display area, and the alternating touch assistance signal being supplied to the voltage supply line by the touch assistance signal supply circuit during the touch sensing period, wherein the DC voltage is one of a gate low voltage for the gate pulses supplied through a gate low voltage supply line, and a gate high voltage for the gate pulses supplied through a gate high voltage line.

2. The touch display device of claim 1, wherein the alternating touch assistance signal has an approximately same signal level and approximately same phase as the alternating touch drive signal during the touch sensing period.

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

a gate driver to provide the gate pulses to the gate lines of the touch panel during the display period;

a data driver to provide data voltages to data lines of the touch panel during the display period; and

wherein each of the gate lines corresponds to a row of pixels and each of the data lines corresponds to a column of pixels in the touch panel, and wherein the touch panel displays respective rows of an image during the display period based on a difference between the data voltages on the data lines and a common voltage when the gate pulses for respective ones of the gate lines corresponding to the respective rows are supplied.

4. The touch display device of claim 3, wherein the data driver is further to supply the alternating touch assistance signal to the data lines during the touch sensing period, and wherein the gate driver is further to supply the alternating touch assistance signal to the gate lines during the touch sensing period.

5. The touch display device of claim 1, wherein the touch sensing circuit is further to supply a common voltage to the plurality of touch electrodes during the display period.

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

an antistatic line providing an antistatic signal to prevent static electricity from interfering with the touch panel during the display period; and

wherein the alternating touch assistance signal supply circuit further supplies the alternating touch assistance signal to the antistatic line during the touch sensing period.

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

a gate driver to sequentially supply the gate pulses to the gate lines of the touch panel during the display period by alternately driving the gate high voltage from the gate high voltage supply line onto the gate lines for a pulse period of the gate pulse and otherwise driving the gate low voltage from the gate low voltage supply line onto the gate lines, wherein the voltage supply line comprises one of the gate high voltage supply line and the gate low voltage supply line.

22. The touch display device of claim 1, wherein the alternating touch assistance signal periodically switches between a first voltage level and a second voltage level during the touch sensing period, and wherein the voltage supply line supplies the DC voltage for an entirety of the of the display period.

7. A method for operating a touch display device, the method comprising:

generating, by a controller, a touch sync signal for controlling timing of a touch sensing period and a display period in each of a plurality of frames;

supplying, by a voltage supply line disposed in a non-display area surrounding a display area of a touch panel, a DC voltage during the display period to drive gate pulses onto gate lines of display pixels of the display area, the voltage supply line disposed outside outer edges of the display area and the voltage supply line at least partially surrounding a plurality of touch electrodes, wherein the DC voltage is one of a gate low voltage for the gate pulses supplied through a gate low voltage supply line, and a gate high voltage for the gate pulses supplied through a gate high voltage line;

supplying, by a touch sensing circuit, an alternating touch drive signal to one or more of the plurality of touch electrodes in the display area of the touch panel during the touch sensing period;

supplying by a touch assistance signal supply circuit, an alternating touch assistance signal on the voltage supply line during the touch sensing period, the alternating touch assistance signal mimicking the alternating touch drive signal;

receiving, from the one or more of the plurality of touch electrodes, touch sensing signals indicating whether or not a touch occurred during the touch sensing period; and

detecting, by the touch sensing circuit, if the touch occurred during the touch sensing period based on the touch sensing signals received from the plurality of touch electrodes.

8. The method of claim 7, wherein the alternating touch assistance signal has an approximately same signal level and an approximately same phase as the alternating touch drive signal.

9. The method of claim 7, further comprising:

sequentially supplying the gate pulses to the gate lines of the touch panel during the display period, wherein each of the gate lines corresponds to a row of pixels in the touch panel;

providing, by a data driver, data voltages to data lines of the touch panel during the display period, wherein each of the data lines corresponds to a column of pixels in the touch panel;

displaying by the touch panel during the display period, respective rows of an image based on a difference between the data voltages on the data lines and a common voltage when the gate pulses for respective ones of the gate lines corresponding to the respective rows are supplied.

10. The method of claim 9, further comprising:

providing the alternating touch assistance signal to the gate lines and to the data lines during the touch sensing period.

11. The method of claim 7, further comprising:

supplying, by the touch sensing circuit, a common voltage to the plurality of touch electrodes during the display period.

12. The method of claim 7, further comprising:

providing an antistatic signal on an antistatic line to prevent static electricity from interfering with the touch panel during the display period; and

supplying the alternating touch assistance signal to the antistatic line during the touch sensing period.

20. The method of claim 7, further comprising:

sequentially supplying the gate pulses to the gate lines of a touch panel during the display period by sequentially driving the gate high voltage from the gate high voltage supply line onto the gate lines for a pulse period and otherwise driving the gate low voltage from the gate low voltage supply line onto the gate lines, the gate high voltage supply line and the gate low voltage supply line in the non-display area of the touch panel, wherein the voltage supply line comprises one of the gate high voltage supply line and the gate low voltage supply line.

23. The method of claim 7, wherein the alternating touch assistance signal periodically switches between a first voltage level and a second voltage level during the touch sensing period, and wherein the voltage supply line supplies the DC voltage for an entirety of the of the display period.

13. A driver circuit for driving a touch display device, the driver circuit comprising:

a controller circuit to generate a touch sync signal for controlling timing of a touch sensing period and a display period in each of a plurality of frames;

a touch sensing circuit to supply an alternating touch drive signal to one or more of a plurality of touch electrodes in a display area of a touch panel during the touch sensing period and to detect if a touch occurred during the touch sensing period based on touch sensing signals received from the plurality of touch electrodes;

a power supply circuit to supply a DC voltage during the display period to a voltage supply line disposed in a non-display area of the touch panel surrounding the display area, the voltage supply line disposed outside outer edges of the display area and the voltage supply line at least partially surrounding the plurality of touch electrodes, the DC voltage to drive gate pulses onto gate lines of display pixels of the display area during the display period, wherein the DC voltage is one of a gate low voltage for the gate pulses supplied through a gate low voltage supply line, and a gate high voltage for the gate pulses supplied through a gate high voltage line; and

a touch assistance signal supply circuit to generate an alternating touch assistance signal on the voltage supply line during the touch sensing period, the alternating touch assistance signal mimicking the alternating touch drive signal during the touch sensing period.

14. The driver circuit of claim 13, wherein the alternating touch assistance signal has an approximately same signal level and approximately same phase as the alternating touch drive signal during the touch sensing period.

15. The driver circuit of claim 13, further comprising:

a gate driver circuit to provide the gate pulses to the gate lines of the touch panel during the display period; and

a data driver circuit to provide data voltages to data lines of the touch panel during the display period; and

wherein each of the gate lines corresponds to a row of pixels and each of the data lines corresponds to a column of pixels in the touch panel, and wherein the touch panel displays respective rows of an image during the display period based on a difference between the data voltages on the data lines and a common voltage when the gate pulses for respective ones of the gate lines corresponding to the respective rows are supplied.

16. The driver circuit of claim 15, wherein the data driver is further to supply the alternating touch assistance signal to the data lines during the touch sensing period, and wherein the gate driver is further to supply the alternating touch assistance signal to the gate lines during the touch sensing period.

17. The driver circuit of claim 13, wherein the touch sensing circuit is further to supply a common voltage to the plurality of touch electrodes during the display period.

18. The driver circuit of claim 13, wherein the alternating touch assistance signal supply circuit further supplies the alternating touch assistance signal to an antistatic line during the touch sensing period, the antistatic line to prevent static electricity from interfering with the touch panel during the display period.

21. The driver circuit of claim 13, further comprising:

a gate driver to sequentially supply the gate pulses to the gate lines of the touch panel during the display period by alternately driving the gate high voltage from the gate high voltage supply line onto the gate lines for a pulse period of the gate pulse and otherwise driving the gate low voltage from the gate low voltage supply line onto the gate lines, wherein the voltage supply line comprises one of the gate high voltage supply line and the gate low voltage supply line.

24. The driver circuit of claim 13, wherein the alternating touch assistance signal periodically switches between a first voltage level and a second voltage level during the touch sensing period, and wherein the voltage supply line supplies the DC voltage for an entirety of the of the display period.