Display device and driving method thereof

• US 9,285,913 B1
• Filed: 05/29/2015
• Issued: 03/15/2016
• Est. Priority Date: 12/31/2014
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lee, Sung Yub, Kang, Seong Kyu, Kim, Hoon Bae
• Primary Examiner(s): Sitta, Grant
• Application Number:
  US14/726,062
• Time in Patent Office: 291 Days
• Field of Search: 345156-175
• US Class Current: 1/1
• 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, the touch sensing period and the display period alternating with each other;

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 occurs during the touch sensing period;

a gate low voltage supply line disposed in the non-display area of the touch panel, the gate low voltage supply line supplying a gate low voltage during the display period;

a gate high voltage supply line disposed in the non-display area of the touch panel, the gate high voltage supply line supplying a gate high voltage during the display period;

a gate driver to sequentially supply gate pulses to 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;

a touch sensing circuit to supply a touch drive signal to 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 plurality of touch electrodes; and

a touch assistance signal supply circuit to generate a touch assistance signal on at least one of the gate low voltage supply line and the gate high voltage supply line during the touch sensing period, the touch assistance signal mimicking the touch drive signal during the touch sensing period.

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

3. The touch display device of claim 1, wherein the gate driver is further to supply the touch assistance signal to the gate lines during the touch sensing period, and wherein the touch display device further comprises:

a data driver to provide data voltages to data lines of the touch panel during the display period and to supply the touch assistance signal to the data lines during the touch sensing 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 1, wherein the touch sensing circuit is further to supply a common voltage to the plurality of touch electrodes during the display period.

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

15. The touch display device of claim 1, wherein the gate high voltage supply line and the gate low voltage supply line surround the display area.

6. 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, the touch sensing period and the display period alternating with each other;

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

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

supplying during the touch sensing period by a touch assistance signal supply circuit, a touch assistance signal on at least one of the gate high voltage supply line and the gate low voltage supply line, the touch assistance signal mimicking the touch drive signal during the touch sensing period;

generating, by 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.

7. The method of claim 6, wherein the touch assistance signal has an approximately same signal level and an approximately same phase as the touch drive signal.

8. The method of claim 6, wherein each of the gate lines corresponds to a row of pixels in the touch panel, the method further comprising:

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; and

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

9. The method of claim 6, further comprising:

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

10. The method of claim 6, 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 touch assistance signal to the antistatic line during the touch sensing period.

16. The method of claim 6, wherein the gate high voltage supply line and the gate low voltage supply line surround the display area.

11. A touch display device, comprising:

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 occurs during a touch sensing period, the plurality of touch electrodes including center touch electrodes and edge touch electrodes disposed at edges of the display area between the center touch electrodes and the non-display area;

a gate low voltage supply line disposed in the non-display area of the touch panel, the gate low voltage supply line supplying a gate low voltage during a display period;

a gate high voltage supply line disposed in the non-display area of the touch panel, the gate high voltage supply line supplying a gate high voltage during the display period;

a gate driver to sequentially supply gate pulses to 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;

a touch sensing circuit to supply a touch drive signal to the plurality of edge touch electrodes and to detect if the touch occurred based on the touch sensing signals received from the plurality of touch electrodes; and

wherein at least one of the gate high voltage supply line and the gate voltage supply line is to supply a touch assistance signal during the touch sensing period, the touch assistance signal mimicking the touch drive signal applied to the edge touch electrodes during the touch sensing period.

12. The touch display device of claim 11, wherein the touch assistance signal has an approximately same signal level and approximately same phase as the touch drive signal during the touch sensing period.

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

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

wherein the touch sensing circuit is further to supply a common voltage to the plurality of touch electrodes during the display period.

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

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

17. The touch display device of claim 11, wherein the gate high voltage supply line and the gate low voltage supply line surround the display area.