Display device and driving method thereof

• US 10,423,262 B2
• Filed: 04/05/2018
• Issued: 09/24/2019
• 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:
  US15/946,725
• Publication Number:
  US 20180224987A1
• Time in Patent Office: 537 Days
• 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 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 detect a touch during a touch sensing period and a plurality of touch electrode lines electrically connected to the plurality of touch electrodes,

a touch sensing circuit to supply an alternating touch drive signal to one or more of the plurality of touch electrodes via the plurality of touch electrode lines during the touch sensing period;

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 gate voltage 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 gate 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,

wherein a first touch electrode of the plurality of touch electrodes is connected to a first touch electrode line of the touch electrode lines and a second touch electrode of the plurality of touch electrodes is connected to a second touch electrode line of the touch electrode lines, and

wherein the first touch electrode line overlaps with the second touch electrode and the first touch electrode line is not overlapped with the second touch electrode 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 the display pixels of the display area during a 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 the display pixels and each of the data lines corresponds to a column of the display pixels, 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, further comprising a data driver and a gate driver,

wherein the data driver is to supply the alternating touch assistance signal to data lines during the touch sensing period, and wherein the gate driver is 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 a 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 a 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.

7. The touch display device of claim 1,

wherein the gate voltage is a DC voltage.

8. 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 detect a touch during a touch sensing period and a plurality of touch electrode lines electrically connected to the plurality of touch electrodes;

a touch sensing circuit to supply an alternating touch drive signal to one or more of the plurality of touch electrodes via the plurality of touch electrode lines during the touch sensing period;

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;

a first voltage supply line disposed in the non-display area of the touch panel, the first voltage supply line disposed outside the plurality of touch electrodes, the first voltage supply line supplying a first gate voltage to drive gate pulses onto gate lines of display pixels of the display area; and

a second voltage supply line disposed in the non-display area of the touch panel, the second voltage supply line disposed outside the plurality of touch electrodes, the second voltage supply line supplying a second gate voltage to drive gate pulses onto gate lines of display pixels of the display area,

wherein the touch assistance signal supply circuit supplies the alternating touch assistance signal to at least one of the first voltage supply line and the second voltage supply line during the touch sensing period,

wherein a first touch electrode of the plurality of touch electrodes is connected to a first touch electrode line of the touch electrode lines and a second touch electrode of the plurality of touch electrodes is connected to a second touch electrode line of the touch electrode lines, and

wherein the first touch electrode line overlaps with the second touch electrode and the first touch electrode line is not overlapped with the second touch electrode line.

9. The touch display device of claim 8, 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.

10. The touch display device of claim 8, further comprising:

a gate driver to provide the gate pulses to the gate lines of the display pixels of the display area during a 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 the display pixels and each of the data lines corresponds to a column of the display pixels, 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.

11. The touch display device of claim 8, further comprising a data driver and a gate driver,

wherein the data driver is to supply the alternating touch assistance signal to data lines during the touch sensing period, and wherein the gate driver is to supply the alternating touch assistance signal to the gate lines during the touch sensing period.

12. The touch display device of claim 8, wherein the touch sensing circuit is further to supply a common voltage to the plurality of touch electrodes during a display period.

13. The touch display device of claim 8, further comprising:

an antistatic line providing an antistatic signal to prevent static electricity from interfering with the touch panel during a 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.

14. The touch display device of claim 8,

wherein the first gate voltage is a gate high voltage as a DC voltage, and

wherein the second gate voltage is a gate low voltage as a DC voltage.