DISPLAY DEVICE HAVING TOUCH SENSOR AND METHOD FOR DRIVING THE SAME

• US 20120256861A1
• Filed: 04/09/2012
• Published: 10/11/2012
• Est. Priority Date: 04/07/2011
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: PARK, Dongjo
• Granted Patent: US 9,310,942 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

According to an embodiment, a touch-sensitive display device includes a display panel including data lines, gate lines crossing the data lines, and a pixel array including pixels arranged in a matrix form; a touch screen including Tx lines, Rx lines crossing the Tx lines, and touch sensors formed at crossings of the Tx lines and the Rx lines; a display driving circuit configured to supply video data voltages to the pixels of the display panel; and a touch screen driving circuit configured to sequentially supply at least one delayed pulse to each of the Tx lines, and sense an output signal of each of the touch sensors through the Rx lines, wherein an edge of each of the at least one delayed pulse is present in a horizontal blank period.

Claims

1. A touch-sensitive display device comprising:

a display panel including data lines, gate lines crossing the data lines, and a pixel array including pixels arranged in a matrix form;

a touch screen including Tx lines, Rx lines crossing the Tx lines, and touch sensors formed at crossings of the Tx lines and the Rx lines;

a display driving circuit configured to supply video data voltages to the pixels of the display panel; and

a touch screen driving circuit configured to sequentially supply at least one delayed pulse to each of the Tx lines, and sense an output signal of each of the touch sensors through the Rx lines,

wherein an edge of each of the at least one delayed pulse is present in a horizontal blank period.

2. The touch-sensitive display device of claim 1, wherein a falling edge of each of the at least one delayed pulse falls during a corresponding horizontal blank period.

3. The touch-sensitive display device of claim 1, wherein each of the at least one delayed pulse supplied to one of the Tx lines is not aligned with a gate pulse supplied to a corresponding one of the gate lines.

4. The touch-sensitive display device of claim 1, wherein the at least one delayed pulse includes a plurality of delayed pulses consecutively supplied to each of the Tx lines.

5. The touch-sensitive display device of claim 4, wherein the plurality of delayed pulses equal at least three delayed pulses consecutively supplied to each of the Tx lines.

6. The touch-sensitive display device of claim 1, further comprising a synchronization control circuit including:

an edge detector configured to detect a rising edge of a timing signal, and

a delay unit configured to generate a Tx timing control signal delayed by a predetermined time period from the detected rising edge of the timing signal, and output the delayed Tx timing control signal to the touch screen driving circuit for generating the at least one delayed pulse.

7. The touch-sensitive display device of claim 1, wherein the display panel and the touch screen are stacked up and aligned with each other.

8. The touch-sensitive display device of claim 1, wherein the display panel includes:

a glass substrate having the data lines, the gate lines, and the pixel array, and

a polarizing layer disposed over the glass substrate; and

wherein the touch screen is disposed over the polarizing layer, or between the polarizing layer and the glass substrate.

9. The touch-sensitive display device of claim 1, wherein the display panel includes a glass substrate having the data lines, the gate lines, and the pixel array, and

wherein the touch sensors are disposed within the pixel array of the glass substrate.

10. The touch-sensitive display device of claim 1, wherein the touch-sensitive display is one of a liquid crystal display, a field emission display, a plasma display panel, an organic light emitting diode display, and an electrophoresis display.

11. A method of operating a touch-sensitive display device, the touch-sensitive display device including a display panel, a touch screen, a display driving circuit and a touch screen driving circuit, the display panel including data lines, gate lines crossing the data lines, and a pixel array including pixels arranged in a matrix form, the touch screen including Tx lines, Rx lines crossing the Tx lines, and touch sensors formed at crossings of the Tx lines and the Rx lines, the display driving circuit configured to supply video data voltages to the pixels of the display panel, the method comprising:

operating the touch screen using the touch screen driving circuit, wherein the operating step includes;

sequentially supplying, by the touch screen driving circuit, at least one delayed pulse to each of the Tx lines of the touch screen, wherein an edge of each of the at least one delayed pulse is present in a horizontal blank period, and

sensing, by the touch screen driving circuit, an output signal of each of the touch sensors through the Rx lines.

12. The method of claim 11, wherein in the supplying step, a falling edge of each of the at least one delayed pulse falls during a corresponding horizontal blank period.

13. The method of claim 11, wherein in the supplying step, each of the at least one delayed pulse supplied to one of the Tx lines is not aligned with a gate pulse supplied to a corresponding one of the gate lines.

14. The method of claim 11, wherein the at least one delayed pulse includes a plurality of delayed pulses, and

wherein the supplying step supplies consecutively the plurality of delayed pulses to each of the Tx lines.

15. The method of claim 14, wherein the plurality of delayed pulses equal at least three delayed pulses consecutively supplied to each of the Tx lines.

16. The method of claim 11, wherein the touch-sensitive display device further comprises a synchronization control circuit including an edge detector and a delay unit, and

wherein the supplying step includes:

detecting, by the edge detector, a rising edge of a timing signal,

generating, by the delay unit, a Tx timing control signal delayed by a predetermined time period from the detected rising edge of the timing signal,

outputting the delayed Tx timing control signal to the touch screen driving circuit, and

generating the at least one delayed pulse based on the delayed Tx timing control signal.