Display device and driving method thereof

• US 8,952,913 B2
• Filed: 12/10/2012
• Issued: 02/10/2015
• Est. Priority Date: 10/23/2012
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lee, Young Joon, Hwang, Sang Soo, Kim, Sun Yeop, Lee, Sung Yub
• Primary Examiner(s): Hicks, Charles V
• Application Number:
  US13/709,268
• Publication Number:
  US 20140111446A1
• Time in Patent Office: 792 Days
• Field of Search: 345/173
• US Class Current: 345/173
• 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

Disclosed is a display device. The display device includes a panel, a display driver IC, and a touch IC. The panel includes a plurality of driving electrodes and a plurality of sensing electrodes. The display driver IC outputs a common voltage to the driving electrode and the sensing electrode in a display driving interval, outputs a reference voltage to the driving electrode during a touch non-sensing period in a touch driving interval, and outputs a driving pulse to the driving electrode to receive a sensing signal from the sensing electrode during a touch sensing period in the touch driving interval. The touch IC transfers a control signal and a selection signal for selecting the touch sensing period and the touch non-sensing period to the display driver, and senses whether there is a touch with the sensing signal and the reference voltage.

Claims

1. A display device, comprising:

a panel comprising a plurality of driving electrodes and a plurality of sensing electrodes;

a display driver IC outputting a common voltage to the driving electrode and the sensing electrode in a display driving interval, outputting a reference voltage to the driving electrode during a touch non-sensing period in a touch driving interval, and outputting a driving pulse to the driving electrode to receive a sensing signal from the sensing electrode during a touch sensing period in the touch driving interval, the driving pulse swinging with respect to the reference voltage; and

a touch IC transferring a control signal and a selection signal for selecting the touch sensing period and the touch non-sensing period to the display driver, and sensing whether there is a touch with the sensing signal and the reference voltage, the control signal allowing the display driver IC to sequentially output the driving pulse to the driving electrodes,

wherein a minimum voltage of the driving pulse is the same as the common voltage.

2. The display device of claim 1, wherein,

when the display driving interval is ended and the touch driving interval starts, the display driver IC outputs the reference voltage to the driving electrode,

in the touch sensing period where the selection signal is received in the touch driving interval, the display driver IC outputs the driving pulse, having a minimum voltage lower than the reference voltage and a maximum voltage higher than the reference voltage, to the driving electrode, and

when the touch sensing period is ended in the touch driving interval, the display driver IC outputs the reference voltage to the driving electrode.

3. The display device of claim 1, wherein the display driver IC comprises:

a maximum voltage generator generating a maximum voltage of the driving pulse;

a reference voltage generator generating the reference voltage;

a common voltage generator generating the common voltage that is the minimum voltage;

a level shifter generating the driving pulse having the maximum voltage and a minimum voltage according to the control signal in the touch sensing interval, and outputting the reference voltage to the driving electrode in the touch non-sensing period;

a selection switch outputting the reference voltage or the common voltage to the level shifter according to the selection signal;

a driving electrode connector connecting a common voltage generator and the driving electrodes in the display driving interval, and connecting the level shifter and the driving electrodes in the touch driving interval;

a sensing electrode connector connecting the common voltage generator and the sensing electrodes in the display driving interval, and connecting the touch IC and the sensing electrodes in the touch driving interval; and

a touch synchronizer outputting a touch synch signal for differentiating the display driving interval and the touch driving interval to the driving electrode connector and the sensing electrode connector.

4. The display device of claim 3, wherein the touch IC comprises:

a touch driver transferring the control signal to the level shifter;

a selection signal generator transferring the selection signal to the selection switch;

a touch sensing unit receiving the sensing signal to determine whether there is a touch; and

a reference voltage transferer transferring the reference voltage to the touch sensing unit.

5. A method of driving a display device, comprising:

outputting a common voltage to a driving electrode and a sensing electrode in a display driving interval, the driving electrode and the sensing electrode being formed in a panel;

applying a reference voltage to the driving electrode during a touch non-sensing period in a touch driving interval, and outputting a driving pulse to the driving electrode to receive a sensing signal from the sensing electrode during a touch sensing period in the touch driving interval, the driving pulse swinging with respect to the reference voltage; and

sensing whether there is a touch with the sensing signal,

wherein a minimum voltage of the driving pulse is the same as the common volt age, and

the touch sensing period and the touch non-sensing period is selected by a selection signal.

6. The method of claim 5, wherein the applying of a reference voltage and outputting of a driving pulse comprises:

outputting the reference voltage to the driving electrode when the display driving interval is ended and the touch driving interval starts;

outputting the driving pulse, having a minimum voltage lower than the reference voltage and a maximum voltage higher than the reference voltage, to the driving electrode when a selection signal is received in the middle of outputting the reference voltage in the touch driving interval; and

outputting the reference voltage to the driving electrode when reception of the selection signal is stopped in the touch driving interval.

7. The method of claim 6, wherein the outputting of a driving pulse to the driving electrode to receive a sensing signal comprises:

outputting the minimum voltage to the driving electrode when the selection signal is received;

outputting, after the minimum voltage is outputted, the driving pulse to the driving electrode, the maximum voltage and minimum voltage of the driving pulse being repeated; and

receiving the sensing signal from the sensing electrode.

8. The method of claim 5, wherein the applying of a reference voltage to the driving electrode during a touch non-sensing period and the outputting of a driving pulse to the driving electrode to receive a sensing signal during a touch sensing period is sequentially performed for the other driving electrodes.