# US 11,307,446 B2 · Display device having touch sensor and method of driving same

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- Number: US 11,307,446 B2
- Document ID: US11307446B2
- Status: Granted
- Kind: B2
- Application number: 16/928,727
- Filed: 2020-07-14
- Published: 2021-03-11
- Granted: 2022-04-19
- Earliest claimed: 2019-09-05
- Assignees: LG Display Co., Ltd.
- Applicants: LG Display Co., Ltd.
- Inventors: Seung-Kuk Ahn
- Web page: https://patentgrep.com/patent/US11307446B2

## CPC

- G02F 1/13338: {Input devices, e.g. touch panels}
- G09G 3/3655: {Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors}
- G06F 3/0412: {Digitisers structurally integrated in a display}
- 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)}
- G06F 3/04182: {Filtering of noise external to the device and not generated by digitiser components}
- G06F 3/0443: {using a single layer of sensing electrodes}
- G06F 3/0446: {using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes}
- G09G 3/36: using liquid crystals
- G09G 2300/0426: Layout of electrodes and connections
- G09G 2300/043: Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver
- G09G 2310/0289: Details of voltage level shifters arranged for use in a driving circuit
- G09G 2320/0219: Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
- G09G 2320/0242: Compensation of deficiencies in the appearance of colours
- G09G 2330/02: Details of power systems and of start or stop of display operation
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A display device is disclosed that has a touch sensor, which includes a display panel, an integrated driving circuit, a common voltage ring line, and a common voltage feedback line. The integrated driving circuit outputs a touch driving signal and a display common voltage for respectively driving a touchscreen and the display panel. The integrated driving circuit outputs the display common voltage through a common voltage ring pad in a period in which the display panel is driven and outputs a load-free common voltage having a form different from that of the display common voltage through the common voltage ring pad in a period in which the touchscreen is driven.

## Claims

### Claim 1

A display device having a touch sensor, comprising:
a display panel having a touchscreen;
an integrated driving circuit outputting a touch driving signal and a display common voltage for respectively driving the touchscreen and the display panel;
a common voltage ring line disposed in the display panel and connected to a common voltage ring pad of the integrated driving circuit;
a common voltage feedback line disposed in the display panel, connected to a common voltage feedback pad of the integrated driving circuit and connected to the common voltage ring line in an area far away from the integrated driving circuit;
a common voltage compensation circuit connected to an input pad of the integrated driving circuit, the common voltage compensation circuit configured to compensate for the display common voltage to be applied to the display panel on a basis of a feedback common voltage transmitted through the common voltage feedback line,
wherein the integrated driving circuit outputs the display common voltage through the common voltage ring pad in a period in which the display panel is driven and outputs a load-free common voltage having a form different from that of the display common voltage through the common voltage ring pad in a period in which the touchscreen is driven,
wherein the integrated driving circuit includes:
a first selector configured to output one selected from the display common voltage, the load-free common voltage, and the touch driving signal through touch pads connected to the display panel having the touchscreen;
a second selector configured to output one selected from the display common voltage and the load-free common voltage through the common voltage ring pad; and
a third selector configured to receive the feedback common voltage or outputting the load-free common voltage through the common voltage feedback pad.

### Claim 2 (depends on 1)

The display device having a touch sensor of claim 1, wherein the display common voltage has a direct current form and the load-free common voltage has a pulse form.

### Claim 3 (depends on 1)

The display device having a touch sensor of claim 1, wherein the integrated driving circuit receives the feedback common voltage through the common voltage feedback pad in the period in which the display panel is driven and outputs the load-free common voltage through the common voltage feedback pad in the period in which the touchscreen is driven.

### Claim 4 (depends on 1)

The display device having a touch sensor of claim 1, wherein the common voltage ring line has a disconnected open region while surrounding all sides of the touchscreen positioned on the display panel.

### Claim 5 (depends on 4)

The display device having a touch sensor of claim 4, wherein the open region is positioned in an upper non-display area of the display panel opposite a lower non-display area of the display panel to which the integrated driving circuit is attached.

### Claim 6 (depends on 1)

The display device having a touch sensor of claim 1, wherein the first to third selectors perform selective operations on the basis of a signal defining the period in which the display panel is driven and the period in which the touchscreen is driven.

### Claim 7 (depends on 6)

The display device having a touch sensor of claim 6, wherein the first to third selectors are implemented as multiplexers or switches which output one or more voltages or signals through a single output terminal in a time division manner.

### Claim 8

A method of driving a display device having a touch sensor, including an integrated driving circuit outputting a touch driving signal and a display common voltage for respectively driving a touchscreen and a display panel, a common voltage ring line disposed in the display panel and connected to a common voltage ring pad of the integrated driving circuit, and a common voltage feedback line disposed in the display panel, connected to a common voltage feedback pad of the integrated driving circuit and connected to the common voltage ring line in an area far away from the integrated driving circuit, and a common voltage compensation circuit connected to an input pad of the integrated driving circuit and configured to compensate for the display common voltage to be applied to the display panel on a basis of a feedback common voltage transmitted through the common voltage feedback line, the method comprising:
a display panel driving step of outputting the display common voltage through the common voltage ring pad in a period in which the display panel is driven; and
a touchscreen driving step of outputting a load-free common voltage having a form different from that of the display common voltage through the common voltage ring pad in a period in which the touchscreen is driven,
wherein the integrated driving circuit includes:
a first selector configured to output one selected from the display common voltage, the load-free common voltage, and the touch driving signal through touch pads connected to the display panel having the touchscreen;
a second selector configured to output one selected from the display common voltage and the load-free common voltage through the common voltage ring pad; and
a third selector configured to receive the feedback common voltage or outputting the load-free common voltage through the common voltage feedback pad.

### Claim 9 (depends on 8)

The method of claim 8, wherein the display panel driving step further comprises a step of receiving a feedback common voltage through the common voltage feedback pad and compensating for the display common voltage to be displayed to the display panel on a basis of the feedback common voltage, and the touchscreen driving step further comprises a step of outputting the load-free common voltage through the common voltage feedback pad.

### Claim 10 (depends on 8)

The method of claim 8, wherein the display common voltage has a direct current form and the load-free common voltage has a pulse form.

### Claim 11 (depends on 8)

The method of claim 8, wherein the common voltage ring line comprises a disconnected open region while surrounding all sides of the touchscreen positioned on the display panel.

### Claim 12 (depends on 11)

The method of claim 11, wherein the open region is positioned in an upper non-display area of the display panel opposite a lower non-display area of the display panel to which the integrated driving circuit is attached.

### Claim 13 (depends on 8)

The method of claim 8, further comprising:
performing, by the first to third selections, selective operations on a basis of a signal defining the period in which the display panel is driven and the period in which the touchscreen is driven.

### Claim 14 (depends on 13)

The method of claim 13, wherein the first to third selectors comprise multiplexers or switches which output one or more voltages or signals through a single output terminal in a time division manner.