Liquid crystal display device having touch sensor embedded therein, method for driving the same, and method for fabricating the same

• US 9,093,331 B2
• Filed: 05/15/2014
• Issued: 07/28/2015
• Est. Priority Date: 08/10/2010
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Cheol-Se
• Primary Examiner(s): CAMPBELL, SHAUN M
• Application Number:
  US14/278,483
• Publication Number:
  US 20140256074A1
• Time in Patent Office: 439 Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods

Abstract

Disclosed is a liquid crystal display device having touch sensors embedded therein. The liquid crystal display device includes a liquid crystal layer interposed between upper and lower substrates, pixels, each of which includes pixel and common electrodes applying a horizontal electric field to the liquid crystal layer, a pixel thin film transistor to drive the pixel electrode, and a common thin film transistor to drive the common electrode, touch sensors, each of which forms a sensing capacitor between an object and the common electrode, sensor power lines, readout lines, and sensor gate lines. Each touch sensor includes the common electrode, a first sensor thin film transistor charging the common electrode with the sensing driving voltage in response to control of the previous sensor gate line, and a second sensor thin film transistor outputting the sensing signal to the readout line in response to control of the current sensor gate line.

Claims

1. A method for fabricating a liquid crystal display device having touch sensors embedded therein, comprising:

forming a gate metal pattern, including gate electrodes of pixel thin film transistors, common thin film transistors, and sensor thin film transistors together with gate lines, common lines, and sensor gate lines, on a substrate;

forming a gate insulating layer on the substrate provided with the gate metal pattern formed thereon;

forming semiconductor layers of the pixel thin film transistors, the common thin film transistors, and the sensor thin film transistors on the gate insulating layer;

forming a data metal pattern, including source electrodes and drain electrodes of the pixel thin film transistors, the common thin film transistors, and the sensor thin film transistors together with data lines and readout lines, on the gate insulating layer provided with the semiconductor layers formed thereon;

forming a passivation layer covering the data metal pattern, and forming a plurality of contact holes; and

forming pixel electrodes connected with the drain electrodes of the pixel thin film transistors, common electrodes connected with the drain electrodes of the common thin film transistors and the sensor thin film transistors, first contact electrodes to connect the source electrodes of the common thin film transistors and the common lines, and second contact electrodes to connect the gate electrodes of the sensor thin film transistors and the sensor gate lines, on the passivation layer, the connection of the electrodes being achieved through the plurality of contact holes.

2. The method according to claim 1, further comprising:

forming sensor power lines together with the data lines; and

forming second sensor thin film transistors, each of which is connected between the previous sensor gate line, each sensor power line, and each common line, together with the pixel thin film transistors, the common thin film transistors, and the sensor thin film transistors.

3. The method according to claim 1, wherein the pixel electrodes are independently formed in the unit of each pixel, and the common electrodes are independently formed in the unit of each touch sensor including plural pixels.

4. A method for fabricating a liquid crystal display device having touch sensors embedded therein, comprising:

forming a gate metal pattern, including gate electrodes of pixel thin film transistors, common thin film transistors, and sensor thin film transistors together with gate lines, common lines, and sensor gate lines, on a substrate;

forming a gate insulating layer on the substrate provided with the gate metal pattern formed thereon;

forming semiconductor layers of the pixel thin film transistors, the common thin film transistors, and the sensor thin film transistors on the gate insulating layer;

forming a data metal pattern, including source electrodes and drain electrodes of the pixel thin film transistors, the common thin film transistors, and the sensor thin film transistors together with data lines and readout lines, on the gate insulating layer provided with the semiconductor layers formed thereon;

forming pixel electrodes connected with the drain electrodes of the pixel thin film transistors on the gate insulating layer provided with the data metal pattern formed thereon;

forming a passivation layer covering the pixel electrodes, and forming a plurality of contact holes; and

forming common electrodes connected with the drain electrodes of the common thin film transistors and the sensor thin film transistors, first contact electrodes to connect the source electrodes of the common thin film transistors and the common lines, and second contact electrodes to connect the gate electrodes of the sensor thin film transistors and the sensor gate lines, on the passivation layer, the connection of the common electrodes, the first contact electrodes, and the second contact electrodes being achieved through the plurality of contact holes.

5. The method according to claim 4, further comprising:

forming sensor power lines together with the data lines; and

forming second sensor thin film transistors, each of which is connected between the previous sensor gate line, each sensor power line, and each common line, together with the pixel thin film transistors, the common thin film transistors, and the sensor thin film transistors.

6. The method according to claim 4, wherein the pixel electrodes are independently formed in the unit of each pixel, and the common electrodes are independently formed in the unit of each touch sensor including plural pixels.