Liquid Crystal Display Device with a Built-in Touch Screen and Method for Manufacturing the Same

• US 20120068944A1
• Filed: 08/04/2011
• Published: 03/22/2012
• Est. Priority Date: 09/20/2010
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: OH, Kum Mi, Lee, Han Seok, Park, Won Keun
• Granted Patent: US 9,218,082 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136231 for reducing the number of lithographic steps
• CPC Class Codes: G02F 1/136236 using a grey or half tone lithographic process
• CPC Class Codes: G02F 1/13629 Multilayer wirings
• CPC Class Codes: G02F 1/136295 Materials; Compositions; Manufacture processes
• 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

Abstract

A liquid crystal display device with a built-in touch screen including a substrate having a pixel region, a thin film transistor formed in the pixel region, a first passivation layer formed on the thin film transistor, a first contact hole formed through a portion of the first passivation layer to expose the data electrode, a common electrode formed on at least one portion of the first passivation layer including inside the first contact hole, the common electrode operable to sense touch, a conductive line formed on at least one portion of the first passivation layer including inside the first contact hole, a second passivation layer formed on the common electrode and the conductive line, a second contact hole formed through a portion of the second passivation layer to expose the conductive line corresponding to the data electrode, and a pixel electrode electrically connected with the conductive line, the pixel electrode formed on the second passivation layer and inside the second contact hole, wherein the second passivation layer and the pixel electrode are simultaneously formed by a mask process using a half-tone mask.

Claims

1. A liquid crystal display device with a built-in touch screen comprising:

a substrate having a pixel region;

a thin film transistor formed in the pixel region;

a first passivation layer formed on the thin film transistor;

a first contact hole formed through a portion of the first passivation layer to expose the data electrode;

a common electrode formed on at least one portion of the first passivation layer including inside the first contact hole, the common electrode operable to sense touch;

a conductive line formed on at least one portion of the first passivation layer including inside the first contact hole;

a second passivation layer formed on the common electrode and the conductive line;

a second contact hole formed through a portion of the second passivation layer to expose the conductive line corresponding to the data electrode; and

a pixel electrode electrically connected with the conductive line, the pixel electrode formed on the second passivation layer and inside the second contact hole,

wherein the second passivation layer and the pixel electrode are simultaneously formed by a mask process using a half-tone mask.

2. The liquid crystal display device according to claim 1, wherein the common electrode and the conductive line are formed by a mask process using a half-tone mask.

3. The liquid crystal display device according to claim 1, wherein the data electrode and the pixel electrode are electrically connected via the common electrode and the conductive line.

4. The liquid crystal display device according to claim 1, wherein the thin film transistor is formed of low-temperature poly silicon (LTPS).

5. The liquid crystal display device according to claim 1, wherein the conductive line connects common electrodes of neighboring pixel regions.

6. The liquid crystal display device according to claim 1, wherein the common electrode senses touch during a non-display period and supplies a common voltage during a display period of the liquid crystal display device.

7. The liquid crystal display device according to claim 1, wherein the first contact hole is formed by etching a predetermined portion of the first passivation layer.

8. The liquid crystal display device according to claim 1, wherein the second contact hole is formed by etching a predetermined portion of the second passivation layer.

9. The liquid crystal display device according to claim 1, wherein the conductive line is formed on the common electrode inside the first contact hole.

10. A method for manufacturing a liquid crystal display device with a built-in touch screen comprising the steps of:

forming a substrate having a pixel region;

forming a thin film transistor in the pixel region;

forming a first passivation layer on the thin film transistor;

forming a first contact hole through a portion of the first passivation layer to expose the data electrode;

forming a common electrode on at least one portion of the first passivation layer including inside the first contact hole, the common electrode operable to sense touch;

forming a conductive line on at least one portion of the first passivation layer including inside the first contact hole;

forming a second passivation layer on the common electrode and the conductive line;

forming a second contact hole through a portion of the second passivation layer to expose the conductive line corresponding to the data electrode; and

forming a pixel electrode electrically connected with the conductive line, the pixel electrode being on the second passivation layer and inside the second contact hole,

wherein the second passivation layer and the pixel electrode are simultaneously formed by a mask process using a half-tone mask.

11. The method for manufacturing a liquid crystal display device according to claim 10, wherein the common electrode and the conductive line are formed by a mask process using a half-tone mask.

12. The method for manufacturing a liquid crystal display device according to claim 10, wherein the data electrode and the pixel electrode are electrically connected via the common electrode and the conductive line.

13. The method for manufacturing a liquid crystal display device according to claim 10, wherein the thin film transistor is formed of low-temperature poly silicon (LTPS).

14. The method for manufacturing a liquid crystal display device according to claim 10, wherein the conductive line connects common electrodes of neighboring pixel regions.

15. The method for manufacturing a liquid crystal display device according to claim 10, wherein the common electrode senses touch during a non-display period and supplies a common voltage during a display period of the liquid crystal display device.

16. The method for manufacturing a liquid crystal display device according to claim 10, wherein the first contact hole is formed by etching a predetermined portion of the first passivation layer.

17. The method for manufacturing a liquid crystal display device according to claim 10, wherein the second contact hole is formed by etching a predetermined portion of the second passivation layer.

18. The method for manufacturing a liquid crystal display device according to claim 10, wherein the conductive line is formed on the common electrode inside the first contact hole.

19. A method for manufacturing an LCD device with a built-in touch screen comprising the steps of:

forming a thin film transistor in each pixel region of a substrate;

forming a first contact hole to expose a data electrode by forming a first passivation layer on the thin film transistor and partially etching the first passivation layer;

forming a common electrode on the first passivation layer and inside the first contact hole, and forming a conductive line electrically connected with the common electrode;

forming a second contact hole to expose the conductive line in the region corresponding to the data electrode by forming a second passivation layer on the common electrode and the conductive line and partially etching the second passivation layer; and

forming a pixel electrode on the second passivation layer and inside the second contact hole, the pixel electrode electrically connected with the conductive line,

wherein the second passivation layer, the second contact hole, and the pixel electrode are simultaneously formed by photolithography, etching, and ashing processes using a mask.

20. The method for manufacturing a liquid crystal display device according to claim 19, wherein the common electrode and the conductive line are simultaneously formed by photolithography, etching, and ashing processes using a mask.

21. The method for manufacturing a liquid crystal display device according to claim 19, wherein the data electrode is electrically connected with the pixel electrode via the common electrode and the conductive line.

22. The method for manufacturing a liquid crystal display device according to claim 19, wherein the thin film transistor is formed of low-temperature poly silicon (LTPS).

23. The method for manufacturing a liquid crystal display device according to claim 19, wherein the conductive line connects the common electrodes of the neighboring pixel regions.

24. The method for manufacturing a liquid crystal display device according to claim 19, wherein the mask corresponds to a half-tone mask which includes a non-transmission region through which light is not transmitted, a semi-transmission region through which light is partially transmitted, and a transmission region through which light is transmitted.

25. The method for manufacturing a liquid crystal display device according to claim 20, further comprising the steps of:

forming a plurality of photoresist patterns having different widths and thicknesses on the metal layer by patterning the photoresist layer through the use of a half-tone mask; and

forming the common electrode and the conductive line such that the plurality of photoresist patterns are used as a mask.

26. The method for manufacturing a liquid crystal display device according to claim 25, wherein at least one portion of at least one of the plurality of photoresist patterns has a thickness greater than the remaining portions during the formation of the pixel electrode.

27. The method for manufacturing a liquid crystal display device according to claim 20, wherein the process of forming the common electrode and the conductive line comprises the steps of:

sequentially forming an ITO layer and a metal layer on the first passivation layer and inside the first contact hole;

forming a photoresist layer on the metal layer;

forming a plurality of photoresist patterns having different widths and thicknesses on the metal layer by patterning the photoresist layer through the use of half-tone mask;

etching the ITO layer and the metal layer under the circumstance that the plurality of photoresist patterns are used as a mask; and

ashing the plurality of photoresist patterns.