Liquid crystal display device in which array substrate includes black matrix and method of manufacturing the same

• US 9,036,106 B2
• Filed: 02/23/2012
• Issued: 05/19/2015
• Est. Priority Date: 03/29/2011
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd., Hefei BOE Optoelectronics Technology Company Limited (BOE Technology Group Co., Ltd.)
• Original Assignee: BOE Technology Group Co., Ltd., Hefei BOE Optoelectronics Technology Company Limited (BOE Technology Group Co., Ltd.)
• Inventors: Wang, Shikai, Hou, Zhi, Zi, Yubao, Jung, JaeYun, Wu, Daiwu
• Primary Examiner(s): NGO, HUYEN LE
• Application Number:
  US13/403,297
• Publication Number:
  US 20120249936A1
• Time in Patent Office: 1,181 Days
• Field of Search: 349/106, 349 44- 47, 349/110
• US Class Current: 349/47
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask
• CPC Class Codes: H01L 29/78633 with a light shield

Abstract

The embodiment of the invention discloses a liquid crystal display and a method of manufacturing the same. The liquid crystal display of the embodiment of the invention comprises an array substrate, a color filter substrate and a liquid crystal layer formed between the array substrate and the color filter substrate. The array substrate comprises a first substrate; a black matrix formed on the first substrate; and a thin film transistor (TFT) device formed on the black matrix. The TFT device is a top gate TFT device having a gate electrode formed on a side of the TFT device facing away the black matrix and an active layer made of a-Si. The color filter substrate comprises a second substrate; and a color filter layer formed on the second substrate. The color filter substrate does not include a black matrix.

Claims

1. A liquid crystal display comprising:

an array substrate comprising;

a first substrate;

a black matrix formed on the first substrate; and

a thin film transistor (TFT) device formed on the black matrix, wherein the TFT device is a top gate TFT device having a gate electrode formed on a side of the TFT device facing away the black matrix and an active layer made of a-Si;

a color filter substrate comprising;

a second substrate; and

a color filter layer formed on the second substrate; and

a liquid crystal layer formed between the array substrate and the color filter substrate,

wherein the color filter substrate does not include a black matrix,

the TFT device comprises;

an active layer formed on the black matrix;

a source electrode and a drain electrode formed on respective parts of the active layer;

an insulating layer formed above the active layer and covering the source electrode and the drain electrode;

the gate electrode formed on the insulating layer between the source electrode and the drain electrode.

2. The liquid crystal display as set forth in claim 1, wherein the array substrate further comprises a pixel electrode formed on the insulating layer and connected with the source electrode through via holes in the insulating layer.

3. The liquid crystal display as set forth in claim 2, wherein the pixel electrode is formed of indium tin oxide (ITO).

4. The liquid crystal display as set forth in claim 1, wherein the TFT device further comprises an ohmic contact layer formed between the source electrode and the active layer and/or between the drain electrode and the active layer.

5. The liquid crystal display as set forth in claim 1, wherein an area occupied by the TFT device on the first substrate is contained within an area occupied by the black matrix on the first substrate.

6. The liquid crystal display as set forth in claim 5, wherein the TFT device and the black matrix occupy the same area on the first substrate.

7. The liquid crystal display as set forth in claim 1, wherein the color filter substrate further comprises a counter electrode formed on the color filter layer.

8. The liquid crystal display as set forth in claim 7, wherein the counter electrode is formed from indium tin oxide (ITO).

9. The liquid crystal display as set forth in claim 1, wherein the first substrate and the second substrate are formed of glass.

10. A method of manufacturing liquid crystal display comprising steps of:

preparing an array substrate comprising steps of;

providing a first substrate;

forming a black matrix on the first substrate and forming a thin film transistor(TFT) device on the black matrix, wherein the TFT device is a top gate TFT device having a gate electrode formed on a side of the TFT device facing away the black matrix and an active layer made of a-Si;

preparing a color filter substrate comprising steps of;

providing a second substrate; and

forming a color filter layer on the second substrate; and

assembling the array substrate and the color filter substrate and injecting liquid crystal between the array substrate and the color filter substrate,

wherein the color filter substrate does not include a black matrix,

the step of forming the black matrix and the TFT device on the first substrate comprises;

forming a stack layer including a black matrix layer, an active layer and an electrode layer in this order on the first substrate;

forming a photoresist layer on the stack layer;

patterning the photoresist layer using a half tone mask by a lithography and etching, so as to remove the photoresist layer outside an area where the black matrix is formed, and the patterned photoresist layer is formed with a first thickness in a first area where the gate electrode of the TFT device is formed and a second thickness in a second area outside the first area, wherein the first thickness is less than the second thickness;

etching off the stack layer outside the black matrix area using the patterned photoresist layer so as to pattern the stack layer;

removing the patterned photoresist layer by the first thickness, and forming separate source electrode and drain electrode using remained photoresist layer;

removing the remained photoresist layer by ashing, and depositing an insulating layer on resulting structure; and

forming a gate electrode on the insulating layer between the source electrode and the drain electrode.

11. The method as set forth in claim 10, wherein said step of preparing array substrate further comprises forming a pixel electrode which is formed on the insulating layer and connected with the source electrode through via holes in the insulating layer.

12. The method as set forth in claim 10, wherein the step of forming the black matrix and the TFT device on the first substrate further comprises forming an ohmic contact layer between the source electrode and the active layer and/or between the drain electrode and the active layer.

13. The method as set forth in claim 10, wherein an area occupied by the TFT device on the first substrate is contained within an area occupied by the black matrix on the first substrate.

14. The method as set forth in claim 13, wherein the TFT device and the black matrix occupy a same area on the first substrate.