Liquid crystal display device and method for manufacturing the same

• US 20040233374A1
• Filed: 03/05/2004
• Published: 11/25/2004
• Est. Priority Date: 03/07/2003
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Takayama, Toru, Yamazaki, Shunpei
• Granted Patent: US 7,426,008 B2
• Time in Patent Office: Days
• US Class Current: 349/153
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G02F 1/1341 Filling or closing of cells
• CPC Class Codes: G02F 1/13415 Drop filling process

Abstract

A liquid crystal display device using a plastic substrate becomes required to have high resolution, high opening ratio, high reliability, or the like, with the increasing of a screen size. Besides, high productivity and cost reduction is also required. According to the present invention, a protective film 123 comprising at least one silicon nitride film, which is formed by a ratio frequency sputtering using a silicon target, is provided over an opposing substrate (a flexible substrate); sealant 112 is drawn; a liquid crystal material 114 is dropped over the opposing substrate in vacuo; and the opposing substrate is pasted to a flexible substrate 110 provided with a pixel electrode 111 and a columnar spacer 115.

Claims

1. A method for manufacturing a liquid crystal display device comprising the steps of:

forming an inorganic insulating film over at least one of a first substrate and a second substrate by ratio frequency sputtering;

forming a pixel electrode over the first substrate;

forming an opposing electrode over the second substrate;

forming a columnar spacer over the first substrate for spacing evenly between the first substrate and the second substrate;

drawing and pre-fixating a sealant over the second substrate;

dropping a liquid crystal material under reduced pressure on a region surrounded by the sealant over the second substrate;

heating and deaerating the liquid crystal material under reduced pressure;

pasting the first substrate and the second substrate together under reduced pressure; and

fixating the sealant.

3. A method for manufacturing a liquid crystal display device according to claim 1, wherein at least one of the first substrate and the second substrate is a plastic substrate.

5. A method for manufacturing a liquid crystal display device according to claim 1, wherein the columnar spacer is formed by an organic resin material containing at least one material as a main component selected from the group consisting of acrylic, polyimide, polyimideamide, and epoxy;

by any one material of silicon oxide, silicon nitride, or silicon oxynitride;

or by an inorganic material composed of a laminated film of these materials.

7. A method for manufacturing a liquid crystal display device according to claim 1, wherein the inorganic insulating film is a silicon nitride film formed by ratio frequency sputtering using a silicon target.

9. A method for manufacturing a liquid crystal display device according to claim 1, wherein the inorganic insulating film is a silicon nitride film formed by sputtering a single crystal silicon target in an N₂ gas or an N₂ and rare gas mixture under a condition that backpressure is set at most 1×

10<sup>−

3</sup> Pa by a turbo molecular pump or a cryopump.

2. A method for manufacturing a liquid crystal display device comprising the steps of:

forming an inorganic insulating film over at least one of the first substrate and the second substrate by ratio frequency sputtering;

forming a pixel electrode over the first substrate;

forming an opposing electrode over the second substrate;

forming a columnar spacer over the first substrate for spacing evenly between the first substrate and the second substrate;

drawing and pre-fixating a sealant over the first substrate;

dropping a liquid crystal material under reduced pressure on a region surrounded by the sealant over the first substrate;

heating and deaerating the liquid crystal material under reduced pressure;

pasting the first substrate and the second substrate together under reduced pressure; and

fixating the sealant.

4. A method for manufacturing a liquid crystal display device according to claim 2, wherein at least one of the first substrate and the second substrate is a plastic substrate.

6. A method for manufacturing a liquid crystal display device according to claim 2, wherein the columnar spacer is formed by an organic resin material containing at least one material as a main component selected from the group consisting of acrylic, polyimide, polyimideamide, and epoxy;

by any one material of silicon oxide, silicon nitride, or silicon oxynitride;

or by an inorganic material composed of a laminated film of these materials.

8. A method for manufacturing a liquid crystal display device according to claim 2, wherein the inorganic insulating film is a silicon nitride film formed by ratio frequency sputtering using a silicon target.

10. A method for manufacturing a liquid crystal display device according to claim 2, wherein the inorganic insulating film is a silicon nitride film formed by sputtering a single crystal silicon target in an N₂ gas or an N₂ and rare gas mixture under a condition that backpressure is set at most 1×

10<sup>−

3</sup> Pa by a turbo molecular pump or a cryopump.

11. A liquid crystal display device comprising:

a first flexible substrate;

a second flexible substrate;

an inorganic insulating film over at least one of the first flexible substrate and the second flexible substrate;

a columnar spacer for spacing evenly formed between the first flexible substrate and the second flexible substrate; and

a liquid crystal material formed between the first flexible substrate and the second flexible substrate,

wherein the first flexible substrate and the second flexible substrate are pasted together with a sealant drawn in a closed pattern.

12. A liquid crystal display device according to claim 11, wherein the inorganic insulating film is a silicon nitride film containing argon at a concentration of from 1×

10²⁰ to 1×

10²¹ cm<sup>−

3</sup>.

13. A liquid crystal display device according to claim 11, wherein the inorganic insulating film is a silicon nitride film containing hydrogen at a concentration of at most 1×

10²¹ cm<sup>−

3</sup>.

14. A liquid crystal display device according to claim 11, wherein the inorganic insulating film is a silicon nitride film containing hydrogen at a concentration of at most 1×

10²¹ cm<sup>−

3</sup>, and oxygen at a concentration of from 5×

10¹⁸ to 5×

10²¹ cm<sup>−

3</sup>.

17. A liquid crystal display device according to any one of claims 11 and 15, wherein the liquid crystal display device is an active matrix type.

18. A liquid crystal display device according to any one of claims 11 and 15, wherein the liquid crystal display device is a passive type.

19. A video camera having the liquid crystal display device according to any one of claims 11 and 15.

20. A digital camera having the liquid crystal display device according to any one of claims 11 and 15.

21. A display having the liquid crystal display device according to any one of claims 11 and 15.

22. An image reproducing apparatus having the liquid crystal display device according to any one of claims 11 and 15.

23. A car navigation system having the liquid crystal display device according to any one of claims 11 and 15.

24. A personal computer having the liquid crystal display device according to any one of claims 11 and 15.

25. A portable information terminal having the liquid crystal display device according to any one of claims 11 and 15.

15. A liquid crystal display device comprising:

a first flexible substrate;

a second flexible substrate;

a liquid crystal material formed between the first flexible substrate and the second flexible substrate;

an inorganic insulating film formed by a multilayer film of a silicon nitride film and a silicon oxide film over at least one of the first flexible substrate and the second flexible substrate; and

a columnar spacer for spacing evenly between the first flexible substrate and the second flexible substrate,

wherein the first flexible substrate and the second flexible substrate are pasted together with a sealant drawn in a closed pattern.

16. A liquid crystal display device according to claim 15, wherein the silicon nitride film containing argon at a concentration of from 1×

10²⁰ to 1×

10²¹ cm<sup>−

3</sup>.