Liquid crystal electro-optical device and manufacturing method for the same

• US 5,309,263 A
• Filed: 09/24/1992
• Issued: 05/03/1994
• Est. Priority Date: 11/24/1989
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Sato, Masahiko
• Primary Examiner(s): Wojciechowicz, Edward
• Assistant Examiner(s): BOWERS, COURTNEY
• Application Number:
  US07/950,771
• Time in Patent Office: 586 Days
• Field of Search: 350/342, 350/339 R, 350/331 R, 359/75, 359/79, 359/72, 359/74
• US Class Current: 349/122
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133711 by organic films, e.g. polymeric films

Abstract

A liquid crystal electro-optical device having gettering means therein and a method for manufacturing such a liquid crystal electro-optical device are disclosed. For example, in a liquid crystal panel disposed in the device, polyvinyl carbazole film is formed as the getting means on at least one of a pair of substrates, and the film has a function to absorb ionized impurities existing in liquid crystal disposed in the device. In virtue of the film, ionized impurities in the liquid crystal layer are decreased, and by heating the liquid crystal panel, the function of the polyvinyl carbazole film, i.e. the function to absorb ionized impurities, is enhanced. Consequently, a liquid crystal electro-optical device free from after-image which was a problem in conventional liquid crystal display devices can be obtained.

Claims

1. A method of manufacturing a liquid crystal electro-optical display producing device comprising a pair of substrates provided with electrodes thereon respectively and a layer of liquid crystal provided between said substrates, said method comprising the steps of:

forming a polyvinyl carbazole film having a thickness up to 1000 Å

on at least one of said substrates;

introducing said liquid crystal between said substrates adjacent said polyvinyl carbazole film to form said layer; and

heating said substrates and said layer to cause absorption of impurities from said layer by said film.

2. A method as in claim 1 further comprising a step of applying a d.c. voltage between said electrodes.

3. A method as in claim 1 wherein said heating step is carried out after hermetically sealing said layer.

4. A method as in claim 1 wherein said heating step is carried out after said introducing step.

5. A method as in claim 2 wherein said applying step is carried out after said introducing step.

6. A method as in claim 2 wherein said heating step and said applying step are carried out at the same time.

7. A method as in claim 1 wherein said liquid crystal is selected from the group consisting of ferroelectric liquid crystal, twisted nematic liquid crystal, and super twisted nematic liquid crystal.

8. A method of manufacturing a liquid crystal electro-optical device comprising a pair of substrates provided with electrodes thereon respectively and a liquid crystal layer provided between said substrates, said method comprising the steps of:

providing an ion absorbing film on at least one of said substrates, said ion absorbing film having a thickness up to 1000 Å

;

forming a liquid crystal layer between said substrates so that said ion absorbing film directly contacts said liquid crystal layer;

heating said device to promote ion absorption by said film; and

applying a voltage across said liquid crystal layer during heating said device to further promote ion absorption by said film.

9. A method as in claim 8 wherein said liquid crystal layer is ferroelectric liquid crystal, twisted nematic liquid crystal, or super twisted nematic liquid crystal.

12. The method according to claim 8 wherein an orientation control film is provided in contact with said ion absorbing film so that said ion absorbing film intervenes between said liquid crystal layer and said orientation control film.

13. The method according to claim 12 wherein said orientation control film polyimide film having been rubbed.

10. A method of manufacturing a liquid crystal electro-optical device comprising a pair of substrates provided with electrodes thereon respectively and a layer of liquid crystal provided between said substrates, said method comprising the steps of:

forming a polyvinyl carbazole film on at least one of said substrates;

introducing said liquid crystal between said substrates to form said layer;

heating said substrates and said layer; and

applying a D.C. voltage between said electrodes at the same time of said heating.

11. A method as in claim 10 wherein said liquid crystal is selected from the group consisting of ferroelectric liquid crystal, twisted nematic liquid crystal, and super twisted nematic liquid crystal.

14. A method of manufacturing a liquid crystal device comprising a pair of substrates, a liquid crystal layer disposed between said substrates and electrode arrangements provided on said substrates for applying voltages to said liquid crystal layer, said method comprising the steps of:

providing an ion absorbing film on at least one of said substrates having said electrode arrangements thereon;

forming a liquid crystal layer between said substrates so that said ion absorbing film directly contacts said liquid crystal layer;

heating said liquid crystal device to promote ion absorption by said film; and

applying a voltage across said liquid crystal layer through said electrode arrangements during heating said device to further promote ion absorption by said film.

15. The method according to claim 14 wherein an orientation control film is provided in contact with said ion absorbing film so that said ion absorbing film intervenes between said liquid crystal layer and said orientation control film.

16. The method according to claim 15 wherein said orientation control film is a polyimide film which has been rubbed.