Liquid crystal device, composition therefor, and method for preparing the composition

• US 4,018,507 A
• Filed: 09/05/1974
• Issued: 04/19/1977
• Est. Priority Date: 09/05/1974
• Status: Expired due to Term

• Current Assignee: American Microsystems Limited Incorporated (ON Semiconductor Corporation)
• Original Assignee: American Microsystems Limited Incorporated (ON Semiconductor Corporation)
• Inventors: Raghavan, N.V. Vijaya
• Primary Examiner(s): Padgett, Benjamin R.
• Assistant Examiner(s): Gron, T. S.
• Application Number:
  US05/503,241
• Time in Patent Office: 957 Days
• Field of Search: 252/408 LC, 252/299, 350/160 LC, 350/150
• US Class Current: 252/299.5
• CPC Class Codes: C09K 19/22 linked by a chain containing carbon and nitrogen atoms as chain links, e.g. Schiff bases

Abstract

A nematic liquid crystal composition comprises a fluorinated Schiff base of the general formula, X--Ph--HC=N--Ph--F, where X is an alkyl, acyl, acyloxy or alkoxy group having from 1 to 10 carbon atoms, and a p-alkoxy benzylidene-p-alkyl aniline, if desired with a small amount of a p-alkoxy benzylidene-p-cyanoaniline. An electro-optical device comprises a container for a layer of the liquid crystal composition described, a layer of such composition therein, and means to supply a current across all or a selected or predetermined area of such layer to cause alignment of the liquid crystals. Methods of making the fluorinated Schiff base, the liquid crystal composition and the device are provided.

Claims

1. An electro-optical light-modulating device containing a nematic liquid crystal composition comprising an admixture of 90% to 60% by weight of (A) p-methoxy benzylidene-p-butyl aniline, and 10% to 40% by weight of (B) at least one fluorinated Schiff base having the general formula X -- Ph -- HC = N--Ph -- F, wherein X is an alkoxy group having from 1 to 10 carbon atoms, Ph is phenylene and F is fluorine, and means for applying an electric field to said admixture.

2. A device as in claim 1 wherein said fluorinated Schiff base is p-ethoxy benzylidene-p-fluoroaniline.

3. A device as in claim 1 wherein said fluorinated Schiff base is p-butoxy benzylidene-p-fluoroaniline.

6. A device as in claim 1 wherein said admixture comprises 0.96 gram p-methoxy benzylidene-p-n-butylaniline, 0.25 gram p-butoxy benzylidene-p-fluoroaniline, 0.12 gram p-ethoxy benzylidene-p-cyanoaniline and 0.107 gram p-ethoxy benzylidene-p-methoxyaniline.

7. A device as in claim 1 wherein said admixture contains about 4 parts by weight of said (A) compound and about 1 part by weight of said fluorinated Schiff base.

4. An electro-optical light-modulating device containing a nematic liquid crystal composition comprising an admixture of 90% to 60% p-methoxy benzylidene-p-n-butylaniline and 10% to 40% p-ethoxy benzylidene-p-fluoroaniline.

5. An electro-optical light-modulating device containing a nematic liquid crystal composition comprising an admixture of 90% to 60% p-methoxy benzylidene-p-n-butylaniline and 10% to 40% p-butoxy benzylidene-p-fluoroaniline.

8. A nematic liquid crystal composition comprising an admixture of 90% to 60% by weight of (A) p-methoxy-benzylidene-p-butyl aniline and 10% to 40% by weight of (B) at least one fluorinated Schiff base having the general formula X--Ph -- HC = N -- Ph --F, where X is an alkoxy group having from 1 to 10 carbon atoms, Ph is phenylene, and F is fluorine.

9. A composition as in claim 8 wherein said fluorinated Schiff base is p-ethoxybenzylidene-p-fluoroaniline.

10. A composition as in claim 8 wherein said fluorinated Schiff base is p-butoxybenzylidene-p-fluoroaniline.

13. A composition as in claim 8 wherein said admixture comprises 0.96 gram p-methoxybenzylidene-p-n-butylaniline, 0.12 gram p-ethoxybenzylidene-p-cyanoaniline, 0.107 gram p-ethoxybenzylidene-p-methoxyaniline and 0.25 gram p-butoxybenzylidene-p-fluoroaniline.

14. A composition as in claim 8 wherein said admixture contains from 15% to 40% of said fluorinated Schiff base.

15. A composition as in claim 14 containing about 25% of said fluorinated Schiff base.

11. A nematic liquid crystal composition comprising an admixture of 90% to 60% p-methoxybenzylidene-p-n-butylaniline and 10% to 40% p-ethoxybenzylidene-p-fluoraniline.

12. A nematic liquid crystal composition comprising an admixture of 90% to 60% p-methoxybenzylidene-p-n-butylaniline and 10% to 40% p-butoxybenzylidene-p-fluoroaniline.

16. Method of preparing a liquid crystal composition comprising admixing 90% to 60% by weight of p-methoxy-benzylidene-p-butylaniline and 10% to 40% by weight of at least one fluorinated Schiff base of the formula X -- Ph -- HC = N -- Ph -- F, where X is an alkoxy group having from 1 to 10 carbon atoms, Ph is phenylene and F is fluorine, heating said admixture until the solution becomes clear and then cooling to room temperature.