IP Library Granted Patent US 7,119,859
Granted Patent B2
US 7,119,859 · App. 10/860,973 · Granted Oct 10, 2006

Contrast chiral nematic liquid crystal displays

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Quick Facts
Patent No.
US 7,119,859
App. No.
10/860,973
Granted
Oct 10, 2006
Kind
B2
Abstract

The present invention relates to a bistable polymer dispersed liquid crystal display comprising a support, at least one patterned first conductor layer having thereon at least one dried imaging layer comprising a substantial monolayer of isolated domains of liquid crystal material dispersed in a continuous polymer matrix, wherein said dried imaging layer further comprises at least one absorber colorant, and wherein said isolated domains have a size distribution such that the coefficient of variation (cv) is less than 0.35.

Claims (38)

1. A bistable polymer dispersed liquid crystal display comprising a support, at least one patterned conductor layer having thereon at least one dried imaging layer comprising a substantial monolayer of isolated domains of liquid crystal material dispersed in a continuous polymer matrix, wherein said dried imaging layer further comprises at least one absorber colorant, and wherein said isolated domains have a size distribution such that the coefficient of variation (cv) is less than 0.35.

2. The bistable polymer dispersed liquid crystal display of claim 1 wherein said coefficient of variation is less than 0.3.

3. The bistable polymer dispersed liquid crystal display of claim 1 wherein said coefficient of variation is less than 0.25.

4. The bistable polymer dispersed liquid crystal display of claim 1 wherein domains further have a minimum thickness of at least 4 microns.

5. The bistable polymer dispersed liquid crystal display of claim 1 wherein said domains are limited coalescence domains having a domain-continuous polymer matrix interface stabilized by particulate species.

6. The bistable polymer dispersed liquid crystal display of claim 5 wherein said particulate species has a size range of from 5 nm to 100 nm.

7. The bistable polymer dispersed liquid crystal display of claim 5 wherein said particulate species is finely divided silica.

8. The bistable polymer dispersed liquid crystal display of claim 5 wherein said particulate species is anchored to said domain-continuous polymer matrix interface by a promoter.

9. The bistable polymer dispersed liquid crystal display of claim 1 wherein said domains comprise chiral nematic liquid crystal material.

10. The bistable polymer dispersed liquid crystal display of claim 9 wherein said domains are flattened to improve reflectance in the reflecting state of said display.

11. The bistable polymer dispersed liquid crystal display of claim 9 wherein said domains have an average diameter of 5 to 30 microns when dispersed in an aqueous suspension prior to drying.

12. The bistable polymer dispersed liquid crystal display of claim 9 wherein said domains have an average diameter of from 8 to 15 microns when dispersed in an aqueous suspension prior to drying.

13. The bistable polymer dispersed liquid crystal display of claim 9 wherein said domains are flattened spheres and have on average a thickness at least 50% less than their length.

14. The bistable polymer dispersed liquid crystal display of claim 9 wherein said domains have a thickness to length ratio of 1:2 to 1:6.

15. The bistable polymer dispersed liquid crystal display of claim 9 wherein said imaging layer has a thickness of 6 to 20 microns.

16. The bistable polymer dispersed liquid crystal display of claim 1 wherein said at least one absorber colorant is an absorber dye compatible with said continuous polymeric matrix.

17. The bistable polymer dispersed liquid crystal display of claim 1 wherein said at least one absorber colorant is soluble in toluene.

18. The bistable polymer dispersed liquid crystal display of claim 17 wherein said at least one absorber colorant is soluble in toluene has a solubility greater than 1 gram absorber colorant per liter of toluene.

19. The bistable polymer dispersed liquid crystal display of claim 1 wherein said absorber colorant comprises at least one member selected from the group consisting of anthraquinone dyes, phthalocyanine dyes, methine dyes or metal complex dyes.

20. The bistable polymer dispersed liquid crystal display of claim 1 wherein absorber colorant comprises a blue absorber dye.

21. The bistable polymer dispersed liquid crystal display of claim 20 wherein said liquid crystal material is a green, yellow, orange or red reflecting liquid crystal material.

22. The bistable polymer dispersed liquid crystal display of claim 1 wherein absorber colorant comprises a mixture of green and blue absorber dye.

23. The bistable polymer dispersed liquid crystal display of claim 22 wherein said liquid crystal material is a red reflecting liquid crystal material.

24. The bistable polymer dispersed liquid crystal display of claim 1 wherein said absorber colorant comprises a green absorber dye.

25. The bistable polymer dispersed liquid crystal display of claim 24 wherein said liquid crystal material is a blue or red reflecting liquid crystal material.

26. The bistable polymer dispersed liquid crystal display of claim 1 wherein said absorber colorant comprises a red absorber dye.

27. The bistable polymer dispersed liquid crystal display of claim 26 wherein said liquid crystal material is a blue or green reflecting liquid crystal material.

28. The bistable polymer dispersed liquid crystal display of claim 1 wherein said absorber colorant absorbs in a wavelength range of from 350 to 450 nm.

29. The bistable polymer dispersed liquid crystal display of claim 1 wherein said continuous matrix comprises gelatin.

30. The bistable polymer dispersed liquid crystal display of claim 1 wherein said at least one conductor is patterned to produce an addressable matrix.

31. The bistable polymer dispersed liquid crystal display of claim 1 wherein said at least one conductor is patterned ITO.

32. The bistable polymer dispersed liquid crystal display of claim 1 wherein said at least one conductor is transparent.

33. The bistable polymer dispersed liquid crystal display of claim 1 wherein said at least one conductor comprises a first conductor and a second conductor, wherein said imaging layer is positioned therebetween.

34. The bistable polymer dispersed liquid crystal display of claim 33 wherein said first and said second conductors are patterned to produce an addressable matrix.

35. The bistable polymer dispersed liquid crystal display sheet of claim 33 wherein said first transparent conductor is patterned ITO.

36. The bistable polymer dispersed liquid crystal display sheet of claim 1 wherein said substrate is a flexible plastic material.

37. The bistable polymer dispersed liquid crystal display sheet of claim 36 wherein said flexible plastic material is transparent.

38. The bistable polymer dispersed liquid crystal display of claim 1 further comprising a radiation absorbing layer.

Assignments (5)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 2, 2018
From: STAR TREND ENTERPRISE CORP
To: HKC CORPORATION LIMITED
Reel/Frame 045092/0784 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 28, 2017
From: INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE
To: STAR TREND ENTERPRISE CORP.
Reel/Frame 044235/0462 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 28, 2017
From: INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE
To: STAR TREND ENTERPRISE CORP.
Reel/Frame 044238/0966 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 18, 2007
From: EASTMAN KODAK COMPANY
To: INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE
Reel/Frame 019834/0987 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 4, 2004
From: CHARI, KRISHNAN; RANKIN JR., CHARLES M.; WELTER, THOMAS R.
To: EASTMAN KODAK COMPANY
Reel/Frame 015443/0072 →