Cholesteric liquid crystal optical bodies and methods of manufacture and use

• US 7,068,344 B2
• Filed: 02/24/2003
• Issued: 06/27/2006
• Est. Priority Date: 02/24/2003
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Pokorny, Richard J., Spawn, Terence D., Radcliffe, Marc D., Solomonson, Steven D.
• Primary Examiner(s): Nguyen, Dung T.
• Application Number:
  US10/373,126
• Publication Number:
  US 20040165140A1
• Time in Patent Office: 1,219 Days
• Field of Search: 349 96- 98, 349/175, 349/185
• US Class Current: 349/175
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 2201/343 cholesteric liquid crystal reflector

Abstract

The method of making an optical body includes coating a mixture that includes a plurality of cholesteric liquid crystal compositions, and a solvent on a substrate. Each cholesteric liquid crystal composition is different. A plurality of layers is formed on the substrate. Each layer includes a majority of one of the cholesteric liquid crystal compositions.

Claims

1. A method of making an optical body, the method comprising steps of:

coating a mixture comprising a first cholesteric liquid crystal composition, a second cholesteric liquid crystal composition, and a solvent on a substrate;

wherein the first cholesteric liquid crystal composition is different than the second cholesteric liquid crystal composition; and

forming from the mixture a first layer disposed on the substrate and a second layer disposed on the first layer;

wherein the first layer comprises a majority of the first cholesteric liquid crystal composition and the second layer comprises a majority of the second cholesteric liquid crystal composition.

2. The method according to claim 1, further comprising converting the first cholesteric liquid crystal composition into an aligned first cholesteric liquid crystal material and converting the second liquid crystal composition into an aligned second cholesteric liquid crystal material.

3. The method according to claim 2, wherein the step of converting the first and second cholesteric liquid crystal composition into an aligned first and second cholesteric liquid crystal material comprises polymerizing at least one of the first and second cholesteric liquid crystal composition.

4. The method according to claim 2, wherein the step of converting the first and second cholesteric liquid crystal composition into an aligned first and second cholesteric liquid crystal material comprises cross-linking at least one of the first and second cholesteric liquid crystal composition.

5. The method according to claim 2, wherein the step of converting the first and second cholesteric liquid crystal composition into an aligned first and second cholesteric liquid crystal material comprises heating at least one of the first and second cholesteric liquid crystal composition.

6. The method according to claim 2, further comprising coating a second mixture comprising a third cholesteric liquid crystal composition and a second solvent on the first or second cholesteric liquid crystal material;

wherein the third cholesteric liquid crystal composition is different than the first or second cholesteric liquid crystal composition.

7. The method according to claim 6, further comprising converting the third cholesteric liquid crystal composition into an aligned third cholesteric liquid crystal material.

8. The method according to claim 2, further comprising;

coating a second mixture comprising a third cholesteric liquid crystal composition, a fourth cholesteric liquid crystal composition, and a second solvent on the first or second cholesteric liquid material;

wherein the third cholesteric liquid crystal composition is different than the first, second or fourth cholesteric liquid crystal composition and the fourth cholesteric liquid crystal composition is different than the first, second or third cholesteric liquid crystal composition; and

forming from the second mixture a third layer and a fourth layer on the first or second cholesteric liquid crystal material;

wherein the third layer comprises a majority of the third cholesteric liquid crystal composition and the fourth layer comprises a majority of the fourth cholesteric liquid crystal composition.

9. The method according to claim 8, further comprising converting the third cholesteric liquid crystal composition into an aligned third cholesteric liquid crystal material and converting the fourth liquid crystal composition into an aligned fourth cholesteric liquid crystal material.

10. The method according to claim 1, wherein the step of forming a first layer and a second layer on the substrate comprises separating the first cholesteric liquid crystal composition front the second cholesteric liquid crystal composition.

11. The method according to claim 1, wherein the step of forming a first layer and a second layer on the substrate comprises removing at least a portion of the solvent from the mixture.

12. The method according to claim 1, wherein the step of forming a first layer and a second layer on the substrate comprises heating the mixture.

13. The method according to claim 1, further comprising curing the first or second cholesteric liquid crystal material.

14. A method of making an optical body, the method comprising steps of:

coating a mixture comprising a first cholesteric liquid crystal composition, a second cholesteric liquid crystal composition, and a solvent on a substrate;

wherein the first cholesteric liquid crystal composition comprises a cholesteric liquid crystal polymer and the second cholesteric liquid crystal composition comprises a cholesteric liquid crystal monomer; and

forming from the mixture a first layer disposed on the substrate and a second layer disposed on the first layer;

wherein the first layer comprises a majority of the first cholesteric liquid crystal composition and the second layer comprises a majority of the second cholesteric liquid crystal composition.

15. The method according to claim 14, further comprising converting the first cholesteric liquid crystal composition into an aligned first cholesteric liquid crystal material and converting the second liquid crystal composition into an aligned second cholesteric liquid crystal material.

16. The method according to claim 15, wherein the step of converting the first cholesteric liquid crystal composition into an aligned first cholesteric liquid crystal material comprises polymerizing the first cholesteric liquid crystal composition.

17. The method according to claim 15, wherein the step of converting the second cholesteric liquid crystal composition into an aligned second cholesteric liquid crystal material comprises cross-linking the second cholesteric liquid crystal composition.

18. The method according to claim 15, further comprising coating a second mixture comprising a third cholesteric liquid crystal composition and a second solvent on the first or second cholesteric liquid crystal material;

wherein the third cholesteric liquid crystal composition comprises a cholesteric liquid crystal polymer or a cholesteric liquid crystal monomer and is different than the first or second cholesteric liquid crystal composition.

19. The method according to claim 18, further comprising converting the third cholesteric liquid crystal composition into an aligned third cholesteric liquid crystal material.

20. The method according to claim 19, wherein the step of converting the third cholesteric liquid crystal composition into an aligned third cholesteric liquid crystal material comprises converting the third cholesteric liquid crystal composition into an aligned third cholesteric liquid crystal thermoplastic material onto an aligned cholesteric liquid crystal cross-linked material.

21. The method according to claim 19, further comprising;

coating a second mixture comprising a third cholesteric liquid crystal composition, a fourth cholesteric liquid crystal composition, and a second solvent on the first or second cholesteric liquid crystal material;

wherein the third cholesteric liquid crystal composition comprises a cholesteric liquid crystal polymer and the fourth cholesteric liquid crystal composition comprises a cholesteric liquid crystal monomer, wherein the third cholesteric liquid crystal composition is different than the first, second or fourth cholesteric liquid crystal composition and the fourth cholesteric liquid crystal composition is different than the first, second or third cholesteric liquid crystal composition; and

forming from the second mixture a third layer and a fourth layer on the first or second cholesteric liquid crystal material;

wherein the third layer comprises a majority of the third cholesteric liquid crystal composition and the fourth layer comprises a majority of the fourth cholesteric liquid crystal composition.

22. The method according to claim 21, further comprising converting the third cholesteric liquid crystal composition into an aligned third cholesteric liquid crystal material and converting the fourth liquid crystal composition into an aligned fourth cholesteric liquid crystal material.

23. The method according to claim 22, wherein the step converting the third cholesteric liquid crystal composition into an aligned third cholesteric liquid crystal material comprises converting the third cholesteric liquid crystal composition into an aligned third cholesteric liquid crystal thermoplastic material on an aligned second cholesteric liquid crystal cross-linked material.

24. The method according to claim 22, wherein the step converting the fourth cholesteric liquid crystal composition into an aligned fourth cholesteric liquid crystal material comprises converting the fourth cholesteric liquid crystal composition into an aligned fourth cholesteric liquid crystal cross-linked material on an aligned third cholesteric liquid crystal thermoplastic material.

25. The method according to claim 14, wherein the step of forming from the mixture a first layer and a second layer on the substrate comprises forming a first layer between the substrate and second layer.

26. The method according to claim 14, wherein the step of forming from the mixture a first layer and a second layer on the substrate comprises forming a second layer between the substrate and first layer.