Modulator with Improved Sensitivity and Life Time

• US 20080186563A1
• Filed: 02/06/2007
• Published: 08/07/2008
• Est. Priority Date: 02/06/2007
• Status: Active Grant

• Current Assignee: Orbotech Limited (KLA Corporation)
• Original Assignee: Photon Dynamics Incorporated (KLA Corporation)
• Inventors: Chen, Xianhai
• Granted Patent: US 7,817,333 B2
• Time in Patent Office: Days
• US Class Current: 359/322
• CPC Class Codes: C09K 19/544 as dispersing or encapsulating medium around the liquid crystal
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: C09K 2323/05 Bonding or intermediate layer characterised by chemical composition, e.g. sealant or spacer
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals

Abstract

An electro-optic modulator assembly includes a sensor layer made from an electro-optic modulator material that comprises liquid crystal droplets encapsulated within a polymer matrix. The sensor layer material comprises an interfacial agent, for example a defoaming agent, in an amount sufficient to lower an intrinsic operating voltage at which the sensor layer transmits light. The defoaming agent can comprise from about 1 to about 10 percent by weight of the electro-optic modulator material, and the defoaming agent may comprise a reactive component to react with the polymer matrix, for example at least one of a siloxane with a reactive end group, a reactive fluorinated polymer or a non-ionic block copolymer to react with the polymer matrix. The assembly can also include a hard coating layer to protect the sensor layer.

Claims

1. An electro-optic modulator assembly comprising:

a sensor layer comprising liquid crystal droplets encapsulated within a polymer matrix, wherein the sensor layer comprises an interfacial agent in an amount sufficient to lower an intrinsic operating voltage at which the sensor layer transmits light; and

a hard coating layer to protect the liquid crystal modulator layer.

2. The assembly of claim 1 wherein the interfacial agent comprises at least one of a non-ionic block copolymer, a reactive surfactant or a defoaming agent.

3. The assembly of claim 1 wherein the hardcoat comprises at least one of UV curable hard coat, sol-gel, thermal curable and organic/inorganic composite materials

4. A method for fabricating a latex-based NCAP modulator, the method comprising:

coating an NCAP latex based material comprising an interfacial agent on a plastic substrate with a transparent electrode;

covering the coated substrate with a plastic cover to sandwich the NCAP material between the plastic substrate and the plastic cover;

laminating the sandwiched NCAP material on an optical block substrate;

removing the plastic cover;

laminating a dielectric mirror pellicle over the NCAP latex based material; and

coating the pellicle with a UV curable organic coating; and

UV curing the curable organic coating to an organic hard coat.

5. The method of claim 4 wherein the interfacial agent comprises a defoaming agent.

6. The method of claim 5 wherein the defoaming agent is present in an amount sufficient to decrease an operating voltage of the modulator.

7. The method of claim 5 wherein the defoaming agent comprises a siloxane with a reactive end group in an amount sufficient to decrease an operating voltage of the modulator.

8. The method of claim 5 wherein the defoaming agent comprises reactive fluorinated molecules present in an amount sufficient to decrease an operating voltage of the modulator.

9. The method of claim 5 wherein the defoaming agent comprises a non-ionic block copolymer in an amount sufficient to decrease the operating voltage of the modulator.

10. The method of claim 4 further including formulating the UV curable organic coating as a mixture of multi-functional acrylates, silicone acrylate as a slip agent, a (meth)acrylate terminated toughener, nano sized silica as an inorganic filler, and photo-initiators.

11. An NCAP latex-based modulator with a protective coating, said modulator comprising:

an NCAP latex based material comprising an interfacial agent;

a dielectric mirror pellicle laminated on top of the NCAP material; and

a cured UV curable organic hard coating on the mirror pellicle.

12. The modulator of claim 11 wherein the interfacial agent comprises a defoaming agent.

13. The modulator of claim 12 wherein an amount of the defoaming agent is sufficient to decrease an operating voltage of the modulator.

14. The modulator of claim 12 wherein the defoaming agent comprises a siloxane with a reactive end group in an amount sufficient to decrease an operating voltage of the modulator.

15. The modulator of claim 12 wherein the defoaming agent comprises a reactive fluorinated polymer present in an amount sufficient to decrease an operating voltage of the modulator.

16. The modulator of claim 12 wherein the defoaming agent comprises a non-ionic block copolymer present in an amount sufficient to decrease an operating voltage of the modulator.

17. The modulator of claim 11 wherein the UV curable organic coating comprises a mixture of multi-functional acrylates, silicone acrylate as a slip agent, a (meth)acrylate terminated toughener, nano sized silica as an inorganic filler, and photo-initiators.

18. An electro-optic modulator material comprising:

droplets comprising liquid crystal molecules;

a polymer matrix that encapsulates and supports the droplets;

a defoaming agent in an amount sufficient to decrease an operating voltage at which an orientation of the liquid crystal molecules changes to transmit light through the material.

19. The electro-optic modulator material of claim 18 wherein the defoaming agent comprises from about 1 to about 10 percent by weight of the electro-optic modulator material.

20. The material of claim 18 wherein the defoaming agent comprises a reactive component to react with the polymer matrix.

21. The material of claim 18 wherein the defoaming agent comprises at least one of a siloxane with a reactive end group, a reactive fluorinated polymer or a non-ionic block copolymer to react with the polymer matrix.

22. An NCAP electro-optic modulator material comprising:

droplets comprising liquid crystal molecules;

a latex based polymer matrix that encapsulates and supports the droplets;

an interfacial agent in an amount sufficient to decrease an operating voltage at which an orientation of the liquid crystal molecules changes to transmit light through the material.

23. The material of claim 22 wherein the interfacial agent comprises a defoaming agent in an amount sufficient to decrease the operating voltage.

24. The material of claim 23 wherein the defoaming agent comprises a reactive defoaming agent in an amount sufficient to react with the latex based polymer matrix and decrease the operating voltage.

25. The material of claim 23 wherein the defoaming agent comprises a siloxane with a reactive end group to react with the latex based polymer matrix.

26. The material of claim 23 wherein the defoaming agent comprises a reactive fluorinated polymer to react with the latex based polymer matrix.

27. The material of claim 23 wherein the defoaming agent comprises from about 1 to 10 percent by weight of the electro-optic modulator material.

28. The material of claim 23 wherein the defoaming agent has a hydrophile lipophile balance less than about 10.

29. The material of claim 22 wherein the interfacial agent comprises at least one of a non-ionic block copolymer or a reactive surfactant.

30. The material of claim 22 wherein the interfacial agent decreases anchoring of the liquid crystal molecules to the polymer matrix.

31. The material of claim 22 wherein the interfacial agent forms an interface layer on the droplets between the droplets and the latex based polymer matrix.

32. The material of claim 22 wherein the interfacial agent forms an interface layer with a first inner portion to lower a surface tension of the liquid crystal molecules and a second outer portion immobilized in the polymer matrix.

33. An NCAP electro-optic modulator material comprising:

droplets comprising liquid crystal molecules;

a water-soluble polymer-based matrix that encapsulates and supports the droplets;

a defoaming agent in an amount sufficient to decrease an operating voltage at which an orientation of the liquid crystal molecules changes to transmit light through the material.

34. The material of claim 33 wherein the defoaming agent comprises a reactive defoaming agent to react with the water-soluble polymer and decrease the operating voltage of the material.

35. A method of making an NCAP electro-optic material, the method comprising:

combining a liquid crystal material with a latex emulsion;

emulsifying the liquid crystal material in the presence of at least one interfacial agent to form an emulsion comprising droplets of the liquid crystal material;

applying the emulsion to a substrate; and

drying the emulsion on the substrate to encapsulate the droplets with a latex based matrix, wherein an amount of the at least one interfacial agent is sufficient to decrease an operating voltage at which a molecular orientation of the liquid crystal material changes to transmit light through the material.

36. The method of claim 35 wherein the interfacial agent comprises a defoaming agent that forms clusters to knock down foam while the liquid crystal is emulsified and wherein the defoaming agent reacts with the latex emulsion to lower the operating voltage of the liquid crystal material.

37. The method of claim 36 wherein the emulsion applied to the substrate has a viscosity from about 1 to 100 cp to allow the defoaming agent clusters to migrate to the liquid crystal droplets to react with the latex emulsion near the liquid crystal droplets.

38. The method of claim 36 wherein the defoaming agent comprises a siloxane with a reactive end group in an amount sufficient to decrease the operating voltage of the modulator.

39. The method of claim 36 wherein the defoaming agent comprises a reactive fluorinated polymer in an amount sufficient to decrease the operating voltage of the modulator.

40. The method of claim 36 wherein the defoaming agent comprises a non-ionic block copolymer in an amount sufficient to decrease the operating voltage of the modulator.

41. A PDLC electro-optic modulator material comprising:

droplets comprising liquid crystal molecules;

a solvent-induced phase separation PDLC formulation that encapsulates and supports the droplets;

a defoaming agent in an amount sufficient to decrease an operating voltage at which an orientation of the liquid crystal molecules changes to transmit light through the material.

42. The material of claim 41 wherein the defoaming agent comprises a reactive defoaming agent to react with the solvent-induced phase separation PDLC formulation to decrease the operating voltage of the material.

43. The material of claim 41 wherein the defoaming agent comprises from about 1 to 10 percent by weight of the PDLC electro-optical modulator material.