Light modulating material and method for preparing same
First Claim
1. A light modulating material comprising a liquid crystal phase formed within a polymer matrix, the polymer matrix comprising:
- an acrylic resin having active hydrogen groups selected from the group consisting of hydroxy-functional acrylic resins;
an organometallic material selected from the group consisting of titanates, zirconates and mixtures thereof; and
a cross-linking agent selected from the group consisting of diisocyanates for reacting with the hydroxy-functional acrylic resin to form a urethane acrylic copolymer;
the light modulating material being capable of reversibly switching between a substantially translucent state and a substantially transparent state when subjected to an electric or magnetic field.
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Accused Products
Abstract
An improved light modulating material for use in electro-optic and thermo-optic display devices is produced by forming a homogeneous solution comprising an acrylic resin containing active hydrogen groups, a liquid crystal material, a diisocyanate or epoxide, and a solvent. The homogeneous solution is preferably applied to a conductive substrate and the solvent is then evaporated, causing phase separation resulting in formation of a liquid crystal phase dispersed within a solid polymer matrix. Application of an electric field to the substrate causes the liquid crystal material to align, which in turn causes the coating to switch from substantially translucent to substantially transparent. If the electric field is removed the light modulating material again becomes substantially translucent. Switching times can be improved by incorporating a titanate or zirconate organometallic material into the light modulating material.
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Citations
33 Claims
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1. A light modulating material comprising a liquid crystal phase formed within a polymer matrix, the polymer matrix comprising:
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an acrylic resin having active hydrogen groups selected from the group consisting of hydroxy-functional acrylic resins; an organometallic material selected from the group consisting of titanates, zirconates and mixtures thereof; and a cross-linking agent selected from the group consisting of diisocyanates for reacting with the hydroxy-functional acrylic resin to form a urethane acrylic copolymer; the light modulating material being capable of reversibly switching between a substantially translucent state and a substantially transparent state when subjected to an electric or magnetic field. - View Dependent Claims (2, 3)
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4. A light modulating material comprising a liquid crystal phase formed within a polymer matrix comprising a urethane-acrylic copolymer, and an organometallic material selected from the group consisting of titanates, zirconates and mixtures thereof, the material being capable of reversibly switching between a substantially translucent state and a substantially transparent state when subjected to an electrical or magnetic field.
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5. A light modulating material comprising a liquid crystal phase formed within a polymer matrix, the polymer matrix comprising:
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an acrylic resin having active hydrogen groups selected from the group consisting of carboxy-functional acrylic resins; and a cross-linking agent selected from the group consisting of epoxides for reacting with the carboxy-functional acrylic resin to form an epoxy-acrylic copolymer; the light modulating material being capable of switching between a substantially translucent state and a substantially transparent state when subjected to an electrical or magnetic field. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A light modulating material comprising a liquid crystal phase formed within a polymer matrix, the polymer matrix comprising an epoxy-acrylic copolymer formed by reacting a carboxy-functional acrylic resin with an epoxide within the polymer matrix, the light modulating material being capable of reversibly switching between a substantially translucent state and a substantially transparent state when subjected to an electrical or magnetic field.
- 13. A light modulating material comprising a liquid crystal phase interspersed with a urethane cross-linked hydroxy functionalized polymer, said polymer being formed by reacting hydroxy functional groups pendent from the polymeric chain with a cross-linking agent selected from the group consisting of isocyanates, the light modulating material being capable of reversibly switching between a translucent state and a transparent state when subjected to an electrical field or a magnetic field.
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25. A method of making a light modulating material comprising the steps of:
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forming a solution of liquid crystal, hydroxy functionalized polymer and isocyanate cross-linking agent; phase separating a liquid crystal phase from the polymer phase; and
,allowing the isocyanate cross-linking agent to react with the hydroxy groups of the hydroxy functionalized polymer to form a urethane cross-linked hydroxy functionalized polymer interspersed with the liquid crystal phase. - View Dependent Claims (26, 27)
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28. The method of making a light modulating material comprising the steps of:
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forming a solution of liquid crystal, carboxy functionalized polymer and epoxide cross-linking agent; phase separating the liquid crystal phase from the polymer phase; and allowing the epoxide cross-linking agent to react with the carboxy groups of the polymer to form an epoxy cross-linked carboxy functionalized polymer interspersed with the liquid crystal phase. - View Dependent Claims (29, 30)
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- 31. A light modulating material comprising a liquid crystal phase interspersed with an epoxy cross-linked carboxy functionalized polymer, said polymer being formed by reacting carboxy functional groups pendent from the polymeric chain with a cross-linking agent selected from the group consisting of epoxides, the light modulating material being capable of reversibly switching between a translucent state and a transparent state when subjected to an electric field or a magnetic field.
Specification