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US 7,008,675 B2Granted
Polymers for orientation and stability of liquid crystals
AssigneeCalifornia Institute of Techology
InventorsJulia A. Kornfield, Michael D. Kempe
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AssigneeCalifornia Institute of Techology
InventorsJulia A. Kornfield, Michael D. Kempe
Estimating the term…
An electro-optically active polymer gel material comprising a high molecular weight alignment polymer adapted to be homogeneously dispersed throughout a liquid crystal to control the alignment of the liquid crystal molecules and/or confer mechanical stability is provided. The electro-optically active polymer gel comprises a homogenous gel in which the polymer strands of the gel are provided in low concentration and are well solvated by the small molecule liquid crystal without producing unacceptable slowing of its electrooptic response. During formation of the gel, a desired orientation is locked into the gel by physical or chemical cross-linking of the polymer chains. The electro-optically active polymer is then utilized to direct the orientation in the liquid crystal gel in the “field off” state of a liquid crystal display. The electro-optically active polymer also provides a memory of the mesostructural arrangement of the liquid crystal and acts to suppress the formation of large scale deviations, such as, for example, fan-type defects in a FLC when subjected to a mechanical shock. A method of making an electro-optically active polymer gel material and an electrooptic device utilizing the electro-optically active polymer gel of the present invention is also provided.
An electro-optically active gel layer having smectic or cholesteric properties comprising a plurality of aligned liquid crystal molecules and an anisotropic three-dimensional polymer network comprising a plurality of sparsely cross-linked polymer molecules, wherein the anisotropic three-dimensional polymer network is homogeneously dispersed within the liquid crystal molecules.
An electro-optically active gel layer having smectic or cholesteric properties comprising a plurality of liquid crystal molecules and an anisotropic three-dimensional polymer network comprising a plurality of sparsely cross-linked polymer molecules, wherein the anisotropic three-dimensional polymer network is homogeneously dispersed within the liquid crystal molecules, and wherein the liquid crystal molecules comprise less than 5% of the gel layer by mass.
An electrooptic device comprising two substrates, which are provided with at least one electrode, and an electro-optically active gel layer which is located between the two substrates, wherein the electro-optically active gel layer has smectic or cholesteric properties and comprises a plurality of aligned liquid crystal molecules and an anisotropic three-dimensional polymer network comprising a plurality of sparsely cross-linked polymer molecules, wherein the anisotropic three-dimensional polymer network is homogeneously dispersed within the liquid crystal molecules.
An electrooptic device comprising two substrates, which are provided with at least one electrode, and an electro-optically active gel layer which is located between the two substrates, wherein the electro-optically active gel layer has smectic or cholesteric properties and comprises a plurality of aligned liquid crystal molecules and an anisotropic three-dimensional polymer network, wherein the anisotropic three-dimensional polymer network is homogeneously dispersed within the liquid crystal molecules, and wherein the liquid crystal molecules comprise less than 5% of the gel layer by mass, and wherein the polymer network mechanically stabilizes the liquid crystal molecules.
Dependencies are inferred from the claim text.