Thin film compensators having planar alignment of polymerized liquid crystals at the air interface
First Claim
1. A method of making a phase retardation plate, comprising the steps of:
- providing a substrate;
applying a liquid crystal alignment layer to the substrate;
applying a thin film of a polymerizable liquid crystal material to the alignment layer such that the free surface of the thin film constitutes a liquid crystal/air interface, the liquid crystal material including a surface active material that reduces the intrinsic tilt orientation of the director of the liquid crystal material at the liquid crystal/air interface;
adjusting the temperature of the thin film to orient the director of the thin film in the bulk of the thin film; and
polymerizing the thin film to preserve the orientation.
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Accused Products
Abstract
The present invention relates to thin film retardation plates, such as cholesteric and A-plate compensators, for improving the viewing angle and contrast of liquid crystal displays. The A-plate is fabricated using a single substrate onto which a layer of polymerizable reactive mesogens (RMs) is solvent cast. Included in the RMs solution is an additive that migrates to the RM/air interface to lower the surface energy and generate an additive-rich surface layer, which in turn lowers the intrinsic tilt angle of the RMs at the air interface to between 25 degrees (25°) and about zero degrees (0°). The solvent is evaporated and the resulting film is polymerized in the liquid crystal phase to permanently orient the liquid crystal. The resulting film may be readily separated from the substrate and shaped into any desired pattern and combined to form novel compensators. In an alternative embodiment, a tilt may be provided by treating the substrate with an oblique alignment layer to form a compensator having a defined splay through the bulk of the thin film.
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Citations
61 Claims
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1. A method of making a phase retardation plate, comprising the steps of:
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providing a substrate; applying a liquid crystal alignment layer to the substrate; applying a thin film of a polymerizable liquid crystal material to the alignment layer such that the free surface of the thin film constitutes a liquid crystal/air interface, the liquid crystal material including a surface active material that reduces the intrinsic tilt orientation of the director of the liquid crystal material at the liquid crystal/air interface; adjusting the temperature of the thin film to orient the director of the thin film in the bulk of the thin film; and polymerizing the thin film to preserve the orientation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A phase retardation plate, comprising:
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a thin film of a polymerized liquid crystal material; and a surface-active material disposed in said thin film near a first surface of said thin film such that said surface-active material reduces the intrinsic tilt orientation of the director of the liquid crystal material near the first surface. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A phase retardation plate, comprising:
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a substrate; a liquid crystal alignment layer disposed on said substrate; a thin film of a polymerized liquid crystal material disposed on said alignment layer, such that the exposed surface of said thin film constitutes a liquid crystal/air interface; and a surface-active material disposed in said thin film near the liquid crystal/air interface, such that said surface active-material produces a substantially parallel orientation of the director of the liquid crystal material at the liquid crystal/air interface, said thin film having the director uniformly oriented in a specific azimuthal direction in the bulk of said thin film. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A method of making a phase retardation plate, comprising the steps of:
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providing a plastic substrate;
applying a thin film of a polymerizable liquid crystal material to said substrate such that the exposed surface of the thin film constitutes a liquid crystal/air interface, the liquid crystal material including a surface-active material that reduces the intrinsic tilt orientation of the director of the liquid crystal material at the liquid crystal/air interface;adjusting the temperature of the thin film to orient the director of the thin film in the bulk of the thin film; and polymerizing the thin film to preserve the orientation. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A phase retardation plate, comprising
a substrate; a thin film of a polymerized liquid crystal material disposed on said substrate such that said thin film has an exposed first surface, said thin film having an orientation of the director of the liquid crystal material at said first surface that is less than the intrinsic tilt orientation of the director and an azimuthal orientation rotation of said director in the bulk of said thin film. - View Dependent Claims (55, 56, 57, 58, 59, 60, 61)
Specification