Liquid crystal information storage device
First Claim
1. A liquid crystal information storage device comprising a layer of material containing a side chain polymeric liquid crystal of a type having a glass transition temperature Tg less than ambient temperature Ta normally experienced atmospherically, and a further temperature Tr at which the viscosity suddenly decreases and above which the material becomes fluid while remaining in the same mesophase up to Tm, corresponding to the point at which the isotropic or clear phase first begins to appear, and is biphasic until Tc at which temperature the material becomes fully isotropic where Tc>
- Tm>
Tr>
Ta>
Tq, means for effecting a thermal transition of at least a part of the material from a viscous state in which its temperature is in the range Tg to Tr, to the fluid region above Tr, and means for addressing at least a part of the material in the fluid region so as to achieve a selective variation in texture and orientation of molecules within the material and so record information, which information is retained on allowing the material to cool out of the fluid region and return to the viscous state.
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Accused Products
Abstract
A liquid crystal information storage device comprising a layer of material containing a side chain polymeric liquid crystal. At least a part of the material is heated from a viscous state above its glass transition temperature, to a fluid region in which the liquid crystalline material can readily undergo field-induced alignment. The material is addressed in this fluid region so as to achieve the selective variation in texture and orientation of molecules within the material and so record information, and the material is subsequently cooled and returned to its viscous state whereupon the information is retained.
77 Citations
21 Claims
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1. A liquid crystal information storage device comprising a layer of material containing a side chain polymeric liquid crystal of a type having a glass transition temperature Tg less than ambient temperature Ta normally experienced atmospherically, and a further temperature Tr at which the viscosity suddenly decreases and above which the material becomes fluid while remaining in the same mesophase up to Tm, corresponding to the point at which the isotropic or clear phase first begins to appear, and is biphasic until Tc at which temperature the material becomes fully isotropic where Tc>
- Tm>
Tr>
Ta>
Tq, means for effecting a thermal transition of at least a part of the material from a viscous state in which its temperature is in the range Tg to Tr, to the fluid region above Tr, and means for addressing at least a part of the material in the fluid region so as to achieve a selective variation in texture and orientation of molecules within the material and so record information, which information is retained on allowing the material to cool out of the fluid region and return to the viscous state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
- Tm>
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19. A method of producing a liquid crystal information storage device, comprising the steps of providing a layer of material containing a side chain polymeric liquid crystal of a type having a glass transition temperature Tg less than ambient temperature Ta normally experienced atmospherically, and a further temperature Tr at which the viscosity suddenly decreases and above which the material becomes fluid while remaining in the same mesophase up to Tm, corresponding to the point at which the isotropic or clear phase first begins to appear, and is biphasic until Tc at which temperature the material becomes fully isotropic where Tc>
- Tm>
Tr>
Ta>
Tg, effecting a thermal transition of at least a part of the material from a viscous state in which its temperature is in the range Tg to Tr, to the fluid region above Tr, addressing at least a part of the material in the fluid region so as to achieve a selective variation in texture and orientation of molecules within the material and so record information, and allowing the material to cool out of the fluid region and return to the viscous state whereupon said information is retained. - View Dependent Claims (20)
- Tm>
-
21. A variable transmission device in which there is provided an area of material containing a side chain polymeric liquid crystal of a type having a glass transition temperature Tg less than ambient temperature Ta normally experienced atmospherically, and a further temperature Tr at which the viscosity suddenly decreases and above which the material becomes fluid while remaining in the same mesophase up to Tm, corresponding to the point at which the isotropic or clear phase first begins to appear, and is biphasic until Tc at which temperature the material becomes fully isotropic where Tc>
- Tm>
Tr>
Ta>
Tq, said crystal being disposed between two transparent surfaces, means to raise the temperature of at least a part of said material above Tr, means to address at least a part of the area containing the polymer to convert it to a transmitting from a less-transmitting state when above Tr which state is retained on allowing the material to cool to a temperature below Tr without an applied field.
- Tm>
Specification