Recording medium
First Claim
Patent Images
1. A rewritable or repeatably employable recording medium comprising a base and a recording layer film deposited on said base;
- said recording layer film being a film of a thermotropic cholesteric liquid crystal polyester;
said recording layer film being reversibly transparent or opaque, said film being transparent at room temperature by heat-melting said film at the liquid crystal forming temperature followed by rapid cooling from said liquid crystal forming temperature to room temperature and being opaque at room temperature by heat-melting said film at the liquid crystal forming temperature followed by either (a) slow cooling to room temperature or (b) the application of an electrical or a magnetic field followed by rapid cooling to room temperature;
said cholesteric liquid crystal polyester of said recording layer film formed by copolymerizing an optically active compound with a mesogen, said mesogen have a structural unit selected from the group consisting of ##STR10## the combination of ##STR11## and the combination of ##STR12## where X and Y are each independently hydrogen, halogen or an alkyl group having no more than four carbon atoms.
0 Assignments
0 Petitions
Accused Products
Abstract
A rewritable or repeatedly employable recording medium having a base and a recording layer film provided on said base, characterized in that said recording layer film is formed by a thermotropic cholesteric liquid crystal polyester.
15 Citations
6 Claims
-
1. A rewritable or repeatably employable recording medium comprising a base and a recording layer film deposited on said base;
- said recording layer film being a film of a thermotropic cholesteric liquid crystal polyester;
said recording layer film being reversibly transparent or opaque, said film being transparent at room temperature by heat-melting said film at the liquid crystal forming temperature followed by rapid cooling from said liquid crystal forming temperature to room temperature and being opaque at room temperature by heat-melting said film at the liquid crystal forming temperature followed by either (a) slow cooling to room temperature or (b) the application of an electrical or a magnetic field followed by rapid cooling to room temperature;
said cholesteric liquid crystal polyester of said recording layer film formed by copolymerizing an optically active compound with a mesogen, said mesogen have a structural unit selected from the group consisting of ##STR10## the combination of ##STR11## and the combination of ##STR12## where X and Y are each independently hydrogen, halogen or an alkyl group having no more than four carbon atoms. - View Dependent Claims (2, 3, 4, 5, 6)
- said recording layer film being a film of a thermotropic cholesteric liquid crystal polyester;
Specification