| 摘要 |
PURPOSE:To enable rewriting by transparentizing a film like recording layer, by a method wherein the film like recording layer comprises cholesteric liquid crystal line polyester opaque in the vicinity of ambient temp. and is brought to a mono-domain state in a liquid crystal forming temp. region and subsequently quenched to hold a mono-domain state at ambient temp. CONSTITUTION:Cholesteric liquid crystal like polyester has a film thickness of 1-100mum and, when said polyester is heated and melted in a liquid crystal forming temp. region of 150-350 deg.C, it can be changed from a poly-domain state to a laminated structure near to a mono-domain state. In poly-domain, the direction of the spiral axis of a cholesteric liquid crystal is not constant and light is scattered from a crystal interface to impart an opaque film. Contrarily, the spiral axis of the mono-domain laminated structure becomes vertical to the surface of the film and, if the pitch length of the spiral axis is near to the wavelength of visible light, said structure selectively reflects light corresponding to a wavelength lambda0 to be looked so as to show a transparent colored state and, if lambda0 is shifted from the wavelength of visible light, said structure is looked so as to be colorless and transparent. As mentioned above, if cholesteric liquid crystal like polyester is used, the change of opacity can be reversibly performed. |
