| 摘要 |
PURPOSE:To contrive a higher recording sensitivity and a simpler construction, by causing a metallic thin film provided on a transparent resin substrate to comprise a platinum group element and other metallic or semimetallic element and to have a specified thermal conductivity. CONSTITUTION:A metallic thin film provided on a transparent resin substrate consists of a composition comprising platinum group element as an essential constituent and other metallic or semimetallic element as an auxiliary element, and has a thermal conductivity of not more than 80% of the thermal conductivity of the platinum group element alone. With the thermal conductivity of the material constituting the metallic thin film thus lowered, the energy of recording laser light is localized, and recording sensitivity is markedly increased. The metallic or semimetallic element may be one which causes a marked lowering in the thermal conductivity of the platinum group element, and may be, for example, bismuth, titanium, aluminum, selenium, silicon, germanium or tin. A transparent resin used for the substrate may be one which sufficiently transmits laser light, for example, a polyester resin, a polyolefin resin or a polyamide resin. |
