| 摘要 |
PURPOSE:To make the recording and reproduction with good accuracy possible, by establishing the recording film containing the benzopyrylium salt or benzothiapyrylium salt having a specific trimethine structure on a transparent substrate. CONSTITUTION:Because the solubility of coloring matter is large when a film is formed by utilizing the benzo(thia)pyrolium salt given by the formula as a constituent of the recording film 2, the film can be made uniformly dense and the signal recorded by laser can be distinctly read by the change of reflectance. In the formula, hydrogen or phenyl group is expressed as R1, hydrogen, phenyl group, 4-methoxyphenyl group, naphthyl group or methoxy naphthyl group as R2, hydrogen, methoxy group, nitro group or phenyl group as R3, hydrogen or methoxy group as R4, oxygen atom or sulfur atom as X and anion functional group as Y<->. |
