| 摘要 |
PURPOSE:To enable high-sensitivity recording and high-contrast reproduction through using a single pickup, by providing a recording layer comprising a mixed coloring matter constituted of a main cyanine coloring matter and an auxiliary cyanine coloring matter on a substrate. CONSTITUTION:A recording layer in a recording medium comprises a mixed cyanine coloring matter comprising a main cyanine coloring matter and an auxiliary cyanine coloring matter, wherein the reflection peak wavelength region of the auxiliary coloring mater substantially coincides with the absorption peak wavelength region of the main coloring matter, and the number of methine groups in the auxiliary coloring matter is smaller than that in the main coloring matter. The cyanine coloring matters may be based on quinoline, benzothiazole or dimethylindolenine. The main cyanine coloring matter is so selected that the absorption peak wavelength region thereof substantially coincides with the wavelength of laser beams used for recording and reproduction. The auxilia ry cyanine coloring matter is used in an amount of 0.5-0.05pts.wt. per 1pt.wt. of the main cyanine coloring matter. The recording medium this constructed is markedly enhanced in reflectance at the absorption peak wavelength of the recording layer, and has high-contrast recording and reproduction characteristics. |
