Write-once information recording medium and coloring matter material therefor

摘要

A write-once information recording medium comprises a transparent resin substrate having a concentrically or spirally shaped groove and a land formed thereon, and a recording firm formed on the groove and the land of the transparent resin substrate, a recording mark being formed on the medium by emission of a short wavelength laser light, the recording medium having an L to H feature in which a light reflectivity of the recording mark portion formed by the emission of the short wavelength laser light is higher than a light reflectivity obtained before the emission of the short wavelength laser light.