OPTICAL INFORMATION RECORDING MEDIUM AND CRYSTALLIZATION TREATMENT OF OPTICAL INFORMATION RECORDING MEDIUM

摘要

PURPOSE:To provide the optical information recording medium which allows the crystallization treatment of the optical information recording medium with a simple optical system and the crystallization treatment method for this optical information recording medium. CONSTITUTION:A part having no recording layer 3 is provided in the inner peripheral part of the optical information recording medium. This medium is so constituted as to satisfy mathematical expression 1 (d1n1+d2n2=lambda/6) or mathematical expression 2 (lambda/3=d1n1+d2n2=2lambda/3) where the film thickness of a 1st transparent intermediate layer 2 is designated as d1 the refractive index as n1, the film thickness of a 2nd transparent intermediate layer 4 as d2, the refractive index as n2, and the wavelength of radiation light 8 as lambda. The reflectivity of the optical information recording medium is specified to =10% so that pull-in focus is facilitated. The crystallization treatment of the recording layer 3 is thereafter executed by the radiation light which is moved to the part having the recording layer 3 and is subjected to focus control.