OPTICAL DISK AND ULTRAVIOLET-CURING TYPE COMPOSITION USED THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide an ultraviolet-curing type composition which enables to form a light transmission layer having high transmissivity of laser beam suitable for an optical disk for recording or reproducing with the laser beam which has an oscillation wavelength in the range of 370-430 nm through the light transmission layer. SOLUTION: A material, of which the absorbance in the laser wavelength measured under the conditions of an optical path length 1 cm of the methanol solution of 1 mass% concentration is <=0.05 is used as a photopolymerization initiator in the ultraviolet-curing type composition.