MULTILAYER OPTICAL DISK, INFORMATION RECORDING METHOD, INFORMATION PLAYBACK METHOD, AND DISK DRIVE

摘要

PROBLEM TO BE SOLVED: To practically perform information recording of a BCA even when a long wavelength laser (600 to 800 nm wavelength) is used in a write-once optical disk wherein a short wavelength laser (≤600 nm wavelength) is used for information recording.SOLUTION: Grooves are previously engraved in a BCA part on a molded substrate of the optical disk and a dyestuff is accumulated in the grooves. Thereby sensitivity of the dyestuff of the BCA is increased and a bar code pattern is recorded in the BCA by using a laser having a wavelength (wavelength in the range of 600 to 800 nm) except a wavelength (e.g. 405 nm) corresponding to information recording of the dyestuff.