OPTICAL INFORMATION RECORDING MEDIUM, REPRODUCING DEVICE FOR OPTICAL INFORMATION RECORDING MEDIUM, AND REPRODUCING METHOD FOR OPTICAL INFORMATION RECORDING MEDIUM

摘要

In an optical information recording medium (1), a light transmitting layer (10) or a transparent substrate, an information recording layer (20) and a substrate (30) are stacked in this order from an entrance face of reproducing light (2). The information recording layer (20) includes at least a reproducing film (21) whose complex refractive index at a light source wavelength (?) of the reproducing light (2) changes by heat. The relationship of 0.67 x (?/NA)>TP>0.04 x (?/NA) is satisfied, where TP is a track pitch of prepits (31) formed on the substrate (30), and NA is a numerical aperture of an objective lens (55) which focuses the reproducing light (2) on the optical information recording medium.