OPTICAL RECORDING MEDIUM AND ITS DRIVE DEVICE

摘要

PROBLEM TO BE SOLVED: To make an optical recording medium and its drive device inexpensive and easy to use by embodying the optical recording medium having the large allowance to a skew and thickness error. SOLUTION: This flexible optical recording medium is constituted by forming a recording layer 2 on a protective layer 1 and forming a transparent protective layer 3 thereon. Recording and reproducing are executed by irradiating the recording layer 2 with a light of 0.2 μm higher wavelength λ through an objective lens of 0.5 μm or higher in a numerical aperture NA from the transparent protective layer 3 side. Thickness (t) of the transparent protective layer 3 is so selected as to satisfy Θ<=84.115.λ/ (NA)3.t}, when the permissible inclination angle of the optical recording medium is defined as Θ( deg.) and the thickness of the transparent protective layer 3 as t (μm).