RECORDING AND REPRODUCING MEDIUM, AND RECORDING AND REPRODUCING DEVICE USING IT

摘要

PROBLEM TO BE SOLVED: To detect information on land prepit and groove with high accuracy. SOLUTION: A groove width (Gw) of a groove 1, a prepit length (Lp) in the line scanning direction θt of a land prepit 3, a groove depth (Gd; unit μm) in the direction of thickness of the groove 1 and the land 2 are to be formed into a shape satisfying the following relations between a numerical aperture (NA) of an object lens 8 and a wavelength (λ) of a light spot; Gw/(λ/ NA)>=0.2093 Lp/(λ/NA)}2-0.4342Lp/(λ/NA)+0.332-(-2.64Gd+0.1276), and Gw/(λ/NA)<=0.2093 Lp/(λ/NA)}2-0.4342Lp)/(λ/NA)+0.332+(-4.48Gd+0.2112).