RECORDING MEDIUM, RECORDING MEDIUM REPRODUCER AND RECORDING MEDIUM RECORDER

摘要

PROBLEM TO BE SOLVED: To satisfactorily improve recording density by using an ordinary medium. SOLUTION: In a recording medium 1 where information is recorded as marks, the min. recording mark size L out of these marks on this recording medium 1 is satisfied with such a relationship with a wavelength λ of a light source used for reading out information and a numerical aperture NA of an objective lens for converging light from this light source onto this recording medium 1 as L<0.175 λ/NA.