Patent ID: 6618349
Filing Date: 2003-09-09
Classification: G11B

Abstract:
An optical recording medium having a light-transmitting substrate formed with grooves wherein the grooves and the region between adjacent grooves are used for the recording track, and a reading beam is irradiated through the light-transmitting substrate, whereinthe relations: âˆ’12.6T+15.6&lE;x&lE;25Tâˆ’3.8, and 0.55&lE;T&lE;0.68 are satisfied when the reading beam has a wavelength of &lgr;, the light-transmitting substrate has a refractive index at the wavelength &lgr; of n, the reading optical system has a numerical aperture of NA, recording track pitch is PT, the groove has a depth of &lgr;/(xÂ·n), and T is PT/(&lgr;/NA).