| 摘要 |
An optical disc substrate (1) with deep grooves (3) having a depth of lambda /4n to lambda /2n, where lambda is the wavelength of a laser beam of an optical pickup and n is the refractive index of a substrate. The optical disc substrate includes: a plurality of deep grooves (3) having a predetermined depth, individual deep grooves having sidewalls slanted at an angle of &thetas;; and a plurality of lands (5) having the same level as the surface of the substrate, wherein a depth D of a groove for minimum crosstalk is determined by the following mathematical relation <DF>D = 0.4022-0.4574x A+0.6458x A<2> </DF> Where D = physical groove depth xn/ lambda <DF>A=NA.TP DIVIDED lambda x1 DIVIDED sin<2>&thetas;, </DF> TR indicates the track pitch of a disc substrate, NA indicates the numerical aperture of an objective lens of an optical pickup, &thetas; is the slant angle of grooves between lateral extension of lands or grooves and extension of groove sidewalls, lambda is the wavelength of a laser beam of the optical pickup; and n is the refractive index of the substrate. <IMAGE> |
