Optical disc substrate

Abstract

Abstract An optical disc substrate (1) with deep grooves (3) having a depth of λ /4n to λ /2n , where λ 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 ; 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 D = 0.4022-0.4574x A+0.6458x A 2 Where D = physical groove depth x n / λ A = NA · TP λ x 1 sin 2  , TR indicates the track pitch of a disc substrate, NA indicates the numerical aperture of an objective lens of an optical pickup,  is the slant angle of grooves between lateral extension of lands or grooves and extension of groove sidewalls, λ is the wavelength of a laser beam of the optical pickup; and n is the refractive index of the substrate.

Inventors

• 👤 Du-Seop Yoon
• 👤 Chang-Min Park

Bibliographic Details