| 摘要 |
An optical disk with sectional trapezoidal pits comprising a substrate having information recorded by a plurality of pit trains formed thereon at a specified track pitch, and a reflective layer formed on the substrate, wherein the information is reproduced by being irradiated with light beam via an objective lens, the track pitch is set within the range of (0.72 to 0.8) alpha x lambda /NA/1.14 mu m when a wavelength of the light beam is mu nm and a numerical aperture of the objective lens is NA, each of the pits is a multiplication ratio used to secure allowable disk tilt angles in an upper width within the range of (0.3 to 0.50) alpha x lambda /NA/1.14 mu m, a bottom width within the range of (0.2 to 0.32) alpha x lambda /NA/1.14 mu m and a depth within the range of (1/4.2x lambda /n) to (1/5.2 lambda /n) (n: refractive index of said substrate and lambda : a wavelength) and obtained by 2.623x10-7x(d/ lambda )2-1.706x10-4 (ds/ lambda )+0.934, where ds is thickness of the substrate. |
