Optical recording medium capable of assuring sufficient levels of signals required for reading/writing data, and stamper for manufacture of the same

Abstract

In an optical recording medium having a writable area in which grooves are formed along recording tracks and a read-only area in which pits are formed along the recording tracks, sufficient levels of signals required for data write and read can be assured even with the track pitch reduced for a higher recording density. Assuming that the refractive index of a medium provided extending from a light-incident surface to a surface in which the grooves and pits are formed is n and the wavelength of a light used for data write and read is &lgr;, the grooves and pits has a width within a range of &lgr;/7.5 n to &lgr;/6. On the assumption that the width of each of the grooves formed in the writable area is Wg and the pitch between the recording tracks in the writable area is Tp , Wg/Tp is within a range of 18.4% to 31.1%. When it is assumed that the width of each of the pitches formed in the read-only area is Wp and the pitch between the recording tracks in the read-only area is Tp , Wp/Tp is within a range of 35.7% to 44.3%.