| 摘要 |
An optical recording medium for recording information by changing the phase of material from amorphus one to crystalline one and vice versa, including the following types. A type which comprises a transparent substrate, a first dielectric layer, a recording layer, a second dielectric layer, a light absorbing layer, and a light reflecting layer, the thickness of the second dielectric layer being in a range from 1 to 50 nm. A type which comprises a transparent substrate, a first dielectric layer, a recording layer, a second dielectric layer, and a light absorbing layer, the thickness of the second dielectric layer being in a range from 1 to 30 nm. A type which comprises a recording layer, a dielectric layer, a light reflecting layer, the thicknesses of the recording layer and the dielectric layer being in a range from 30 to 60 nm and in a range from 1 to 25 nm, respectively. A type in which the amplitudes of the signals reproduced from recording marks made at intervals longer than lambda /NA in the recording direction are less than five times those at intervals shorter than lambda /NA, where lambda is the wavelength of the recording light, and NA is the numerical aperture of the objective of the optical head. A type in which the C/N ratio of the signals reproduced from the former recording marks is lower than that of the latter. A type in which the areas of the former are smaller than those of the latter. A type in which the amplitudes of the signals reproduced from the latter which are overwritten on the former are more than five times those of the residual former after overwrite. Such a recording medium has good erasure characteristic, jitter characteristic, and durability against repeated overwrite. |
