초록 ▼

Tracking control is carried out by a push-pull method or by mechanical feed at the time of recording signals, and tracking control is carried out by a phase difference tracking method at the time of reproduction. Thus, a phase change type optical disk which enables phase difference reproduction and

Tracking control is carried out by a push-pull method or by mechanical feed at the time of recording signals, and tracking control is carried out by a phase difference tracking method at the time of reproduction. Thus, a phase change type optical disk which enables phase difference reproduction and is erasable may be realized. In a phase change type optical disk having a phase difference reproduction structure, servo mechanism at the time of reproducing signals may be stably controlled by causing the reflectance of a blank portion to be higher than the reflectance of a recording mark portion.

대표청구항 ▼

1. An optical information recording medium comprising at least a recording thin film that effects a phase change between an amorphous state and a crystalline state by irradiation of a laser beam, the recording thin film formed on a disk-shaped substrate including guide grooves having a groove depth

1. An optical information recording medium comprising at least a recording thin film that effects a phase change between an amorphous state and a crystalline state by irradiation of a laser beam, the recording thin film formed on a disk-shaped substrate including guide grooves having a groove depth d (nm), wherein the groove depth d, a wavelength λ 1(nm) of laser beam for forming a record mark on the recording thin film based on an information signal and a refractive index n1of the substrate at the wavelength λ1satisfy a relationship:0.05λ 1/n1≦d; the groove depth d (nm), a wavelength λ 2(nm) of laser beam for reproducing the record mark formed on the recording thin film and a refractive index n2of the substrate at the wavelength λ2satisfy a relationship:d≦ 0.09×λ2/n2; a phase &phgr; 1of light reflected from the record mark and a phase &phgr;2of light reflected from a non-record mark region with respect to laser beam at the wavelength λ2satisfy a relationship:(2 n+0.7)×&pgr;<&phgr;2−&phgr;1(2n+1.3)×&pgr;, where n is an integer; and an amplitude intensity I 1of light reflected from the record mark in the optical information recording medium and an amplitude intensity I2of light reflected from a non-record mark region with respect to incident laser beam at the wavelength λ2(nm) satisfy a relationship:I 1