Optical recording media and information recording and reproducing units

Abstract

The present invention provides an optical recording medium using an amorphous-crystalline phase-change for recording and erasing, wherein reflectivity of an optical recording medium-constituting recording film in an amorphous state is larger than that of the optical recording medium-constituting recording film in a crystalline state, or wherein absorptivity of an optical recording medium-constituting recording film in an amorphous state is smaller than that of the optical recording medium-constituting recording film in a crystalline state.

What is claimed is: 
     
       1. An optical recording medium using an amorphous-crystalline phase change for recording and erasing of information, the medium comprising a substrate, a recording film, a dielectric film and a metal reflection film, the recording film comprising a composition of In x  Sb y  Te z  defined by a triangular area in a ternary diagram bounded by the points x, y, z of 22, 33, 45; 20, 37, 43; and 32, 40, 28 (in atomic %) and wherein the reflectivity of the recording film at the amorphous state is larger than that at the crystalline state at a wavelength of laser employed for recording and erasing.   
     
     
       2. An optical recording medium according to claim 1, wherein the dielectric film is one of Si 2  N 3 , AlN, SiO 2 , ZrO 2 , ZnS, Ta 2  O 5 , TiN, Cr 2  O 3 , GeN, TiO 2  and SiC films or one of their nonstoichiometric composition films. 
     
     
       3. An optical recording medium according to claim 1, wherein the metal reflection film is one of Ni-Cr alloy, Au and Al films. 
     
     
       4. An optical recording medium according to claim 1, wherein the wavelength of laser employed for recording and erasing is in the vicinity of 800 or 830 nm. 
     
     
       5. An optical recording medium using an amorphous-crystalline phase change for recording and erasing of information, the medium comprising a substrate, a recording film, a dielectric film and a metal reflection film, the recording film comprising one of In 22  Sb 33  Te 45 , In 22  Sb 37  Te 41 , In 20  Sb 37  Te 43 , and In 32  Sb 40  Te 28  and wherein the reflectivity of the recording film at the amorphous state is larger than that of the crystalline state at a wavelength of laser employed for recording and erasing. .Iadd.   
     
     
       6.  An optical recording medium using an amorphous-crystalline phase change for recording and erasing of information, the medium comprising a substrate, a recording film, a dielectric film and a metal reflection film, the recording film comprising a composition of In x  Sb y  Te z  defined by a triangular area in a ternary diagram bounded by the points x y, z of 22, 33, 45; 20, 37, 43; and 32, 40, 28 (in atomic %) and wherein the absorptivity of the recording film at the amorphous state is smaller than that at the crystalline state at a wavelength of laser employed for recording and erasing. .Iaddend..Iadd.7. An optical recording medium according to claim 6, wherein the dielectric film is one of Si 2  N 3 , AlN, SiO 2 , ZrO 2 , ZnS, Ta 2  O 5 , TiN, Cr 2  O 3 , GeN, TiO 2  and SiC films or one of their nonstoichiometric composition films. .Iaddend..Iadd.8. An optical recording medium according to claim 6, wherein the metal reflection film is one of Ni-Cr alloy, Au and Al films. .Iaddend..Iadd.9. An optical recording medium according to claim 6, wherein the wavelength of laser employed for recording and erasing is in the vicinity of 800 or 830 nm.   
     
     
        .Iaddend..Iadd.10.  An optical recording medium using an amorphous-crystalline phase change for recording and erasing of information, the medium comprising a substrate, a recording film, a dielectric film and a metal reflection film, the recording film comprising one of In 22  Sb 33  Te 45 , In 22  Sb 37  Te 41 , In 20  Sb 37  Te 43 , and In 32  Sb 40  Te 28  and wherein the absorptivity of the recording film at the amorphous state is smaller than that of the crystalline state at a wavelength of laser employed for recording and erasing. .Iaddend..Iadd.11. An optical recording medium according to claim 10, wherein the dielectric film is one of Si 2  N 3 , AlN, SiO 2 , ZrO 2 , ZnS, Ta 2  O 5 , TiN, Cr 2  O 3 , GeN, TiO 2  and SiC films or one of their nonstoichiometric composition films. .Iaddend..Iadd.12. An optical recording medium according to claim 10, wherein the metal reflection film is one of Ni-Cr alloy, Au and Al films. .Iaddend.