OPTICAL INFORMATION RECORDING MEDIUM AND RECORDING/REPRODUCING METHOD THEREFOR

摘要

An optical information recording medium (100) includes an information layer (011) on/from which information can be recorded/reproduced by irradiation with a laser beam (040).  The information layer (011) includes a reflecting layer (002), a first dielectric layer (003), a recording layer (005) the phase of which can be changed by irradiation with the laser beam (040), and a second dielectric layer (007) formed in order of mention from the opposite side to the side which the laser beam (040) strikes.  The recording layer (005) contains Ge, Sb, and Te.  If the atomic ratio of Ge, Sb, and Te contained in the recording layer (005) is expressed by GexSbyTez, x, y, and z satisfy 0.39=x<0.48, 0.02=y<0.11, 0.40=z<0.56, and x+y+z=1.  The thickness of the recording layer (005) ranges from 10 nm to 15 nm.  If R(%) is the ratio of the intensity of light reflected from the information layer (011) to the intensity of the laser beam (040) striking the information layer (011), Rc(%) is R when the recording layer (005) is in a crystalline state, and Ra(%)is R when the recording layer (005) is in an amorphous state, Rc and Ra satisfy 6.0=Rc/Ra=12.0 and 1.0=Rc=3.0.