To improve the recording density of a carrier by laminating two reflecting layers respectively carrying recording information as fine recess/ projections through a transparent layer so as to include silicon in one of the reflecting layers and aluminum in the other.
In the case of setting the two reflecting layers of mutually different reflected light bands respectively to be silicon and aluminum, at the time of reading the pit of a first reflecting layer, light of wavelength to be sufficiently reflected by this first reflecting layer is used but at the time of reading the pit of a second reflecting layer, light having a wavelength to be transmitted through the first reflecting layer and reflected by the second reflecting layer is used. By differentiating the materials of the respective reflecting layers like this, their reflected light bands are made respectively different reflecting layer. By adjusting the film thickness of each layer then, the light transmittance of each layer can be varied. In addition, a prescribed process is repeated while using a reflecting layer material with mutually different reflected-light band to obtain an optical disk with at least two layers of reflecting layers.
| WO/1987/002934 | STAMPING OPTICAL RECORDING MEDIA |
| JPH07214686 | GATE CUTTING MECHANISM OF MOLD FOR OPTICAL DISK |
IIDA TETSUYA
OGOSHI KUNIZO
YOKOZEKI SHINICHI
