Abstract

A five-layered phase change optical disk, which has a thin metal layer between the substrate and the lower dielectric layer, has been proposed by Kobori et al (1) and Nishimura et al (2). The light absorbance in a recording layer is able to be controlled by using the five-layered structure, so as to improve overwriting jitter at high linear velocity. The thickness of the lower dielectric layer of the five-layered disk was designed so that the reflectivity of the amorphous state (Ra) was higher than that of the crystalline state (Rc), thereby the absorptivity of the crystalline state (Ac) can be kept larger than that of the amorphous state (Aa). But the low reflectivity of the initialized state, that is crystalline state, causes servo instability.

© 1998 Optical Society of America