| 摘要 |
<P>PROBLEM TO BE SOLVED: To easily attain enhancement of recording density by heightening an NA of an optical system of an optical head. <P>SOLUTION: A film consisting essentially of Ag, Cu, Ti or Ni which can form a film having a small particle diameter and low surface roughness is used for a reflection layer 102. Reflectance of a disk when a recording layer 105 is in a crystal state is made lower than the reflectance of the disk when the recording layer 105 is in an amorphous state to increase Ac/Aa (light absorbance in the crystal state/light absorbance in the amorphous state). <P>COPYRIGHT: (C)2005,JPO&NCIPI |
