| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical information recording medium, the substrate of which warps little in both the radial direction and circumferential direction and is reduced in the increase of birefringent phase difference in its innermost section. <P>SOLUTION: This optical information recording medium is constituted, by sticking at least a first optical disk substrate and a second optical disk substrate to each other. In the clamping area 2 of at least either one of the first and second optical disk substrates, a recessed section 4 is formed around a center hole 3 and the disk substrates are stuck to each other so that the surface of the substrate having the recessed section 4 becomes the inside. Therefore, it is preferable that the surface roughness (Ra) of the recessed section 4 be adjusted to 3.0-15.0 nm, and the section 4 be formed on the outer periphery of the center hole 3. <P>COPYRIGHT: (C)2003,JPO |
