| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk structure body that is inexpensive or friendly to environment. SOLUTION: The disk structure body has a stuck structure of a disk substrate [A] having 0.3-0.9 mm thickness and a disk substrate [B] having 0.9-0.3 mm thickness, one recording layer of compact disk families on the surface of the substrate [A] opposite to the substrate [B] and nearly 1.2 mm thickness of the total substrates, wherein the disk substrate [A] consists of resin having <=30,000 pieces/g foreign matters having >=0.5 μm and <1.0 μm particle size and <=1 piece/kg foreign matter having >=50 μm particle size and the disk substrate [B] consists of resin having more foreign matters having >=0.5 μm and <1.0 μm particle size than the resin substrate [A] and <=20,000,000 pieces/g foreign matters having >=0.5 μm and <1.0 μm particle size, <=1 piece/kg foreign matter having >=100 μm particle size and >=80% light transmittance in 780 nm wavelength. |
