| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical disk substrate having excellent heat resistance, light resistance and low hygroscopicity, having satisfactory optical characteristics and made of a polymer having a low specific gravity and to provide an optical disk using the same. <P>SOLUTION: The optical disk substrate is formed by using a β-pinene polymer having a specific gravity equal to or higher than 0.85 and lower than 1.0 and ≥90% transmittance of light having 400 to 850 nm wavelength. <P>COPYRIGHT: (C)2008,JPO&INPIT |
