| 摘要 |
PROBLEM TO BE SOLVED: To make an optical disk of large capacity by increasing surfaces of information carrier on which pits for information and laser beam guiding grooves are formed. SOLUTION: A double-sided information carrier 2 on whose both surfaces of a substrate pits for information and laser beam guiding grooves 10 are formed is arranged in an inner layer part and single-sided information carriers 3, 3' on whose single surfaces of substrates pits for information and laser beam guiding grooves are formed are arranged at outer sides of the double-sided information carrier 2. All information carriers are formed by a plastic injection molding method excellent in productivity. Since in the double-sided information carrier 2 of the inner layer part and the single-sided information carriers 3, 3', information are recorded or reproduced with a laser beam from surfaces of outer sides of the single-sided information carriers 3, 3', the sticking of the information carriers with each other are performed with adhesive by ultraviolet ray hardenable resin transmitting the laser beam. Moreover, the recording and the reproducing of the information carrier 2 and the information carriers 3, 3' are performed by using an optical system having two focal depths. |
