| 摘要 |
PURPOSE:To execute recording and reproduction by reducing an output of a laser beam, by executing the recording and reproduction through a recording layer which is laminated and provided on the surface of the recording layer. CONSTITUTION:An optical card 5 is formed by laminating a protective layer 21, a recording layer 22 and a substrate 23. The protective layer 21 records information by making it transmit through this protective layer 21 by a laser beam irradiated from an optical head and forming a pit on the recording layer 22, therefore, a transparent material is used. Since the information can be recorded and reproduced through a thin protective layer, an energy of the laser beam is scarcely absorbed, therefore, recording and reproduction can be executed by reducing an output of the laser beam by that portion.
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