| 摘要 |
An optical disc includes a first substrate having a first surface having a first recording layer formed thereon, a first reflective film formed on the first recording layer, a second substrate having a second surface and a third surface on both sides with a second recording layer and a third recording layer formed thereon, respectively, a second semi-transparent reflective film formed on the second recording layer, a third semi-transparent reflective film formed on the third recording layer, an adhesive layer provided between the first and second reflective films, and a transparent cover layer having a fourth surface and a fifth surface on both sides, formed on the third semi-transparent reflective film at the fourth surface. The first recording layer is capable of storing first data in compliance with first specifications. The second recording layer is capable of storing second data in compliance with the first specifications. The third recording layer is capable of storing third data in compliance with second specifications different from the first specifications. The second semi-transparent reflective film has a thickness in the range from 5 nm to 15 nm. The transparent cover layer has a thickness of 100 mum±3 mum. The cover layer allows a laser beam to pass therethrough via the fifth surface in reproduction of the first, the second or the third data from the first, the second, or the third recording layer, respectively.
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