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|1. (WO2018146905) OPTICAL DISC|
|Applicants:||PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
The present invention provides an optical disc which is configured so as to be formed by bonding a first information recording medium and a second information recording medium to each other and which allows information to be recorded and read from both sides thereof. Each information recording medium includes a substrate, one or more dielectric films and recording films formed on one side of the substrate, and a cover layer for protecting the dielectric films and recording films. Both information recording media are bonded to each other on the opposite side from the substrate surface on which the dielectric films and the recording films are formed. Of the bonding sides, which are the sides of the substrates where the information recording media are bonded to each other, at least one bonding side includes a recess dented in the thickness direction of the optical disc and a projection provided at a location in the recess separated by a prescribed distance or greater from the outer diameter end of the recess along the radial direction of the optical disc.