Magneto-optical disk system with specified thickness for protective layer relative to the numerical aperture of the objective lens

An optical recording medium for use in an optical recording and/or reproducing apparatus having at least one light source for generating a light beam and at least one objective lens for converging said light beam on an optical axis thereof, the numerical aperture of said objective lens falling within a range of 0.55 to 0.70, said recording medium comprising:

• a first recording layer;
• a first light-transmitting cover layer provided on one surface of said first recording layer to cover said first recording layer and having a first light incident surface irradiated by said light beam through said objective lens;
• a second recording layer arranged parallel to said first recording layer;
• a second light-transmitting cover layer provided on one surface of said second recording layer to cover said second recording layer and having a second light incident surface irradiated by said light beam through said objective lens;
• and
• interconnecting means provided between said first and second recording layers for connecting said first recording layer to second recording layer,
• wherein each thickness of said first and second light-transmitting cover layers falls within a range of 0.6 to 0.1 mm.