BigPatents India

An optical disk has transparent substrate layer provided at light incidence side, first information layer which has first groove of first depth, adhesive layer provided on the first information layer, and second information layer which has second groove of second depth that is deeper than the first depth, and irreversibly records information therein, wherein the first depth and the second depth are /2n or less, the width of the first and second grooves is 0.3 )m or less, the track pitch of the first and second grooves is 0.45 m or less, the first and second information layers include organic dye material having light absorption in the range of the wavelength X of laser beam for use in recording and reproducing information from 390 nm to 420 nm.