Patent ID: 6768712
Filing Date: 2004-07-27
Classification: G11B

Abstract:
An optical disk having an individual recognizing function, said optical disk comprising:a first substrate having a first principal surface; a second substrate having a second principal surface; an adhesive layer which is sandwiched between the first principal surface of said first substrate and the second principle surface of said second substrate, and to which said first substrate and said second substrate are adhered; and a ring disk-shaped main-information area to which main information is recorded or is read by laser beams, said ring disk-shaped main-information area being provided on at least one of said first principal surface and said second principal surface, wherein at least one of said first principal surface and said second principal surface has an individual recognizing area to which identification information for uniquely recognizing said optical disk is recorded to at least one of an inner-circumference portion and an outer-circumference portion relative to said main-information area on said substrates when said optical disk is perspectively viewed in the vertical direction of said first principal surface and said second principal surface, before adhering said first substrate and said second substrate, and in said individual recognizing area, after adhering said first substrate and said second substrate to said adhesive layer, said identification information can be read but cannot be recorded and changed by using the laser beams used for recording or reading the main information of said main-information area.