Optical discs compatible with two different reading systems

摘要

The present invention relates to an optical disk constituted by two basic disks (D1, D2) adhered to each other by a transparent adhesive layer (3). The first basic disc includes the information surface (4b) according to the DVD standard, and the second basic disc includes the information according to the CD standard. The optical disc can be read by the CD player for the CD information and read by the DVD player for the DVD information. Therefore, the problem of cost and other difficulties for enhancing the compatibility of the DVD player is solved while ensuring a simple and smooth change from the CD disc to the DVD disc for the consumer.