Optical disk compatible with two different reading systems

摘要

An optical disc comprising two elementary discs glued to each other by a transparent glue layer. The first elementary disc comprises an information surface according to DVD standard and the second elementary disc comprises an information surface according to CD standard. The present optical disc may be read by a CD player for CD information and by a DVD player for DVD information. The problem of costs and other difficulties for ascending compatibility of DVD players is therefore solved while assuring a simple and smooth transition from CD discs to DVD discs for consumers.