Compact disk with anti-piracy marking, pressing mould and method of anti-piracy marking for compact disks

摘要

The compact disc comprises a substrate (1) carrying micro-grooves (2) on one of its faces. These micro-grooves correspond to information which is to be read from the disc by the disc player. On the opposite face of the disc (6), there are further micro-grooves which refract light of visible wavelength. The grooves on the reverse of the compact disc form a pattern which mark the disc and making it difficult to produce pirate copies. The set of grooves form an optical grating covering the whole surface of the disc. A press is also provided for applying this design to the surface of the disc.