MFDigital CD DVD Information Library
Thursday, June 10, 2004
CD Construction
The compact disc comprises a sandwich. A 1.2 mm thick polycarbonate substrate containing pits moulded into the upper surface is coated with aluminum which is then protected by a lacquer on which the disc label is printed.

An infra red laser beam is focused on the pits through the clear optical grade polycarbonate plastic. Pits are embossed into the polycarbonate surface by an injection moulding process.

The aluminum layer provides a reflective surface which is protected from corrosion and damage by a lacquer on which a disc label can be printed.