: A film of acrylic lacquer seals the reflective layer to prevent corrosion and physical damage. How It Works
: Microscopic depressions called pits and flat areas called lands are pressed into the plastic. audio compact disc
CD players use a to scan the disc from the center outward along a spiral track. When the laser hits a pit , it scatters the light; when it hits a land , the light is reflected back to a sensor. The sensor translates these light changes into electrical signals (zeros and ones), which are then converted back into high-fidelity audio. The Compact Disc: An Introduction : A film of acrylic lacquer seals the
A standard audio CD is a 120 mm (4.7 in) circular disc composed of several layers: When the laser hits a pit , it
: A thin coating of aluminum (or gold) reflects the laser beam used for reading.
: A 1.2 mm thick layer of clear polycarbonate plastic .
The , officially known as Compact Disc Digital Audio (CD-DA) , is a digital optical disc data storage format. Co-developed by Sony and Philips and commercially introduced in 1982 , it revolutionized the music industry by offering superior sound quality, durability, and portability compared to analog formats like vinyl and cassettes. Technical Design & Functionality