In computing, sound reproduction, and video, an optical disc is flat, circular, usually polycarbonate disc whereon data is stored. This data is generally accessed when a special material on the disc (often aluminum) is illuminated with a laser diode.
David Paul Gregg developed an analog optical disk for recording video and patented it in 1961 and 1969 (US patent 3430966). His company, Gauss Electrophysics, was aquired, along with Gregg's patents, by MCA in the early 60's. MCA released a consumer optical disc player called Discovision in 1978.
Jim Russell developed a digital optical disc for recording music in 1965 while he worked for Battelle in Richland, Washington. Since Battelle was not interested in pursuing this invention, Jim Russell worked with venture capitalist Eli Jacobs and, by 1974, was able to record video onto glass plates. That year several companies, including Sony and Philips, looked at this work but did not license the invention.
Philips and Sony formed a consortium in 1977 to develop a standardized digital audio disc, which resulted in the compact disc in 1979. Philips developed the general manufacturing process (Piet Kramer was the main inventor), based on their earlier Laserdisc technology, while Sony contributed the error-correction method.
The promotion of standardised optical storage is undertaken by the Optical Storage Technology Association (OSTA).
The information on an optical disc is stored sequentially on a continuous spiral track from the innermost track and outwardmost track.
Types of disc
There are many standards using optical discs: