Optical recording
The history of optical recording can be divided into a few number of distinct major contributions. The pioneers of optical recording worked mostly independently, and their solutions to the many technical challenges have very distinctive features, such as
- reflective disc (Compaan and Kramer)
- transparent disc (Gregg)
- floppy disc (Russell)
- rigid disc (Compaan and Kramer)
- focused laser beam for read-out through transparent substrate (Compaan and Kramer).
Gregg 1958
Russell 1965
While working at Pacific Northwest National Laboratory, James Russell invented an optical storage system for digital audio and video, patenting the concept in 1970.[4]
The earliest patents by Russell, US 3,501,586, and 3,795,902 were filed in 1966, and 1969. respectively.[5][6] He built prototypes, and the first was operating in 1973.
Russell had found a way to record digital information onto a photosensitive plate in tiny dark spots, each spot one micrometre from centre to centre, with a laser that wrote the binary patterns. Russell's first optical disc was distinctly different from the eventual compact disc product: the disc in the player was not read by laser light. A key characteristic of Russell's invention is that a laser is not used for the reading the disc, instead the entire disc or oblong sheet to be read is illuminated by a large playback light source at the back of the transparent foil. As a result, the information density is relatively low.
By 1985, Russell held over 25 patents to various technologies related to optical recording and playback.[7] Russell's intellectual property was purchased by Optical Recording Corporation (ORC) in
In the 1970 patent, the spot diameter was around 10 micrometres. Thus, the areal information density was around a factor hundred less than that of the CD as later developed. Russell continued to refine the concept throughout the 1970s.[4] Philips and Sony, however, were able to put far greater resources into the parallel development of the concept, arriving at a smaller and more sophisticated product in just a few years. Russell's various partners and ventures failed to produce a single consumer product.[8]
Korpel 1968
Adrianus Korpel[9] worked for the Zenith Electronics Corporation, when he developed very early optical videodisc systems, including holographic storage.[10][11]
Kramer and Compaan 1969
The Philips development of the videodisc technology began in 1969 with efforts by Dutch physicists Klaas Compaan and Piet Kramer to record video images in holographic form on disc.
Immink and Doi 1979
The
Standard CDs have a diameter of 120 mm and can hold up to 80 minutes of audio (700 MB of data). The
See also
References
- ^ U.S. patent 3,430,966 Transparent recording disc, 1969.
- ^ U.S. patent 3,530,258 Video signal transducer, 1970.
- ^ U.S. patent 4,893,297 Disc-shaped member, 1990.
- ^ a b "Inventor of the Week Archive: The Digital Compact Disc". Massachusetts Institute of Technology. Archived from the original on 2003-04-17.
- ^ U.S. patent 3,501,586 Analog to digital to optical photographic recording and playback system, March 1970.
- ^ U.S. patent 3,795,902 Method and apparatus for synchronizing photographic records of digital information, March 1974.
- ^ "The Invention of Optical Digital Recording with James T. Russell". Audio Engineering Society.
- ^ ISBN 978-0-7614-7761-7.
- ^ "ADRIAN KORPEL, FICTION AND SCIENCE". user.engineering.uiowa.edu.
- ^ U.S. patent 3,585,848 Method and Apparatus for Recording Acoustic Images and Holograms, June 1971.
- ^ U.S. patent 3,931,459 Video disc, Jan. 1976.
- ^ U.S. patent 4,041,530Video disc with phase structure, 1977.
- ^ U.S. patent 5,068,846Reflective optical record carrier, 1991.
- ^ Kees A. Schouhamer Immink (2007). "Shannon, Beethoven, and the Compact Disc". IEEE Information Theory Newsletter: 42–46. Archived from the original on 2014-11-04. Retrieved 2009-03-15.
- ^ Compact Disc hits 25th birthday