Record playback apparatus for optical data records

摘要: Multi-layered optical data records and playback apparatus are described in which a plurality of layers provided on at least one side record substrate the scans tracks such with light beam to produce an electrical readout signal corresponding scanned tracks. The includes selection means for selectively playing back different ones layers. track may be formed by lines spots binary coded digital information or frequency modulated pulse length analog photographically recorded extremely high density so that they used audio video signals including television signals. While transparent, preferably reflective source associated focusing scanning supported same as detector provide more compact apparatus. This also enables some elements transmitting reflected from record. Selection accomplished changing focus layer another, making optically materials, using color dyes photoluminescent positioning filters front detectors.