Abstract: A recording medium utilizing metal azides as an energy amplifying substance is disclosed. A photosensitive material comprises an energy absorptive dye and a metal azide dispersed in an inert binder. Low to moderate pulses of laser light cause the azide particles to react exothermally creating a void in the photosensitive material which can be read by an optical readout device.

Abstract: An optical playback system for reading data from a record includes a focusing system for focusing a scanning light beam onto data on the record without need for precision positioning of the record and optical elements of the system. The light beam is modulated by the data and then transmitted to a light detector to produce a playback data signal corresponding to the recorded data. The focusing system includes a source of light having an axially symmetric intensity distribution and a lens designed to focus such light into a focal zone with a specified intensity distribution along the zone. This distribution is preferably uniform so as to provide the detector with a modulated light beam of uniform average intensity regardless of the position of the record along to focal zone .

Abstract: Recording and playback optical scanners are relatively movable with respect to each other and with respect to a movable recording medium such as reel of tape adapted for recording variations in applied light. The playback scanner reproduces recorded information at a time delayed with respect to the time of recording, wherein the amount of delay can vary within wide limits. When the playback scanner is moved relative to recording scanner, the playback rate will be faster or slower than the recording rate.

Abstract: A track intercept apparatus is described for use in an optical playback machine which plays back data recorded on an optical record in track segments. The apparatus deflects the scanning light beam of such machine so that the light beam intercepts each selected track segment properly when the scan is initiated. A track intercept control circuit is employed having storage means for storage of variable values of track alignment data, adjust means for producing an adjustment signal corresponding to the stored data which is applied to a light beam deflection means, and timing means for controlling gating circuitry and for coordinating events within the circuit with the operation of the playback machine as a whole. One embodiment of the invention includes a circuit which compensates for track-following corrections made during scanning by returning the scanning light beam to a stored starting position. Another embodiment has a circuit for electronically aligning the scanner optics.

Abstract: Recording and playback optical scanners are relatively movable with respect to each other and with respect to a movable recording medium such as reel of tape adapted for recording variations in applied light. The playback scanner reproduces recorded information at a time delayed with respect to the time of recording, wherein the amount of delay can vary within wide limits. When the playback scanner is moved relative to recording scanner, the playback rate will be faster or slower than the recording rate.