Optical tracking method and system.

摘要

An optical apparatus is described for use with a video disc (7) having frequency modulated video information (9) recorded thereon in the form of a plurality of concentric circles or a single spiral. The information track comprises successively positioned light reflective and light non-reflective regions (10, 11). A focused light beam (4) is caused to be positioned over the centre of an information track and the light reflected from the information track is gathered by an objective lens (17) for application to electronic circuitry (30) for recovering the recorded frequency modulated video signals. Servo means are described for handling the selective change of the intersection of the reading beam along the length of the track in the tangential direction on the video disc member in predetermined modes of operation whereby the reading beam leaves the following of a first track and jumps back one track to re-read the same track in a stop motion mode of operation.