Laser beam recording of video master disks

A method for real time recording of video information on a disk by means of a laser beam is described. The laser beam is focused on a rotating substrate, covered with a thin film of positive photoresist. During exposure the laser beam is intensity modulated by means of an electrooptic modulator driven by the encoded video signal. After etching away the exposed areas of photoresist a master disk is obtained with pits, containing the video information in their periodicity and length. Such a master disk will serve as the source for generating submasters, stampers, etc. for the production of a large number of replicas as is usually done in the phonograph record industry.