device for reading out a plattenfoermigen informationstraegers, in optical form coded picture and / or sound signals is.

摘要

An apparatus is described for reading, by means of a beam of radiation, a disk-shaped information carrier which contains spirally arranged video and/or audio signals coded in optical form, which apparatus comprises a source of radiation and a radiationsensitive signal detector cell, the information carrier being disposed in the radiation path between this source and this detector cell. By providing at least one grating, consisting of radiation-transmitting and radiation-absorbing stripes and on which an image of part of the grating-shaped structure of the information track in the vicinity of the portion of this track to be read may be formed, and a radiation-sensitive detection system, an accurate indication of axial and radial displacements of the optical imaging system relative to the information carrier can be obtained.