Optical play-back system for recorded signals with oscillating beam

Abstract

This invention relates to a system for optically playing back recorded signals from a recorded medium on which signals of images or sounds are continuously recorded so as to constitute a signal recorded line or signal track. In play-back the images or sounds are optically recognized by the width-change of the signal recorded line. A narrow light beam for the play-back is deflected at a predetermined frequency in the direction perpendicular to the signal recorded line, i.e. in the direction of the width of the signal recorded line, in order to perform the optical scanning. The narrow light beam which is reflected or transmitted on the recorded medium surface reaches photo-sensitive elements such as photo-diodes. Electrical outputs obtained from the photo-sensitive elements are relatively compared with electric signals (standard pulses) obtained from fundamental electric signals for deflecting the said narrow light beam at a predetermined frequency, so that the amplitude of the recorded signal at each differential point of the signal recorded line is continuously detected as length-amount, and a modulated wave is continuously obtained from the length-amount. The modulated wave is further decoded, compensated, and amplified so as to obtain the play-back signals corresponding to the continuous width-change of the signal recorded line. The play-back system is provided with a tracking mechanism by which the play-back mechanism can follow the signal recorded line, and an interval adjusting mechanism for maintaining the vertical interval between the play-back mechanism and the signal recorded line uniform.