Modulated light video recorder - uses modulation by variation of scanning speed at full intensity to avoid beam power loss

摘要

An optical method for recording video signals is esp. by means of a modulated laser light beam tracing a spiral track on a recording medium. The power loss involved in intensity modulation by passing the beam through a variable stop aperture is avoided. The modulation is effected by varying the time of exposure whilst maintaining full intensity of the beam. This may be effected by continuous variation of the relative velocity of beam and recording base caused by deflection of the beam backwards or forwards along the direction of the track. The rigid, rectangular body (23) has a mirror (22) on one side. A piezoelectric oscillator (20, 21) is mounted at opposite ends of the body (23). An apparent widening of the approaching beam (26) leads to the formation of the recording bundle (27).