198050 ⎘
Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation , reproducing using an optical beam at lower power ; Record carriers therefor; Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection; Arrangements for positioning the light beam only without moving the head, e.g. using static electro-optical elements using acousto-optical elements