A device for the thermomagnetic recording of information on a highly coercive magnetizable recording medium. For this purpose is used, for example, a video recorder of the "helical scan" or "transversal scan" type whose drum has a co-rotating mirror and system of lenses with which an energy beam is directed and focussed on the recording medium at a small distance in front of the recording gap of the magnetic head. As a result of this the coercive force of the recording medium is locally reduced while using a very short heating time so that the medium can be recorded there by the head.
An optical recording device for forming recording tracks of an indented pattern on a magnetic recording tape comprises a rotary drum which has at least two windows, the magnetic recording tape being driven obliquely on the windows along an outer surface of the drum, and an optical system, disposed inside the rotary drum, for converting a modulated laser beam incident on the optical system into two slit beams, major axes of sections of which form a predetermined angle and for emitting the slit beams on the magnetic recording tape through the windows, whereby the recording tracks of the indented pattern in correspondence with the signal are formed obliquely on the magnetic recording tape with respect to a longitudinal direction of the magnetic recording tape by the slit beams so as to form different azimuths between adjacent recording tracks.
A multiple track playback headwheel is disclosed for use in a helical scan optical tape recording system. The headwheel includes optical diffraction gratings at the center of rotation of the headwheel positioned normal to the rotational axis. A collimated light beam supplied from a laser external to the headwheel, directed along the rotational axis of the headwheel, is split into a plurality of beams by the gratings. The plurality of beams are imaged at the entrance pupil of the playback objective lens which focuses the beams to diffraction limited spots on the surface of an optical tape having information recorded thereon. The illuminated spots are reflected back through the objective lens and are formed into beams which are directed to an information and tracking detecting apparatus and to a focus detecting apparatus.
A magneto-optic recording system includes a scanning wheel head around which is wound a magneto-optic recording tape in spiral fashion. A first magnetic pole piece surrounds the tape outward of the wheel. A second pole piece extends between an aperture on the wheel opposite the tape to a point proximate the first pole piece and is coupled to source of magnetic flux. A light source is directed from inside the wheel toward the aperture and thus to the tape. The wheel, second pole piece, flux source and light source rotate together relative to the tape to direct a magnetic field to successive points of incidence on the tape.
