Abstract: In a method of reproducing information from an optical disk, the disk is scanned with a laser beam forming a light spot on the disk, at least some of the recording pits being smaller in size than the light spot, the laser beam heating the disk so that effective detection area being formed at only part of the light spot, a sequence of preformatted pits of a minimum size are formed, playback signals are produced in accordance with a reflected light from the disk, and a power of the laser beam is so controlled so as to maximize the level of the playback signals produced from the reflected light from the sequence of pits of the minimum size. In another method using a magneto-optical disk, information is recorded by scanning the disk with a laser beam, each of the recording pits being substantially crescent-shaped, the direction of rotation during playback is opposite to the direction of rotation during playback, and the order of bits forming the information is reversed either during the playback or recording.

Abstract: The second harmonic wave of a solid laser light which is emitted from a second harmonic wave light source is divided into a plurality of laser beams by a diffraction grating. The divided laser beams are converged on a record carrier into a plurality of light spots by an optical head. Magnetic field generating coils for applying magnetic fields to the respective light spots in accordance with the recording signals from a signal line are disposed under the record carrier. Part of the solid laser light is reflected and input to a beam splitter. Since part of the light input to the beam splitter is taken out, a stabilizer controls the output of the solid laser light from the second harmonic wave light source, parallel recording/reproduction using the plurality of light spots which are arranged on the record carrier is enabled and the formation of the plurality of light spots is effectively controlled.

Abstract: An optical recording apparatus which reduces light loss by expanding the laser beam diameters irradiated from a plurality of beam sources, and reducing the expanded beam diameters immediately before focusing the beams onto an information recording/reproducing medium to make the beams circular, thereby minimizing deviation of the laser beam from the optical axis.An optical system for use in recording apparatus with a multi-beam optical head provided with a plurality of laser beam sources in a fixed unit which reduces light loss by minimizing deviation of the laser beam from the optical axis, and also by maintaining the laser power of each laser beam at a predetermined intensity independent of changes in distance between the fixed unit half and the moving unit half of the optical system by detecting intensities of the laser beams focused on a recording medium.

Abstract: An optical recording apparatus which reduces light loss by expanding the laser beam diameters irradiated from a plurality of beam sources, and reducing the expanded beam diameters immediately before focusing the beams onto an information recording medium to make the beams circular, thereby minimizing deviation of the laser beam from the optical axis. An optical system for use in recording apparatus with a multi-beam optical head provided with a plurality of laser beam sources in a fixed unit which reduces light loss by minimizing deviation of the laser beam from the optical axis, and also by maintaining the laser power of each laser beam at a predetermined intensity independent of changes in distance between the fixed unit half and the moving unit half of the optical system by detecting intensities of the laser beams focused on a recording medium.

Abstract: An optical head which optically records and regenerates data by condensing light beams from a light source on the disk surface, wherein a plurality of piezoelectric elements are arranged to correct the tilt of a condensing lens or the tilt of optical system supporting means for making the optical axis of the condensing lens for condensing light beams on the disk surface or the light beams orthogonal to the disk surface.An optical disk drive provided with an optical head, wherein a plurality of piezoelectric elements are arranged to correct the tilt of the disk for making the optical axis of a condensing lens which condenses light beams on the disk surface orthogonal to the disk surface.