Abstract: An magneto-optical memory device for recording, reproducing or erasing information by applying an optical beam such as a laser beam onto a magneto-optical recording medium, the magneto optical memory device including a recorded region detecting circuit for detecting information recorded region formed in the recording medium. In the memory, a timing control for recording, reproducing or erasing is performed with the use of one result obtained through detection of a synchronizing signal such as a sector mark indicative of a starting point of an information block and another result obtained through detection in the recorded region detecting circuit.

Abstract: An optical memory storage media is described, e.g. a compact disc. A method of preparing the media (e.g. discs) is also taught. The storage media is formed from a substrate material having tightly bonded to the surface a highly reflective soft metal alloy formed of, for example, an alloy including at least five percent by weight of each of at least two metals selected from the group consisting of cadmium, indium, tin, antimony, lead, bismuth, magnesium, copper, aluminum, zinc and silver.

Abstract: A magneto-optical disk recording apparatus sequentially pulse-drive a plurality of semiconductor laser elements in a time-divisional manner so that spots of light are sequentially formed along a plurality of recording tracks of a magneto-optical disk with clock information recorded in advance along a plurality of recording tracks thereon. A magnetic modulating signal is generated by combining pieces of information desired to be recorded along the plurality of recording tracks so that a modulating magnetic field whose polarity is reversed in accordance with the magnetic modulating signal is applied to the plurality of recording tracks by means of a magnetic head.

Abstract: The present invention relates to an optical information medium for recording and reproducing information optically. Particularly, it is concerned with a so-called sample servo type optical information medium wherein an optical head traces over the center line of an imaginary track on the basis of information obtained from at least a pair of wobble pits disposed on both sides of the said imaginary track center line. A continuous groove is formed between the paired wobble pits along the imaginary track center line in a certain area of the optical information medium so that the deviation of each wobble pit from the imaginary track center line can be easily grasped and the conditions of the wobble pits being formed can be estimated. The quality of the medium being manufactured can be easily judged by the presence of such continuous groove.

Abstract: Sensor are widely used to read magnetic data and to read the magnetic and the optical patterns printed on notes and so on. A multichannel head in accordance with the present invention has plural magnetic cores arranged in a row and a cancellation core for noise removal, the head can detect magnetic characteristics as a whole in a stationary state without depending on the relative speed of the magnetic member with the head, and therefore is least affected by noise. Since one cancellation core is shared by plural magnetic cores, the structure as a whole becomes simple, and the cost of manufacture can be remarkably reduced. Since a magnetic head is combined with optical fibers in an integral structure according to this invention, it can read magnetic patterns and the optical patterns on the same location simultaneously by a parallel operation.

Abstract: An opto-magnetic recording apparatus for radiating a light beam onto an opto-magnetic recording medium. The opto-magnetic recording apparatus includes a magnet for generating a magnetic field for biasing the opto-magnetic recording medium while the same is irradiated by light, thereby recording information thereon. The opto-magnetic recording apparatus is adapted to receive the opto-magnetic recording medium in a direction extending substantially along a recording surface of the opto-magnetic recording medium. The opto-magnetic recording apparatus further includes a mechanism for removing the magnet from an insertion path when the opto-magnetic recording medium is inserted.

Abstract: A multiple-disk player which detects a time period during which for the player operates in the non-playback mode after the playback start command is issued and calculates a time period value on the basis of the difference between the current value of the time information datum read out of the disk and its preceding value; the detected non-playback mode time period is added to the playback time period to produce the total time period; and performs a fade-out operation for music being played back when such total time period reaches a given allowable time period. Consequently, it is possible to quickly and accurately check the fade-out operation even before all the pieces of music to be played back are actually played back.

Abstract: An optical disc consists of a base plate, a reflective thin layer, and a protective thin layer. The optical disc has a sample mark area having two sample marks, one of which is off-set on one side of a track, another of which is off-set at an opposite side of a track. These sample marks are produced by an injection molding with replica technique. At the time of the injection molding, additional pressure moves soft injected plastic resin, which causes double transcription of the sample marks. For preventing the double transcription, groove areas are provided on opposite sides of the sample mark area. The groove areas provide an anchor effect at the time of injection molding.

Abstract: Apparatus for playing-back information on a magneto-optic recording element includes a diffraction grating for splitting a read beam reflected from the recording element and modified by the recorded information into three beams. Two of such beams (i.e., the upper and lower first order diffracted beams) are used in a differential detection scheme to recover the recorded information, and the third beam (i.e., the zero order beam) is used to provide focus and/or tracking information.

Abstract: A record carrier for recording, reproducing and erasing information. A circular disc-like substrate has a recording layer thereon such that information is written onto the recording layer by changing the direction of magnetization. A guide groove of a plurality of tracks is formed in advance and extends in the radial direction with flat portions therebetween. Each flat portion between the tracks of the guide groove is divided into a plurality of sectors, each of which includes a header portion in which a header signal containing an address for distinguishing at least a respective sector is formed in advance with pits of a phase structure and a data portion adjacent to the header portion. The guide groove serves as an optical guide for a light beam which records, reproduces and erases information onto the data portion.

Abstract: An improved optical information recording and reproducing apparatus which is capable of detecting recording errors simultaneously with recording function for reduction of recording time, without requiring particular high accuracy for an optical system, and avoiding complication in the construction and consequent large size of the optical system.

Abstract: To reduce the size and thickness of a magnetooptic head, a single hollow cylindrical permanent magnet magnetized in the radial direction thereof is arranged at the center of a condenser lens. The axial component of the magnetic flux is available for an external magnetic field required for recording and erasing operations, while the radial component of the magnetic flux is available for a magnetic field required for focusing operation in cooperation with a cylindrical focusing coil arranged coaxially with the cylindrical magnet.

Abstract: In a magnetic field generating apparatus, a coil is wound around a core and a magnetic extending section is extended from the core member. The magnetic extending section is formed into a taper form and has a magnetic field applying surface. A magnetic flux generated in the core by supplying a current to the coil is led into the extending section and emerged from the magnetic field applying surface to an opto-magnetic memory. The magnetic flux penetrates the opto-magnetic memory and is returned to the core through a yoke.

Abstract: A recording head of a magneto-optical disk apparatus for recording and/or erasing an information signal on and from a magneto-optical disk mounted on the apparatus comprises optical pickup device disposed at a first side of the magneto-optical disk for producing an optical beam such that the optical beam is focused on the first side of the magneto-optical disk, pickup feeding mechanism provided on a frame of the magneto-optical disk apparatus for moving the optical pickup device along a path extending in a radial direction of the disk, a stepping motor disposed at a second side of the magneto-optical disk, the stepping motor having a housing containing a rotor magnet and a stator winding surrounding the rotor magnet, the rotor magnet including a plurality of elongated magnetic parts magnetized to either one of the N-pole and S-pole and arranged with alternate polarity about a rotary axis of the stepping motor such that each of the elongated magnetic parts extends parallel to the rotary axis, the rotor magnet

Abstract: An optical information recording carrier which comprises an information recording film susceptible to a change in atomic arrangement upon exposure to a recording beam, a first transparent film for preventing diffusion of heat generated in the recording film upon exposure to the recording beam and provided on each side of the recording film, a second transparent film for diffusing the heat in the in-plane direction of the film and provided on at least one outside thereof, and an organic member further provided on at least one outside thereof, the recording beam being irradiated onto the recording film through the organic member has distinguished characteristics of repeated recordings and erasings.

Abstract: A magneto-optical recorder comprising an optical head for projecting a light beam on a magneto-optical recording medium so as to form a light spot thereon, a magnetic head disposed at a predetermined distance from the optical head and applying a magnetic field modulated according to information to be recorded to the magneto-optical recording medium; and light intensity controlling means for varying the intensity of the light spot, responding to at least one of a focusing error signal indicating deviations of the light spot from the magneto-optical recording medium and a position signal indicating the relative position of the magneto-optical recording medium and the optical head, wherein, even if the intensity of the magnetic field applied to the recording medium varies, depending on vertical oscillations of the recording medium or on the position of the light spot, influences of variations in the intensity of the applied magnetic field are compensated by varying the intensity of the light spot so that fluctua

Abstract: An information recording medium comprises a plurality of record bands each having a plurality of information recording tracks arranged orthogonally to a direction of the track, and the record bands are arranged orthogonally to a direction of arrangement of the tracks. Identification fields are provided in the respective bands to allow identification of track groups.

Abstract: Optical information carrier comprising an optically transparent layer and a reflective layer adjacent to each other whereby the interface comprises an optically readable information structure containing alternate areas with such different properties, so that a scanning light beam is modulated in correspondence with the information present in said structure. Between the surface of optically transparent layer and the surface of the reflective layer, one or more gas-filled interconnected buffer spaces are provided at positions described over the interface between the layers, and an excavation is provided at the edge of the carrier.

Abstract: The bias magnetic field abnormality detecting apparatus is used in a photomagnetic recording and reproducing apparatus for recording information on a recording medium or for reproducing and erasing the information from the recording medium and is provided with a field magnetic coil generating a magnetic field in the reverse direction at the time of recording and erasing information but generating no magnetic field at the time of reproducing information. A magnetic field detecting circuit detects the polarity of at least the magnetic field of the field magnetic coil and detects whether the magnetic field is abnormal or not. A writing in protecting circuit prohibits the recording and erasing operations by the output of the magnetic field detecting circuit.

Abstract: A combination portable magnetic tape cassette player and multiband radio receiver in which the sensitive elements of the radio receiver are arranged within a hinged, plastic cover of the combined apparatus and the circuitry of the radio receiver is formed on a printed circuit board having an AM band antenna mounted thereto, whereby the AM receiver antenna is electromagnetically unshielded by the plastic cover and the combined tape player and radio receiver is of a size substantially equal to that of the tape player alone.