Abstract: A portable disc player has a casing. In the casing, there are enclosed: disc rotation driving means for rotating an optical disc; an optical head which is arranged so as to be movable in the radial direction of the optical disc; a signal processing section for executing a predetermined signal process to a signal which has been read out by the optical head; and control means for controlling the operations of the rotation driving means, the optical head, and the signal processing section on the basis of an input from an X-Y device and trigger buttons. A display unit comprising an outer cover on which an LCD display is arranged is rotatably attached to the casing.

Abstract: A circuit for simultaneously detecting both MO and ROM signals reflected from an optical disk so that both signals are present and useable without switching from one to the other. The circuit eliminates switching time and switching transients. Two photodetectors are arranged to sense P and S components of polarized light in order to stimulate a differential amplifier and produce an output representative of MO recorded data. A second amplifier is connected to at least one of the photodetectors to produce an output representative of ROM recorded data and also representative of defects in the MO portion of the optical disk.

Abstract: A mass storage device includes a media sheet supported on a substrate for storing digital data bit manifestations and a planar, integrated array of transducers arranged in rows and columns. The array is mounted in registration with the substrate, and its columns of transducers are oriented at an acute angle with respect to a movement axis. A piezoelectric device provides relative movement between the substrate and the array of transducers along the movement axis. Circuitry accesses rows of transducers in each column in a timed manner, so as to operate each transducer in a column at the time the transducer is adjacent a row of stored digital data in the media sheet. The acute angular relationship between the transducer array and the movement axis enables digital data to be stored in the media sheet in a fraction of the surface area occupied by an individual transducer and its associated circuitry.

Abstract: An optical disk drive is located in a housing having a centrally pivoted door. An optical disk cartridge is inserted into the drive and is received by a sealing member. The cartridge and sealing member divides the interior of the drive into two compartments. The first compartment contains the electronics which need to be cooled and the second compartment contains the optical elements. The door and sealing member allow airflow in the first compartment but prevent it from reaching the second compartment. An airfoil is positioned over the optical elements in the second compartment to protect them from airflow developed by the spinning disk.

Abstract: A tracking method for reading/writing data with respect to an optical recording medium having clock tracks each formed of clock bits of optical patterns and data tracks. The method is carried out by irradiating from an optical lead side a pair of light beams onto a pair of clock tracks, with the beams so deviated from each other in a direction of relative movement of the optical head with respect to the medium that beam detection signals may have a difference in phase therebetween. Reflections of the respective light beams from the clock tracks are detected and a difference signal between reflections determined from the detection signals is obtained. A tracking-error signal from the difference signal is extracted and a zero-crossing point of the difference signal then is detected to extract a clock signal.

Abstract: The optical path difference between two reflecting surfaces of an etalon 2 is monitored by directing a light beam B onto the etalon, directing the reflected beam Ba from the etalon onto an optical reference wedge 3 and directing the reflected beam Bb from the wedge onto a linear photo-detector array 4. The position along the array 4 of a peak of light intensity represent the location of an interference maximum and corresponds to reflection of light at that position along the length L of the wedge 3 at which the optical path difference of the wedge equals the optical path difference of the etalon being measured. The etalon 2 may comprise a data carrier encoded by variations in its relief (and therefore in its optical path difference), which data carrier may comprise a rotatable disc and the apparatus may comprise an optical head movable radially of the disc to read different concentric tracks.

Abstract: An optical system is described for use in processing information on a surface of an erasable record disc. The system decreases erasure time by forming an elongated spot from the generally circular cross section of a collimated laser beam so as to provide increased illumination time to an area recorded on the disc. The system includes a source of collimated light having a generally circular cross section, a cylindrical lens for focusing one aspect of the collimated light at a finite distance f, and a beam expander having the principal plane of its input lens at the distance f from the cylindrical lens, where the light forms a beam waist. An objective lens focuses the expanded elongated beam to a diffraction spot on the surface of the record disc. A linear actuator, such as a voice coil, responds to a control signal to position the cylindrical lens in the path of the collimated light beam for the erasing process, or out of the light path for the recording process.

Abstract: A case provided with an information carrier consisting of a tape, one side of which has a structure carrying optically readable information as well as an apparatus for writing, reading or erasing such information. In the dustproof case containing a tape having on one side a structure carrying optically readable information, the tape is accomodated on two reels. The case is provided with one window through which a part of the tape between the reels is visible and with pressing means for urging that visible part of the tape against the window. This pressing means may be a wheel and the window may have the shape of a cylindrical lens.