Abstract: The present invention provides an optical data storage medium prepared by laminating face-to-face two substrates, at least one of which has a recording layer provided thereon, such that the recording layer faces inwardly, wherein the color difference between the two substrates is 10 or more. Alternatively, the present invention provides an optical data storage medium prepared by laminating face-to-face two substrates, at least one of which has a recording layer provided thereon, such that the recording layer faces inwardly, wherein optically recognizable different patterns are provided on the two substrates. Since the colors or the patterns on the two substrates are different, the two substrates are easily distinguishable from each other.

Abstract: A near-field optical recording medium comprises a recording layer capable of writing, reading and erasing information using an evanescent light, the evanescent light having a beam spot size smaller than the wavelength of a source light, wherein the recording layer is a stable amorphous layer mainly comprising a photochromic compound having a glass transition point of 55° C. or higher and a molecular weight of 3000 or less.

Abstract: A method for recording and reproducing a data into and from an optical recording medium, includes the steps of: reading blocks having a predetermined size of byte unit arranged in a pre-set number of rows and columns in an optical recording medium in a zigzag direction and rearranging the read blocks; recording the rearranged data in the optical recording medium; reading the data recorded in the optical recording medium: and reproducing the read data.

Abstract: An optical tape including an optical recording layer for permitting information to be optically recorded thereon and a light-reflective magnetic layer; the light-reflective magnetic layer which reflects light projected onto the recording layer, also permits magnetic recording or magneto-optical recording to be performed thereon, thereby increasing a storage capacity of the optical tape remarkably; further, the optical tape is provided with a layer to form guiding grooves for tracking control, which layer to form guiding grooves is made up of ultraviolet-hardening resin, photo-resist, or a photochromic material.

Abstract: In an optical pickup apparatus, including a laser source (11) arranged along an optical axis (0-0'), a polarization beam splitter (14) and an objective lens (13), wherein light emitted from the laser source (11) is emitted on a recording plane (1a) of an optical-magnetical recording media (1) as a converged beam, light beams reflected from the recording media (1a) of the optical-magnetical recording media (1) are separated by said polarization beam splitter (14) to obtain a predetermined polarized light component, a phase change means, which changes a phase of light passing through one side of said optical axis (0-0') and a phase of light passing through another side of said optical axis (0-0') by a predetermined angle, such as 1/2 wavelength plate (15), a phase retardation type prism (39) and a combination optical rotation plate (52), is provided between the polarization beam splitter (14) and the objective lens (13), and, an optical detection element, which detects the light polarized by the polarization be

Abstract: A recording/reproducing apparatus for an optical tape for optically recording and reproducing information on an optical tape having a thermal converting layer. An optical pickup is divided into two separate parts, one for recording and the other for reproducing, and has an erasing device for optically erasing with the optical pickup for reproducing. The optical pickup for reproducing has a collimating lens for collimating the divergent light beam of a laser diode for reproducing or erasing the information group recorded on at least one track of the optical tape at the same time, a cylindrical lens for focussing the collimated light beam in the vertical direction, and a photodiode array for detecting light reflected from the tape. Also, the optical pickup for reproducing employs an aperture having a square hole for effectively focussing the light beam.

Abstract: An optical recording system in which the optical head is operated in physical contact with the surface of the optical recording medium during system operation at a selected operating speed. The optical head includes one or more optical elements mounted on a substrate which is in physical, sliding contact with the recording medium. The substrate is fabricated from a crystalline material which has a non-linear load versus friction characteristic in the negative load region. When the head is in sliding contact with the recording medium surface, a restoring force is generated which maintains the optical head in physical contact with the recording medium overcoming any lifting forces generated by the moving air layer adjacent the recording medium surface. This allows the head to be operated with a negative external load applied.

Abstract: An optical recording apparatus employing a plurality of modulated laser beams as means for recording information on an optical recording medium, comprising a laser beam source which emits a laser beam, a plurality of carrier sources which generate carriers respectively of different frequencies, a plurality of switching circuits respectively connected to the carrier sources to interrupt the carriers intermittently for modulation according to information data signals applied respectively thereto to provide driving signals, an acoustooptic reflector which splits the laser beam into a plurality of discrete laser beam intermittently interrupted respectively according to the driving signals, a focusing lens for focusing the plurality of discrete laser beams on spots on the recording surface of a recording medium, and a polygonal rotating mirror disposed between the acoustooptic deflector and the focusing lens to reflect the plurality of discrete laser beams so as to sweep the recording surface of the recording medi

Abstract: A servo control circuit for an image rotator used in an optical tape recording apparatus that employs a rotary tape drum. Pairs of pulse generators and frequency generators are provided on the image rotator and on the tape drum, respectively. Initially, the pulse generators are used for servo control and, upon detecting a phase lock, servo control is subsequently switched over to be controlled by the frequency generators.

Abstract: A laser diode (4) emits a beam which is reflected by a plane mirror (12) and by a spherical focusing mirror (2) in order to form a beam (40) which is focused on a read window which is a segment of a read line (6). Said line extends transversely relative to a film (16) running over a drum (20) which rotates about an axis (22). The window occupies the width of the soundtrack on the film. The light passing through said soundtrack is received by a photo cell (34) which provides the sound signal. The invention is particularly applicable to sound motion pictures.

Abstract: An optical information carrier includes a cylinder (1) with a recording layer (2) and bushings (3,4) located at butt ends of the hollow cylinder (1) and insulating the recording layer (2) from the environment. A method for erasing information recorded on the optical carrier uses a high-frequency electrical discharge produced inside the air-tight closed space (5) of the hollow cylinder (1). An optical storage device realizing the method includes an erasing unit (11) having a circuit for initiating a high-frequency discharge, which has electrodes (12,13) between which the optical carrier (10) is located so that the high-frequency discharge is initiated inside the closed air-tight space (5).

Abstract: An optical information carrier includes a cylinder (1) with a recording layer (2) and bushings (3,4) located at butt ends of the hollow cylinder (1) and insulating the recording layer (2) from the environment. A method for erasing information recorded on the optical carrier uses a high-frequency electrical discharge is produced inside the air-tight closed space (5) of the hollow cylinder (1). An optical storage device realizing the method includes an erasing unit (11) having a circuit for initiating a high-frequency discharge, which has electrodes (12,13) between which the optical carrier (10) is located so that the high-frequency discharge is initiated inside the closed air-tight space (5).

Abstract: Disclosure is made of an optical memory wherein a cylindrical information carrier (2) is disposed in a stationary cylindrical container (14) filled with a liquid or gaseous medium transparent for the radiation flux emitted by a source (1) of modulated coherent radiation. The cylindrical information carrier (2) is equipped with a rotational drive. A recording coating (12) is applied on a tubular base (11) of the cylindrical information carrier (2). The cylindrical information carrier (2) is optically connected with the source (1) of modulated coherent radiation and with an addressing unit (3) arranged so that its optical elements can move axially with respect to the cylindrical information carrier (2).

Abstract: Disclosure is made of an optical storage device wherein a cylindrical information carrier (2) with a recording medium (12) applied on a tubular base (9) is disposed in a stationary cylindrical container (3) having a window (4) in the lateral wall thereof. A lens (5) is secured in the window (4) of the cylindrical container (3) to let through the radiation flux from a source (1) of modulated coherent radiation. The cylindrical container (3) is filled with a liquid or gaseous medium transparent for the radiation flux. The length of this cylindrical container (3) is at least twice as long as that of the recording coating (12) applied on the tubular base (9) of the cylindrical information carrier (2) equipped with drives for rotation and axial motion.

Abstract: An apparatus for controlling the monoplanar motion of an object, more in particular a tape containing optically readable information, comprising two opposite clamping means on either side of the object. The object as well as at least one of the clamping means are accommodated within a dustproof case. One of the clamping means can be moved relative to the other by generating an (electro)magnetic field outside the case.

Abstract: An optical transducer system reproduces a videodisk record by rotating the disc at a low speed. A record guiding means is comprised of a ribbed gate region. The ribs engage the disc on opposite margins of the optical images recorded on the disc and extend in a circumferential direction.

Abstract: A method and apparatus are provided for converting into digital form the analog ultrasonic echo signals received as a result of cyclically transmitted ultrasonic search signals intercepting an acoustic discontinuity in a workpiece. The ultrasonic echo signals are divided into a discrete number of raster-like scan lines which are scanned electronically by a microprocessor. Digital signals are generated for each line of the raster-like scan and such signals assume either a first or second state along the scan line in accordance with the signal amplitude along that line. As successive scans are made at progressively higher amplitudes of the echo signal, the amplitude required for varying the digital signal between the states for a particular scan line is incrementally increased with each scan line. A comparator receives at a first input the echo signals and at a second input a signal from a digital-to-analog converter whose output is incrementally increased on successive scan lines by the microprocessor.