Abstract: A ROM-RAM recording medium includes a ROM portion in which main information is recorded by a physical change on an optically transparent substrate and a RAM portion formed on the ROM portion as a recording layer that allows writing of main information at least once. The ROM portion is provided with a sub-code area for recording sub-information. A sub-code area for recording sub-information is provided in the RAM portion arranged at physically substantially the same position as the sub-code area of the ROM portion in a track direction.

Abstract: A phase compensation method uses a phase plate to compensate for an optical phase of a reproduced signal in a reproducing optical system which is provided with respect to the reproduced signal from an optical recording medium. The position of the phase plate is controlled within a predetermined variable range depending on a type of the optical recording medium, so that a CNR of a reproduced signal becomes a maximum or, a DC fluctuation of the reproduced signal becomes a minimum or, a crosstalk level from adjacent tracks becomes a minimum.

Abstract: A ROM-RAM recording medium includes a ROM portion in which main information is recorded by a physical change on an optically transparent substrate and a RAM portion formed on the ROM portion as a recording layer that allows writing of main information at least once. The ROM portion is provided with a sub-code area for recording sub-information. A sub-code area for recording sub-information is provided in the RAM portion arranged at physically substantially the same position as the sub-code area of the ROM portion in a track direction.

Abstract: A miniaturized optical disc memory is receivable in a slot, of about 17 mm height, normally accommodating a floppy disc drive. A base includes a base plate with integral, peripheral sidewalls and an internal lateral partition wall which define a cartridge receiving slot on the upper surface of the base plate. First and second support plates extend from the partition wall to the rear peripheral sidewall of the base and define respective, first and second upper mounting surfaces and lower first and second cavities respectively receiving an ejection motor and a fixed optical system, individual optical components being mounted and aligned on integral, precision machined blocks in the second cavity for transmitting a laser beam and receiving a reflected beam along a central, longitudinal optical axis beneath the base plate.

Abstract: An optical storage device including a carriage movable in the radial direction of an optical storage medium, a light source, a first lens fixed to the carriage for focusing a light beam emitted from the light source onto the optical storage medium, a second lens interposed between the first lens and the light source, a beam splitter for reflecting at least a part of the light beam transmitted through the second lens in a direction perpendicular to the optical storage medium, and an actuator for supporting the second lens so that the second lens is movable in a given direction. The actuator includes an actuator base fixed to the carriage, a lens holder for holding the second lens so that the optical axis of the second lens extends in a direction substantially parallel to the optical storage medium, a supporting mechanism for movably supporting the lens holder to the actuator base, and a driving mechanism for moving the second lens in the above given direction.

Abstract: A magneto-optical memory device includes a first unit projecting a light beam onto a desired position on a recording medium, and a second unit applying a magnetic field to a position onto which the light beam is projected. The second unit applies, to the recording medium, a predetermined magnetic field within a magnetic field intensity range wherein a rate of change of a reproduced signal amplitude at the time of reproduction with respect to a magnetic field intensity becomes large. The relative positions of the second unit and the first unit are adjusted in accordance with a reproduced signal amplitude thus obtained.

Abstract: Disclosed herein is an optical storage device having an objective lens actuator for moving an objective lens in a focusing direction. The objective lens actuator includes an actuator base fixed to a carriage movable in the radial direction of an optical disk, a lens holder for holding the objective lens, and a supporting mechanism for elastically supporting the lens holder to the actuator base. The actuator base has an elongated hole extending in the radial direction of the optical disk. A relative position between the actuator base and the carriage is adjusted so that the tilt of the optical axis of the objective lens in the radial direction of the optical disk occurring in displacing the lens holder in the focusing direction is minimized, and thereafter the actuator base is fixed to the carriage by means of screws.

Abstract: A phase compensation method uses a phase plate to compensate for an optical phase of a reproduced signal in a reproducing optical system which is provided with respect to the reproduced signal from an optical recording medium. The position of the phase plate is controlled within a predetermined variable range depending on a type of the optical recording medium, so that a CNR of a reproduced signal becomes a maximum or, a DC fluctuation of the reproduced signal becomes a minimum or, a crosstalk level from adjacent tracks becomes a minimum.

Abstract: An optical storage device including a carriage movable in the radial direction of an optical storage medium, a light source, a first lens fixed to the carriage for focusing a light beam emitted from the light source onto the optical storage medium, a second lens interposed between the first lens and the light source, a beam splitter for reflecting at least a part of the light beam transmitted through the second lens in a direction perpendicular to the optical storage medium, and an actuator for supporting the second lens so that the second lens is movable in a given direction. The actuator includes an actuator base fixed to the carriage, a lens holder for holding the second lens so that the optical axis of the second lens extends in a direction substantially parallel to the optical storage medium, a supporting mechanism for movably supporting the lens holder to the actuator base, and a driving mechanism for moving the second lens in the above given direction.

Abstract: A miniaturized optical disc memory is receivable in a slot, of about 17 mm height, normally accommodating a floppy disc drive. A base includes a base plate with integral, peripheral sidewalls and an internal lateral partition wall which define a cartridge receiving slot on the upper surface of the base plate. First and second support plates extend from the partition wall to the rear peripheral sidewall of the base and define respective, first and second upper mounting surfaces and lower first and second cavities respectively receiving an ejection motor and a fixed optical system, individual optical components being mounted and aligned on integral, precision machined blocks in the second cavity for transmitting a laser beam and receiving a reflected beam along a central, longitudinal optical axis beneath the bass plate.

Abstract: A miniaturized optical disc memory is receivable in a slot, of about 17 mm height, normally accommodating a floppy disc drive. A base includes a base plate with integral, peripheral sidewalls and an internal lateral partition wall which define a cartridge receiving slot on the upper surface of the base plate. First and second support plates extend from the partition wall to the rear peripheral sidewall of the base and define respective, first and second upper mounting surfaces and lower first and second cavities respectively receiving an ejection motor and a fixed optical system, individual optical components being mounted and aligned on integral, precision machined blocks in the second cavity for transmitting a laser beam and receiving a reflected beam along a central, longitudinal optical axis beneath the base plate.

Abstract: Disclosed herein is an optical storage device having an objective lens actuator for moving an objective lens in a focusing direction. The objective lens actuator includes an actuator base fixed to a carriage movable in the radial direction of an optical disk, a lens holder for holding the objective lens, and a supporting mechanism for elastically supporting the lens holder to the actuator base. The actuator base has an elongated hole extending in the radial direction of the optical disk. A relative position between the actuator base and the carriage is adjusted so that the tilt of the optical axis of the objective lens in the radial direction of the optical disk occurring in displacing the lens holder in the focusing direction is minimized, and thereafter the actuator base is fixed to the carriage by means of screws.

Abstract: A magneto-optical memory device includes a first unit projecting a light beam onto a desired position on a recording medium, and a second unit applying a magnetic field to a position onto which the light beam is projected. The second unit applies, to the recording medium, a predetermined magnetic field within a magnetic field intensity range wherein a rate of change of a reproduced signal amplitude at the time of reproduction with respect to a magnetic field intensity becomes large. The relative positions of the second unit and the first unit are adjusted in accordance with a reproduced signal amplitude thus obtained.

Abstract: A magneto-optical memory device includes a first unit projecting a light beam onto a desired position on a recording medium, and a second unit applying a magnetic field to a position onto which the light beam is projected. The second unit applies, to the recording medium, a predetermined magnetic field within a magnetic field intensity range wherein a rate of change of a reproduced signal amplitude at the time of reproduction with respect to a magnetic field intensity becomes large. The relative positions of the second unit and the first unit are adjusted in accordance with a reproduced signal amplitude thus obtained.

Abstract: A miniaturized optical disc memory is receivable in a slot, of about 17 mm height, normally accommodating a floppy disc drive. A base includes a base plate with integral, peripheral sidewalls and an internal lateral partition wall which define a cartridge receiving slot on the upper surface of the base plate. First and second support plates extend from the partition wall to the rear peripheral sidewall of the base and define respective, first and second upper mounting surfaces and lower first and second cavities respectively receiving an ejection motor and a fixed optical system, individual optical components being mounted and aligned on integral, precision machined blocks in the second cavity for transmitting a laser beam and receiving a reflected beam along a central, longitudinal optical axis beneath the base plate.