Canon Kabushiki Kaisha

Makoto Shiho

Shigeru Aoi

Yasuo Suzuki

Osamu Koyama

Yoshikazu Miyajima

Hisatoshi Baba

Nobuhiro Kasama

Takayuki Aizawa

Masaharu Tsukada

Takaaki Ashinuma

Takehiko Shibata

Kazuo Uzuki

Naoki Imokawa

In a magnetooptical recording/reproducing apparatus, a beam spot is formed on a recording medium by radiating a laser beam from an optical head to the recording medium. In magnetic field modulation recording, a bias magnetic field is applied from a first bias magnetic field generation device onto a very small region where the beam spot is formed. In optical modulation recording, bias magnetic field is applied from a second bias magnetic field generation device to the very small region. The first bias magnetic field generation device is adapted to be evacuated from a position above the very small region by an evacuating mechanism. The second bias magnetic field generation device is adapted to be moved to the position above the very small region to be mechanically interlocked with the evacuating mechanism.

Magnetooptical recording/reproducing apparatus with bias magnetic field

An optical information recording/reproducing apparatus for stably recording, reproducing, or erasing the information by a laser beam with respect to different kinds of optical disks is represented. This apparatus includes a processor to record, reproduce, or erase the information for an optical disk, a disk sort detector to detect the sort of optical disk, and a controller to control the processing parameters of the processor in response to an output signal from the disk sort detector. The disk sort detector reads the disk sort identifying information preliminarily recorded on the optical disk by the processor to detect the sort of disk. Or, this detector irradiates light onto labels having different reflection factors or transmission factors preliminarily provided on the optical disks by the processor and detects the reflected light amounts or transmitted light amounts from the labels, thereby detecting the sort of disk. The optical disks include disks of the type only for use of reproduction, the rerecordable type, and the writable type.

Optical information recording/reproduction apparatus including means for

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.

Opto-magnetic recording apparatus with a bias magnetic field generating

An optical information processing apparatus including a light source, a lens system for condensing the light beam emitted from the light source as a minute spot on the track of a recording medium, tracking signal detectors for receiving the light beam from the spot modulated by the recording medium to thereby detect the positional deviation of the spot relative to the track in the tracking direction crossing the track, a correcting device for moving the lens system in the tracking direction in response to the output signal from the tracking signal detectors to thereby correct the positional deviation, and lens position detectors including at least one photoelectric converting element provided outside the effective diameter of the lens system so as to be movable with the lens system, and directly receiving part of the light beam emitted from the light source by the photoelectric converting element to thereby detect the position of the lens system in the tracking direction.

Optical tracking apparatus with photodetector disposed outside part of

A magnetooptical information recording apparatus is provided with a device for irradiating a magnetooptical recording medium with a light beam, and a device for applying a bias magnetic field to a portion, irradiated by the light beam, of the magnetooptical recording medium. The applying device is provided with a yoke member having a first projecting portion positioned in the vicinity of the irradiated portion and a second projecting portion spaced from the first projecting portion in a direction along the surface of the recording medium, wherein the distance of the second projecting portion from the first projecting portion at a closer side to the recording medium is smaller than that at a farther side to the recording medium.

Magnetooptical information recording apparatus having intensified

A magneto-optical information recording apparatus comprises an objective for condensing a light beam on a magneto-optical recording medium, a bias magnetic field producing device provided on the opposite side of the objective with respect to the magneto-optical recording medium and applying a magnetic field from outside to the magneto-optical recording medium near the condensed point of the light beam, and a protective outer frame containing the objective therein and having an opening for transmitting the light beam therethrough at a location opposed to the magneto-optical recording medium, at least a portion of the protective outer frame being formed of a ferromagnetic material.

Recording head for magneto-optical information recording apparatus

A magnetic field generator includes: a first coil group, including at least one coil, for generating a magnetic field upon energization; a second coil group, including at least one coil, and arranged such that a magnetic field is generated in substantially the same space as that of the magnetic field generated by the first coil group, a self-inductance of the second coil group being smaller than that of the first coil group; and a driving means for selectively energizing the first and second coil groups. The driving means energizes the second coil group first, and after the magnetic field is caused to rise by the second coil group, energizes the first coil group, thereby holding a constant magnetic field. A method of driving a magnetic field generator including a first coil group for generating a magnetic field and a second coil group for generating a magnetic field in substantially the same space as that of the magnetic field generated by the first coil group and having a self-inductance smaller than that of the first coil group, includes the steps of: energizing only the second coil group to generate a magnetic field; and energizing the first coil group after the magnetic field generated by the second coil group rises, thereby holding a constant magnetic field.

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Yokohama, Japan

Makoto Shiho