Hitachi, Ltd.

Hirachi, Ltd.

Tokuya Kaneda

Takeshi Maeda

Masateru Watanabe

Shigeru Nakamura

Yoshito Tsunoda

Masahiro Takasago

Toshimitsu Kaku

Nobuo Suzuki

Wasao Takasugi

Atsushi Ichikawa

Akira Saito

Chikazu Yokoi

Toshiyasu Hattori

Yasumitsu Mizoguchi

Koji Muraoka

Matsuo Morikawa

Tomoji Osumi

Akira Kuribayashi

Toshihiko Ishizaka

A sealed library type optical disc unit is combined with an exchangeable cartridge type disc unit in a data storage and retrieval system. The optical discs within the sealed unit are exposed, as opposed to being encased in cartridges. A data access unit can quickly and efficiently access the exposed optical discs for loading them on an optical disc recording/reproducing unit. A control unit manages the transfer of data from a host computer to the storage and retrieval system. If a data write request exceeds the storage capacity of the optical disc within the sealed space, the excess data is written to the cartridge type disc unit without intervention by an operator and without interruption of the post processor. During a read operation, if data is requested that has been previously recorded on a cartridge type disc, the disc ID is displayed so that an operator can insert the disc into the cartridge type disc unit for the read operation. Data can also be copied from the cartridge type disc to the sealed space discs and vice versa, as well as between the sealed space discs by inputting such a command to a keyboard by an operator.

Disc recording system

An optical disk apparatus optically records and reproduces data from an optical information recording medium by an optical head. A first chamber is formed to accommodate at least an optical disk cartridge accommodating therein the recording medium and the optical head and is isolated from ambient air. The first chamber is spatially isolated from heat sources, such as a power supply or a circuit board package which needs cooling. Ambient air is supplied to the heat sources while bypassing the first chamber. In this manner, dust contained in ambient air is prevented from adhering to optical parts such as the optical disk and the optical head.

Optical information recording and reproducing apparatus

A disk apparatus includes a disk holder for holding a disk, and the disk holder is reciprocatively movable between a loading position and an unloading position. The disk apparatus further includes a motor for driving the disk at the loading position for reading or writing purposes, a power transmission mechanism for converting the rotation of the shaft of the motor into a reciprocative motion and for transmitting the reciprocative motion to the disk holder, and a switching mechanism for switching the power transmission mechanism to an inoperative state so as to prevent the power of the motor from being transmitted from the motor to the disk holder when the motor is operating to rotate the disk for reading or writing purposes.

Disk loading device

A recording medium loading mechanism for use in a signal processing apparatus has a motor which operates uni-directionally, and a power transmission mechanism operative to convert the rotation of the motor output shaft into reciprocating movements of a recording medium carrier between a loading position and a recording-reproducing position. The power transmission mechanism includes a crank pin (18) connected to the motor output shaft, a lost-motion connection for converting the rotational motion of the motor output shaft into reciprocal movements to move a reciprocating member (19), and cams cooperative with cam followers to transmit the reciprocating movements to the recording medium carrier.

Recording medium loading mechanism

A magneto-optical recording/reproducing apparatus includes a frame, a cartridge containing therein a magneto-optical recording disk, an optical head for applying an optical beam on the recording disk, an electromagnet for applying a bias magnetic field on the recording disk, a cartridge holder for holding therein the cartridge, a mechanism for reciprocating the cartridge holder between an insertion position and a loading position in which a recording, a reproducing and an erasing operations are carried out, a turn table for rotating the recording disk on the loading position, and a driving mechanism. The driving mechanism drives the electromagnet close to the recording disk when it is to be in the loading position and away from the recording disk when it is to be in the insertion position in opposite directions perpendicular to a plane of the recording disk in accordance with movement of the cartridge holder. The driving mechanism is disposed on the cartridge holder and the electromagnet is so disposed as to interpose the recording disk between the optical head and the electromagnet.

Magneto-optical recording/reproducing apparatus

The present invention relates to an optical head of an optical disk apparatus and a method of making the same, and more particularly, to an optical head which projects a light spot onto a track recess, receives the reflected light of the light spot by at least two photoelectric converters and focuses the light spot based on a differential output from the photoelectric converters. The optical head can accurately focus the light spot even if the reflected light beams that are nonuniform in intensity due to the influence of the comatic aberration of a lens composing the optical head are projected on to the photoelectric converters. This is because the influence of the comatic aberration of the lens is corrected for by marking the direction of central parallel ones of S-like interference fringes on the lens and optically forming a predetermined angle between the marked direction and the direction of the track recess.

Correcting for comatic aberration in an optical head of an optical disk

In an optical position detecting apparatus using moire, two light receiving elements are associated with a single light emitting element, and moire or grating portions of an auxiliary moire i.e., fixed sub-scale opposing the respective light receiving elements are arranged such that detection signals produced from the two light receiving elements upon movement of a movable moire i.e., main scale are substantially 180.degree. out of phase. The difference between the detection signals from the light receiving elements is used as a positioning signal, and the sum of the detection signals from the light receiving elements is used as a signal for controlling the input of the light emitting element.

Optical position detecting apparatus for positioning an actuator

A driving circuit for driving a semiconductor laser by a driving signal containing a pulse signal representing given information and superposed on a DC bias signal includes means for monitoring intensity of laser light emitted when the DC bias is applied, and means for monitoring the intensity of laser light emitted when the pulse signal is applied. The DC bias signal and the pulse signal are varied in dependence on the result of comparisons between the outputs of the monitoring means and respective predetermined reference values.

Driving apparatus for semiconductor laser

A focal position detecting optical apparatus wherein a light beam focused by a first optical system is irradiated on an object to be illuminated, focal point images are formed at two foci spaced apart from each other by a cylindrical lens disposed in a path of light beam reflected from the object, and a shielding element having a tip edge making an angle of approximately 45.degree. with an operating axis of the cylindrical lens is inserted at a site between the two foci and at which the light beam has a circular cross section to extract a portion of the light beam travelling between the two foci. The extracted portion is detected by two photodetectors disposed symmetrically with an axis lying in substantially the same direction as the tip edge, and the difference between outputs of the two photodetectors is produced for detection of an actual focal position of the first optical system.

Growing community of inventors

Odawara, Japan

Tokuya Kaneda