Hitachi, Ltd.

Hirachi, Ltd.

Masateru Watanabe

Shigeru Nakamura

Tokuya Kaneda

Akira Saito

Toshiyasu Hattori

Takeshi Maeda

Akira Arimoto

Toshimitsu Kaku

Yoshito Tsunoda

Nobuo Suzuki

Toshimasa Kamisada

Atsushi Ichikawa

Sadao Takahashi

Tomoji Osumi

Toshihiko Ishizaka

Masaaki Hishiki

Tuyoshi Kato

An apparatus for a disc type medium capable of performing smooth recording/reproducing operations while maintaining gaps between a cartridge and a disc type medium encased therein with a fixed accuracy. The cartridge is held and pressed between support members disposed on a base on which a disc driving spindle motor is mounted and a holder is moved down due to the biasing force of prestressed springs provided on the holder so that warping deformation of the cartridge is corrected. As a result, fixed gaps can be formed surely between an optical disc and the cartridge during operation, thereby making it possible to keep them out of contact with each other.

Apparatus for ensuring operational clearance between a rotating disc type medium and a disc cartridge enclosing the medium

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

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

Prism optics for changing the shape of a light beam, including a composite prism consisting of at least two types of prisms made of materials having different variations in the refractive index due to variations of the refractive index due to wavelength variations and to temperature variations, which materials are so chosen that the angle of the light beam exitting from the prism optics remains almost constant, independent of variations in the wavelength of the light beam and temperature, and an optical information processing apparatus using these prism optics.

Prism optics stable with respect to wavelength and temperature

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

A focus error detection apparatus and an optical disk apparatus comprising a focusing lens for focusing reflected light coming from a light reflecting surface which is to be adjusted at the focal point of a projected light beam; a beam splitter means for dividing the output light of said focusing lens into a first and a second focused light beam; a first and a second photo-detector disposed respectively on the optical paths of said first and said second focused light beam, one of which is located behind the convergence point of said first focused light beam and the other of which is located before the convergence point of said second focused light beam, each of them generating outputs proportional to the amount of light within a predetermined region of the received light image, when it varies so that it is enlarged; and a circuit generating a focus error signal by using the difference between the outputs of said two photo-detectors.

Focus error detection apparatus utilizing focusing an front and rear

Growing community of inventors

Chigasaki, Japan

Masateru Watanabe