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: 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: There is provided an optical storage device that can position a lens carriage and objective lens even when position sensors for the lens carriage and objective lens are excluded in an effort to make an optical disk unit thinner. When a seek of the carriage relative to an optical disk is started, the carriage is accelerated smoothly, decelerated smoothly, and thus positioned on a target track. The vibration of a lens actuator on the carriage occurring during seek can be minimized, and the lens actuator is locked substantially in the center of the carriage. During a seek operation of the carriage, a false lens signal equivalent to a lens signal used to lock the lens actuator in the center of the carriage is produced using the envelope of a tracking error signal obtained from reflected light of the light beam emanating from the optical disk. With the false lens signal, the lens actuator is locked in the center of the carriage.

Abstract: There is provided an optical storage device that can position a lens carriage and objective lens even when position sensors for the lens carriage and objective lens are excluded in an effort to make an optical disk unit thinner. In an optical storage device according to the first aspect of the present invention, when a seek of the carriage relative to an optical disk is started, the carriage is accelerated smoothly, decelerated smoothly, and thus positioned on a target track. The vibration of a lens actuator on the carriage occurring during seek can be minimized, and the lens actuator is locked substantially in the center of the carriage. According to the second aspect, during a seek operation of the carriage, a false lens signal equivalent to a lens signal used to lock the lens actuator in the center of the carriage is produced using the envelope of a tracking error signal obtained from reflected light of the light beam emanating from the optical disk.

Abstract: In an apparatus for supplying a current for driving a laser diode, an amount of current is supplied to the laser diode. During a read mode, a read peak current modified by a high frequency signal in addition to the amount of current is supplied to the laser diode, and during a write mode, a base read current in addition to the amount of current is supplied to the laser diode so that a light output of the laser diode is equal to a base read output. The read peak current is adjusted so that a mean value of the light output of the laser diode is equal to the base read output. An automatic control is performed upon the amount of current so that the light output of the laser diode is close to or approaches the base read output.

Abstract: A system for obtaining an optimum focusing position in an optical disc system. An optical beam is impinged onto a track of an optical disc, and a reflection signal having information regarding an intensity of an optical beam reflected by an optical disc is obtained. A predetermined frequency component, the frequency component being generated by a modulation caused by an existence of a pit on a track of the optical disc in a reflecting signal, is extracted from the reflection signal. Then a focus position in which a maximum intensity of the extracted frequency component is obtained is searched by changing the focus position of the optical beam. Further, the above system is incorporated in a focus servo control system for maintaining an optimum focusing position in an optical disc system during reading and writing operations, to determine an optimum offset value which is to be adjusted to compensate an error arisen from a construction of the focus servo control system, during an offset adjusting operation.

Abstract: An optical disk access system capable of varying the focus position of a beam spot illuminating the optical disk. The focus position of the beam spot is varied in accordance with a mode of operation of the optical disk system. The various focus positions are automatically selected by the optical disk access system by intentionally vibrating the beam spot in a radial direction of the optical disk and detecting the amount of light reflected from the optical disk while varying a signal that changes the focus position of the beam spot. The optical disk system automatically selects a value of the signal determining the focus position of the beam spot that corresponds to maximum values derived from the light reflected from the optical disk.

Abstract: An optical writing and reading method and apparatus for writing data on a recording medium. To prevent an over-writing of data, a mark is written to indicate that data is already written. Before writing data, a mark is written on a mark recording region. Simultaneously with the writing of the mark, the light quantity reflected from the mark recording region is detected. When the reflected light quantity indicates that data is already written, subsequent data writing is inhibited.