Canon Kabushiki Kaisha

Satoshi Shikichi

Hideki Hosoya

Kazuo Minoura

Akio Aoki

Masahiko Enari

Kazuhiko Matsuoka

Kenichi Suzuki

Hiroshi Matsuoka

Masayuki Usui

Fumiaki Kawaguchi

Takashi Nakahara

Shigeto Kanda

Hiroto Kitai

In an optical information recording-reproducing apparatus or method, a sum signal is generated from a divided sensor to be used for auto-focus (AF) and/or auto-tracking (AT) control. The AF servo is closed after an objective lens is moved to a location in the neighborhood of an in-focus position while working a position servo for an objective lens actuator using the sum signal. Further, the fact that a light spot is on a track is detected from the sum signal. If this fact is detected as well as the fact that a tracking error signal is in the neighborhood of zero, the AT servo is closed.

Optical information recording-reproducing method and apparatus including

A card-like optical information recording medium is used to effect recording and/or reproducing of information thereon. Relative movement between the recording medium and an optical head for irradiating the medium with light beam is conducted to record or reproduce information on or from the recording medium. A relative velocity between the optical head and the recording medium caused by the relative movement is detected to check if the velocity is being changed. When it is detected that the relative velocity is being changed as an acceleration or deceleration therebetween, a light spot formed by the optical head on the recording medium is shifted from the current track to another track such as a neighboring or desired track.

Optical information recording and/or reproducing method and apparatus

The information recording method of the present invention comprises steps of recording information on a recording medium by a recording head during forward movement, reading the information recorded during the forward movement in the opposite sequence to the recording sequence during backward movement, and checking if the information has been correctly written or not based on the information read during the backward movement.

Information recording method for reciprocally recording and verifying

An apparatus for effecting recording and/or reproduction of information by illuminating a recording medium with a light beam. This apparatus is provided with a motor for moving the medium and the light beam, one actuator for moving the light beam in a direction transverse to information tracks, another actuator for moving an optical head in a direction transverse to the information tracks, a control circuit for moving the light beam from one track to another, and another control circuit for moving the optical head toward an area excluding the recording area of the track at a predetermined timing. A recording/reproducing method of this invention utilizes the aforesaid apparatus, after the light beam has reached the area excluding the recording area on a particular track, the light beam is moved to a different track and the optical head is then moved in the same direction as the direction of movement of the light beam at a predetermined timing. Then, the light beam scans the recording area to record or reproduce information.

Apparatus for and method of recording and/or reproducing information by

A data processing apparatus includes a light source and an objective lens for radiating first and second light beams on a recording medium having a plurality of data and trucking tracks alternately formed and parallel to each other, photodetectors for detecting the tracking error signal from a beam obtained by reflection of the second light beam by the medium, a switching circuit for selectively supplying the tracking error signal to an actuator, a circuit for supplying a moving signal to the actuator to move the first and second light beams, respectively, to a data track different from one data track and a tracking different from one tracking track, and a control unit for monitoring the tracking error signal, for switching the switching circuit to supply the tracking error signal to the actuator in a tracking mode in which a data track is traced with the first light beam, and for switching the switching circuit not to supply the tracking error signal to the actuator in a moving mode for moving the first light beam to a different data track, the control unit interrupting monitoring of the tracking error signal during a period for which the second light beam is passing data tracks in the moving mode.

Method and apparatus for processing data

A tracking device usable in an optical information recording and reproducing apparatus for an optical information record medium on which a plurality of tracks are arranged substantially parallel in a first direction. The device includes a light source, a first optical system for forming a small spot on the record medium by converging a light beam from the light source, a second optical system for obtaining the light beam from the record medium, a detecting device for receiving the light beam obtained by the second optical system to output a tracking signal, a vibrating device for vibrating the spot relative to the record medium in a second direction intersecting the first direction, a control device for effecting tracking control with respect to a track, and a selecting device for selectively actuating the vibrating device and the control device in accordance with the tracking signal from the detecting device.

Tracking device to effect tracking pull-in in an optical recording and

An optical information processing apparatus effects recording and/or reproduction of information by scanning information tracks of an optical recording medium by at least one condensed light beam while effecting tracking and/or focusing control. The apparatus comprises at least two groups of optical sensors for receiving the light of the light beam reflected. By the medium, a circuit for producing a signal for effecting the control from the output of each of the groups of optical sensors, a reference signal generating source, and a switching circuit for causing, when at least one of the outputs of the groups of optical sensors exhibits an abnormal value, the reference signal, instead of the at least one output, to be input to the control signal producing circuit.

Optical information processing apparatus in which the output of an

An optical information recording apparatus includes a recording device for condensing a light beam into a spot-like shape, the light beam having been intensity-modulated between at least two levels which are not zero, scanning the light beam on a recording medium and recording information thereon; a detector for detecting a signal indicative of the position error between the light beam spot and the medium in the focusing direction perpendicular to the surface of the medium or the tracking direction in a plane parallel to the surface of the medium which is perpendicular to tracks formed on the medium; a servo device for correcting the position error on the basis of the detected signal; a device for varying the gain of the servo device in conformity with the intensity level of the light beam for producing a gain output; and a device for sampling and holding the gain output as the intensity of the light beam shifts between different levels.

Optical information recording apparatus provided with means for sampling

In an optical information recording and/or reproducing apparatus, tracking and/or focusing error signals from relected light which are caused when a light spot is irradiated onto an optical recording medium are detected. Tracking and/or focusing servo circuits in the apparatus cause an objective lens to follow the medium on the basis of the result of the detection of the tracking and/or focusing error signals. When it is detected that the tracking and/or focusing error signals have reached a target value which is previously set to exceed a zero-cross point or a zero-cross level at the signal level, the tracking and/or focusing servo circuit is closed and the tracking and/or focusing servo is pulled in.

Method and apparatus for effecting at least one of tracking and servo

An optical information processing apparatus includes a scanning device for scanning an information track on an optical recording medium by a focused light spot, a moving device for moving the light spot in the direction of an optical axis of the scanning device and/or in a direction which is perpendicular to the optical axis with respect to the information track, a detecting device for detecting focusing and/or tracking error signals of the light spot with respect to the information track, a control device for returning the detected error signal to the moving device, a limiting device for electrically limiting a range of movement of the light spot, and an adjusting device for adjusting the range of movement of the light spot which is limited by the control device in accordance with a sensitivity of the moving device.

Optical information processing apparatus including a limiter for

In an optical information recording medium of the type wherein information is recorded or reproduced when a light beam scans each of a plurality of mutually parallel tracking tracks, an auxiliary track is extended between the adjacent tracking tracks and has at least one portion in parallel with the tracking tracks. In a method of recording or reproducing information by scanning a light beam on each of a plurality of mutually parallel tracking tracks on the recording medium, the recording medium has an auxiliary track which is extended between the adjacent tracking tracks and which has at least one portion in parallel with the tracking tracks and the light beam is kicked in the parallel portion of the auxiliary track.

Optical information recording medium and method for recording

There is disclosed an optical card recorder-reader, in which erroneous signal recording, caused by a low-level light beam when it is stopped at a position for a prolonged period between writing and/or reading operation, either by interruping the irradiation, or by reducing the power of irradiation, or by placing the light beam outside the recording area, when the recording or reading operation is not in progress.

Optical information recording-reproducing apparatus

An optical information recording and reproducing apparatus comprises, an optical head for recording and reproducing information on and from a card-shaped optical recording medium, first means for relatively reciprocally moving said optical head to said card-shaped optical recording medium, and control means for controlling a relative speed between said optical head and said optical recording medium, said control means keeping a constant relative speed between said optical head and said optical recording medium in a record area of said optical recording medium and changing the relative speed between said optical head and said optical recording medium and reversing the direction of the relative movement between said optical head and said optical recording medium in areas outside of the record area.

Optical information recording and reproducing apparatus

Method and apparatus for recording information on a card-shaped optical information recording medium with a light beam and/or for reproducing information recorded on the medium. The apparatus includes a device for irradiating the medium with a light beam, a device for causing relative reciprocal movement between the medium and the light beam, and a device for terminating or displacing the light beam on the medium, after the lapse of a predetermined period of time from a moment when the relative speed of the medium and the light beam is reduced below a predetermined speed. The method includes the steps carried out by the apparatus.

Apparatus and method for preventing recording errors due to a reduction

An optical information recording and reproducing apparatus for an optical information record medium on which a plurality of tracks are arranged substantially in parallel, comprises a light source, a first optical system for guiding a light beam from the light source, onto the record medium, a second optical system for obtaining the light beam from the record medium, a detecting device for receiving the light beam obtained by the second optical system to output at least one of a focusing signal and a tracking signal, an adjusting device for adjusting at least one of focusing and tracking operation in accordance with at least one of the focusing and tracking signals, a reciprocating device for causing the record medium to reciprocate, a control device for controlling the reciprocating device, and a change device for changing at least a servo gain of the adjusting device in accordance with at least a signal from the control device.

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Tokyo, Japan

Satoshi Shikichi