Canon Kabushiki Kaisha

Masayuki Usui

Kazuhiko Matsuoka

Kazuo Minoura

Takeshi Baba

Masahiko Enari

Akio Aoki

Kenichi Suzuki

Hideki Hosoya

Hiroshi Matsuoka

Satoshi Shikichi

Fumiaki Kawaguchi

Hiroyasu Nose

Hiroyuki Imataki

Atsushi Someya

Takashi Serizawa

Shinji Sakai

Osamu Koyama

Kenji Tamaki

Hisatoshi Baba

Hirotake Ando

Yoshihiko Watanabe

Hideo Nakajima

Tadashi Kato

Yukuo Nishimura

Yuko Suga

Masayuki Suzuki

Yuko Miyajima

Takesi Baba

Kazuyo Matsumoto

An optical information processing apparatus and method of correcting an offset of a tracking error signal. The apparatus includes an optical head for irradiating a light beam onto an optical recording medium, an objective lens, mounted on the optical head, for condensing the light beam onto the recording medium, a photodetector for receiving a light beam reflected by or transmitted through the recording medium and for generating a tracking error signal indicative of a positional deviation between the light beam irradiated position and a track, a tracking actuator for moving the objective lens in a direction intersecting the tracks and for causing the objective lens to vibrate in the vicinity of the center of the light beam, a tracking controller for driving the tracking actuator in accordance with the tracking error signal so as to correct the positional deviation, a measuring device for measuring an offset of the tracking error signal from an output of the photodetector when the objective lens is caused to vibrate in the vicinity of the center of the light beam and a correction device for correcting the offset of the tracking error signal on the basis of the offset measured by the measuring device.

Optical information processing method and apparatus including measuring

An optical information processing apparatus includes an optical head for irradiating a light beam onto an optical recording medium, an objective lens, mounted on the optical head, for condensing the light beam onto the recording medium, a photodetector for receiving a light beam from the recording medium and for generating a tracking error signal indicative of a positional deviation between a light beam irradiated position and a track, a tracking actuator for moving the objective lens in a direction intersecting tracks of the recording medium, a tracking controller for driving the tracking actuator in accordance with the tracking error signal so as to correct the positional deviation, a position detector for detecting a relative position of the objective lens with respect to the optical head in the direction intersecting the tracks, a measuring device for measuring a relationship between an offset of the tracking error signal and a position of the objective lens from the tracking error signal and an output of the position detector, a memory for storing the relationship measured by the measuring device and a correction device for correcting the offset of the tracking error signal in accordance with the stored relationship, in response to the position detector output signal.

Optical information processing apparatus in which the offset of a

An optical information processing apparatus includes a unit for scanning a track formed on an optical recording medium with a light beam, a tracking control unit for correcting a position shift between a radiation position of the light beam on the medium and the track, and an offset correction unit for automatically correcting an offset of the tracking control unit.

Optical information processing apparatus including a correction circuit

An optical information processing apparatus includes a light source for radiating a light beam onto an optical information recording medium. A first photosensor is provided for partially receiving the light beam emitted from the light source and generating an output, and a second photosensor is provided for receiving either a light beam reflected by the recording medium or a light beam transmitted through the recording medium and generating an output. A control circuit controls power of the light beam emitted from the light source using the output from the first photosensor, and a correction circuit automatically corrects linearity of the output of the first photosensor with respect to the power of the light beam emitted from the light source in accordance with the output from the second photosensor.

Optical information processing apparatus for correcting linearity of a

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

Disclosed is a device for reproducing information from an information recording medium having, on its information recording surface, a surface layer transmitting light therethrough. The information reproducing device includes a light source generating an illuminating light beam, a photodetector for receiving light from the information recording medium illuminated by the light beam from the light source, information reproduction being effected by the result of the detection by the photodetector, and an illuminating optical system for condensing the light beam from the light source and for directing it onto the information recording medium, the position of the condensing point by the illuminating optical system being spaced apart from the information recording surface of the information recording medium during the information reproduction by the detection by the photodetector.

Optical apparatus for effecting recording and/or reproducing of

An information recording and reproducing apparatus includes a head unit for recording information on and reproducing information from an information recording medium having a plurality of linear tracks arranged in parallel, a device for moving the head unit relative to the recording medium, and a detector for detecting whether the record medium has been loaded into the apparatus in a normal state. The detector includes a photo-detection unit having a light projector for projecting a light beam to the recording medium and a photo-detector for detecting a light beam from the recording medium. The photo-detection unit is arranged such that when the recording medium is inserted in the normal state, the light beam from the light projector illuminates a track of the recording medium and the photo-detector detects high-order diffracted light from the illuminated track.

Information recording and reproducing apparatus including detection of

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 element whose focal length is variable comprises a medium whose refractive index is variable by temperature, a heating device for imparting heat to the medium to cause an index gradient resulting from a temperature distribution to be created in the medium, and a device for controlling the amount of heat imparted to the medium by the heating device to vary the shape of the index gradient formed in the medium.

Varifocal optical element

A variable aberration imaging optical system comprises an imaging optical system and an optical device disposed in the optical system and capable of controlling the imaging characteristic of the imaging optical system. The optical device has a medium for forming an index gradient therein by heat, and a device for imparting heat to a desired position on the medium.

Variable aberration imaging optical system

This specification discloses a light modulating device comprising a liquid medium whose physical properties are variable by heat, and a heat-generating element for heating the liquid medium to such a degree that boiling does not occur to the liquid medium. The specification also discloses a light modulation apparatus comprising a liquid medium whose physical properties are variable by heat, a heat-generating element for heating the liquid medium to such a degree that boiling does not occur to the liquid medium, and a optical system for taking out one of a light flux modulated by the variation in physical properties of the liquid medium and a light flux not modulated by said variation from a state in which the light fluxes are mixedly present.

Light modulating device

An optical information recording medium in the form of a card having tracking tracks for obtaining a tracking signal and clock tracks for obtaining a clock signal arranged alternately and record zones for recording information between each of the tracking tracks and each of the clock tracks, and apparatus for recording/reproducing information using the recording medium.

Growing community of inventors

Yokohama, Japan

Masayuki Usui