Canon Kabushiki Kaisha

Shinichi Ohta

Haruhisa Madate

Kazunobu Kobayashi

Naoto Kawamura

Takashi Kitamura

Isao Matsumura

Yuji Nishigaki

Hiroto Kitai

Moritoshi Miyamoto

Different tracks on an optical information recording medium are irradiated with first and second light spots for auto-tracking. The light of the first light spot via the recording medium is detected to produce a first detection signal and light of the second light spot via the recording medium is also detected to produce a second detection signal. On the basis of a difference between the first and second detection signals, a signal used for performing tracking control of a third light spot for recording or reproducing information is generated. When recording or reproduction of information is effected on/from one of a first recording medium having a track pitch P.sub.1 and a second recording medium having a track pitch P.sub.2 and the first and second recording media satisfy a relation P.sub.1 -P.sub.2 =d (d is the width of the tracking track) while executing auto-tracking control, a relationship of a direction of movement of the third light spot in a track intersecting direction with respect to a polarity of a signal obtained by subtracting the second detection signal from the first detection signal between the first and second recording media is inverted.

Optical information recording/reproducing method and apparatus for

An optical information recording apparatus for at least recording information by irradiating an optical information recording medium having a plurality of information tracks with at least one light beam. The apparatus includes a recorder for recording information on the recording medium with an information recording light beam and a plurality of detecting elements for detecting reflected light from the recording medium. Also provided is a high-frequency component detector for detecting a high-frequency component of a signal corresponding to an output signal from at least one of the plurality of detecting elements. Also provided is a controller for stopping recording of information by the recorder when the high-frequency component detector detects the high-frequency component during recording of information by the recorder.

Optical information recording and reproducing apparatus having a

An information reproduction apparatus is provided with a reproduction signal processing system for reproducing digital information recorded on an information track of a recording medium by a pit edge recording method and for reproducing the digital information by converting a reproduction signal read out from the recording medium into a binary signal after the reproduction signal is subjected to AC-coupling. The information reproduction apparatus is further provided with a phase compensation circuit arranged in the reproduction signal processing system to compensate for a phase distortion of the reproduction signal under the influence of the AC coupling.

Information reproduction apparatus including a phase compensation

A recorded signal detection apparatus detects information recorded on an information recording medium in the form of a digital signal so as to prevent a detection error caused by defects without lowering the detection sensitivity to information pits. In the recorded signal detection apparatus, any change in a binary signal reproduced from the recording medium is detected, and when the binary signal changes a plurality of number of times within a predetermined period of time, a detection signal of a recorded information signal is output.

Recorded signal detection apparatus

In an optical information reproduction apparatus, digital information recorded as an optical mark on an optical information recording medium is reproduced in the following manner. A light beam is applied to the recording medium, and the obtained reproduction signal is binarized. The binary reproduction signal is sampled by a sampling clock which is generated by a PLL control signal generator, and is synchronized with the binary reproduction signal so as to reproduce the digital information. The PLL control signal generator achieves synchronization based on the leading and trailing edges of a change point of the binary reproduction signal.

Optical information reproduction apparatus and optical information

An apparatus for effecting the recording and reproduction of information on an information track on a recording medium, includes a device for applying a first light spot to the information track to thereby record information, a device for applying a second light spot to the information track to thereby reproduce the information, a device for moving the recording medium relative to the first and second light spots in the lengthwise direction of the information track, a detector for detecting a tracking signal from the reflected light of the second light spot by the recording medium, a tracking controller for moving the first and second light spots in the tracking direction orthogonal to the lengthwise direction of the information track in conformity with the tracking signal, and a device for providing to the tracking signal an offset corresponding to the positional deviation between the center of the first light spot and the center of the second light spot in the tracking direction, during the recording of the information. A method of effecting the recording and reproduction of information by the use of the apparatus described above is also provided.

Information recording and reproducing apparatus provided with means for

An apparatus and a method for recording and reproducing an information signal onto an optical recording medium are disclosed. The apparatus includes a laser light source for radiating a laser beam onto the optical recording medium, a laser driver for driving the laser light source and a device for moving the medium relative to the laser beam. The laser driver controls the laser light source to selectively perform continuous light emission or intermittent light emission with a sufficiently higher frequency than that of the information signal during reproducing. By adopting the light intermittent emission of the light source, the formation of pits with some errors can be prevented and the reliability of the recording and reproduction can be enhanced.

Method and apparatus for recording and reproducing information by

An image beam recording apparatus including an image data input device, a comparator for forming a plurality of pulse width modulated signals on the basis of the image data input by the input device, and a laser for scanning a laser beam modulated in accordance with the pulse width modulated signals output by the comparator and for recording an image on a recording medium. The comparator is capable of forming a plurality of pulse width modulated signals so as to reproduce a variable density image. The plurality of pulse width modulated signals have the same number of pulses, but different pulse widths. The laser effects a scanning operation so that a plurality of beams modulated by the pulse width modulated signals form spots which overlap each other.

Image recording apparatus for producing a plurality of pulse width

A recorder has a beam generator for generating a beam to form a dot image on a record medium. The beam generator has first and second beam generation sources to generate first and second beams and forms each dot by using both of the first and second beams.

Dual beam recorder

An image recording apparatus has a memory for storing a plurality of image data, a read-out section for reading out a predetermined number of image data to be recorded from the memory in order to display them in substantially the same order as that for recording, a display section for displaying the read-out image data, and a recording section for reading out the image data to be recorded from the memory and for recording the read-out image data.

Image recording apparatus

An eye examining instrument comprises an ultrasonic wave generating source, reflecting members and a receiver. A concave reflecting mirror is provided to direct the generated ultrasonic waves in the direction along the optical axis of the objective lens of the instrument while converging the waves. Also, a concave reflecting mirror is provided to converge the ultrasonic waves reflected upon the cornea of the eye under test and examination into the receiver. The ultrasonic waves received by the receiver are transformed into an electric signal. The electric signal thus produced includes a component informing of the time required to receive the ultrasonic waves after the generation thereof and a component informing of the intensity of the received ultrasonic waves. The time component signal is compared with a reference signal representative of a predetermined working distance between the objective lens and the eye whereas the intensity component signal is compared with a reference signal representative of the alignment of the objective lens with the eye.

Eye examining instrument

In an eye fundus camera an optical system illuminates the eye fundus and a sensor detects the intensity of reflection from the eye. When the intensity of reflection is sufficient to indicate that the person being examined has blinked his eye, the photographic system is disabled.

Eye fundus camera

The present invention relates to an optical instrument for examining the eye fundus which is so designed that in the optical system including an objective lens visible, targets are built for orientating the visual line of the eye to be inspected along the direction convenient for the inspection of the desired part of the eye fundus in order to be able to inspect the desired part. The visible targets are located at the position conjugate to the eye fundus with regard to the optical system including the objective lens in order that the light beam coming from the targets through the objective lens reaches the eye to be inspected. The image of the visible targets is formed on the eye fundus of the eye to be inspected while the eye to be inspected observes the visible targets through the objective lens in such a manner that the visual line is oriented in the direction along which the targets are seen.

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Tokyo, Japan

Shinichi Ohta