Nippon Conlux Co., Ltd.

Kabushiki Kaisha Nippon Conlux

Nhk Spring Co., Ltd.

Murata Kikai Kabushiki Kaisha

Nippon Hoso' Kyokai

Kazuo Noda

Koichi Yamazaki

Eiichi Nakamura

Yasuyuki Kimura

Tetsuya Honda

Osamu Yamada

Masayuki Takada

Yonezo Furuya

Susumu Kojima

Hiroaki Yoshida

Toru Kuroda

Hiroaki Nishiguma

Kenzou Yoshihara

Kenjiro Kachi

An optical information recording and reproducing method and device, whereby it is possible to prevent reduction in information recording capacity of an optical card and increase in recording and reproduction time due to track jump operations, and there is no occurrence of track jumping errors due to oscillations associated with acceleration and deceleration of the relative speed of movement between the optical card and an optical head. A region where the optical head and optical card are moved at a constant speed relative to each other is provided in the acceleration or deceleration of the relative speed of movement, and a track jump operation is implemented in this region.

Track jump for optical information recording and reproducing method and device

During recording of data on a recording medium, tracking is performed using auxiliary beams to refer to guide tracks as done in the conventional three-beam method. During reproduction of data from the recording medium, tracking is performed using a main beam to refer to a data pit recorded in a recording track in accordance with the push-pull method. In addition, there are provided two tracking control circuits based on the three-beam method and push-pull method, and the use of tracking control signals based on the three-beam and push-pull methods that are output from the two circuits is selected via a switch.

Tracking method and device for use with an optical recording medium

A laser light beam generated from a light source is divided by a diffraction grating into a plurality of light beams, i.e., a single main beam to be used for recording information and plural auxiliary beams distributed on two imaginary straight lines crossing each other. One of the straight lines extends parallel to tracks of a recording medium. The resultant divided beams are converged to be irradiated onto a recording medium, and reflected components, from the recording medium, of the beams are received by corresponding light receiving elements. Thus, the main and auxiliary beams distributed on one of the two imaginary straight lines are used to perform focusing and tracking. Further, one of the two auxiliary beams distributed on the other straight line are used to determine whether a track where information is to be recorded is a blank area or not, and the other of the auxiliary beams is used to verify whether the information has been recorded correctly.

Optical information recording device and method for detecting and

In an optical information recording and reproducing apparatus, information is recorded or reproduced by moving a recording medium relative to an optical head. In order to execute information recording onto the medium in the course of the relative movement involving acceleration and deceleration, the generation timing and intensity of a light beam to be generated in correspondence with the information to be recorded are controlled in response to a varying speed of the relative movement so that data pits to be formed in the recording medium can be standardized in pitch and size irrespective of the relative movement speed. Also, in order to permit information reproduction from the medium in the course of the relative movement involving acceleration and deceleration, reproduction timing of data read by the optical head is set in synchronism with variation in the relative movement speed so that the data can be reproduced at proper timing irrespective of the relative movement speed. With such arrangements, there can be achieved a highly increased information recording/reproduction speed, extended information recording area, reduced size and cost of the apparatus, and reduced power consumption in the apparatus.

Method of and apparatus for recording and reproducing optical information

In a laser output control device for use in an optical information recording and reproducing apparatus which uses output light from a semiconductor laser device to record and reproduce information onto and from an optical information recording medium, a light receiving element is provided on the peripheral portion of a laser light emitting window formed in a housing of the semiconductor laser device. The peripheral component of forward radiated light of the laser light output from the semiconductor laser device is received by the light receiving element, so as to control the output power of the semiconductor laser device in accordance with output of the light receiving element corresponding to the received light.

Laser output control device for an optical information recording and

In a tracking or focusing servo control loop, there are provided a switch element for switch-controlling a tracking or focusing error signal, and a smoothing circuit for switching passage the error signal. An amount of detected reflection from an optical recording medium is monitored by a controller section, and the switching action of the switch element is ON/OFF-controlled by the controller section so as to maintain a servo loop gain at a predetermined standard. Thus, it is possible to maintain a constant servo loop gain without being influenced by variation in the laser light amount or difference in reflectivity characteristics of the recording layers of individual optical recording media, and constantly stable tracking servo control and/or focusing servo control can be performed.

Optical recording and reproducing system using servo control, switches

A position detector detects a relative position of an optical head to a recording medium, and on the basis of the thus-detected relative position, a position detection signal is generated in response to movement of a light beam over a predetermined distance. Then, in response to the position detection signal, a comparison is made between the number of track crossing counted for the predetermined movement distance on the basis of reception of reflection of the light beam, and a predetermined reference value for the predetermined movement distance. Then, track crossing count compensation data is generated which corresponds to a difference between the counted number of track crossing and the reference value, and the counted number of track crossing is corrected by use of such compensation data.

Track seek method and device for use with an optical information

A write once type information recording medium having a recording format that includes sectors. Each Sector includes x pieces of p-bit frames. Each frame contains an f-bit synchronization signal region and a d-bit data region. Each bit of at least one x-bit packet in which a v-bit error correction code has been added to u-bit data, is distributed to each one of the data regions of the x pieces of frames. This makes it possible for the write once type information recording medium to have an increased data storage efficiency and an effective error correction capability for a burst error.

Write once type information recording medium, method and apparatus for

To provide a driving device for an objective lens that has a high driving sensitivity and superior driving frequency characteristics. The present invention relates to a device for driving the objective lens (1) of an optical head that uses a device for recording information on an optical information recording medium, and for reproducing information therefrom, by irradiating a beam of light thereon while positioning and focusing the light with respect to an information track on the optical information recording medium. The device has a loose linkage member which supports an objective lens within a cylindrical member and comprises the cylindrical member (14 ) and a cylindrical hole portion (19 ) into which the cylindrical member is inserted so as to face the cylindrical hole with an air gap therebetween and with the axes thereof oriented vertically, and the driving force generated by a tracking coil (3 ) is transmitted through this loose linkage member to the objective lens.

Driving device for objective lens

The present invention provides an optical card wherein the irradiation position of laser beams is pulled back into an information recording section 1 in such a manner that the operation of recording or reproducing information can continue. In this optical card, information is recorded on or reproduced from a prescribed information recording section on a card surface in accordance with optical scanning along guide tracks provided in the card surface, and the optical card is provided with a mirror section arranged adjacent to the information recording section in the direction parallel to the direction of optical scanning of the information recording section. The optical card is characterized in that the mirror section is provided with at least one pair of curved auxiliary guide tracks that are connected to the guide tracks in the information recording section.

Optical card having a mirror section with a pair of auxiliary guide

A linear motor having a magnetic circuit and a moving coil, the magnetic circuit comprising a linear yoke provided at the center of the circuit and a pair of linear magnets, the linear yoke and the pair of linear magnets forming a pair of linear gaps with the linear yoke interposed therebetween, the magnetic circuit applying a magnetic field to the linear gaps, the movable coil mounted on the linear yoke of the magnetic circuit being moved along the linear yoke by an electromagnetic action to the magnetic circuit when the movable coil is powered, wherein the linear magnet has a larger magnetic force at opposite end portions in the longitudinal direction of the linear magnet than at an intermediate area, the magnetic reluctance of the magnetic circuit is made large to obtain a driving current of the movable coil corresponding to the magnetic reluctance when the moving coil moves at the intermediate area of the linear magnet, or the magnetic circuit is mounted on a plate made of material having the same magnetic reluctance as the linear yoke. An information recording/reproducing apparatus having a card transport stage for transporting an information recording medium and a laser unit for radiating a laser beam to the information recording medium, the information recording/reproducing apparatus writing and reading information to and from the information recording medium while reciprocally moving the card transport stage and linearly and reciprocally moving the information recording medium and applying a laser beam to the information recording medium, wherein the apparatus comprising a transport unit wherein the plane of driving force by driving means for reciprocally moving the card transport stage is made substantially flush with the center of a guide shaft for sliding the transport stage.

Linear motor with permanent magnets

In an optical information recording and reproducing apparatus, the recording operation is interrupted when an information pit, dust, scratch, stain, etc. is present on an optical recording medium. However, the recording operation is resumed and kept continued when a dust, scratch, stain, etc. other than the information pit is present on the medium. The apparatus comprises a double recording detecting circuit for detecting a pseudo double recording signal generated by a dust, scratch, stain, etc. on the medium at a period of a recording operation; and a recording signal supply circuit for interrupting the recording operation when the double recording detecting circuit detects the pseudo double recording signal to switch the recording period to a monitor period, for maintaining the interruption of the recording operation when a real double recording signal generated by an information pit is detected at the monitor period, and for resuming the recording operation when the real double recording signal generated by an information pit is not detected at the monitor period. After the recording operation has been resumed and further when the pseudo double recording signal generated by a dust, scratch, stain, etc. still remaining on the medium is detected, the monitor and recording periods are repeated alternately. However, after the medium has become free from a dust, scratch, stain, etc. finally and therefore the real and pseudo double recording signals are not both generated, the recording operation is kept continued normally.

Optical information recording and reproducing apparatus

An optical head for reading and/or writing information from and in an optical recording medium having an improved sensor structure for focusing and tracking error detections. A light beam is separated into a 0th-order diffraction light beam and .+-.1st-order diffraction light beams, and these light beams are impinged upon a recording track of the optical recording medium. The light beams reflected from the optical recording medium is separated into two different directions, and the tracking and focusing error detections are carried out with multi-segment optical sensors which are connected in a complementary manner. As a result, the influence of the tracking error on the focusing error detection is eliminated, and the linearity of the focusing error detection is improved.

Optical head with improved tracking and focusing error capabilities

A method and an apparatus for recording and reproducing information comprising irradiating a light spot for recording and reproducing information and a plurality of light spots for tracking an information-recording region of an optical information-recording medium including tracks or guiding, projecting reflected beams from the optical information-recording medium due to said light spot for recording and reproducing information and plurality of light spots for tracking on a photosensor, and selecting two outputs from a plurality of electrical outputs for tracking from said photosensor to provide tracking-control signals.

Method and apparatus for recording and reproducing information on an

An apparatus for optically recording and reproducing information in and from an optical information recording medium having a guide track. The apparatus uses an optical head having a diffraction grating, for recording and reproducing information. In recording information, a zero-order diffraction light beam from the diffraction grating is used for the information recording, and plus/minus first-order diffraction light beams from the diffraction grating are used for the tracking. In reproducing information, the zero-order diffraction light beam is used for the tracking, and higher- and odd-order diffraction light beams including at least plus/minus first-order diffraction light beams are used for information reproduction.

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Yokohama, Japan

Kazuo Noda