Sony Corporation

Asahi Glass Company, Limited

Jujo Paper Co., Ltd.

Takashi Ohmori

Hirotoshi Fujisawa

Makoto Yamada

Kentaro Odaka

Tadao Yoshida

Ryo Ando

Hiraku Sugiki

Hidekazu Okamoto

Atsushi Ono

Kazuhiko Fujiie

Shin Tatematsu

Toshihiro Tanuma

Hajime Yano

Shunichi Samejima

Shinsuke Morikawa

Keiichi Ohnishi

Yutaka Kojima

Eiji Tadokoro

Yoshimoto Ohmura

Tadashi Yamagata

Tomoji Satake

A magnetic head for supplying a magnetic field in recording an. information signal to a recording medium is provided. This magnetic head has a substantially. prism-shaped magnetic core portion having a distal end portion cut out to form a step, the magnetic core portion being form so that the cross-sectional area of the distal end portion is smaller than the cross-sectional area of a proximal end portion, and a coil wound on the outer circumferential surface of the magnetic core portion, wherein the length of one side of the distal end portion is not less than 0.3 mm and not more than 0.45 mm, and the length of the other side orthogonal to the one side is not less than 0.4 mm and not more than 0.55 mm.

Magnetic head including stepped core and magneto-optical recording device using the same

An error voltage which includes serious fluctuation due to noise is applied to a LPF, and high frequency component due to noise is removed. The error voltage supplied through the LPF and a reference level, for example, 0-level voltage are supplied to a comparator. The comparator compares magnitude of theses two voltage each other, and outputs a signal which indicates polarity corresponding to the comparison result. As described herein above, by removing high frequency component included in the error voltage to be supplied to the comparator with the LPF, the polarity signal with reduced fluctuation due to noise and good quality can be obtained. Thus the polarity of an error voltage for controlling rotation of a disc can be judged correctly.

Recording/reproducing apparatus and recording medium rotation control

The present invention relates to a recording medium recorded with audio data and general data (including image data for computers and character data) mixed together, provided with data for each control region, where by providing a special simple control region, editing of complicated control regions does not have to be carried out and a memory region is not necessary as a working region for editing. The present invention also provides a playback device where playback can be achieved without mixing the simple control region with the control region for the audio and general data and, by also recording copy-protection information at the simple control region, a playback operation from a recording medium which has been copied illegally will not be possible. The present invention further relates to a recording device a recording device for updating each control region while data updating is being carried out at the recording medium.

Recording medium capable of recording a first data-type and a second

A recording medium has a user recordable area in which two types of information may be recorded, such as audio data and user data, and a control area having a first area for management information regarding the first type of information and a second area for management information regarding the second type of information. A reproducing apparatus uses the first management information to reproduce the first type of information and to avoid reproducing the second type of information as the first type of information, and uses the second management information to reproduce the second type of information and to avoid reproducing the first type of information as the second type of information. A recording apparatus generates the first management information when the first type of information is recorded and generates the second management information when the second type of information is recorded.

Efficient recording medium

In a magneto-optical recording apparatus wherein a beam of light is irradiated upon a face of a recording medium while a magnetic field is applied to the other face of the recording medium at a location where the light beam is irradiated, production of control pulses for controlling the magnetic head so as to prevent, upon high speed recording, the magnetic head from being turned on before a terminal voltage of the magnetic head drops sufficiently to a predetermined power source voltage because the transfer rate of a recording signal is high and the reversal interval of the recording signal is short.

Magnetic head driving circuit, including magnetic head coil switching

Method and apparatus for the recording and reproducing of data on a

The present invention relates to a recording medium recorded with audio data and general data (including image data for computers and character data) mixed together, provided with data for each control region, where by providing a special simple control region, editing of complicated control regions does not have to be carried out and a memory region is not necessary as a working region for editing. The present invention also provides a playback device where playback can be achieved without mixing the simple control region with the control region for the audio and general data and, by also recording copy-protection information at the simple control region, a playback operation from a recording medium which has been copied illegally will not be possible. The present invention further relates to a recording device for updating each control region while data updating is being carried out at the recording medium.

System for expansion of data storage medium to store user data

In a magneto-optical recording apparatus wherein a beam of light is irradiated upon a face of a recording medium while a magnetic field is applied to the other face of the recording medium at a location where the light beam is irradiated, production of control pulses for controlling the magnetic head is controlled so as to prevent, upon high speed recording, the magnetic head from being turned on before a terminal voltage of the magnetic head drops sufficiently to a predetermined power source voltage because the transfer rate of a recording signal is high and the reversal interval of the recording signal is short.

Magnetic head driving circuit operable with recording data transferred

A magneto-optical disc having an optical-magnetic recording layer, formed on the surface of a transparent base plate opposite its beam incident surface is disclosed, wherein a layer excellent in lubriciousness is formed in superimposition on the optical-magnetic recording layer to enable the magnetic head to be in direct sliding contact with the disc surface to provide for stable recording and improved recording performance as well as to reduce adverse effects caused by deposition of foreign matter such as dust and dirt.

Magneto-optical disc

A reproduction apparatus which can perform error correction decoding processing which allows data at a linking portion of linking recording to be regenerated as much as possible to restrict the invalid data area at the linking portion to a necessary minimum magnitude is disclosed. The production apparatus reproduces a recording medium on which data coded in two or more different series by error correction coding are linking-recorded such that they are recorded at continuous positions at discontinuous points of time and comprises linking position detection means for detecting a linking portion of linking-recording, wrong correction detection means for detecting wrong correction based on the error correction code, and means for rendering the wrong correction detection means inoperative at the linking portion detected by the linking position detection means.

Apparatus for reproducing a recording with reduced error correction

A magnetic head driving circuit for driving a magnetic head device adapted for recording information signals on a magneto-optical disc by applying a magnetic field to the magneto-optical disc is disclosed. The magnetic head driving circuit includes a pair of switching elements for performing a push-pull operation in accordance with input recording signals, a pair of rectifiers connected in series with each other between the switching elements, a magnetic field generating coil having one terminal connected to a junction line between the rectifying elements via a coupling capacitance and having its other terminal grounded. The magnetic field generating coil generates a magnetic field by being supplied with a driving current corresponding to the recording signals. An amplifier capacitor is connected in parallel with the magnetic field generating coil in an ac path for amplifying the driving current supplied to the magnetic field generating coil. With the above-described magnetic head driving circuit, the driving current supplied to the magnetic head generating coil may be amplified to increase the strength of the magnetic field generated by the magnetic field generating coil. A magnetic head device is also disclosed which includes a substrate provided integrally with a magnetic core about which the magnetic field generating coil is wound and with the above-mentioned driving circuit for simplifying the structure and reducing the size of the head device.

Magnetic head device for magneto-optical disc system and magnetic head

An optical head applies a laser beam to a region of the magnetooptical disc, and a magnetic head applies a magnetic field to the region of the magnetooptical disc while the laser beam is being applied thereto, thereby to record information in the region. The optical and magnetic heads are interconnected by a link mechanism so that they are movable in unison with each other radially with respect to the magnetooptical disc. An electromagnetic shield is disposed around the magnetic head for blocking magnetic and electric fields parallel to the magnetooptical disc.

Electromagnetic shield device for magneto-optical recording apparatus

A disc recording apparatus in which continuous recording data is subdivided and recorded in plural recording zones of the disc in the subdivided state, is disclosed, A system controller controls the recording position and the reproducing position of the recording data with respect to data zones of a recording/reproducing region of a magneto-optical disc. The continuous recording data are subdivided for recording in plural data recording zones, while track number data indicating the continuous recording data recorded in the data zones, address data indicating the positions of the data zones and address data indicating the linking destination for one to another data zone, are recorded in a lead-in region of the recording/reproducing region under control of the system controller. A disc reproducing apparatus fop reproducing the recorded data recorded by the disc recording apparatus and a disc-shaped recording medium used in the disc recording apparatus and in the disc reproducing apparatus are also disclosed.

Disc recording and/or reproducing apparatus for recording continuous

This invention relates to a recording sheet for an ink jet printer comprising fibrous base material and a back-coating layer formed on the back surface of the base material, which characterized by that the base material contains a cationic polymer size (a), and the back-coating layer comprises a pigment, a binder and two or more of sizes (b1) and (b2), said size (b1) being alkyl ketene dimer, alkenyl succinic anhydride, or wax emulsion, and said size (b2) being a cationic polymer.

Growing community of inventors

Tokyo, Japan

Takashi Ohmori