公开(公告)号：DE3885000T2

公开(公告)日：1994-05-19

申请号：DE3885000

申请日：1988-04-29

Applicant: SONY CORP

Inventor： HORIMAI HIDEYOSHI ,  OGAWA HIROSHI

IPC: G11B11/10 ,  G11B11/105

Abstract: An apparatus for reproducing a magneto-optical disk (1) which is adapted to intermittently irradiate a magneto-optical disk with a light beam emitted from a laser light source (5) at a predetermined sampling period, detect a polarized component of the light beam emitted from the laser light source (5) and reflected from the disk (1) by detecting elements (9,8,10,11,12,13A,13B), derive the reproduced output of an information signal recorded on the magneto-optical disk by taking the difference between the detected outputs from the respective detecting elements, and in which there is provided a random noise removing circuit (21A, 21B)at the rear stage of the detecting elements for removing photo-electric converting noises generated in the detecting elements.

公开(公告)号：CA1328689C

公开(公告)日：1994-04-19

申请号：CA534641

申请日：1987-04-14

Applicant: SONY CORP

Inventor： HORIMAI HIDEYOSHI ,  AOKI YOSHIO

IPC: G11B11/10 ,  G11B11/105 ,  G11B13/04

Abstract: A magnetooptical recording apparatus is disclosed which is capable of performing real-time overwrite operation. The apparatus comprises a laser beam and focusing parts thereof, and a pulse magnetic field generator device, provided on both sides of a magnetooptical recording medium, respectively. The laser beam and focusing parts thereof are formed of an objective lens connected to a moving coil which is provided with a magnet, thus the objective lens is movable relative to a magnetic layer of themagnetooptical recording medium by the interaction between the magnet and the moving coil. The magnet generates and applies a D.C. magnetic field of one polarity perpendicular to the magnetic thin film around a point where the laser beam is focused, while the pulse magnetic field generator device generates pulse magnetic field of the opposite polarity modulated by information signal around the point where the laser beam is focused. Thus one and opposite polarity magnetic field pulse row obtained by a sum of the D.C. magnetic field and the pulse magnetic field is applied to the magnetic thin film upon laser beam irradiation to perform the real-time overwrite operation.

公开(公告)号：CA1314768C

公开(公告)日：1993-03-23

申请号：CA523928

申请日：1986-11-27

Applicant: SONY CORP

Inventor： HORIMAI HIDEYOSHI ,  AOKI YOSHIO ,  WATANABE KENJIRO

IPC: G11B11/10 ,  G11B5/66 ,  G11B11/105 ,  G11B13/04

Abstract: Disclosed is herein a magneto-optical recording medium comprising a first ferrimagnetic layer formed of rare earth metal element and transition metal element, having magnetization perpendicular to a surface of the first ferrimagnetic layer derived by excess magnetization of the rare earth metal element to the transition metal element, and having no compensation temperature upon room temperature; and a second ferrimagnetic layer formed of rare earth metal element and transition metal element, having magnetization perpendicular to a surface of the second ferrimagnetic layer derived by excess magnetization of the transition metal element, and having no compensation temperature upon room temperature, the first and second ferrimagnetic layers being superposed with each other and coupled with exchange interaction, the magnetization of the first ferrimagnetic layer and the magnetization of the second ferrimagnetic layer being arranged to opposite direction with each other at a temperature between room temperature and recording temperature around Curie temperature of at least one of the ferrimagnetic layers.

公开(公告)号：DE3686480D1

公开(公告)日：1992-09-24

申请号：DE3686480

申请日：1986-12-23

Applicant: SONY CORP

Inventor： HORIMAI HIDEYOSHI ,  KAWAKUBO OSAMU ,  AOKI YOSHIO

IPC: G11B5/02 ,  G11B11/10 ,  G11B11/105 ,  G11B13/00 ,  G11B13/04

Abstract: A magneto-optical recording technique comprises: preparing a magneto-optical recording medium (10) comprising a magneto-optical recording layer (12) and a bias magnetic layer (14) formed on a transparent substrate (11), the recording layer (12) having a Curie temperature higher than room temperature, the bias magnetic layer (14) having a compensation temperature lower than a Curie temperature, and the recording layer (12) and the bias magnetic layer (14) being superposed with a non-magnetic layer (13) therebetween; and applying heating (for example by means of a laser beam L.B) to the magneto-optical recording medium (10) at first and second heating power levels, the first level being sufficient to heat the recording layer (12) to a temperature higher than the Curie temperature of the recording layer (12) and to heat the bias magnetic layer (14) to a temperature higher than the compensation temperature of the bias magnetic layer (14), and the second level being sufficient to heat the recording layer (12) to a temperature higher than the Curie temperature of the recording layer (12) while keeping the bias magnetic layer (14) below the compensation temperature of the bias magnetic layer (14).

公开(公告)号：AU586924B2

公开(公告)日：1989-07-27

申请号：AU7180887

申请日：1987-04-21

Applicant: SONY CORP

Inventor： HORIMAI HIDEYOSHI ,  AOKI YOSHIO

IPC: G11B11/10 ,  G11B11/105 ,  G11B13/04

Abstract: A magnetooptical recording apparatus is disclosed which is capable of performing real-time overwrite operation. The apparatus comprises a laser beam (3) and focusing parts (4) thereof and a pulse magnetic field generator device (6) provided on both sides of a magnetooptical recording medium (1) respectively. The laser beam (3) and focusing parts (4) thereof are formed of an objective lens (5) connected to a moving coil (8) which is provided in a magnet (7), thus the objective lens (5) is movable relative to a magnetic layer (1A) of the magnetooptical recording medium (1) by the interaction between the magnet (7) and the moving coil (8). The magnet (7) generates and applies a D.C. magnetic field of one polarity perpendicular to the magnetic thin film (1A) around a point (P) where the laser beam (3) is focused. While the pulse magnetic field generator device (6) generates pulse magnetic field of the opposite polarity modulated by information signal around the point (P) where the laser beam (3) is focused. Thus one and opposite polarity magnetic field pulse row obtained by a sum of the D.C. magnetic field and the pulse magnetic field is applied to the magnetic thin film (1A) upon laser beam (3) irradiation to perform the real-time overwrite operation.

公开(公告)号：AU7180887A

公开(公告)日：1987-10-29

申请号：AU7180887

申请日：1987-04-21

Applicant: SONY CORP

Inventor： HORIMAI HIDEYOSHI ,  AOKI YOSHIO

IPC: G11B11/10 ,  G11B11/105 ,  G11B13/04

Abstract: A magnetooptical recording apparatus is disclosed which is capable of performing real-time overwrite operation. The apparatus comprises a laser beam (3) and focusing parts (4) thereof and a pulse magnetic field generator device (6) provided on both sides of a magnetooptical recording medium (1) respectively. The laser beam (3) and focusing parts (4) thereof are formed of an objective lens (5) connected to a moving coil (8) which is provided in a magnet (7), thus the objective lens (5) is movable relative to a magnetic layer (1A) of the magnetooptical recording medium (1) by the interaction between the magnet (7) and the moving coil (8). The magnet (7) generates and applies a D.C. magnetic field of one polarity perpendicular to the magnetic thin film (1A) around a point (P) where the laser beam (3) is focused. While the pulse magnetic field generator device (6) generates pulse magnetic field of the opposite polarity modulated by information signal around the point (P) where the laser beam (3) is focused. Thus one and opposite polarity magnetic field pulse row obtained by a sum of the D.C. magnetic field and the pulse magnetic field is applied to the magnetic thin film (1A) upon laser beam (3) irradiation to perform the real-time overwrite operation.