公开(公告)号：DE69225159T2

公开(公告)日：1998-08-13

申请号：DE69225159

申请日：1992-02-07

Applicant: SONY CORP

Inventor： OHTA MASUMI ,  NAKAO ISAMU ,  UDAGAWA TOSHIKI ,  FUKUMOTO ATSUSHI ,  YOSHIMURA SHUNI

IPC: G11B11/105 ,  G11B19/12 ,  G11B11/10

Abstract: The present invention concerns an apparatus for recording and/or reproducing on/from a magneto-optical recording medium (10). This apparatus comprises means (62) for generating a first channel clock used to write and/or read data in and/or from a first magneto-optical recording medium (10). The first magneto-optical recording medium (10) has a recording layer (13), the reproducing layer (11) and an intermediate layer (12) for magnetically coupling the recording layer (13) the reproducing layer (11) in stationary state, in which a magnetic coupling between said recording layer (13) and said reproducing layer (11) is lost in area (14) in which the temperature is increased to be higher than a predetermined temperature by the radiation of a light upon reproducing and in which a recorded information held on said recording layer (13) is read out from said reproducing layer (11) in the radiated area (5) except the area (14) in which said magnetic coupling is lost. Furthermore, the apparatus comprises means (62) for generating a second channel clock used to write and/or read data in and/or from a second magneto-optical recording medium (10) in which a recorded information is reproduced by using substantially whole area of the radiated area (5). Moreover, the apparatus comprises a discriminating means (70) for discriminating said first magneto-optical recording medium (10) and the second magneto-optical recording medium (10) and means (40) for switching first and second channel clocks in response to a discriminating signal from said discriminating means (70).

公开(公告)号：DE69128884D1

公开(公告)日：1998-03-12

申请号：DE69128884

申请日：1991-10-18

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI ,  ONO MASUMI ,  YASUDA KOUICHI

IPC: G11B7/005 ,  G11B11/105 ,  G11B11/10 ,  G11B7/00

Abstract: An optically recording medium in which by projecting a light beam for reading out signals onto a recording layer of a multilayer film including a record retaining layer and a reproducing layer which is coupled magnetically to the record retaining layer, the data recorded in the record retaining layer and the reproducing layer is erased or the signals recorded magnetically in the record retaining layer are transferred to the reproducing layer, and simultaneously the signals are read out through the conversion of the signals into optical signals by the magnetooptic effect. Another optically recording medium in which by projecting a light beam for reading out signals onto the optically recording medium in which phase pits whose reflection factors change with temperature are formed, the reflection factor are varied partially in the scanning spot of the light beam for reading out signals, and the phase pits are read out. When the wavelength of the light beam is lambda and the numerical aperture of an objective lens is NA, the minimum spaces between the phase pits in the scanning direction of the light beam is lambda /2NA or less. Thereby, the linear recording density is increased, and the recording capacity of the medium can be increased.

公开(公告)号：AT151907T

公开(公告)日：1997-05-15

申请号：AT92102084

申请日：1992-02-07

Applicant: SONY CORP

Inventor： NAKAO ISAMU ,  FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI

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

Abstract: A method and apparatus for recording and reproducing information onto and from a magneto-optic recording medium (100) is disclosed. The magneto-optic recording medium (100) has at least a reproducing layer (110) and a recording layer (130). A recording optical head (51) records information on the magneto-optic recording medium (100). A reproducing optical head (61) has a reading light beam for reading information recorded in a region within a spot of the reading light beam by magneto-optic effect by changing a state of magnetization of the reproducing layer (110) and at the same time irradiating the recording medium (100) with the light beam. A wavelength of the recording light beam emitted by the recording optical head (51) is substantially smaller than a wavelength of the reading light beam emitted by the reading optical head. A minimum ratio of the wavelength of the recording light beam to that of the reproducing light beam is 1:3.

公开(公告)号：DE69120671D1

公开(公告)日：1996-08-08

申请号：DE69120671

申请日：1991-10-19

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI ,  ONO MASUMI ,  YASUDA KOUICHI

IPC: G11B7/005 ,  G11B11/105 ,  G11B11/10

公开(公告)号：DE69129300T2

公开(公告)日：1998-12-03

申请号：DE69129300

申请日：1991-10-18

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI ,  OHTA MASUMI ,  ONO MASUMI ,  YASUDA KOUICHI

IPC: G11B7/005 ,  G11B11/105 ,  G11B11/10 ,  G11B7/00 ,  G11B7/007

Abstract: An optically recording medium in which by projecting a light beam for reading out signals onto a magneto-optical recording medium having a multilayer film including the record retaining layer and the reproducing layer which is coupled magnetically to the record retaining layer, the signals recorded magnetically in a record retaining layer are transferred to a reproducing layer and the signals are read out through the conversion of the signal to optical signals by the magneto-optic effect. Another optically recording medium in which by projecting a light beam for reading out signals onto an optically recording medium in which phase pits are formed and their reflection factors change with temperature, the reflection factors are varied partially in a scanning spot, and the phase pits are read out. The track pitch (p) of a pit RP, which is a recorded signal, in the direction perpendicular to the scanning direction of a laser beam is a half or less of the diameter D of the spot of the laser beam. Thereby the track density is increased, and the recording capacity of the medium can be increased.

公开(公告)号：DE69128884T2

公开(公告)日：1998-09-03

申请号：DE69128884

申请日：1991-10-18

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI ,  ONO MASUMI ,  YASUDA KOUICHI

IPC: G11B7/005 ,  G11B11/105 ,  G11B11/10 ,  G11B7/00

Abstract: An optically recording medium in which by projecting a light beam for reading out signals onto a recording layer of a multilayer film including a record retaining layer and a reproducing layer which is coupled magnetically to the record retaining layer, the data recorded in the record retaining layer and the reproducing layer is erased or the signals recorded magnetically in the record retaining layer are transferred to the reproducing layer, and simultaneously the signals are read out through the conversion of the signals into optical signals by the magnetooptic effect. Another optically recording medium in which by projecting a light beam for reading out signals onto the optically recording medium in which phase pits whose reflection factors change with temperature are formed, the reflection factor are varied partially in the scanning spot of the light beam for reading out signals, and the phase pits are read out. When the wavelength of the light beam is lambda and the numerical aperture of an objective lens is NA, the minimum spaces between the phase pits in the scanning direction of the light beam is lambda /2NA or less. Thereby, the linear recording density is increased, and the recording capacity of the medium can be increased.

公开(公告)号：DE69129300D1

公开(公告)日：1998-05-28

申请号：DE69129300

申请日：1991-10-18

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI ,  OHTA MASUMI ,  ONO MASUMI ,  YASUDA KOUICHI

IPC: G11B7/005 ,  G11B11/105 ,  G11B11/10 ,  G11B7/00 ,  G11B7/007

Abstract: An optically recording medium in which by projecting a light beam for reading out signals onto a magneto-optical recording medium having a multilayer film including the record retaining layer and the reproducing layer which is coupled magnetically to the record retaining layer, the signals recorded magnetically in a record retaining layer are transferred to a reproducing layer and the signals are read out through the conversion of the signal to optical signals by the magneto-optic effect. Another optically recording medium in which by projecting a light beam for reading out signals onto an optically recording medium in which phase pits are formed and their reflection factors change with temperature, the reflection factors are varied partially in a scanning spot, and the phase pits are read out. The track pitch (p) of a pit RP, which is a recorded signal, in the direction perpendicular to the scanning direction of a laser beam is a half or less of the diameter D of the spot of the laser beam. Thereby the track density is increased, and the recording capacity of the medium can be increased.

公开(公告)号：DE69218986T2

公开(公告)日：1997-11-20

申请号：DE69218986

申请日：1992-02-07

Applicant: SONY CORP

Inventor： NAKAO ISAMU ,  FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI

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

Abstract: A method and apparatus for recording and reproducing information onto and from a magneto-optic recording medium (100) is disclosed. The magneto-optic recording medium (100) has at least a reproducing layer (110) and a recording layer (130). A recording optical head (51) records information on the magneto-optic recording medium (100). A reproducing optical head (61) has a reading light beam for reading information recorded in a region within a spot of the reading light beam by magneto-optic effect by changing a state of magnetization of the reproducing layer (110) and at the same time irradiating the recording medium (100) with the light beam. A wavelength of the recording light beam emitted by the recording optical head (51) is substantially smaller than a wavelength of the reading light beam emitted by the reading optical head. A minimum ratio of the wavelength of the recording light beam to that of the reproducing light beam is 1:3.

公开(公告)号：DE69030656D1

公开(公告)日：1997-06-12

申请号：DE69030656

申请日：1990-12-17

Applicant: SONY CORP

Inventor： UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI ,  OHTA MASUMI

IPC: G11B7/0045 ,  G11B7/125 ,  G11B11/105 ,  G11B20/10

Abstract: The optical recording apparatus comprises a pattern detector (31) is provided to detect a pattern of recording signal pulses. If the pulses spacing of the signal is shorter than a predetermined value, the amplitude of the subsequent signal pulses is decreased by a control signal from am amplitude limiting memory (33) so as to reduce the irradiation energy of the laser pulse. This offsets the influences of remaining heat of the recording medium due to the laser pulse corresponding to the preceding signal pulse and makes it possible to record accurately the pulse signals in a high density . @(24pp DWg.No. 4/9)@.

公开(公告)号：DE69119418T2

公开(公告)日：1997-01-09

申请号：DE69119418

申请日：1991-10-19

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI ,  ONO MASUMI ,  YASUDA KOUICHI

IPC: G11B7/005 ,  G11B11/105 ,  G11B19/02 ,  G11B11/10

Abstract: A method for reproducing signals in an optically recording medium of the type in which recording pits are erased or embossed by the temperature rise of the medium caused through projecting a light beam for reading out signals, or of the type in which the reflection factors of recording pits are changed by the temperature rise of the medium caused through projecting a light beam. The change of the substantial size of a reproducing region because of the change of the linear velocity of the medium is prevented. For this prevention, for example, a sensing means (17) for sensing the position of the reproducing region in a radial direction of the magneto-optical disc (11) during the rotation of the disc (11) at a constant speed is provided. By controlling the laser power and the external magnetic field according to the output of the sensing means (17), the substantial size of the reproducing region is so controlled as to be constant always independently of the linear velocity in each reproducing position.