公开(公告)号：DE69119414T2

公开(公告)日：1997-01-02

申请号：DE69119414

申请日：1991-10-19

Applicant: SONY CORP

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

IPC: G11B7/004 ,  G11B7/005 ,  G11B7/125 ,  G11B7/126 ,  G11B11/105 ,  G11B19/02 ,  G11B19/04 ,  G11B33/14 ,  G11B11/10 ,  G11B7/00

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 variation of the substantial size of the reproducing region because of the change of the temperature of the medium is prevented. For this prevention, for example, a temperature sensor (20) for sensing the temperature of a magnetooptical disc (11) is provided. By controlling the laser power and the external magnetic field according to the temperature sensed by this temperature sensor (20), the substantial size of the reproducing region is kept constant always.

公开(公告)号：DE69120671T2

公开(公告)日：1997-02-27

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：DE69217800D1

公开(公告)日：1997-04-10

申请号：DE69217800

申请日：1992-10-07

Applicant: SONY CORP

Inventor： ONO MASUMI ,  FUKUMOTO ATSUSHI ,  YASUDA KOUICHI

IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/005 ,  G11B7/09 ,  G11B7/095 ,  G11B7/135 ,  G11B11/105

Abstract: In an optical disk reproducing apparatus, such an optical disk (11) is reproduced.The optical disk (11) is manufactured in such a way that a material layer (3) whose reflectivity is lowered when a temperature of this material becomes higher than a preselected temperature, is fabricated on a transparent substrate (2). A plurality of phase pits (1) have been formed in this substrate in response to an information signal. The optical disk (11) reproducing apparatus comprises: an optical pickup (12-21) for reading the information signal by irradiating on a recording plane of the optical disk (11), both of a first optical spot (SP )for reproducing the information signal, and also second and third optical spots (+/- SP ) each having light intensity lower than light intensity of the first optical spot (SP ) and located at positions where there is no adverse influence caused by a thermal history of the first optical spot (SP ); and a tracking control unit (23, 26) for performing a tracking control of the optical pickup based upon a difference signal between detection signals derived from first and second photo detecting units (21B, 21F) of the optical pickup (12 - 21), for receiving light of the second and third optical spots (+/- SP ) reflected from the optical disk (11).

公开(公告)号：DE69119418D1

公开(公告)日：1996-06-13

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.

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：DE69217800T2

公开(公告)日：1997-06-12

申请号：DE69217800

申请日：1992-10-07

Applicant: SONY CORP

Inventor： ONO MASUMI ,  FUKUMOTO ATSUSHI ,  YASUDA KOUICHI

IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/005 ,  G11B7/09 ,  G11B7/095 ,  G11B7/135 ,  G11B11/105

Abstract: In an optical disk reproducing apparatus, such an optical disk (11) is reproduced.The optical disk (11) is manufactured in such a way that a material layer (3) whose reflectivity is lowered when a temperature of this material becomes higher than a preselected temperature, is fabricated on a transparent substrate (2). A plurality of phase pits (1) have been formed in this substrate in response to an information signal. The optical disk (11) reproducing apparatus comprises: an optical pickup (12-21) for reading the information signal by irradiating on a recording plane of the optical disk (11), both of a first optical spot (SP )for reproducing the information signal, and also second and third optical spots (+/- SP ) each having light intensity lower than light intensity of the first optical spot (SP ) and located at positions where there is no adverse influence caused by a thermal history of the first optical spot (SP ); and a tracking control unit (23, 26) for performing a tracking control of the optical pickup based upon a difference signal between detection signals derived from first and second photo detecting units (21B, 21F) of the optical pickup (12 - 21), for receiving light of the second and third optical spots (+/- SP ) reflected from the optical disk (11).

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.