公开(公告)号：JPH05120752A

公开(公告)日：1993-05-18

申请号：JP27911891

申请日：1991-10-25

Applicant: SEIKO EPSON CORP

Inventor： ISHIDA MASAYA ,  KAWASE TAKEO ,  SHIMOKAWATO SATOSHI

IPC: G11B5/86 ,  G11B7/125 ,  G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To obtain constant reproducing characteristics over the full surface of a disk with lasers of two wavelengths, and in addition, to prevent temperature rise in the reproduction area and to increase the CN ratio of a regenerative signal. CONSTITUTION:In a magneto-optical recording system reproducing information while transferring the information of a recording magnetic layer in a reproducing magnetic layer by using magneto-optical recording medium having the reproducing magnetic layer and the recording magnetic layer, at the time of reproducing the information, two laser beams of different wavelengths are converged on a recorded surface and the parts of two laser spots 1 and 2 are superposed in the direction of the medium moving on the medium.

公开(公告)号：JPH05120751A

公开(公告)日：1993-05-18

申请号：JP27911791

申请日：1991-10-25

Applicant: SEIKO EPSON CORP

Inventor： ISHIDA MASAYA ,  KAWASE TAKEO ,  SHIMOKAWATO SATOSHI

IPC: G11B5/86 ,  G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To enable the adoption of a modulation system reading information from a magneto-optical recording medium recorded with super high density and recording the information with higher density. CONSTITUTION:In a magneto-optical recording method using the recording medium consisting of a reproducing magnetic layer and a recording magnetic layer, after the reproducing magnetic layer is magnetized to one direction and initialized previous to reproducing, is irradiated by a continuous or an intermittent laser pulse, and the information recorded on the recording layer is transferred to the reproducing layer, thereafter, the magnetized information is read by a magneto-optical effect.

公开(公告)号：JPH04332941A

公开(公告)日：1992-11-19

申请号：JP10124991

申请日：1991-05-07

Applicant: SEIKO EPSON CORP

Inventor： ISHIDA MASAYA

IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/0055 ,  G11B7/125 ,  G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To achieve an overwrite system which enables signal to be reproduced without any errors by keeping a time interval from termination of irradiation of an optical pulse to starting of irradiation of a continuous next optical pulse to be a specified amount of time. CONSTITUTION:In an optical magnetic recording system where a protection film 2, a recording film 3, a protection film 4, a reflection film 5, and further a protection film are formed on a polycarbonate substrate 1 by the sputtering method and information is recorded and erased by changing only intensity of a laser beam and its pulse width while keeping the intensity of the magnetic field to be constant all the time while using a disk which is laminated by an ultra-violet rays cured resin 6, a time interval from ending of irradiation of an optical pulse to starting of irradiation of the continuous next pulse is kept to be 15 nano seconds or longer, thus enabling a desired recording to be performed positively and achieving an improved direct overwrite with a low pit error rate of reproduction signal.

公开(公告)号：JPH035931A

公开(公告)日：1991-01-11

申请号：JP13970789

申请日：1989-06-01

Applicant: SEIKO EPSON CORP

Inventor： ISHIDA MASAYA ,  SHIMOKAWATO SATOSHI ,  HORIKAWA MITSUHIRO ,  IDE TSUGIO ,  ITO HIROSHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To realize direct overwriting by light modulation method and to improve long-term reliability of the medium by forming a heat conducting layer adjacent to a recording layer, opposite to the substrate side of the recording layer, then forming a heat insulating layer on the heat conducting layer, and sticking this medium with a transparent substrate or another medium of same structure. CONSTITUTION:The magneto-optical recording medium has a rare earth- transition metal thin film formed on a transparent substrate. A heat conducting layer 4 is formed adjacent to the recording layer and on the opposite side to the substrate side, and then a heat insulating layer 5 is formed thereon. A transparent substrate 7 or another medium of same structure is stuck to said medium to form a magneto-optical recording medium. Thereby, overwriting can be performed without changing direction of the magnetic field applied on the medium, and further, deterioration of a film due to temp. can be prevented. The obtd. medium has long-term stability in recording/erasing property and has long-term reliability.

公开(公告)号：JPH02302950A

公开(公告)日：1990-12-14

申请号：JP12382089

申请日：1989-05-17

Applicant: SEIKO EPSON CORP

Inventor： SHIMOKAWATO SATOSHI ,  ISHIDA MASAYA

IPC: C22C38/00 ,  G11B11/10 ,  G11B11/105 ,  H01F10/14

Abstract: PURPOSE:To allow the direct overwriting of information even with a small modulating magnetic field by specifying the content of Nd or Pr to 3 to 10 atm.% and the content of Dy to 18 to 28 atm.% CONSTITUTION:This magneto-optical recording medium executes the recording of information by irradiating a magnetic film with the convergent light of a specified intensity or modulated according to the recording information simultaneously with the impression of the magnetic fields modulated according to the recording information. The recording layer of the magneto-optical recording medium of this case is formed of the thin film of the rare earth transition metal alloy contg. 3 to 10 atomic% Nd or Pr and 18 to 28 atomic% Dy or Tb and contg. at least Fe. The magneto-optical recording medium which allows the direct overwriting of the information even with the small modulating magnetic fields in the magnetic field modulation recording system is obtd. in this way and the higher speed of a data transfer rate is realized.

公开(公告)号：JPH02265060A

公开(公告)日：1990-10-29

申请号：JP8740389

申请日：1989-04-06

Applicant: SEIKO EPSON CORP

Inventor： HORIKAWA MITSUHIRO ,  ITO HIROSHI ,  IDE TSUGIO ,  SHIMOKAWATO SATOSHI ,  ISHIDA MASAYA

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To directly perform over-lighting and to obtain a high-quality signal by arranging a permanent magnet so that the generated magnetic field direction thereof may be same at the time of recording and at the time of erasing and modulating the intensity of a light beam by the use of an electro-optical effect optical modulator. CONSTITUTION:First, recording and reproducing a signal is performed with recording laser power and reproducing laser power under a specified condition to confirm recording and erasion. At such a time, the permanent magnet 1 is arranged so that the generated magnetic field direction thereof may be the same. By setting the intensity of the laser at the time of modulation between the levels of the recording or reproducing laser power and modulating the intensity of the light beam by the use of the electro-optical effect optical modulator, the reproducing signal is prevented from being deteriorated and the high- quality signal is obtained. In a magneto-optical disk memory device whose both sides can be used and where disks can be interchanged, it is unnecessary to invert the direction of the magnetic field necessary for recording and erasing information, thereby directly performing the over-lighting.

公开(公告)号：JPH02265048A

公开(公告)日：1990-10-29

申请号：JP8590789

申请日：1989-04-05

Applicant: SEIKO EPSON CORP

Inventor： MIYAZAWA HIROSHI ,  SHIMOKAWATO SATOSHI ,  ISHIDA MASAYA

IPC: C22C45/02 ,  C22C45/04 ,  G11B11/10 ,  G11B11/105 ,  H01F10/12 ,  H01F10/13 ,  H01F10/16

Abstract: PURPOSE:To allow a good recording and erasing with a low biasing magnetic field by using a thin film consisting of a specific compsn. as an amorphous alloy thin film having the axis of easy magnetization in the direction perpendicular to the film plane. CONSTITUTION:The recording layer is the amorphous alloy thin film having the axis of easy magnetization in the direction perpendicular to the film plane and the compsn. thereof, when expressed by formula I in atomic ratio, is so formed that x, y, z in the formula I attain the values satisfying formula II. The ratios of Fe, Co and Ni in this compsn. can be arbitrarily set in order to maintain the properties, such as Curie temp. and compensation temp., at desired values according to the recording and reproducing conditions of the medium. The compsn. of the formula I is required to have x+y, i.e., the ratio of the entire rare earth in the film within a 15 to 40 atomic % range in order to be a perpendicularly magnetized film which is the essential requirement as the magneto-optical recording medium. The satd. biasing magnetic field of C/N is decreased in this way without lowering the C/N of the magneto-optical recording medium.

公开(公告)号：JPH02216641A

公开(公告)日：1990-08-29

申请号：JP3540089

申请日：1989-02-15

Applicant: SEIKO EPSON CORP

Inventor： MIZUTANI TADASHI ,  SHIMOKAWATO SATOSHI ,  ISHIDA MASAYA

IPC: C22C45/00 ,  C22C45/02 ,  C22C45/04 ,  G11B11/10 ,  G11B11/105 ,  H01F10/12 ,  H01F10/13 ,  H01F10/16

Abstract: PURPOSE:To obtain a magneto-optical recording medium which enables good recording/erasing even in a low bias magnetic field by constituting the recording layer of a specific amorphous metal thin film having the easily magnetizing axis perpendicular to the film surface. CONSTITUTION:The magneto-optical recording medium has the recording layer of an amorphous film having the easily magnetizing axis perpendicular to the surface thereof and the composition expressed by (Nd,Pr)x(SmzTb1-z)y(Fe, Co, Ni)100-x-y, wherein x, y and z satisfy the formula I. Proportions of the amounts of Fe, Co and Ni can be arbitrarily controlled according to the conditions of recording/erasing for the medium so as to obtain desired values of physical properties such as Curie temp. and compensation temp. However, to obtain a perpendicularly magnetized film, which is the requirement for the magneto- optical recording medium, from the composition above described, it is necessary to make the proportion of total rare earth elements (x+y) in the film in the range from 15at.% to 40at.%. Thus, the obtd. recording medium enables good recording/erasing even in a low bias magnetic field.

公开(公告)号：JPH02216637A

公开(公告)日：1990-08-29

申请号：JP3539689

申请日：1989-02-15

Applicant: SEIKO EPSON CORP

Inventor： MIZUTANI TADASHI ,  SHIMOKAWATO SATOSHI ,  ISHIDA MASAYA

IPC: C22C45/00 ,  C22C45/02 ,  C22C45/04 ,  G11B11/10 ,  G11B11/105 ,  H01F10/12 ,  H01F10/13 ,  H01F10/16

Abstract: PURPOSE:To obtain a magneto-optical recording medium which enables good recording/erasing even in a low bias magnetic field by constituting the recording layer of a specific amorphous metal thin film having the easily magnetizing axis perpendicular to the film surface. CONSTITUTION:The magneto-optical recording medium has the recording layer of an amorphous film having the easily magnetizing axis perpendicular to the surface thereof and the composition expressed by (Nd,Pr)x(SmzGd1-z)y(Fe, Co, Ni)100-x-y, wherein x, y and z satisfy the formula I. Proportions of the amounts of Fe, Co and Ni can be arbitrarily controlled according to the conditions of recording/erasing for the medium so as to obtain desired values of physical properties such as Curie temp. and compensation temp. However, to obtain a perpendicularly magnetized film, which is the requirement for the magneto- optical recording medium, from the composition above described, it is necessary to make the proportion of total rare earth elements (x+y) in the film in the range from 15at.% to 40at.%. Thus, the obtd. recording medium enables good recording/erasing even in a low bias magnetic field.

公开(公告)号：JPH02201756A

公开(公告)日：1990-08-09

申请号：JP2151189

申请日：1989-01-31

Applicant: SEIKO EPSON CORP

Inventor： ISHIDA MASAYA ,  SHIMOKAWATO SATOSHI ,  ITO HIROSHI ,  HORIKAWA MITSUHIRO ,  IDE TSUGIO

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To obtain the magneto-optical recording medium which is less deteriorated in film quality by a temp. rise, is small in the jitter quantity of reproduction signals and is suitable for overwriting by forming a thermally conductive film in contact with a recording film on the side of the recording film opposite to a substrate and respectively specifying the thermal conductivity and film thickness thereof. CONSTITUTION:The recording film 3 essentially consisting of a rare earth- transition metal and protective films 1, 4 are formed on the substrate 5 and the thermally conductive film 2 is formed on contact with the recording film 3 on the side of the recording film 3 opposite to the substrate 5. The thermally conductive film 3 is so formed as to have >=50W/m.K thermal conductivity and the film thickness ranging >=20nm to