公开(公告)号：JPH05250741A

公开(公告)日：1993-09-28

申请号：JP4874892

申请日：1992-03-05

Applicant: SEIKO EPSON CORP

Inventor： KAWASE TAKEO ,  ISHIDA MASAYA

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To realize mass production and distribution of music information, video information, and the like by recording binary information while discriminating between two type of regions having heat absorbent layers of different thickness and increasing the recording density through ultra-resolution method. CONSTITUTION:The optical recording medium has two type of regions where the film thickness of heat absorbent layer 105 is different. A target optical recording medium can be obtained by removing excessive heat absorbent layer 105 through dry etching until a target thickness is achieved. Since waveform interference does not take place between pits, the reproduction of high density pit, which is difficult in conventional optical recording medium, can be realized and thereby ultra-high resolution reproduction can be carried out on a recording medium dedicated for reproduction.

公开(公告)号：JPH05198020A

公开(公告)日：1993-08-06

申请号：JP771992

申请日：1992-01-20

Applicant: SEIKO EPSON CORP

Inventor： TANAKA TARO ,  SHIMOKAWATO SATOSHI ,  ISHIDA MASAYA

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To enable recording at a low magnetic field and to improve stability at the time of reproducing by forming a recording layer which has a specific or higher coercive force and the magnetic wall antimagnetic force smaller by a specific value or above than the coercive force at room temp. CONSTITUTION:A dielectric layer 12, the recording layer 13, a reflection film 15, a protective film layer 16, etc., are successively formed on a substrate 11. The recording layer 13 is formed of NdDyFeCo, etc., having >=5.0kOe coercive force and the magnetic wall antimagnetic force smaller by >=2.0kOe than the coercive force. The coercive force of the layer 13 is changed by changing the compsn. ratios of the NdDyFeCo and the magnetic wall antimagnetic force is lowered by executing reverse sputtering of the layer 12 before forming the layer 13 after the formation of the layer 12 and changing the time of the reverse sputtering. As a result, C/N is satd. by the small magnetic field at the time of recording and the stability of data at the time of reproducing is assured.

公开(公告)号：JPH04146544A

公开(公告)日：1992-05-20

申请号：JP26761190

申请日：1990-10-05

Applicant: SEIKO EPSON CORP

Inventor： ISHIDA MASAYA ,  SHIMOKAWATO SATOSHI ,  ITO HIROSHI ,  HOSHINA SHOJI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To obtain a good overwrite system by specifying a laser pulse. CONSTITUTION:Information is recorded by a laser pulse having a relatively short pulse duration and high laser power and a laser pulse having a relatively long pulse duration and low laser power, and a laser pulse repeating frequency is specified as >=15MHz. In this case, when an erasing pulse repeating frequency is decided to be >=15MHz, unerased remainders are eliminated, and very good rewrite is feasible. By this method, good direct overwrite can be realized.

公开(公告)号：JPH04146541A

公开(公告)日：1992-05-20

申请号：JP26761090

申请日：1990-10-05

Applicant: SEIKO EPSON CORP

Inventor： ISHIDA MASAYA ,  SHIMOKAWATO SATOSHI ,  ITO HIROSHI ,  HOSHINA SHOJI

IPC: G11B11/10 ,  G11B7/00 ,  G11B7/0055 ,  G11B7/30 ,  G11B11/105

Abstract: PURPOSE:To facilitate an erasing operation and further to simultaneously allow a recording operation as well by providing a magnetic film having the axis of easy magnetization in the direction perpendicular to the film plane via a an intra-surface magnetized film of a film thickness is contact with a magneto-optical recording layer. CONSTITUTION:The magnetic film having the axis of easy magnetization in the direction perpendicular to the film is formed in contact with the recording film. If a magnetic wall exists at the boundary between the recording layer and the magnetic layer, the state of the energy higher by as much as the presence of the boundary magnetic wall is resulted. The magnetic walls contracts in the direction where a magnetic domain diminishes in order to decrease the energy of the boundary magnetic wall if the recording film is irradiated with such laser pulses as to steepen the temp. distribution of the recording film in this state. Then, the magnetic film is formed in contact with the recording film even with the recording film having such magnetic characteristics as not to allow the magnetic wall to cause shrinkage in the case of the single layered recording film or even with such a temp. distribution as not to allow the magnetic wall to cause sufficient shrinkage in the case of the single layer. The magnetic wall is shrink in this way and the erasing is well executed. Further, the recording and erasing are both well executed.

公开(公告)号：JPH02297741A

公开(公告)日：1990-12-10

申请号：JP11971589

申请日：1989-05-12

Applicant: SEIKO EPSON CORP

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

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To securely erase information and to obtain excellent overwrite characteristics by unproviding a guide groove on an information recording part of an information recording medium. CONSTITUTION:No guide groove for making a beam spot follow is provided on a disk of the magneto-optical recorder capable of overwriting information only by optical modulation without changing the size and direction of an impressing magnetic field for recording and erasing information. Consequently, since thermal conduction is not impeded in the radial direction of the disk, and hence a temp. gradient can be secured enough, a control on magnetic domains can securely be performed. By this method, no erasing remainder of information takes place, and hence the high reliable overwriting is feasible.

公开(公告)号：JPH02265056A

公开(公告)日：1990-10-29

申请号：JP8592089

申请日：1989-04-05

Applicant: SEIKO EPSON CORP

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

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To realize a high transfer rate being capable of overwrite directly by providing separately plural optical systems, and installing a semiconductor laser in a fixed part so that a pulse oscillation for an erasion can be facilitated. CONSTITUTION:A semiconductor laser LD 3 attached to a chassis base 2 is connected directly to a drive stage 35 of an LD driving circuit 34. Therefore, a laser oscillation for an erasion is obtained easily, and a high transfer rate being capable of overwrite directly is realized. Thereafter, the laser LD 3 is shaped to parallel beams by a galvanomirror 7, and emitted from a fixed optical system 1. Also, the optical system 1 detects a magnetic signal and a servo-signal from a laser beam reflected from a magneto-optical disk 11. Moreover, the laser LD 3 is brought to optical path conversion by a mirror 9 of a moving optical system 8, and condensed to a recording film 12 of the disk 11 by an objective lens 10. The optical system 8 is loaded on a voice coil motor, and moves between the innermost periphery 16 and the outermost periphery 17 of a recording area of the disk 11.

公开(公告)号：JPH02265049A

公开(公告)日：1990-10-29

申请号：JP8590889

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：JPH02265047A

公开(公告)日：1990-10-29

申请号：JP8590689

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：JPH02265045A

公开(公告)日：1990-10-29

申请号：JP8590489

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 x, y, z in formula I are set at the value satisfying formula II when the compsn. is expressed in atomic ratio by the formula I. The ratios of Fe, Co and Ni can be arbitrarily set in order to regulate the properties, such as Curie temp. and compensation temp., to desired values by the recording and reproducing conditions of the medium. However, x+y in the compsn. of the formula I, i.e. the ratio of the entire rare earth in the film are required to be confined in a 15 to 40 atomic % range in order for the compsn. to be the perpendicularly magnetized film which is the essential requirement as the magneto-optical recording medium. The satd. biasing magnetic field of the C/N is lowered in this way without lowering the C/N of the magneto-optical recording medium.

公开(公告)号：JPH02265044A

公开(公告)日：1990-10-29

申请号：JP8590389

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 x, y, z in formula I are set at the value satisfying formula II when the compsn. is expressed in atomic ratio by the formula I. The ratios of Fe, Co and Ni can be arbitrarily set in order to regulate the properties, such as Curie temp. and compensation temp., to desired values by the recording and reproducing conditions of the medium. However, x+y in the compsn. of the formula I, i.e. the ratio of the entire rare earth in the film are required to be confined in a 15 to 40 atomic % range in order for the compsn. to be the perpendicularly magnetized film which is the essential requirement as the magneto-optical recording medium. The satd. biasing magnetic field of the C/N is lowered in this way without lowering the C/N of the magneto-optical recording medium.