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1. 发明专利

DE69032931D1 未知
公开(公告)号：DE69032931D1
公开(公告)日：1999-03-18
申请号：DE69032931
申请日：1990-11-13
申请人： HITACHI MAXELL , HITACHI LTD
发明人： MIYAMOTO HARUKAZU , NIIHARA TOSHIO , TERAO MOTOYASU , OHTA NORIO , KUREBAYASHI MASAAKI
IPC分类号： G11B11/105 , G11B11/10
摘要： A magneto-optical recording medium having a substrate (1) and a magnetic layer composed of at least a recording layer (3) and a supporting layer (4) and being capable of retrieving information by utilizing the fact that when it is irradiated with a laser beam it produces the magneto-optical effect which affects its reflected light, characterized in that the recording layer (3) has a lower Curie temperature than has the supporting layer (4) and the recording layer (3) is thin enough for the laser beam to pass through. A magneto-optical recording medium as defined above, wherein the supporting layer (4) is composed of a first supporting layer and a second supporting layer, and the recording layer (3), the first supporting layer, and the second supporting layer have Curie temperatures of T1, T2, and T3, respectively, which satisfy the following relationship. T1 /= T3 A magneto-optical recording medium defined as above, wherein the recording layer (3) has a higher Curie temperature than has the supporting layer (4). Owing to the above-mentioned features, the magneto-optical recording media of the present invention are capable of overwriting and have improved recording sensitivity.

2. 发明专利

DE68928712T2 未知
公开(公告)号：DE68928712T2
公开(公告)日：1998-10-15
申请号：DE68928712
申请日：1989-11-06
申请人： HITACHI MAXELL , HITACHI LTD
发明人： KIRINO FUMIYOSHI SANIKOPO TAKA , MIYAMOTO HARUKAZU , OKAMINE SHIGENORI , OGIHARA NORIYUKI , TAKAHASHI MASAHIKO , OHTA NORIO , NIIHARA TOSHIO
IPC分类号： G11B11/105 , G11B11/10
摘要： In a magneto-optical disk for recording, reproduction or erasing with a laser beam, which comprises a film of four-layer structure consisting of a first dielectric layer (2), a magneto-optical recording layer (3), a second dielectric layer (4) and a metallic layer (5), laid on a disk substrate (1) provided with guide tracks, temperature distribution of the magneto-optical recording layer (3) is controlled by controlling the thermal diffusivity of the metallic layer (5), and recording/reproduction/erasing repetition characteristics are improved thereby. In the disk of the present structure, the temperature is elevated in a broader area from the center of laser beam, and thus a thoroughly broad erasing domain width taking a track offset into account can be obtained and not recording domains remain after the erasing. The reproduced signal output is increased by 4 dB, as compared with that obtained by a disk of three-layer structure without any metallic layer, because the beam utilization efficiency is increased owing to both Kerr effect and Faraday effect. When the disk of the present structure is subjected to field modulation recording, tails of arrow-feather-shaped recording domains peculiar to the field modulation recording can be shortened and interbit interferences can be overcome, resulting in an increase in C/N (S/N) ratio and the high density recording can be made. By endowing a Kerr enhancement action to the second dielectric layer (4) and a protective action on the magneto-optical layer (3) to the first dielectric layer (2), only the reliability can be improved without lowering the C/N ratio. By improving the corrosion resistance of the magneto-optical recording layer, the first dielectric layer (2) can be omitted to the contrary, and a magneto-optical disk of simple structure can be obtained and used as memory for domestic applications or communication fields.

3. 发明专利

DE69032931T2 未知
公开(公告)号：DE69032931T2
公开(公告)日：1999-06-10
申请号：DE69032931
申请日：1990-11-13
申请人： HITACHI MAXELL , HITACHI LTD
发明人： MIYAMOTO HARUKAZU , NIIHARA TOSHIO , TERAO MOTOYASU , OHTA NORIO , KUREBAYASHI MASAAKI
IPC分类号： G11B11/105 , G11B11/10
摘要： A magneto-optical recording medium having a substrate (1) and a magnetic layer composed of at least a recording layer (3) and a supporting layer (4) and being capable of retrieving information by utilizing the fact that when it is irradiated with a laser beam it produces the magneto-optical effect which affects its reflected light, characterized in that the recording layer (3) has a lower Curie temperature than has the supporting layer (4) and the recording layer (3) is thin enough for the laser beam to pass through. A magneto-optical recording medium as defined above, wherein the supporting layer (4) is composed of a first supporting layer and a second supporting layer, and the recording layer (3), the first supporting layer, and the second supporting layer have Curie temperatures of T1, T2, and T3, respectively, which satisfy the following relationship. T1 /= T3 A magneto-optical recording medium defined as above, wherein the recording layer (3) has a higher Curie temperature than has the supporting layer (4). Owing to the above-mentioned features, the magneto-optical recording media of the present invention are capable of overwriting and have improved recording sensitivity.

4. 发明专利

DE68928712D1 未知
公开(公告)号：DE68928712D1
公开(公告)日：1998-07-23
申请号：DE68928712
申请日：1989-11-06
申请人： HITACHI MAXELL , HITACHI LTD
发明人： KIRINO FUMIYOSHI , MIYAMOTO HARUKAZU , OKAMINE SHIGENORI , OGIHARA NORIYUKI , TAKAHASHI MASAHIKO , OHTA NORIO , NIIHARA TOSHIO
IPC分类号： G11B11/105 , G11B11/10
摘要： In a magneto-optical disk for recording, reproduction or erasing with a laser beam, which comprises a film of four-layer structure consisting of a first dielectric layer (2), a magneto-optical recording layer (3), a second dielectric layer (4) and a metallic layer (5), laid on a disk substrate (1) provided with guide tracks, temperature distribution of the magneto-optical recording layer (3) is controlled by controlling the thermal diffusivity of the metallic layer (5), and recording/reproduction/erasing repetition characteristics are improved thereby. In the disk of the present structure, the temperature is elevated in a broader area from the center of laser beam, and thus a thoroughly broad erasing domain width taking a track offset into account can be obtained and not recording domains remain after the erasing. The reproduced signal output is increased by 4 dB, as compared with that obtained by a disk of three-layer structure without any metallic layer, because the beam utilization efficiency is increased owing to both Kerr effect and Faraday effect. When the disk of the present structure is subjected to field modulation recording, tails of arrow-feather-shaped recording domains peculiar to the field modulation recording can be shortened and interbit interferences can be overcome, resulting in an increase in C/N (S/N) ratio and the high density recording can be made. By endowing a Kerr enhancement action to the second dielectric layer (4) and a protective action on the magneto-optical layer (3) to the first dielectric layer (2), only the reliability can be improved without lowering the C/N ratio. By improving the corrosion resistance of the magneto-optical recording layer, the first dielectric layer (2) can be omitted to the contrary, and a magneto-optical disk of simple structure can be obtained and used as memory for domestic applications or communication fields.

5. 发明专利

DE3538852A1 未知
公开(公告)号：DE3538852A1
公开(公告)日：1986-05-07
申请号：DE3538852
申请日：1985-10-31
申请人： HITACHI LTD , HITACHI MAXELL
发明人： ASADA SEIICHI , SUZUKI HIROYUKI , NIIHARA TOSHIO , YOSHIDA KAZUETSU , FUTAMOTO MASAAKI , HONDA YUKIO , TSUMITA NORIKAZU , SHIIKI KAZUO
IPC分类号： G11B5/66 , G11B5/73 , G11B5/706 , B05D5/12
摘要： A perpendicular magnetic recording medium according to this invention comprises an electrically conductive underlayer formed on a non-magnetic substrate, in the case where no high permeability magnetic film is deposited, and a magnetic thin film having a perpendicular magnetic anisotrophy is formed thereon. In the case of a so-called double-layer structure including a high permeablilty magnetic film, on the non-magnetic substrate are formed the high permeablilty magnetic film, an intermediate film, and a magnetic thin film one on another in this order. The nearest neighbor's distance of atoms of the underlayer and the intermediate film is not smaller than 0.25 nm (2.5 ANGSTROM ) and not greater than 0.32 nm (3.2 ANGSTROM ) and they are made of at least one selected from the group consisting of V, Ru, Zn, Os, Rh, Ir, Mo, W, Re, Pd, Pt, Nb, Ta, Sn, Al, Au, Ag, Ti, nitrides and oxides of these elements.

6. 发明专利

JPH0773529A MAGNETO-OPTICAL RECORDING SYSTEM AND MAGNETO-OPTICAL RECORDING MEDIUM 失效
公开(公告)号：JPH0773529A
公开(公告)日：1995-03-17
申请号：JP21573893
申请日：1993-08-31
申请人： HITACHI LTD , HITACHI MAXELL
发明人： NAKAMURA KIMIO , MIYAMOTO JIICHI , NIIHARA TOSHIO
IPC分类号： G11B11/10 , G11B11/105 , G11B19/04
摘要： PURPOSE:To reduce the fluctuation of recording/reproducing performance against the variation of ambient temperature, movement speed, etc. CONSTITUTION:At the time of recording or reproducing operation, the temperature of a magneto-optical disk 10 is detected by a temperature detector 42, and from the detection result, the variation of temperature distribution on a magnetic layer of the disk 10 generated at the time of irradiation with laser beam is detected. In accordance with this result, the magnetic field is impressed on the magneto-optical disk 10 by an electromagnet 41 to compensate the fluctuation of recording or reproducing performance of the magneto-optical disk 10. Then, the stable magnetic domain is formed even though the temperature distribution is varied by the ambient temperature and the movement speed, heat sensitivity, etc., of the magneto-optical disk.

7. 发明专利

JPH05298758A 失效
公开(公告)号：JPH05298758A
公开(公告)日：1993-11-12
申请号：JP10268392
申请日：1992-04-22
申请人： HITACHI LTD , HITACHI MAXELL
发明人： NIIHARA TOSHIO , MIYAMOTO JIICHI , ANDO KEIKICHI , KIRINO FUMIYOSHI , OSHIMA MASAHIRO
IPC分类号： G11B11/10 , G11B11/105
摘要： PURPOSE:To incorporate excellent corrosion resistance and magnetic characteristics equivalent to those in a magnetic layer in which corrosion resistance improving element is not added therein. CONSTITUTION:A recording layer 6 containing an element for passivating a memory layer 5 when it is brought into contact with oxygen, moisture in the atmosphere is formed at an opposite side to a board 1 is formed on the layer 5 for storing information, and a reproducing layer 5 containing the similar passivation element is formed on the layer 5 at the same side as the board 1. Such a passivation element is not added to the layer 5. With this structure, it can be used for a long period and magnetic characteristics equivalent to those in which corrosion resistance improving element is not added in the magnetic layer are provided. High reliability is provided.

8. 发明专利

JPH04186544A OVERWRITABLE OPTOMAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPH04186544A
公开(公告)日：1992-07-03
申请号：JP31394690
申请日：1990-11-21
申请人： HITACHI LTD , HITACHI MAXELL
发明人： MIYAMOTO MAKOTO , NIIHARA TOSHIO , MIYAMOTO JIICHI , SUZUKI YOSHIO , ANDO KEIKICHI , AWANO HIROYUKI , OSHIMA MASAHIRO
IPC分类号： G11B11/10 , G11B11/105
摘要： PURPOSE:To increase the power margin at an erasure operation and a replay operation and to enhance reliability by a method wherein, at an exchanged and bonded double-layer film, the change rate of the inversion magnetic field of a first magnetic layer near an erasure start temperature with reference to a temperature is controlled to a prescribed value. CONSTITUTION:An overwritable recording medium is irradiated with light whose level (for replay use) is much lower than a low level (for erasure use) at a replay operation; the temperature of the medium is raised. At this time, a change in the inversion magnetic field Ht1 of a first magnetic layer with reference to a temperature T is set at Ht1=K.T+A (where A is a constant) at an erasure start temperature TES at which the erasure operation of recorded information is started. At this time, the first magnetic layer is composed in such a way that a proportionality constant K satisfies 50 (Oe/ deg.C)

9. 发明专利

JPH0464933A BOTH SIDES SIMULTANEOUS RECORDING AND REPRODUCING OPTICAL DISK, ITS PRODUCTION, AND OPTICAL DISK DEVICE USING THE DISK 失效
公开(公告)号：JPH0464933A
公开(公告)日：1992-02-28
申请号：JP17635190
申请日：1990-07-05
申请人： HITACHI LTD , HITACHI MAXELL
发明人： MIYAMURA YOSHINORI , NIIHARA TOSHIO , TERAO MOTOYASU
IPC分类号： G11B23/36 , G11B7/007 , G11B7/14 , G11B7/24 , G11B7/26 , G11B19/02 , G11B19/12 , G11B20/12 , G11B23/42
摘要： PURPOSE:To simultaneously read and write data on both sides by symmetrically arranging address pits or the like to be preliminarily formed so that they have the same contents by forward reproducing and backward reproducing. CONSTITUTION:Digital code '=A.B.C' corresponding to an address signal is concentrically or spirally exposed on the photo resist on the surface of a rotating glass substrate in the order of left digital information 3. After separation information 2 '-' is exposed, information 3 '=A.B.C' is reproduced in the opposite order, and right digital information 4 is so exposed that '=A.B.C' is correctly arranged. The exposed photo resist surface is developed and a photosensitive part is dissolved to form the address pit array of a track number or a sector number. By the simple method to combine two disk substrates obtained in this manner, optical heads are arranged on both sides of a disk and data on both sides are simultaneously recorded or reproduced to increase the access speed.

10. 发明专利

JPH0417140A METHOD OF MAGNETO-OPTICAL RECORDING/REPRODUCING, MAGNETO-OPTICAL RECORDING/REPRODUCING DEVICE AND RECORDING MEDIUM TO BE USED THEREFOR 失效
公开(公告)号：JPH0417140A
公开(公告)日：1992-01-21
申请号：JP12103190
申请日：1990-05-10
申请人： HITACHI LTD , HITACHI MAXELL
发明人： MIYAMOTO JIICHI , NIIHARA TOSHIO , TERAO MOTOYASU , OTA NORIO , TODA TAKESHI , SUKETA YASUSHI
IPC分类号： G11B11/10 , G11B11/105
摘要： PURPOSE:To enable overwriting with high sensitivity without a danger of erasing the recorded information with reproducing light by applying a bias magnetic field on the magneto-optical recording medium in a different direction or with different intensity from the bias magnetic field used on recording when the recorded information is to be reproduced. CONSTITUTION:Magnetization of the first magnetic layer 3 of the medium is transferred to the second magnetic layer 4 with reproducing bias magnetic field on overwriting, and thereby, the first magnetic layer 3 and the second magnetic layer 4 have the same magnetization direction. In this state, a light beam for reproducing is made to irradiate the medium. The magnetization of the first magnetic layer 3 and second magnetic layer 4 is oriented to give exchange coupling to each other, and this state is stable and can not be changed even when the reproducing light has same intensity as the low level of light for recording. Thereby, breaking of the recorded information is avoided even when irradiated by reproducing light of large intensity, and high-sensitive overwriting can be performed.

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