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1. 发明专利

JPH11328632A MAGNETIC HEAD 失效
公开(公告)号：JPH11328632A
公开(公告)日：1999-11-30
申请号：JP11181399
申请日：1999-04-20
申请人： HITACHI LTD
发明人： KOYAMA NAOKI , TAKANO KOJI , MORIWAKI HIDETOSHI , SHIIKI KAZUO
IPC分类号： G11B5/31 , G11B5/265 , G11B5/39
摘要： PROBLEM TO BE SOLVED: To reduce a record blurring at a recording head by making sizes of an upper and a lower parts of a shared magnetic layer agree with breadths necessary for a shield layer and a magnetic pole respectively. SOLUTION: When an upper and a lower parts of a shared magnetic layer have different specific magnetic permeabilities and saturation magnetic flux densities, with a recording magnetic pole being layered on a magnetoresistance effect type reproduction head, the reproduction head has a magnetoresistance effect element 4 of a thin film of Permalloy via an insulating layer between magnetic shield layers 2 and 6 serving also as magnetic poles. A lower magnetic pole 19 of a recording head is formed on the upper magnetic shield layer 6. At this time, the magnetic shield is formed of Permalloy of a film thickness of 0.7 μm and the magnetic pole 19 is formed of CoTaZr of a saturation magnetic flux density of 1.3T. Thereafter, a coil is formed via an insulating layer 8, onto which an upper magnetic pole 7 is formed. The lower magnetic shield layer 2, upper magnetic shield layer 6, lower magnetic pole 19 and upper magnetic pole 7 have sizes in a breadthwise direction of tracks of 100 μm, 90 μm, 8 μm and 6 μm respectively.

2. 发明专利

JP2539349B2 失效
公开(公告)号：JP2539349B2
公开(公告)日：1996-10-02
申请号：JP19072983
申请日：1983-10-14
申请人： HITACHI LTD
发明人： SHIROISHI YOSHIHIRO , SHIIKI KAZUO , KAMISAKA YASUTARO , HISHAMA SADAO , SHINAGAWA KIMINARI
IPC分类号： G11B5/66 , G11B5/64 , G11B5/667

3. 发明专利

JP2502965B2 失效
公开(公告)号：JP2502965B2
公开(公告)日：1996-05-29
申请号：JP21838484
申请日：1984-10-19
申请人： HITACHI LTD
发明人： SHIROISHI YOSHIHIRO , SHIIKI KAZUO , KUMASAKA TAKAYUKI , OOTOMO MOICHI , KUDO SANEHIRO
IPC分类号： G11B5/31 , G11B5/39 , H01F10/12

4. 发明专利

JPH06223308A MAGNETIC RECORDING/REPRODUCING APPARATUS 失效
公开(公告)号：JPH06223308A
公开(公告)日：1994-08-12
申请号：JP922893
申请日：1993-01-22
申请人： HITACHI LTD
发明人： SUDA MITSUO , SHIIKI KAZUO , TANABE MASANORI , NARUSHIGE SHINJI , NAKANISHI EIJI , SHIMIZU KOICHI , MIYAMOTO NORIFUMI , FUKUOKA HIROTSUGU
IPC分类号： G11B5/00 , G11B5/012 , G11B5/02 , G11B5/09 , G11B5/31 , G11B5/39 , G11B19/04
摘要： PURPOSE:To eliminate the Barkhousen noises and base line shift by altering a reading current to a magneto resistance effect type (MR) head magnetic film to perform a retrial when read errors are not restored by a repeating retrial. CONSTITUTION:When read errors occur with the reproduction of record information of a magnetic disc 1 by a compound head 3 of the MR head, a repeating retrial is performed through an offsetting function 62 and a retrial function 63 of a disc controller 6. Then, when the read errors are not restored after a specified number of retrials, a reading current to be applied to the MR film of the head 3 is altered by a reading current control function 61 of the controller 6 and the same repeating trial is performed. This achieves an elimination of the Barkhousen noises and base line shift of the MR head thereby preventing the generation of the lead errors.

5. 发明专利

JPH06111247A MAGNETIC DISC 失效
公开(公告)号：JPH06111247A
公开(公告)日：1994-04-22
申请号：JP25436292
申请日：1992-09-24
申请人： HITACHI LTD
发明人： SHIIKI KAZUO , NARUSHIGE SHINJI , TANABE MASANORI , SUDA MITSUO , YONEKAWA TAKAO , AMANO HIDEAKI , MATSUDA KENJI , HANADA KAZUYOSHI
IPC分类号： G11B5/39
摘要： PURPOSE:To obtain a magnetic disc employing a magnetoresistive effect type head which allows highly reliable high density recording. CONSTITUTION:The magnetic disc comprises a power supply 6 for applying voltage between a magnetic disc 1 and main element parts of a magnetic head 3, and an electrode 5 for applying a voltage onto a rotating magnetic disc 1. When the voltage being applied between the magnetic disc 1 and the main element parts of the magnetic head 3 is controlled, adhesion of foreign matter and leakage current can be prevented while avoiding sliding destruction.

6. 发明专利

JPH0660338A MAGNETO-RESISTANCE EFFECT TYPE HEAD, INSPECTION DEVICE FOR MAGNETO-RESISTANCE EFFECT TYPE HEAD AND MAGNETIC STORAGE DEVICE MOUNTING MAGNETO-RESISTANCE EFFECT TYPE HEAD 失效
公开(公告)号：JPH0660338A
公开(公告)日：1994-03-04
申请号：JP21689092
申请日：1992-08-14
申请人： HITACHI LTD
发明人： KOYANAGI HIROAKI , KAWAKAMI HIROJI , NARUSHIGE SHINJI , SHIIKI KAZUO
IPC分类号： G11B5/39 , G11B5/455
摘要： PURPOSE:To prevent the generation of damages to the magneto-resistance effect type head by providing a protection circuit for short-circuiting between a pair of electrodes when current more than a specified value is impressed to the pair of electrodes. CONSTITUTION:Electrodes 110 are mutually linked at the rear parts of the electrodes 110 via a Schottky diode 100 and a metal line 120. This diode 100 is a protection circuit in which no electricity is conducted when a specified driving power of a magneto-resistance effect type head 40 is applied. For example, current value of about 24mA and voltage of about 200mV are applied and when a voltage more than 300mV is instantaneously impressed, electricity is connected and the interval between the electrodes 110 is short-circuited. No electricity is conducted in the head 40 constituted like this by a normal driving power and when excess current generated by charge and static electricity through human intervention during an inspection process, etc., is given, electricity is conducted in the diode 100, the rear end part of the electrode is short-circuited and thus, the impression of the excess current to a magneto- resistance effect element 85 is prevented. Thus, damages to the element 85 is prevented by the short-circuiting between the electrode 110.

7. 发明专利

JPH0644527A THIN-FILM MAGNETIC HEAD 失效
公开(公告)号：JPH0644527A
公开(公告)日：1994-02-18
申请号：JP27524991
申请日：1991-10-23
申请人： HITACHI LTD
发明人： HAMAKAWA YOSHIHIRO , SHIIKI KAZUO , SASAKI SHINOBU
IPC分类号： G11B5/31
摘要： PURPOSE:To provide the thin-film magnetic head having a good recording capacity and reproducing efficiency by using a Co alloy film having a prescribed saturation magnetic flux density in a part of magnetic poles and forming this alloy film in such a manner as not to contain fine crystal grains of >=50nm diameter in the amorphous phase. CONSTITUTION:An Al2O3 film 23 is formed by sputtering on an insulating substrate 21 made of Al2O3-TiO2 ceramics or Ni-Zn ferrite. A Co92Ta2Zr3 alloy film is then formed by an RF sputtering method as the lower magnetic pole 23 at 1.5mum film thickness. A resist is used for an insulating layer 26 of a coil conductor 25 and the coil conductor 25 is formed by a sputtering method using Cu. A Co92Ta5Zr3 alloy film having 1.3T saturation magnetic flux density is then formed by the RF sputtering method as the upper magnetic pole 27 at 2mum film thickness. A protective film 28 is formed of Al2O3 at 20mum thickness. The lower magnetic pole 23, a magnetic gap 24, the coil conductor 25 and the upper magnetic pole 27 are patterned by ion milling.

8. 发明专利

JPH05143911A MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH05143911A
公开(公告)日：1993-06-11
申请号：JP30162091
申请日：1991-11-18
申请人： HITACHI LTD
发明人： SHIIKI KAZUO , HAMAKAWA YOSHIHIRO
IPC分类号： G11B5/09 , G11B20/12
摘要： PURPOSE:To provide a narrow-track recorder which enables a small-sized and large-capacity magnetic disk device. CONSTITUTION:This magnetic disk device of a high track density is recorded with signals for identifying adjacent tracks or is recorded with the signals converted to enable identification so as to eliminate guard bands by deciding the signal components as the signals from which tracks. The track density is greatly improved.

9. 发明专利

JPH03189914A MAGNETO-RESISTANCE EFFECT TYPE HEAD 失效
公开(公告)号：JPH03189914A
公开(公告)日：1991-08-19
申请号：JP32845589
申请日：1989-12-20
申请人： HITACHI LTD
发明人： SHINODA YASUSHI , KOYAMA NAOKI , YUHITO ISAMU , TAKANO KOJI , SHIIKI KAZUO
IPC分类号： G11B5/39
摘要： PURPOSE:To suppress Barkhausen noises and to decreases the noises from adjacent tracks by the formation of narrower tracks by forming an MR element of a closed magnetic path shape which does not have any element pieces having the longitudinal direction perpendicular to a track width direction and parts from a recording medium surface exclusive of the track width of the magnetic sensing part. CONSTITUTION:The magnetic sensitive part 1 has the width approximately equal to the track width and the parts exclusive of the magnetic sensitive part 1 have the shape parting gradually from the medium surface 5 at angle theta. Anisotropic energy does not largely increase if the theta is set small and, therefore, the magnetization state stabilizes. On the other hand, a magnetic wall is generated if the theta increases to >=45 deg.. The upper limit of the theta is, therefore, 40 deg. and the lower limit is 10 deg.. The width of the element piece is reduced gradually near to the end part 2 from the magnetic sensitive part 1. The anisotropy in the longitudinal direction of the element piece is increased by the effect of a diamagnetic field and the extremely stable magnetization state is attained. The generation of the Barkhausen noises is entirely obviated in this way and the reduction of the noises from the adjacent tracks by half is possible.

10. 发明专利

JPH0345445B2 失效
公开(公告)号：JPH0345445B2
公开(公告)日：1991-07-11
申请号：JP12070881
申请日：1981-08-03
申请人： HITACHI LTD
发明人： SHIIKI KAZUO , SHIROISHI YOSHIHIRO , YUHITO ISAMU , SAIKI ATSUSHI , FUJIWARA HIDEO , KUDO SANEHIRO , KUMASAKA TAKAYUKI , OOTOMO MOICHI
IPC分类号： G11B5/31

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