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41. 发明专利

JPH05242433A 失效
公开(公告)号：JPH05242433A
公开(公告)日：1993-09-21
申请号：JP4439092
申请日：1992-03-02
申请人： HITACHI LTD
发明人： NAKATANI RYOICHI , KOYAMA NAOKI , HAMAKAWA YOSHIHIRO
IPC分类号： G11B5/39
摘要： PURPOSE:To obtain the magneto-resistance effect type head which is less affected by the magnetic field in the track width direction of the magnetic head by having a magnetic shield in the track width direction. CONSTITUTION:The magnetic shielding layer 12 is formed of 'Permalloy(R)' at 1mum film thickness on a nonmagnetic substrate 11 consisting essentially of Al2O3.TiC in order to produce the magnetic head having the magnetic shield in the track width direction. An insulating layer 13 consisting of Al2O3 is then formed at 0.27m film thickness on the layer 12. A yoke plate 17 having two sheets of Ni-Zn ferrite plates 14 and a gap 16 of glass 15 is polished to reduce its thickness to the track width. A magneto-resistance effect film 18 consisting of an Ni-Fe alloy and having 30nm thickness and a shunt film 19 consisting of Ti and having 30nm film thickness is then formed on the yoke plate 17. Lead wires 20 having multilayered structures consisting of Cr/Cu/Cr are formed. The resulted magneto-resistance effect element 21 is superposed on the insulating layer 13 and after the element is flattened by forming an insulating layer 22 consisting of Al2O3, the magnetic shielding layer 23 of an Ni-Fe alloy having 1mum film thickness is formed. The magneto-resistance effect element 24 is thus obtd.

42. 发明专利

JPH05225528A MAGNETIC RECORDING AND REPRODUCING DEVICE 失效
公开(公告)号：JPH05225528A
公开(公告)日：1993-09-03
申请号：JP2233692
申请日：1992-02-07
申请人： HITACHI LTD
发明人： KOYAMA NAOKI , YUHITO ISAMU , TANABE HIDEO , KITADA MASAHIRO
IPC分类号： G11B5/39
摘要： PURPOSE:To provide the structure of a head preventing the electrical damage of the head due to the contact between a magneto-resistance effect type head and a disk. CONSTITUTION:A magneto-resistance effect element 8 and magnetic shield layers 2 and 3 around the element 8 are electrically connected, and the tip of the magneto-resistance effect element 8 is recessed from the tips of the magnetic shield layers 2 and 3. Consequently, since electric current flows through the magnetic layers previous to the magneto-resistance effect element when the head comes into contact with the disk, the element is prevent from damaging.

43. 发明专利

JPH05166137A MAGNETIC HEAD AND RECORDING/REPRODUCING DEVICE 失效
公开(公告)号：JPH05166137A
公开(公告)日：1993-07-02
申请号：JP33106391
申请日：1991-12-16
申请人： HITACHI LTD
发明人： KOYAMA NAOKI , HAMAKAWA YOSHIHIRO , YUHITO ISAMU , KAWAKAMI HIROJI , SHIIKI KAZUO , KITADA MASAHIRO
IPC分类号： G11B5/31 , G11B5/39
摘要： PURPOSE:To reduce the influence of the noises produced from the adjacent tracks despite the small track width by securing the coincidence between the center of magnetic sensitivity of a reproduction head end the center of geometric track width of a recording head. CONSTITUTION:A record/reproduction separation type magnetic head 2 consists of a magneto-resistance effect type reproduction heed 1 and a conductive recording head 5 put on each other. The coincidence is secured between the center of magnetic sensitivity of the heed 1 and the center of geometric track width of the head 5. Then the track width center of the heed 5 is positioned between the sensitivity center and the track width center of the heed 1 when the error between these two centers is larger than the coincidence error between the track width centers of the head 1 and the heed 5. Thus it is possible to reduce the influence of the noises produced from the adjacent tracks.

44. 发明专利

JPH05101340A COMPOSITE MAGNETIC HEAD 失效
公开(公告)号：JPH05101340A
公开(公告)日：1993-04-23
申请号：JP25500891
申请日：1991-10-02
申请人： HITACHI LTD
发明人： KOIZUMI MAKOTO , KOYAMA NAOKI
IPC分类号： G11B5/31 , G11B5/39
摘要： PURPOSE:To suppress an amplitude fluctuation of a base line of a reproducing output of a composite magnetic head and to reduce a peak shift caused thereby. CONSTITUTION:A permeability of a magnetic pole 20 of a guiding type recording head is made smaller than 1/50 of permeabilities of an upper part shield film 21 of an MR type reproducing head and a lower part shield film 24. Since the amplitude fluctuation of a base line of the composite magnetic head can be suppressed, a peak shift caused thereby is reduced.

45. 发明专利

JPH04205903A METHOD AND DEVICE FOR REPRODUCING SIGNAL BY MAGNETORESISTANCE EFFECT TYPE HEAD AND RECORDING DEVICE USING THE SAME 失效
公开(公告)号：JPH04205903A
公开(公告)日：1992-07-28
申请号：JP33019390
申请日：1990-11-30
申请人： HITACHI LTD
发明人： YUHITO ISAMU , KITADA MASAHIRO , KOYAMA NAOKI , KATO YASUHIRO
IPC分类号： G11B5/39 , G11B5/02 , G11B5/035
摘要： PURPOSE:To reduce asymmetry in a regenerative signal waveform and fluctuation of an output due to variations of head characteristics by providing a means for optimizing the magnetizing direction of a magnetoresistance effect film in changing the intensity of a bias magnetic field to be impressed upon the magnetoresistance effect film. CONSTITUTION:The subject device is provided with the means for optimizing the magnetizing direction of the magnetoresistance effect film in changing the intensity of the bias magnetic field to be impressed upon the magnetoresistance effect film. For example, a waveform reproduced by a magnetoresistance effect type head 2 is detected by a waveform asymmetry degree detecting part 4 in an unbalanced ant. between the plus side and minus side of the regenerative signal, and the unbalanced amt. and a reference symmetry degree signal are compared with each other by a comparing part 5 to detect their difference. An output of the comparing part 5 is given to a sense power source 6 for deciding a conductive current value to the magnetoresistance effect film, and a sense current value is varied according to the size of the output of the comparing part 5. By this method, the bias magnetic field is optimized, and asymmetry of the regenerative signal waveform and fluctuation of the reproducing output can be prevented.

46. 发明专利

JPH04182912A MAGNETO-RESISTANCE EFFECT TYPE HEAD 失效
公开(公告)号：JPH04182912A
公开(公告)日：1992-06-30
申请号：JP31149290
申请日：1990-11-19
申请人： HITACHI LTD
发明人： YUHITO ISAMU , MORIJIRI MAKOTO , TAKEURA TORU , KOYAMA NAOKI , KITADA MASAHIRO
IPC分类号： G11B5/39
摘要： PURPOSE:To allow the production of the head used for reproduction of the signals recorded at a high density at a high yield by forming a protective film under a film to be etched and sufficiently increasing the thickness of the protective film by taking the thickness distribution of the film to be etched and the distribution of etching speeds into consideration. CONSTITUTION:A lower shield 2, a lower gap film 3, a magneto-resistance effect film 4, a shunt bias film 5, an electrode 6 and an upper gap film 7 are formed on a substrate 1. The protective film 9 is thereafter formed. The protective film 9 is an electrical insulating material which does not arrive at the sliding surface and covers the upper gap film 7 and the electrode 6. The upper shielding film 8 on the protective film 9 is formed in succession and is patterned. The upper shielding film 8 is so formed that its one end arrives at the protective film 9. The thickness of the protective film is determined by taking the thickness distribution of the upper shielding film 8 and the distribution of the etching speeds into consideration and is usually sufficient at 1mum. The electrode 6 and the upper gap film 7 are prevented form being etched at the time of etching the upper shielding film 8 in this way.

47. 发明专利

JPH043305A MAGNETO-RESISTANCE EFFECT TYPE HEAD 失效
公开(公告)号：JPH043305A
公开(公告)日：1992-01-08
申请号：JP10295390
申请日：1990-04-20
申请人： HITACHI LTD
发明人： YUHITO ISAMU , MORIWAKI HIDETOSHI , KOYAMA NAOKI
IPC分类号： G11B5/39
摘要： PURPOSE:To obtain a high regenerative output value by concentrating a sense current only in the vicinity of the area, where the electric resistance is most changed for a signal magnetic field, in a magneto-resistance effect film. CONSTITUTION:A head consists of a magneto-resistance effect film 2 and an insulating layer 4 on a substrate 1 and signal detecting electrodes 3a and 3b connected to the film 2 with through holes 5a and 5b of the insulating layer 4 between them. Connection areas between electrodes 3a and 3b and the film 2 are a part of the film when viewed in the direction perpendicular to the track width. The sense current flows from the through hole 5a and flows in the film 2 and flows out from the through hole 5b. Most of the sense current flows in the area of the shortest distance between holes 5a and 5b. The area where the electric resistance is most changed is included in this area to obtain a large regenerative output value. The value of the current shunt to the outside of the area is smaller according as the track width is narrower. Forms of through holes are so selected that W1

48. 发明专利

JPH03290812A MAGNETIC HEAD 失效
公开(公告)号：JPH03290812A
公开(公告)日：1991-12-20
申请号：JP9030290
申请日：1990-04-06
申请人： HITACHI LTD
发明人： KOYAMA NAOKI , TAKANO KOJI , SHINODA YASUSHI , YUHITO ISAMU , SHIIKI KAZUO
IPC分类号： G11B5/39
摘要： PURPOSE:To obtain an excellent offtrack characteristic and shielding characteristic even with the narrow-track MR head by disposing electrode patterns in such a manner as to decrease the magnetic fluxes crossing the electrode patterns. CONSTITUTION:The MR element 1 is inserted between two shielding patterns 2 and 3 and is thus formed. The electrode patterns 4, 5 are formed at both ends of the MR element 1 and are so formed as to be nearly perpendicular to the surface of a medium 7. Since the magnetic fluxes from adjacent tracks do not cross each other, the deterioration in the offtrack by the induced electromotive force is prevented. The electrode patterns 4, 5 are so disposed as to reduce the area of the loop formed of the electrode patterns 4, 5 drawn out of both ends of a magnetosensitive part and the magnetosensitive part, by which the quantity of the magnetic flux crossing this loop is decreased and the induced electromotive force is decreased. The excellent shielding characteristic and offtrack characteristic are obtd. even with the track MR head in this way.

49. 发明专利

JPH0395714A THIN-FILM MAGNETIC HEAD 失效
公开(公告)号：JPH0395714A
公开(公告)日：1991-04-22
申请号：JP23157189
申请日：1989-09-08
申请人： HITACHI LTD
发明人： MORIWAKI HIDETOSHI , HAMAKAWA YOSHIHIRO , YUHITO ISAMU , TAKANO KOJI , KOYAMA NAOKI , SASAKI SHINOBU , SHIIKI KAZUO
IPC分类号： G11B5/31
摘要： PURPOSE:To prevent the formation of a local battery and to attain the manufacture of the thin-film magnetic head having an excellent recording capacity by preventing metals or alloys provided on the upper or lower layer or both layers of a Co amorphous alloy used for an upper magnetic layer and lower magnetic layer from being exposed from a surface opposite to media. CONSTITUTION:The metal or alloy films 7, 8 formed on the upper or lower layer or both layers of the Co amorphous alloy of the upper magnetic layer 1 and the lower magnetic layer 2 is prevented from being exposed to the surface 9 opposite to the media. The steps between the surface 9 opposite to the media and the front ends of the upper and lower magnetic layers 1, 2 generated by the formation of the local battery are, therefore, eliminated while the reaction with the upper and lower medium layers 1, 2, an insulating layer 4 and resist and the peeling of a magnetic gap 3 and Al2O3 are prevented. Thus, the thin-film magnetic head having excellent recording and reproducing efficiency is manufactured.

50. 发明专利

JPH0349008A MAGNETIC HEAD AND RECORDING AND REPRODUCING DEVICE USING THE SAME 失效
公开(公告)号：JPH0349008A
公开(公告)日：1991-03-01
申请号：JP18270689
申请日：1989-07-17
申请人： HITACHI LTD
发明人： KOYAMA NAOKI , YUHITO ISAMU , HAMAKAWA YOSHIHIRO , TAKANO KOJI , SHIIKI KAZUO
IPC分类号： G11B5/31
摘要： PURPOSE:To obtain output with little fluctuation by realizing stable magnetic domain structure by changing film thickness or conductivity of nonmagnetic intermediate layers and controlling the distribution of a current flowing on a multilayer film when controlling magnetic domain structure by permitting the current to flow on the multilayer film compulsorily. CONSTITUTION:In a thin film magnetic head, the multilayer film is formed as a laminate layer of four layers 1-4 via the nonmagnetic intermediate layer by laminating Fe-C(5atm %) that is the crystal material of Fe group and the multilayer of 'Permalloy(R)' sequentially. Cr layers with prescribed thickness is used in intermediate layers 6 and 7 which form first and third layers, and a boron nitride layer with prescribed thickness is used in the nonmagnetic intermediate layer 5 which forms a second layer. Following that, a gap layer 12 is formed, and a coil 13 and a flattening layer 14 are formed. Furthermore, an upper magnetic pole layer 15 is laminated, and electrode layers 8 and 9 are provided at the tip and rear end parts of the magnetic pole, which are brought into contact with respective magnetic pole film. Cu of prescribed thickness is used in the electrode layer. In such a way, it is possible to control the distribution of the current flowing on the multilayer by changing the film thickness or the conductivity of the nonmagnetic intermediate layer.

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