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111. 发明专利

JPH0448417A MAGNETIC HEAD 失效
公开(公告)号：JPH0448417A
公开(公告)日：1992-02-18
申请号：JP15471790
申请日：1990-06-13
申请人： HITACHI LTD
发明人： FUKUOKA HIROTSUGU , FUKUI HIROSHI , AIHARA MAKOTO , KOYANAGI HIROAKI , FUTAMOTO MASAAKI , KUGIYA FUMIO , TAKANO KOJI , MIYAMURA YOSHINORI , MATSUDA YOSHIFUMI , NAKAO TAKESHI , AKAGI KYO , SUZUKI MIKIO , MUNEMOTO TAKAYUKI , TAKAGAKI ATSUSUKE
IPC分类号： G11B5/33 , G11B5/265
摘要： PURPOSE:To allow the position where information is recorded to be correctly detected by juxtaposing plural pieces of magnetic detecting elements along the moving direction of a recording medium and shifting at least the two magnetic detecting elements among these elements respectively opposite directions by the same length each along the recording width on the recording medium. CONSTITUTION:This magnetic head is constituted of the magnetic detecting element 3 for recording information and the magnetic detecting elements 4, 4' for follow-up. Electrodes 3A are fixed to both ends of the magnetic detecting element 3 and electrodes 4A, 4A' are respectively fixed to both ends of the magnetic detecting elements 4, 4'. The magnetic detecting elements 4, 4' exist before and behind the magnetic detecting element 3 and are disposed by being shifted in the directions opposite from each other by the same length along the recording width direction of the recording medium so that the recording medium moves in the direction perpendicular to the recording width direction. A good follow-up characteristic is obtd. and the reproduced output is made higher even if the recording width narrows.

112. 发明专利

JPH0444610A COMPOSITE THIN FILM MAGNETIC HEAD AND PRODUCTION OF THE HEAD 失效
公开(公告)号：JPH0444610A
公开(公告)日：1992-02-14
申请号：JP15322690
申请日：1990-06-12
申请人： HITACHI LTD
发明人： KOYANAGI HIROAKI , AIHARA MAKOTO , FUKUOKA HIROTSUGU , FUKUI HIROSHI , TADOKORO SHIGERU , HOSHIYA HIROYUKI , MITSUOKA KATSUYA , NARUSHIGE SHINJI , KAWAKAMI HIROJI
IPC分类号： G11B5/31 , G11B5/39 , G11B5/60
摘要： PURPOSE:To prevent the influence of a signal magnetic field from an adjacent track and to reduce noise by projecting the sliding face sides of a recording head and a reproducing head and improving accuracy for matching the positions of the recording head and the reproducing head. CONSTITUTION:As a figure to be obliquely observed while cutting a magnetic head at the center and as a figure enlarging the important part when observing the head in an arrow A direction, a base layer 11 is formed on a ceramic base 10 and a lower magnetic shield member 16 is formed on it. On the shield member 16, a gap member 13, magneto-resistance effect element 2, electrode 1 and gap member 14 are filmed and patterned and further on them, a lower magnetic film 3 of the induced magnetic head, gap member 12 and upper magnetic film 4 are filmed and patterned. The highest surface is covered with a protecting member 7. Then, a groove is formed on the sliding face, and a part sandwiched between the two grooves is shaped in a projecting form by cutting both corner parts in a track width direction on the sliding face of the magnetic head. Thus, the accuracy of work is improved, a resistance change is enlarged as well and a reproducing output to the signal magnetic field is increased.

113. 发明专利

JPH03108113A COMPOSITE THIN-FILM MAGNETIC HEAD 失效
公开(公告)号：JPH03108113A
公开(公告)日：1991-05-08
申请号：JP24553689
申请日：1989-09-21
申请人： HITACHI LTD
发明人： KOYANAGI HIROAKI , AIHARA MAKOTO , YAMAGATA KOJI , FUKUI HIROSHI , FUYAMA MORIAKI , NARUSHIGE SHINJI
IPC分类号： G11B5/31 , G11B5/265 , G11B5/39
摘要： PURPOSE:To eliminate misregistration and to prevent the decrease in reproducing output and crosstalks by successively forming an induction type thin-film magnetic head for recording and a magneto-resistance effect type magnetic head for playback on the same substrate. CONSTITUTION:Alumina 20 is sputtered on the ceramic substrate 10 and recesses are formed by an ion milling method. A magnetic film 30 is sputtered as a lower magnetic core thereon and is patterned to the shape of a magnetic core. A coil 50 consisting of a copper conductor and an insulating material 40 are disposed in the recesses of the lower magnetic film 30 and alumina as a gap material 60 is sputtered thereon. An upper magnetic film 65 is sputtered thereon and further the alumina is sputtered as a gap material 90 thereon; thereafter, a magneto-resistance effect film 100 is sputtered. The composite thin-film magnetic head is obtd. by eliminating the misregistration and preventing the decrease in the reproducing output and the crosstalks in such a manner.

114. 发明专利

JPH02203410A THIN-FILM MAGNETIC HEAD 失效
公开(公告)号：JPH02203410A
公开(公告)日：1990-08-13
申请号：JP2071789
申请日：1989-02-01
申请人： HITACHI LTD
发明人： ARAI REIKO , NARUSHIGE SHINJI , MITSUOKA KATSUYA , IMAGAWA TAKAO , SANO MASAAKI , NISHIOKA KOICHI , SUDO SHUJI , KOYANAGI HIROAKI , KOBAYASHI TETSUO
IPC分类号： G11B5/31
摘要： PURPOSE:To prevent the lowering of a magnetic permeability when a large anisotropic stress is applied on a magnetic core and the deterioration in the electromagnetic conversion characteristics of the magnetic head by forming an upper magnetic film and a lower magnetic film to a circular shape. CONSTITUTION:This magnetic head consists of the lower magnetic film 2 formed on an Al2O3 film 12 of a substrate 1 and the upper magnetic film 3 which is formed on the lower magnetic film 2 in such a manner as to bring one end 31 into contact with one end 21 of the lower magnetic film 2 and to dispose the other end 32 to face the other end of the lower magnetic film 22 via a magnetic gap G and constitutes a magnetic circuit having a magnetic gap S in a part together with the lower magnetic film 2. The stress acting on the films is determined by the shape of the magnetic core and since the region in the front end part of the core is sensitive to recording and reproducing characteristics, the lower and upper magnetic materials 2, 3 are formed to the circular shape so as to relieve the stress in the front end part of the core. The magnetic anisotropy of the upper magnetic film 3 and the lower magnetic film 2 of the thin-film magnetic head is diminished in this way and the stable electromagnetic conversion characteristics which obviates the generation of the reproducing waveform distortions are obtd.

115. 发明专利

JPH0283810A THIN-FILM MAGNETIC HEAD 失效
公开(公告)号：JPH0283810A
公开(公告)日：1990-03-23
申请号：JP23528988
申请日：1988-09-20
申请人： HITACHI LTD
发明人： KOYANAGI HIROAKI , FUKUI HIROSHI , TANABE MASANORI , AIHARA MAKOTO , YAMAGATA KOJI , SANO MASAAKI , MITSUOKA KATSUYA , ARAI REIKO , KOBAYASHI TETSUO
IPC分类号： G11B5/31
摘要： PURPOSE:To stabilize magnetic domain structure and to obtain the reproduction signal which is decreased in waveform distortions and bit shifts by determining the magnetorestriction constant of magnetic films by the quality of the material which comes into contact with the magnetic films and maintaining stress induced type magnetically anisotropic energy at nearly the same level in the film thickness direction. CONSTITUTION:The stress induced type magnetically anisotropic energy of the magnetic films is expressed by the function of the magnetorestriction constant which is the property of the magnetic films and the main stress generated in the magnetic films. The main stress is generated by the difference between the coefft. of thermal expansion of the magnetic films and the coefft. of thermal expansion of the material with which the magnetic films are in contact. One side of the lower magnetic film 3 comes into contact with an underlying layer 2 and the opposite side comes into contact with an insulating layer 5. On the other hand, one side of the upper magnetic film 7 comes into contact with the insulating layer 5 and the opposite side comes into contact with the protective layer 8. The magnetically anisotropic energy is, thereupon, brought to the similar value of the insulating layer 5 side and the protective layer 8 and underlying layer 2 by changing the magnetorestriction constant of the surface of the magnetic films in accordance with the coefft. of thermal expansion of the material which comes into contact therewith, by which the magnetic domain structure is stabilized and the reproduction signal decreased in the waveform distortions and bit shifts is obtd.

116. 发明专利

JPH01300438A OPTICAL PICKUP, OPTICAL DISK DEVICE EQUIPPED WITH THE SAME, AND ROTARY ENCODER 失效
公开(公告)号：JPH01300438A
公开(公告)日：1989-12-04
申请号：JP12993588
申请日：1988-05-27
申请人： HITACHI LTD
发明人： MINEMURA HIROYUKI , SATO YOSHIO , TSUBOI NOBUYOSHI , KOYANAGI HIROAKI , OYAMA SHINJI
IPC分类号： G01P3/486 , G11B7/12 , G11B7/124 , G11B7/135
摘要： PURPOSE:To prevent return light to a light source from being generated by combining a filter to transmit either TE polarized light or TM polarized light with a polarization switching means. CONSTITUTION:Emitted light from the light source 10 becomes only the TE polarized light (S polarized light), for example, by cutting the TM polarized light (P polarized light) by the filter 100, and passes an optical waveguide path 40, and the light is converged on an information recording medium 50 via an optical path conversion means 90 and the polarization switching means 110, and reflected light is introduced to the optical waveguide path 40 again via a reverse path. At this time, the TE polarized light becomes the TM polarized light by the polarization switching means 110, and is branched from the emitted light by a beam splitter 80, and is introduced to an optical detector 70, then, information is read. Also, since noise light advancing to the light source 10 is also the TM polarized light, the noise light is cut by the filter 100, which prevents the light from being made incident on the light source. In such a way, the return light to the light source can be prevented from being generated.

117. 发明专利

JPS64934A OPTICAL SWITCH 失效
公开(公告)号：JPS64934A
公开(公告)日：1989-01-05
申请号：JP15546287
申请日：1987-06-24
申请人： HITACHI LTD
发明人： MINEMURA HIROYUKI , SATO YOSHIO , TSUBOI NOBUYOSHI , KOYANAGI HIROAKI
IPC分类号： G02F1/31 , G02B6/12 , G02F1/01
摘要： PURPOSE:To enable an optical switch to operate even if a conductive path is not used by using a superconductor which makes a state change between superconduction and normal conduction. CONSTITUTION:This optical switch is constituted by utilizing the change in the interaction with light arising from the state change between the superconduction and the normal conduction of the superconductor 10 formed on a transparent substrate 20. Light is reflected by a Meissner effect when the light is projected on the material in the superconducting state. The Meissner effect disappears and the quantity of reflected light decreases when the material is transited to the normal conducting state by temp., electric current and magnetic field, etc. The change in the reflectivity or transmissivity of the superconducting state and the normal conducting state is settable as desired by adequately selecting the film thickness of the superconducting material at this time. The optical switch of the simple constitution is thereby obtd.

118. 发明专利

JPS63316388A INFORMATION RECORDING MEDIUM 失效
公开(公告)号：JPS63316388A
公开(公告)日：1988-12-23
申请号：JP15117687
申请日：1987-06-19
申请人： HITACHI LTD
发明人： MORI YUJI , NAGAE KEIJI , KOSAKA MASAHIRO , ASANO HIDEKI , SHIMADA SATOSHI , KOYANAGI HIROAKI , SATO YOSHIO , TSUBOI NOBUYOSHI , MINEMURA HIROYUKI , KAWAKAMI HIROJI
IPC分类号： G11B23/42
摘要： PURPOSE:To enable the prompt knowing of the position of written information desired to be known by writing visible retrieval information to the end of the writing regions of blocks for the written information by each block. CONSTITUTION:The visible retrieval information 3 is written to the end of the information writing regions 2 of an information recording medium 1 on which the information is written. An operator which is going to read out the information from the recording medium 1 knows, on the spot, the region of the recording medium 1 where the information desired to be known is written, from the visible retrieval information written in each of the information blocks 2. The time for reading out is shortened by reading out only the block 2 where said information is written.

119. 发明专利

JPS63209031A INTEGRATION TYPE OPTICAL HEAD 失效
公开(公告)号：JPS63209031A
公开(公告)日：1988-08-30
申请号：JP4029787
申请日：1987-02-25
申请人： HITACHI LTD
发明人： SHIMADA SATOSHI , OYAMA SHINJI , SATO MANABU , IBAMOTO MASAHIKO , SATO YOSHIO , TSUBOI NOBUYOSHI , MIYAMOTO NORIFUMI , MINEMURA HIROYUKI , KOYANAGI HIROAKI
IPC分类号： G02B6/12 , G02B6/122 , G02B6/124 , G11B7/09 , G11B7/12 , G11B7/1245 , G11B7/135
摘要： PURPOSE:To obtain an optical head whose focusing control speed is fast and time of accessing information is small by making a part where a collimating lens or an objective lens is formed flexible and making it freely move by a piezo-electric element. CONSTITUTION:A focusing controller is integrated to be formed on a substrate 1 and a lens element 10 provided on a part of the substrate 1 is worked to be thin so as to obtain flexible quality, a part of which a piezo-electric film is formed on, to get the lens element with an actuator. Since the lens element 10 is made to move up and down according to the up-and-down motion of a rotating optical disk so as to focus a laser beam on a recording medium 9, high quality information can be stably recorded there. As for the stagger of tracking, the control for focusing the laser light beam on an information bit is executed by deflecting the laser light beam to follow the stagger of tracking with the motion of tilting the lens 10 with the actuator. Thus, the information can be accurately read out and reproduced because it is possible to always focus on the information bit.

120. 发明专利

JPS63201923A INFORMATION RECORDING AND REPRODUCING DEVICE 失效
公开(公告)号：JPS63201923A
公开(公告)日：1988-08-22
申请号：JP3330287
申请日：1987-02-18
申请人： HITACHI LTD
发明人： MINEMURA HIROYUKI , KOYANAGI HIROAKI , SATO YOSHIO , TSUBOI NOBUYOSHI , MIYAMOTO NORIFUMI , SATO MANABU , SHIMADA SATOSHI
IPC分类号： G11B7/135
摘要： PURPOSE:To reduce the number of parts and to easily adjust an optical axis by providing a detector on the optical axis common for incident beams and reflected beams. CONSTITUTION:The detector 30 is arranged on the optical axis common for the incident beams and the reflected beams. A part of laser beams 21 which have been emitted from an optical source 20 are converted into electric signals 33, beams which have transmitted the detector 30 are converted into convergence beams 41 in a converging lens 40 and they are focused on a recording medium 50. The reflected beams 52 from the recording medium 50 are converted into beams 42 through the converging lens 40. A part of the beams 42 are converted into electric signals 34 in the detector 30, and the rest beams 32 return to the optical source 20. Information on the incident beams 21 and the reflected beams 42 which have been converted into the electric signals 33 and 34 are inputted to a control part 10, and are converted into the control electric signals of the optical source 20, the control electric signals of the converging lens and recording information 13 on the recording medium 50.

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