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31. 发明专利

JPH04102223A MAGNETIC RECORDING MEDIUM AND PRODUCTION THEREOF AND MAGNETIC RECORDER 失效
公开(公告)号：JPH04102223A
公开(公告)日：1992-04-03
申请号：JP21704890
申请日：1990-08-20
申请人： HITACHI LTD
发明人： MATSUDA YOSHIFUMI , FUTAMOTO MASAAKI , MIYAMURA YOSHINORI , TAKAGAKI ATSUSUKE , TAKANO KOJI , KUGIYA FUMIO , NAKAO TAKESHI , AKAGI KYO , SUZUKI MIKIO , FUKUOKA HIROTSUGU , MUNEMOTO TAKAYUKI
IPC分类号： G11B5/64 , G11B5/65 , G11B5/66 , G11B5/73 , G11B5/738 , G11B5/85 , G11B5/851
摘要： PURPOSE:To greatly improve the S/N of reproduced signals at the time of high-density recording by decreasing the saturation magnetic flux density and coercive force of magnetic films from the front surface side of the recording medium toward a nonmagnetic substrate side. CONSTITUTION:Chromium underlying films 2 are first formed at 250nm thickness on both surfaces of a disk like nonmagnetic substrate 1 consisting of tempered glass and having 95mm diameter and 1.5mm thickness by using a DC magnetron sputtering device which can discretely sputter chromium and carbon and can simultaneously sputter Co-15Cr-5T and Co-10Cr-5Pt. The magnetic films 3 are thereafter formed at 100nm thickness thereon and further, carbon protective lubricating films 4 are formed at 20nm thickness thereon, by which the magnetic disk is produced. The magnetic films 3 are formed by simultaneously sputtering the Co-15Cr-5T and Co-10Cr-5Pt at the relation of the time and charging power density as shown in Fig. In the Fig., P1 and P2 respectively denote the charging powers of the Co-15Cr-5T and Co-10Cr-5Pt.

32. 发明专利

JPH03183072A HEAD SLIDER AND MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH03183072A
公开(公告)日：1991-08-09
申请号：JP32240889
申请日：1989-12-12
申请人： HITACHI LTD
发明人： MUNEMOTO TAKAYUKI , YAMAGUCHI YUZO , FUTAMOTO MASAAKI , KUGIYA FUMIO , AKAGI KYO , MIYAMURA YOSHINORI , NAKAO TAKESHI , SUZUKI MIKIO , MATSUDA YOSHIFUMI , TAKANO KOJI , FUKUOKA HIROTSUGU , TAKAGAKI ATSUSUKE
IPC分类号： G11B21/21 , G11B21/10 , G11B21/12
摘要： PURPOSE:To realize positioning at high speed with high accuracy by displacing a transducer by a driving member provided on a head slider. CONSTITUTION:A slider 1 composed of slider rails 3 and a coupling member 4 to support the both slider rails, transducer 2 formed on the slider and electrode member 8 are provided. Electrode members 8 and 9 are provided on a side surface 7 of the slider 1 and by applying electric energy to the electrodes 8 and 9, the transducer 2 can be displaced symmetrically in a direction so as to be separated or closed to a symmetric surface.

33. 发明专利

JPH03183011A PERPENDICULAR MAGNETIC RECORDING MEDIUM AND RECORDING DEVICE FOR THE SAME 失效
公开(公告)号：JPH03183011A
公开(公告)日：1991-08-09
申请号：JP31875489
申请日：1989-12-11
申请人： HITACHI LTD
发明人： SUZUKI MIKIO , KUGIYA FUMIO
IPC分类号： G11B5/66 , G11B5/02 , G11B5/64 , G11B5/65 , G11B5/667 , G11B5/73 , G11B5/738
摘要： PURPOSE:To increase a reproducing output without degrading a recording density property by specifying the film thickness and the specific initial permeability of a soft magnetic base film to be provided on a non-magnetic base. CONSTITUTION:A perpendicular magnetic recording medium 1 is constituted by laminating a soft magnetic base film 12, recording film 13, which is equipped with perpendicular magnetic anisotropy, and protecting film 14 on a non- magnetic base 11. The soft magnetic base film 12 is formed so that the film thickness can be

34. 发明专利

JPH03152710A MAGNETIC RECORDING MEDIUM AND MAGNETIC HEAD 失效
公开(公告)号：JPH03152710A
公开(公告)日：1991-06-28
申请号：JP28887689
申请日：1989-11-08
申请人： HITACHI LTD
发明人： MIYAMURA YOSHINORI , KIRINO FUMIYOSHI , FUTAMOTO MASAAKI , TAKANO KOJI , MATSUDA YOSHIFUMI , KUGIYA FUMIO , AKAGI KYO , SUZUKI MIKIO , NAKAO TAKESHI
IPC分类号： G11B5/62 , G11B5/64 , G11B5/65 , G11B5/73 , G11B11/10 , G11B11/105
摘要： PURPOSE:To increase leak magnetic fluxes and to improve a recording density by providing magnetized regions at the ends of recording bits carrying information in the direction perpendicular to a substrate and executing recording with the units combining these regions and the parts of the regions magnetized in the intrasurface direction. CONSTITUTION:A recording film 12 consisting of Gd-Tb-Fe is laminated at 500Angstrom by sputtering in a gaseous argon atmosphere on the aluminum substrate 11 having 2mm thickness. A protective film 13 which protects the recording film against the sliding of the magnetic head is formed thereon at several 10 to 100Angstrom . The recording film exhibiting the characteristics to constitute an intrasurface magnetized film or perpendicularly magnetized film by the intensity of an external magnetic field when the concn. of the Tb exceeds 10% and increases up to 40% is obtd. The intrasurface magnetic recording is executed if the recording first made by the head 34 for the weak magnetic field of 200 oersted. The perpendicular magnetic recording is executed when the recording is made by the head 35 for the strong magnetic field of 300 oersted at the end of information. A pair 36 of the intrasurface recording and the perpendicular recording is, therefore, the min. recording unit. The outflow of the magnetic fluxes to the outside of the surface of the magnetic film is accelerated in this way and the intensity of the magnetic fluxes leaking to the outside increases.

35. 发明专利

JPH03105778A MAGNETIC HEAD SLIDER 失效
公开(公告)号：JPH03105778A
公开(公告)日：1991-05-02
申请号：JP24199989
申请日：1989-09-20
申请人： HITACHI LTD
发明人： HAMAGUCHI TETSUYA , KUGIYA FUMIO , TSUCHIYAMA RYUJI , MATSUMOTO MASAAKI , SUZUKI MIKIO
IPC分类号： G11B21/21
摘要： PURPOSE:To prevent adhesion between a head slider and a disk and to improve anti-head-crash performance by providing a notch or a chamferring to part or several positions of outside of a rail face of a magnetic head slider. CONSTITUTION:An intermittent notch 12 or a chamferring 10 is provided to a part or several positions at the outside of a rail face 9 of a head slider 1 with mechanical processing. Thus, the notch 12 provided at the outer contour of the rail face 9 cuts off minisci 7, 11 to reduce the adhesive force sufficiently to a degree of releasing the adhesion of a lubricant. Moreover, the length, width, and position of the notch 12 are selected so as to decrease the area of the rail toward the flowing-out end 5 or the chamferring 10 is applied to decrease the floating start speed of the head slider 1 and to increase a pitch angle of the head slider in floating. Thus, adhesion between a head slider and a disk is prevented and to the anti-head-crash performance is improved.

36. 发明专利

JPH0393018A MAGNETIC HEAD AND MAGNETIC MEMORY DEVICE FORMED BY USING THIS HEAD 失效
公开(公告)号：JPH0393018A
公开(公告)日：1991-04-18
申请号：JP22836389
申请日：1989-09-05
申请人： HITACHI LTD
发明人： TAKANO KOJI , FUTAMOTO MASAAKI , KUGIYA FUMIO , MIYAMURA YOSHINORI , NAKAO TAKESHI , AKAGI KYO , MATSUDA YOSHIFUMI , SUZUKI MIKIO
IPC分类号： G11B5/33 , G11B5/02 , G11B5/37
摘要： PURPOSE:To detect recording signals with a high sensitivity and high resolving power by detecting the leak magnetic fluxes from a medium which are the recording information written on the magnetic recording medium by utilizing the quantum interference effect of quantum wells. CONSTITUTION:The magnetic flux detecting part of a magnetic head is formed by providing an Fe single crystal shielding layer 20 and an insulating layer on a single crystal GaAs substrate 19, providing 1st and 2nd GaAs current passages 23, 23 and an AlGaAs quantum well 24 thereon, then providing contact layers 25 at both ends. Further, an insulating layer 26, a Cu conductor 28 and an insulating layer 27 are formed. After this magnetic flux detecting part is cut by providing a margin in width, a protective layer 18 consisting of Al2O3 is formed by lapping on the side face to serve as the surface for sliding with the perpendicular magnetic recording medium 17. Necessary wiring is then executed to constitute the magnetic head. The leak magnetic fluxes from the medium 17 which are the recording information written on the perpendicular magnetic recording medium 17 are detected by utilizing the quantum interference effect of the quantum wells 24. The magnetic recording and reproducing are executed with the high sensitivity and high resolving power in this way.

37. 发明专利

JPH0312044A HIGH DENSITY OPTICAL REPRODUCING DEVICE 失效
公开(公告)号：JPH0312044A
公开(公告)日：1991-01-21
申请号：JP14294589
申请日：1989-06-07
申请人： HITACHI LTD
发明人： KUGIYA FUMIO , SUZUKI MIKIO , AKAGI KYO , NAKAO TAKESHI , FUTAMOTO MASAAKI , MIYAMURA YOSHINORI , TAKANO KOJI , MATSUDA YOSHIFUMI
IPC分类号： G11B11/10 , G11B7/135 , G11B11/105
摘要： PURPOSE:To reproduce magnetization information smaller than the diameter of a spot by irradiating a recording medium with two kinds of laser light beams having a different wavelengths, superposing the parts of both spots on each other and setting the difference of the detection signals of reflected light from both spots as a reproducing signal. CONSTITUTION:The laser light beams which are emitted from semiconductor lasers 1 and 1' and have the wavelengths lambda1 and lambda2 respectively are made incident on a beam splitter BS5 directly or through a polarizing plate 3 to be synthesized. The synthesized light beam is made incident on a recording film 10 through a BS5' and a lens 6 to generate two spots whose parts are superposed. After the reflected light is reflected on the BS5' and separated in accordance with the wavelength by a wavelength separating filter 7, it is made incident on photodetectors 9 and 9' through polarizing plates 8 and 8'. Output from the photodetectors 9 and 9' is inputted in a differential amplifier and the difference signal is outputted as the reproducing signal.

38. 发明专利

JPH02267701A MAGNETIC RECORDING SYSTEM 失效
公开(公告)号：JPH02267701A
公开(公告)日：1990-11-01
申请号：JP8791389
申请日：1989-04-10
申请人： HITACHI LTD
发明人： MIYAMURA YOSHINORI , FUTAMOTO MASAAKI , TAKANO KOJI , MATSUDA YOSHIFUMI , KUGIYA FUMIO , AKAGI KYO , SUZUKI MIKIO , NAKAO TAKESHI
IPC分类号： G11B5/012
摘要： PURPOSE:To fix recording densities in the inner circumference and outer circumference of a disk and to increase a recording capacity by fixing the number of rotation of the disk and making the frequency of information to be recorded higher as a radius position is increased. CONSTITUTION:In the case of recording information, the radius position of a magnetic head 12 on a magnetic disk 11 to be rotated is detected by a scale. A frequency conversion is executed in proportion to the radius so that the recording linear density of the recorded information can be made equal in any radius position, and the information is recorded through a recording and reproducing circuit onto the disk. In the case of reproducing, for an information signal obtained by the head 12, the frequency is inversely converted corresponding to the radius position, in which the head 12 is positioned, through the recording and reproducing circuit, further, an amplitude correction is executed, and thereafter, the signal is taken out as a reproducing signal. Thus, the recording densities in the inner circumference and outer circumference of the disk are fixed, and the recording capacity is increased.

39. 发明专利

JPH0281301A PERPENDICULAR MAGNETIC RECORDER 失效
公开(公告)号：JPH0281301A
公开(公告)日：1990-03-22
申请号：JP23235488
申请日：1988-09-19
申请人： HITACHI LTD
发明人： KUGIYA FUMIO , SUZUKI MIKIO , SUGANO FUMIKO , TAKANO KOJI
IPC分类号： G11B5/02
摘要： PURPOSE:To improve recording characteristics and reproducing characteristics by specifying the saturation magnetic flux densities of a recording layer and soft magnetic underlying layer. CONSTITUTION:The product of the saturation magnetic flux density Bb and film thickness deltab of the soft magnetic underlying layer and the product of the saturation magnetic flux density Bm and recording wavelength lambda of the recording film are in the relation BpXdeltab>=BmXlambda/4; in addition, the saturation magnetic flux density Bb of the soft magnetic underlying layer is specified to Bb>=1.2XBp with respect to the saturation magnetic flux density Bp of the main magnetic pole of a single magnetic pole head. Recording is executed in this way without saturating the soft magnetic underlying layer of the medium by the main magnetic pole excitation type single magnetic pole head having good recording characteristics; further, reproduction is executed by the ring type magnetic head or MR head having the good reproducing characteristics in the state of decreasing the diamagnetic field of the magnetization recorded on the recording film by the effect of the soft magnetic underlying layer.

40. 发明专利

JP2004192676A Magnetic disk drive and guarantee method of its magnetic recording function 审中-公开
公开(公告)号：JP2004192676A
公开(公告)日：2004-07-08
申请号：JP2002356466
申请日：2002-12-09
申请人： Hitachi Ltd , 株式会社日立製作所
发明人： NISHIYAMA NOBUMASA , SUZUKI MIKIO , YOSHINAGA MAKI , KOBAYASHI YOICHIRO , AOI MOTOI
IPC分类号： G11B5/024 , G11B5/00 , G11B5/012 , G11B5/55 , G11B5/596 , G11B27/36
CPC分类号： G11B27/36 , G11B5/012 , G11B5/5526 , G11B5/59605 , G11B2005/001
摘要： PROBLEM TO BE SOLVED: To provide a magnetic disk drive, in which the normal/abnormal state of the magnetic recording function is discriminated by detecting the magnitude of a crosstalk between lines and the magnetic recording function is guaranteed.
SOLUTION: By utilizing the fact that an amplitude of the crosstalk between lines to a reproducing side line from a recording side line is increased when a load inductance of the recording side line is reduced due to the short circuit of a coil for recording head, or the like, a detection part 36 of the amplitude of the crosstalk between lines is arranged in a preamplifier 20 as a detection means of the abnormality of the coil (change of inductance). A detection circuit 31 of the amplitude of the crosstalk between lines is arranged by being branched from a branching circuit 30 in a reproduction circuit of the preamplifier 20, and by preparing the function to conclude the abnormal recording state when the amplitude is further increased to the threshold or larger, the recording function on the preamplifier 20 can be guaranteed. Also, for the short circuit in the line around the head, the abnormal recording state is detectable since the inductance is similarly reduced.
COPYRIGHT: (C)2004,JPO&NCIPI

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