With Magnetic Bias Patents (Class 360/17)
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Patent number: 7054082Abstract: An accurate magnetic transfer to a high-density slave medium having two magnetic layers and utilizing antiferromagnetic coupling is performed. By applying a first magnetic field that causes both the first and second magnetic layers of the magnetic layer of a slave medium to reach saturation magnetization unidirectionally along the circumferential direction of the track, the first and second magnetic layers are magnetized uniformly in the same direction as the first magnetic field. Then, a second magnetic field that inverts the magnetization of the first magnetic layer and has no effect on the magnetization of the second magnetic layer is applied in the opposite direction, whereby only the magnetization direction of the first magnetic layer is inverted in the direction of the second magnetic field. Thereby, a favorable initial magnetization state in which the magnetization directions of the first and second magnetic layers are oriented antiparallel can be obtained.Type: GrantFiled: June 7, 2002Date of Patent: May 30, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Tadashi Yasunaga
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Patent number: 7050248Abstract: An apparatus for forming a magnetic transition pattern in a magnetic material by contact printing, comprising: (a) a stamper having an imprinting surface comprising a plurality of projections and depressions arranged according to the magnetic transition pattern, the stamper being formed of at least one high saturation magnetization, high permeability magnetic material; (b) means for supporting a workpiece such that a surface thereof comprised of the magnetic material is in contact with the imprinting surface; (c) magnet means for applying a unidirectional re-alignment magnetic field to the stamper and workpiece to effect selective re-alignment of magnetic domains of portions of the magnetic material facing the depressions of the imprinting surface, such that the pattern of selectively re-aligned magnetic domains forms a pattern replicating the pattern of projections and depressions; and (d) means for applying sufficient pressure to the stamper and workpiece to overcome magnetic attraction between the stampType: GrantFiled: May 6, 2003Date of Patent: May 23, 2006Assignee: Seagate Technology LLCInventor: Li-Ping Wang
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Patent number: 7038868Abstract: When magnetically transferring information represented by a pattern of magnetic layer formed on a master information carrier to a disc-like slave medium, an initial DC magnetic field is applied to the slave medium to initially magnetize the slave medium in one direction of concentric recording tracks and a transfer magnetic field is applied to the slave medium in the direction opposite to the direction of the initial-magnetization with the initially-magnetized slave medium held in close contact with the master information carrier. At least one of applying the initial DC magnetic field and applying the transfer magnetic field is effected by applying the magnetic field while the slave medium is being rotated relatively to the magnetic field and stopping the rotation of the slave medium after the intensity of the magnetic field is gradually reduced to not stronger than a predetermined value.Type: GrantFiled: February 12, 2003Date of Patent: May 2, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazuhiro Niitsuma, Masakazu Nishikawa
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Patent number: 7019925Abstract: Reference patterns in accordance with the present invention can include variable frequency chevrons incorporated into a reference pattern on a printed media surface to improve servo demodulation. In one embodiment, the reference pattern can include one or more servo wedges having a preamble including digital information at a first frequency relative to the head when the rotatable medium is rotated at a spin speed. The servo wedges further include at least one field having a first set of a plurality of phase-bursts forming a positive chevron angle relative to the preamble and a second set of a plurality of phase-bursts forming a negative chevron angle relative to the preamble, wherein a frequency of the at least one field relative to the head when the rotatable medium is rotated at the spin speed varies between a first end of the media surface and a second end.Type: GrantFiled: April 2, 2004Date of Patent: March 28, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventor: Richard M. Ehrlich
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Patent number: 7012770Abstract: A magnetic pattern of a master disc is transferred to both sides of a magnetic recording medium with no displacement. The origin of a magnetic recording medium can be determined by observing the inner or outer periphery of the magnetic recording medium. Back-side alignment marks are formed on the front side of the magnetic recording medium based on the origin thus determined. The back-side alignment marks can be observed with a microscope and front-side alignment marks for the magnetic recording medium can be provided on the back side of the magnetic recording medium. The alignment marks provided on the front/back sides of the magnetic recording medium are aligned with the corresponding alignment marks provided on the master disc, and a magnetic pattern formed on the soft magnetic material of the master disc is can be transferred to the magnetic recording medium.Type: GrantFiled: September 9, 2003Date of Patent: March 14, 2006Assignee: Fuji Electric Co., Inc.Inventors: Hiroyuki Yoshimura, Kiminori Sato
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Patent number: 7009790Abstract: The present invention enables to execute accurate magnetic transfer without signal omission and the like, by bringing a master carrier which bore transfer information and a slave medium to undergo transfer into close contact with each other uniformly and without a gap when they are received in a holder and brought into confronted close contact with each other. In a magnetic transfer apparatus for executing magnetic transfer by applying magnetic field for transfer generated by a magnetic field applying apparatus after master carriers 3, 4 which bore transfer information and a slave medium 2 to undergo transfer are brought into confronted close contact with each other and received in a holder 10, materials 6, 7 having elastic characteristic are interposed between the holder 10 and master carriers 3, 4, thereby allowing microdeformation of master carriers 3, 4 to enhance the close contact capability with the slave medium.Type: GrantFiled: June 21, 2002Date of Patent: March 7, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Kazuhiro Niitsuma
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Patent number: 6994029Abstract: A magnetic transfer method which superposes on a magnetic disk surface a magnetic transfer master disk (2) on which a magnetic film is formed so as to have an array pattern shape corresponding to a preset information signal, and magnetizes the magnetic film on the master disk (2) to thereby magnetic-transfer-record the array pattern of the information signal on the master disk (2) onto the magnetic disk as the magnetized pattern of the information signal, the method characterized by comprising a step of contacting/separating to/from a dummy disk (1) the magnetic film-formed surface of the master disk (2) to thereby clean the master disk (2), and a step of superposing, after the cleaning, the master disk (2) on the magnetic disk for magnetic transfer recording; and a magnetic transfer device for the method.Type: GrantFiled: September 3, 2003Date of Patent: February 7, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideyuki Hashi, Taizo Hamada, Toshio Makabe, Kiyokazu Toma, Tatsuaki Ishida, Yasuaki Ban, Keizo Miyata
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Patent number: 6987627Abstract: A device for use in performing simultaneous contact printing of magnetic patterns in opposing surfaces of a dual-sided magnetic or magneto-optical (MO) recording medium, comprising: (a) a fixedly mounted first magnetic pole having a first end surface; (b) an axially movable second magnetic pole in axial alignment with the first magnetic pole, the second magnetic pole having a second end surface opposite to and facing the first end surface of the first magnetic pole; (c) a first portion of a centering insert fixture mounted on the first end surface of the first magnetic pole; and (d) a second portion of a centering insert fixture mounted on the second end surface of the second magnetic pole.Type: GrantFiled: April 17, 2003Date of Patent: January 17, 2006Assignee: Seagate Technology LLCInventors: Gennady Gauzner, David Shiao-Min Kuo
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Patent number: 6985314Abstract: A method of forming a magnetic transition pattern in a magnetic material by contact printing comprises steps of providing a stacked assembly including a workpiece including a surface comprised of the magnetic material including a plurality of initialized, unidirectionally aligned magnetic domains, and a high saturation magnetization stamper having an imprinting surface in intimate contact with the workpiece surface, the imprinting surface comprising a plurality of projections and depressions arranged in a pattern corresponding to the magnetic transition pattern to be formed in the magnetic material, and selectively magnetically re-aligning the initialized, unidirectionally aligned magnetic domains by placing the assembly in a fixed gap contact printing apparatus including a magnet means having a pair of spaced-apart, stationary magnetic poles providing an oppositely directed, uniform intensity, unidirectional re-alignment magnetic field.Type: GrantFiled: May 9, 2003Date of Patent: January 10, 2006Assignee: Seagate Technology LLCInventor: Li-Ping Wang
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Patent number: 6982845Abstract: A magnetic recording apparatus comprises a magnetic field impression unit, a current supplying unit and a controlling unit t. The magnetic field impression unit impresses a magnetic field to a magnetic recording medium. The current supplying unit supplies a current to the magnetic recording medium. The controlling unit makes the current supplying unit supply the current to the magnetic recording medium while making the magnetic field impression unit impress the magnetic field to at least a unit of a magnetic recording unit of the magnetic recording medium. Thus, a information is recorded magnetically by making a direction of a magnetization of the magnetic recording unit of the magnetic recording medium in a predetermined direction.Type: GrantFiled: March 28, 2003Date of Patent: January 3, 2006Assignee: Kabushiki Kaisha ToshibaInventors: Tadashi Kai, Masayuki Takagishi, Masashi Sahashi, Junichi Akiyama, Hitoshi Iwasaki, Akira Kikitsu
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Patent number: 6980380Abstract: A master information carrier includes a high-level region and a low-level region that are formed on a non-magnetic base. The high-level region includes a ferromagnetic thin film pattern that corresponds to preformat information signals. The master information carrier is brought into close contact with a magnetic disk by exhausting a gas from a hole of the magnetic disk to generate negative pressure in a space between the low-level region and the magnetic disk. In this case, to prevent deformation of the central portion of the master information carrier, an inner edge of the high-level region in the radial direction is extended to the vicinity of a hole edge of the magnetic disk so that a portion of the high-level region comes into contact with the vicinity of the hole edge. This configuration can improve the close contact between the master information carrier and the magnetic disk, thus achieving higher reliability of magnetic transfer recording.Type: GrantFiled: December 27, 2002Date of Patent: December 27, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Keizo Miyata, Hideyuki Hashi, Tatsuaki Ishida
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Patent number: 6979524Abstract: A method of forming a magnetic transition pattern in a longitudinal magnetic recording medium, comprising steps of: (a) providing a magnetic recording medium including a layer of a magnetic material having a surface comprised of a plurality of longitudinally extending magnetic domains; (b) contacting the surface of the layer of magnetic material with a topographically patterned imprinting surface of a stamper/imprinter formed of at least one high saturation magnetization, high permeability magnetic material; and (c) applying a unidirectional magnetic field perpendicular to the imprinting surface of the stamper/imprinter, the perpendicular magnetic field creating a longitudinal magnetic field component of sufficient strength to effect selective alignment of the magnetic domains of those portions of the layer of magnetic material which face the depressions of the imprinting surface while retaining the alignment of the magnetic domains of those portions of the layer of magnetic material which face the projectType: GrantFiled: April 18, 2003Date of Patent: December 27, 2005Assignee: Seagate Technology LLCInventors: Koichi Wago, Shih-Fu Lee, Li-Ping Wang, Joseph Leigh
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Patent number: 6977785Abstract: A magnetic-pattern transferring method is a method for transferring a magnetic pattern to a magnetic recording medium. The method comprises steps as follows. In a master transferring step, a magnetic field is applied to a master placed close to the magnetic recording medium. The magnetic field excites a magnetic layer having a pattern patterned on the master according to the magnetic pattern. Thereby, the pattern of the magnetic layer is transferred to the magnetic recording medium. In a pattern-difference measuring step, a magnetic condition of the magnetic recording medium is measured so as to measure a magnetically different part between the pattern transferred to the magnetic recording medium and the magnetic pattern. In a magnetic transferring step, a pattern transfer is performed to the magnetic recording medium by using the master while applying the magnetic field so as to correct a magnetic condition of the magnetically different part.Type: GrantFiled: March 27, 2002Date of Patent: December 20, 2005Assignee: Fujitsu LimitedInventors: Yutaka Nakamura, Hitoshi Komoriya, Hiroyuki Suzuki, Takao Hirahara
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Patent number: 6977789Abstract: A disk drive is disclosed comprising a disk and a head actuated radially over the disk. An external servo writer is used to write reference servo bursts to the disk at a coarser radial resolution than product servo bursts. During a self servo writing operation, the reference servo bursts are processed to servo circularly to write a first set of product servo bursts to the disk. The reference servo bursts are also processed to servo spirally to write a second set of product servo bursts to the disk.Type: GrantFiled: January 31, 2002Date of Patent: December 20, 2005Assignee: Western Digital Technologies, Inc.Inventor: Robert L. Cloke
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Patent number: 6977786Abstract: In an information recording method of the present invention by carrying out recording data while carrying out tracking servo accurately, high density recording of signals at a good S/N can be carried out, and high density recording by a vertical magnetic recording system can be carried out. A magnetic disk comprises a magnetic recording layer, and the magnetic recording layer is magnetized in advance such that magnetized regions A and B having different magnetization directions are formed. At a time of recording data, vertical magnetic recording is carried out by a magnetic head while carrying out accurate tracking servo by optically tracking by a magneto-optical effect utilizing a difference in the magnetization directions of the magnetized regions A and B. Therefore, high-density recording at a good S/N is possible.Type: GrantFiled: October 4, 2002Date of Patent: December 20, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazuyuki Usuki, Masakazu Nishikawa, Makoto Nagao
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Patent number: 6972915Abstract: Information represented by a pattern of a magnetic layer formed on a master information carrier is magnetically transferred to a slave. An initial DC magnetic field is applied to the slave medium with the slave medium supported from one side thereof so that the other side of the slave medium is directly opposed to the magnetic field generator, and a transfer magnetic field is applied to the slave medium and the master information carrier held in close contact with each other by a holder, which covers both the sides of the slave medium/master information carrier assembly, with the magnetic field generator positioned to oppose both the sides of the slave medium/master information carrier assembly so that the magnetic field generated by the magnetic field generator is applied to the slave medium and the master information carrier through the holder.Type: GrantFiled: February 24, 2003Date of Patent: December 6, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazunori Komatsu, Masashi Aoki
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Patent number: 6961196Abstract: A master information carrier comprises a substrate whose surface has an embossed pattern corresponding to an information signal. At least a surface of the protruding portion of the embossed pattern is made of a ferromagnetic material. A method for writing an information signal into a sheet or disk magnetic record medium with a ferromagnetic thin film or coating is performed by putting the surface of the magnetic record medium into contact with the master information carrier so as to write a magnetized pattern corresponding to the embossed pattern of the master information carrier into the magnetic record medium.Type: GrantFiled: March 25, 2003Date of Patent: November 1, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tatsuaki Ishida, Ryuji Sugita, Kiyokazu Tohma, Kazunari Yoshimoto, Keizou Miyata, Hiroshi Ryonai
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Patent number: 6954317Abstract: When a master medium and a slave medium are brought into close contact and a transfer magnetic field is applied thereto to perform magnetic transfer, the leakage magnetic field intensity of the transfer magnetic field is regulated to within a permissible range, making possible the transfer of an exact magnetic pattern. After a magnetic field is applied to the slave face in the track direction thereof to initially magnetize the slave medium in the track direction, the master medium and the slave medium are brought into close contact. When applying a transfer magnetic field in the track direction of the slave face to perform a magnetic transfer, the magnetic field intensity component in the direction opposite that in which the transfer magnetic field is to be applied is regulated to less than or equal to ½ the magnetic coercive force Hcs of the slave medium over the entire slave surface.Type: GrantFiled: January 31, 2002Date of Patent: October 11, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Masashi Aoki, Kazunori Komatsu, Masakazu Nishikawa, Junichi Nakamikawa
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Patent number: 6950253Abstract: A magnetic printing apparatus includes a dipole magnet that supplies a magnetic field to a magnetic media, a holder for holding the magnetic media, a set of stampers with servo patterns and a press for pressing the magnetic media firmly against the stampers while the magnetic media and stampers are being exposed to a magnetic field and a set of elastomer pads to distribute and equalize the force of the press on the magnetic media. Servo formatting, using the contact magnetic printing apparatus, is done by positioning the magnetic media against the stampers. A force is then applied to the magnetic media and stamper so that the two are in firm contact with each other. A sequence of magnetic fields is then applied to the stampers and magnetic media which duplicates the servo patterns of the stamper onto the magnetic media.Type: GrantFiled: September 30, 2002Date of Patent: September 27, 2005Assignee: Seagate Technology LLCInventors: Li-Ping Wang, Andrew George Prax, David Shaio-Min Kuo
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Patent number: 6950254Abstract: A magnetic transfer apparatus is utilized to establish magnetization on the surface of a magnetic disk. A support mechanism supports the magnetic disk in the magnetic transfer apparatus. A magnetizing mechanism is designed to get opposed to the magnetic disk held by the support mechanism. The magnetizing mechanism applies a magnetic field of variable intensity in response to a change of position in the radial direction of the magnetic disk. The magnetic transfer apparatus enables establishment of a magnetic field of an appropriate intensity at any positions in the radial direction of the magnetic disk. Magnetization of a constant intensity can be established over the surface of the magnetic disk irrespective of a position in the radial direction of the magnetic disk. The magnetic transfer apparatus alone serves to establish a servo pattern of a clear magnetization on the magnetic disk.Type: GrantFiled: August 4, 2003Date of Patent: September 27, 2005Assignee: Fujitsu LimitedInventors: Hiroyuki Suzuki, Hitoshi Komoriya, Yutaka Nakamura, Takao Hirahara
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Patent number: 6950252Abstract: A master carrier for magnetic transfer is equipped with a substrate with a land/groove pattern of lands and grooves, and a magnetic layer formed on the land/groove pattern. The adhesion between the substrate and the magnetic layer is 1.2×109 N/m2 or greater. A first oxygen concentration Do at the magnetic layer formed on the land is reduced gradually toward the direction of the depth of the substrate and is greater than a second oxygen concentration Dh at the magnetic layer formed on the groove.Type: GrantFiled: June 25, 2002Date of Patent: September 27, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Tadashi Yasunaga
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Patent number: 6947231Abstract: A magnetic transfer holder holds a contact body including superimposed master information carriers bearing transfer information in pattern areas and a slave medium. At least one of the two sides of the contact body is held via an elastic body. A surface of this elastic body that faces the master information carrier is circular. An outer diameter D1 of this elastic body is smaller than an outer diameter D2, which is the smaller one of an outer diameter of the master information carrier and that of the slave medium, and larger than an outer diameter D3 of the pattern area. A diameter d1 of a center hole of the elastic body is larger than an outer diameter d2, which is the larger one of a center hole of the master information carrier and that of the slave medium, and smaller than an inner diameter d3 of the pattern area.Type: GrantFiled: March 26, 2004Date of Patent: September 20, 2005Assignee: Fuji Photo Film Co., Ltd.Inventor: Akito Kamatani
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Patent number: 6940667Abstract: A plurality of redundant sets of servo data are recorded on a magnetic hard disk. The set meeting a predetermine criteria is employed when the hard disk is assembled into a hard disk drive. The determination of which set has the criteria may be conducted by the disk drive itself. The criteria may include a determination the set of servo data having meeting a minimum quality criteria or the fewest errors. The criteria may include a selection of a set of servo data having a specific pattern where the prerecorded sets may comprise a differing servo patterns that may be used by disk drives requiring specific servo patterns. The servo data are printed onto the hard disk by means of a stamper or mask having all the sets of servo data.Type: GrantFiled: January 10, 2003Date of Patent: September 6, 2005Assignee: Seagate Technology LLCInventors: David S. Kuo, Shih-Fu Lee, Neil N. Deeman
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Patent number: 6940668Abstract: A magnetic transfer apparatus including a holder for accommodating a slave medium subjected to transfer of information and master carriers bearing an information to be transferred which are to be kept in the state of being sucked to pressure-reducing suction parts of an inner surface of the holder for mutual close contact of surfaces of the slave medium and the master carriers, a vacuum suction unit for providing a vacuum condition of the inner space, and a magnetic field application unit for applying a transfer magnetic field to the holder. At the time of performing the magnetic transfer, the pressure of the inner space of the holder by the vacuum suction unit is set higher than the suction pressure of the pressure-reducing suction parts by 1-50 kPa, whereby before mutual contact of the slave medium and the master carriers, a suction state of the master carriers is kept constant.Type: GrantFiled: February 14, 2003Date of Patent: September 6, 2005Assignee: Fuji Photo Film Co., Ltd.Inventor: Akito Kamatani
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Patent number: 6924951Abstract: A magnetic transfer apparatus for transferring patterned information formed on a surface of a master disk to a magnetic recording medium as a slave disk placed in intimate contact with the surface of the master disk by applying a magnetic field to the disks, which comprises: a magnet; a first holder for holding the master disk and the slave disk; and a second holder facing the first holder, the first holder being supported by a supporting member, the magnet being disposed on only an outer side of the second holder, and the second holder being formed solely of a lid.Type: GrantFiled: March 8, 2004Date of Patent: August 2, 2005Assignee: Fuji Photo Film Co., Ltd.Inventor: Minoru Araki
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Patent number: 6914735Abstract: In a manufacturing method for a magnetic recording medium, when the length of a ferromagnetic thin film on a master information carrier corresponding to the length between a pair of magnetization transition regions adjacent to each other is A in magnetization information recorded onto a magnetic recording medium, the film thickness of the ferromagnetic thin film is t and A/t is k, k is set from not less than 0.8 to not more than 8.Type: GrantFiled: October 2, 2002Date of Patent: July 5, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Taizou Hamada, Tatsuaki Ishida, Yasuaki Ban
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Patent number: 6914736Abstract: A magnetic transfer apparatus includes a holder which contains therein a master information carrier carrying thereon information to be transferred and a slave medium to which the information born by the master information carrier is to be transferred. The master information carrier and the slave medium are pressed against each other under pressure acting on the holder when the holder is evacuated, and a transfer magnetic field is applied to the slave-medium-master-information-carrier assembly. The holder includes upper and lower holder portions having flat plate portions which are brought into abutment against the other side of the slave medium or the master information carrier and are movable toward and away from each other. At least one of the flat plate portions is flexible.Type: GrantFiled: October 15, 2002Date of Patent: July 5, 2005Assignee: Fuji Photo Film Co., Ltd.Inventor: Akito Kamatani
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Patent number: 6909564Abstract: By bring a master carrier and a slave medium into close contact with uniform force when executing magnetic transfer by applying transfer magnetic field in the state that the master carrier and slave medium is in confronted close contact and received within a holder, inferiority of transfer such as omission of signals is prevented and quality of transfer signals is enhanced. The magnetic transfer apparatus executes magnetic transfer by applying transfer magnetic field by means of a magnetic field applying apparatus 5 after a master carrier 3, 4 bearing transfer information and a slave medium 2 to be transferred are brought into confronted close contact and received within a holder 10, wherein said holder 10 has a substantially circular shape and in particular, the circularity of holder is not less than 98%, wherein the flexural rigidity=Ed3/12 determined by Young's modulus E and thickness d of the holder is in the range of 0.Type: GrantFiled: June 13, 2002Date of Patent: June 21, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Kazuhiro Niitsuma, Akito Kamatani
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Patent number: 6909563Abstract: A master carrier for magnetic transfer is equipped with a substrate having a land/groove pattern. The land/groove pattern is formed from a magnetic material and corresponds to information that is transferred to a magnetic recording disk. Each land in the land/groove pattern has four round corners whose radius is from 1% through 47% of the width of a data track on the disk.Type: GrantFiled: May 13, 2002Date of Patent: June 21, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Tadashi Yasunaga, Kazuhiro Niitsuma
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Patent number: 6909565Abstract: A magnetic transfer method includes a first step (ST103) of preparing a magnetic disk, a second step (ST105) of forming a layer of lubricant on the magnetic disk, a third step (ST108) of bringing a surface of the magnetic layer on the magnetic disk into close contact with a magnetic transfer master having a magnetic film formed on at least one side and magnetically transferring a pattern of the magnetic film on the magnetic transfer master onto the surface of the magnetic disk through application of an external magnetic field, and a fourth step (ST104, ST106) of burnishing at least a surface of the magnetic disk that comes into contact with the magnetic transfer master. The first step, the fourth step, the second step, the fourth step, and the third step are performed in the stated order.Type: GrantFiled: November 20, 2003Date of Patent: June 21, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideyuki Hashi, Taizou Hamada, Tatsuaki Ishida, Kiyokazu Tohma
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Patent number: 6906876Abstract: A favorable magnetic transfer is performed on a perpendicular magnetic recording medium. A permanent magnet apparatus provided with two permanent magnets, each having a width extending the length of the radial direction of a discoid magnetic recording medium, is used as a transfer magnetic field generating means. A conjoined body formed of the perpendicular magnetic recording medium, which has been initially magnetized unidirectionally in the direction perpendicular to the track surface thereof, and two master mediums, disposed on respective surfaces of the slave medium, is inserted between the permanent magnets. A rotating means rotates the conjoined body, in the direction along the tracks of the slave medium, while a transfer magnetic field is applied to the conjoined body in the direction substantially opposite that in which the initial magnetization of the magnetic layer of magnetic recording medium has been performed, so as to perform the magnetic transfer.Type: GrantFiled: May 20, 2002Date of Patent: June 14, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazunori Komatsu, Masakazu Nishikawa
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Patent number: 6906874Abstract: A magnetic transfer wherein the exchange of master mediums is made easy to perform is provided, whereby the operational efficiency and transfer efficiency are improved, leading to an overall improvement in productivity in the manufacture of preformatted slave mediums. A master fixing base for determining and supporting the position of a master medium, which bears transfer data, and a conjoining apparatus for conjoining the master medium and the slave medium that is to receive the transfer therefrom are provided. The master medium is exchanged along with the master fixing base. It is preferable that a cleaning means be provided.Type: GrantFiled: April 15, 2002Date of Patent: June 14, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Akito Kamatani, Tsuneo Inui, Masashi Aoki, Masakazu Nishikawa
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Patent number: 6906875Abstract: A magnetic transfer device for bringing a master carrier with information and a slave medium into intimate contact with each other and then applying a transfer field to transfer the information to the slave medium. The master carrier has an inclined face on its radially outer end. After the magnetic transfer of the information, claws are inserted in the gas formed by the inclined face of the master carrier and the slave medium. The slave medium held in intimate contact with the master carrier is separated from the master carrier by lifting the slave medium with the claws.Type: GrantFiled: May 14, 2002Date of Patent: June 14, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Akito Kamatani, Masakazu Nishikawa, Makoto Nagao, Kazunori Komatsu, Tsuneo Inui, Kazuhiro Niitsuma
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Patent number: 6906877Abstract: A method of performing an accurate magnetic transfer to a high-density slave medium having two magnetic layers and utilizing antiferromagnetic coupling. The magnetic layer, which has been initially magnetized in advance, of a magnetic recording medium is conjoined with the data bearing surface of a master medium. A transfer magnetic field is applied to the conjoined body in the circumferential direction of the track of the first magnetic layer in the direction opposite the initial magnetization direction of the second magnetic layer. At this time, the thickness of the magnetic layer of the master medium, the permeability (material) of the magnetic layer, the form of the patterned magnetic layer, the separation distance between the master medium and the magnetic recording medium, etc., may be controlled so that the magnetic field of the transfer magnetic field does not effect the magnetization state of the first magnetic layer.Type: GrantFiled: June 7, 2002Date of Patent: June 14, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Tadashi Yasunaga
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Patent number: 6903888Abstract: Defects of a hard disk drive servo pattern stamper are detected by comparing a scattered light beam pattern against the known servo pattern. A magnetic field is applied to stamper and the beam is linearly polarized. Variations in the physical offset of the beam, its scatter, are indicative of physical defects. Variations in the Kerr rotation of scattered beam are indicative of magnetic defects.Type: GrantFiled: January 15, 2003Date of Patent: June 7, 2005Assignee: Seagate Technology LLCInventors: Joseph Leigh, Nobuo Kurataka
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Patent number: 6898031Abstract: A system and method for replicating magnetic patterns on hard disk media includes a mask located over or above a magnetic recording layer. The recording layer may include a single, dual, or multi-layer recording layer. A pattern is or has been formed in the mask, where the pattern defines the recordable regions and the non-recordable regions to be created in one or more layers within the recording layer. Portions of the recording layer are then exposed. An etch may then be performed to create grooves within one or more layers in the exposed regions of the recording layer. The magnetic properties of at least one layer in the exposed portions of the recording layer are then altered in order to create recordable or non-recordable regions. The mask is then removed from the recording layer.Type: GrantFiled: April 19, 2001Date of Patent: May 24, 2005Assignee: Seagate Technology LLCInventors: Karl A. Belser, Neil Deeman, Ga-Lane Chen
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Patent number: 6898032Abstract: A magnetic transfer method includes a first step (ST103) of preparing a magnetic disk, a second step (ST105) of forming a layer of lubricant on the magnetic disk, a third step (ST108) of bringing a surface of the magnetic layer on the magnetic disk into close contact with a magnetic transfer master having a magnetic film formed on at least one side and magnetically transferring a pattern of the magnetic film on the magnetic transfer master onto the surface of the magnetic disk through application of an external magnetic field, and a fourth step (ST104, ST106) of burnishing at least a surface of the magnetic disk that comes into contact with the magnetic transfer master. The first step, the fourth step, the second step, the fourth step, and the third step are performed in the stated order.Type: GrantFiled: March 28, 2001Date of Patent: May 24, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideyuki Hashi, Taizou Hamada, Tatsuaki Ishida, Kiyokazu Tohma
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Patent number: 6887593Abstract: A master information carrier for magnetic transfer includes a substrate having an irregularity pattern representing information to be transferred to a slave medium and a magnetic layer formed on the irregularity pattern on the substrate. The depth d of the recessed portions of the irregularity pattern and the thickness t of the magnetic layer formed on the recessed portions satisfy formula ?0.004?(t?d)/d?0.1. At the same time, the magnetic layer formed on the protruding portion of the irregularity pattern and the magnetic layer formed on the recessed portions of the irregularity pattern are connected with each other.Type: GrantFiled: September 15, 2003Date of Patent: May 3, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Ryuji Sugita, Masakazu Nishikawa, Tadashi Yasunaga
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Patent number: 6885513Abstract: A system and method for incrementally recording blocks of data such as servo information on magnetic media such as hard disks, flexible disks or tapes. The system comprises a master element with permeable features configured according to the block of data and corresponding to a small fraction of the area of the medium. A predetermined portion of the medium is advanced and brought in proximity to the master element. An electromagnet applies a localized field to copy the data to the selected portion of the medium. The field of the electromagnet is decreased before the next predetermined portion of the medium is advanced thereby avoiding damage to previously recorded data.Type: GrantFiled: December 24, 2002Date of Patent: April 26, 2005Inventor: Bill Richard Baker
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Patent number: 6882484Abstract: A magnetic transfer system includes magnetic recording medium stocker which holds a plurality of magnetic recording media, a magnetic transfer apparatus which magnetically transfers information represented by a magnetic layer on a master information carrier to the magnetic recording medium by applying a transfer magnetic field to the magnetic recording medium and the master information carrier with the magnetic recording medium and the master information carrier held in close contact with each other, and a conveyor which conveys the magnetic recording medium between the magnetic recording medium holding means and the magnetic transfer means. The magnetic recording medium holding stocker, the magnetic transfer apparatus and the conveyor are formed of material which contains substantially no chlorine, sulfur compound or nitric oxide at least at a part which is brought into contact with the magnetic recording medium.Type: GrantFiled: June 25, 2003Date of Patent: April 19, 2005Assignee: Fuji Photo Film Co., Ltd.Inventor: Masakazu Nishikawa
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Patent number: 6879453Abstract: A method of magnetic transfer allows transfer of magnetic signals independently to two recording layers included in a magnetic recording medium. The coercive force Hc1 of an upper recording layer, the coercive force Hc2 of a lower recording layer formed below the upper recording layer, the strength Hex2 of a first transfer magnetic field, and the strength Hex1 of a second transfer magnetic field are set so that the following relations hold true: Hc1<Hc2, Hex1<Hex2, Hc1<Hex2, and Hex1<Hc2. The first transfer magnetic field Hex2 is applied to the recording medium to transfer magnetization patterns exclusively to the lower recording layer and to uniformly magnetize the upper recording layer. The second transfer magnetic field Hex1 is applied to the recording medium to transfer magnetization patterns exclusively to the upper recording layer 1a, while keeping the magnetization patterns in the lower recording layer 1b unaffected.Type: GrantFiled: September 13, 2002Date of Patent: April 12, 2005Assignee: Fuji Electric Co., Ltd.Inventor: Akira Saito
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Patent number: 6867935Abstract: A magnetic transfer apparatus for magnetically transferring information represented by a pattern of a magnetic layer formed on a master information carrier to a slave medium includes a magnet unit which applies an initial DC magnetic field to a slave medium and a magnet unit which applies a transfer magnetic field to the slave medium and the master information carrier in the direction opposite to the direction of the initial-magnetization with the slave medium held in close contact with the master information carrier. The initial DC magnetic field and the transfer magnetic field are not larger than the diameter of an innermost recording track in the half-width of a curve representing an intensity distribution in the direction of a tangent of the innermost recording track.Type: GrantFiled: April 4, 2003Date of Patent: March 15, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazunori Komatsu, Toshihiro Usa
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Patent number: 6865039Abstract: A master medium for magnetic transfer includes a substrate having a concave portion formed in its surface corresponding to a pattern of recorded information to be transferred; a first perpendicular ferromagnetic layer deposited in the concave portion; and a second perpendicular ferromagnetic layer layered on the substrate surface and the first perpendicular ferromagnetic layer surface. The substrate surface and the first perpendicular ferromagnetic layer surface are flattened to form a single flat surface. In the master medium for magnetic transfer, a magnetic field change in a direction parallel to the substrate surface at a magnetization boundary of the first perpendicular ferromagnetic layer is steep. Since the influence of the change of an external magnetic field is reduced, it is possible to perform accurate transfer from the master medium for magnetic transfer to a slave medium for magnetic recording.Type: GrantFiled: March 20, 2002Date of Patent: March 8, 2005Assignee: Fujitsu LimitedInventors: Shingo Hamaguchi, Sumio Kuroda, Kazuyuki Ozaki, Ken Tamanoi, Koji Matsumoto
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Patent number: 6865038Abstract: In the magnetic transferring method for magnetically transferring an information signal such as a servo signal from the master medium to the slave medium, when magnetic transfer is performed by bringing a master medium and a slave medium into close contact with each other, the master medium bearing an information signal and the slave medium having a lubricating layer formed on the surface of its recording plane during use, and applying a transfer magnetic field, the magnetic transfer is performed by bringing the slave medium before the formation of the lubricating layer and the master medium into close contact with each other. Thus, the separation of the slave medium from the master medium after the magnetic transfer is facilitated, and the adsorption of dust on the slave medium is prevented.Type: GrantFiled: November 28, 2001Date of Patent: March 8, 2005Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Makoto Nagao
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Patent number: 6859339Abstract: The master information recording apparatus 100 includes a master information carrier, a master information carrier facing member, and a magnetic field applying member. A ferromagnetic thin film pattern formed on the surface of the master information carrier includes not less than two kinds of different patterns each having a different pattern angle showing an angle with respect to the direction of the relative movement between a magnetic head and a rotating magnetic recording medium. The magnetic field applying unit applies a magnetic field along the direction, which is perpendicular to the direction shown by an angle that is smaller than the pattern angle of the maximum pattern and larger than the minimum pattern angle of the pattern among the not less than two kinds of patterns.Type: GrantFiled: January 30, 2003Date of Patent: February 22, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yasuaki Ban, Keizo Miyata, Taizou Hamada, Kouji Taniguchi, Masaya Sakaguchi
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Patent number: 6858328Abstract: A master information carrier with excellent durability is provided, for the use of static and a real lump-sum recording of digital information signals on magnetic recording medium. The master information carrier comprises a non-magnetic substrate on which a ferromagnetic film is disposed with an embossed pattern. Protrusions of the embossed pattern correspond to a disposition of the digital information signals. Recessed portions of the embossed pattern of the ferromagnetic film are filled with non-magnetic solid material. Alternately, A non-magnetic substrate has an embossed pattern and recessed portions of the embossed pattern correspond to a disposition of the digital information signals. A ferromagnetic film is filled in the recessed portions of the embossed pattern.Type: GrantFiled: March 18, 1999Date of Patent: February 22, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tatsuaki Ishida, Kiyokazu Tohma, Keizo Miyata, Yoriko Takai, Taizou Hamada, Hiroshi Ryonai
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Patent number: 6850377Abstract: Instead of directly performing defect inspection using a master information carrier, an inspection substrate is prepared to then bring the master information carrier in close contact therewith, to thereby transfer a defect on the master information carrier to the inspection substrate, thus indirectly inspecting any defect of the master information carrier on the inspection substrate. Defect inspection is performed on the first-state inspection substrate before close contacting, so that a defect inspection result on the second-state inspection substrate after close contacting and that on the first-state inspection substrate are compared to each other.Type: GrantFiled: April 17, 2002Date of Patent: February 1, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideyuki Hashi, Taizou Hamada, Tatsuaki Ishida
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Patent number: 6839192Abstract: A holder for magnetic transfer is formed by a chamber base and a chamber body which are moved toward and away from each other and form therebetween an inner space in which a master information carrier and a slave medium are accommodated and held in close contact with each other. The holder is provided at different parts with a first sealing portion for sealing the inner space between the chamber base and the chamber body and a second sealing portion allowing the pressing faces of the chamber base and the chamber body to move toward each other to press the master information carrier and the slave medium against each other with the inner space kept sealed.Type: GrantFiled: March 14, 2003Date of Patent: January 4, 2005Assignee: Fuji Photo Film Co., Ltd.Inventor: Akito Kamatani
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Publication number: 20040257687Abstract: A master information carrier capable of manufacturing a magnetic recording medium in which a preformat recording of information signals causing no reproduction signal detection errors arising from a pulse shift of a reproduction waveform is performed. A master information carrier 1 has an array of ferromagnetic thin films 3 arranged according to the pattern of information signals and is used for forming magnetization 4 of a pattern corresponding to the array pattern of the ferromagnetic thin film 3 in a magnetic recording medium by applying a magnetic field while opposing the master information carrier 1 against a magnetic recording medium 2. Each of the ferromagnetic thin films 3 is formed such that each pattern length A becomes equal to a length including a correction amount a in addition to a length a between magnetic transition areas 6 of the magnetization 4 to be formed in the magnetic recording medium 2.Type: ApplicationFiled: October 14, 2003Publication date: December 23, 2004Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Tatsuaki Ishida, Keizo Miyata, Nobuyuki Komura, Yasuaki Ban, Taizou Hamada, Hideyuki Hashi
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Patent number: 6833969Abstract: A master information carrier for magnetic transfer has a concentric irregularity pattern representing information to be transferred to a disc-like magnetic recording medium. The top surface of the protruding portions of the irregularity pattern is formed of magnetic material. The irregularity pattern is formed so that the width L [nm] in a circumferential direction of a protruding portion at a distance R [nm] from the center satisfies the condition L=&agr;(&ohgr;·&Dgr;T·R), 0.8≦&agr;≦1.4, wherein &ohgr; represents in [rad/sec] the angular velocity of the magnetic recording medium when a signal is read out from the magnetic recording medium after the magnetic transfer and &Dgr;T represents in [sec] a desired signal time width of a reproduction signal waveform in a magnetization transition region corresponding to an interval between the ends of the protruding portion in the circumferential direction.Type: GrantFiled: March 20, 2003Date of Patent: December 21, 2004Assignee: Fuji Photo Film Co., Ltd.Inventors: Toshihiro Usa, Kazunori Komatsu