Patents by Inventor Tatsuaki Ishida
Tatsuaki Ishida has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7095575Abstract: A self-servo reference signal including a timing pattern and an oblique phase pattern is transferred in advance on a magnetic disk 1 by magnetic printing. A phase difference detection section 13 detects a phase difference between the two patterns to detect the position of a magnetic head 2. A burst signal generated by a record signal generation section 14 is recorded in a region of the magnetic disk 1 where no self-servo reference signal is recorded. A track pitch calculation section 11 determines a relationship between the reproduction output of the burst signal detected by a reproduction signal processing section 12 and the phase difference detected by the phase difference detection section 13, thus calculating an optimum data track pitch.Type: GrantFiled: September 2, 2004Date of Patent: August 22, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Keizo Miyata, Hiroshi Kohso, Makoto Kimura, Tatsuaki Ishida
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Patent number: 7061703Abstract: 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 ? 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: GrantFiled: October 14, 2003Date of Patent: June 13, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tatsuaki Ishida, Keizo Miyata, Nobuyuki Komura, Yasuaki Ban, Taizou Hamada, Hideyuki Hashi
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Patent number: 7057834Abstract: 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 ? 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: GrantFiled: March 29, 2001Date of Patent: June 6, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tatsuaki Ishida, Keizo Miyata, Nobuyuki Komura, Yasuaki Ban, Taizou Hamada, Hideyuki Hashi
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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: 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: 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: 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: 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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Publication number: 20050111123Abstract: On a translucent non-magnetic substrate, a master information carrier having an information signal pattern made of light-proof ferromagnetic thin-film is prepared, and a magnetic recording medium having undergone DC erasing is placed opposite to the carrier. The carrier in the foregoing state is irradiated with light while a bias magnetic field having a reverse polarity to the DC erasing magnetic field is applied to the medium. As a result, a magnetized pattern corresponding to the information signal array can be transcribed and recorded on the medium. In the case of using a magnetic recording medium having so great coercive force that a transcribing and recording magnetic field is not enough to work on this medium, the foregoing structure allows transcribing and recording a signal having excellent performance because a section having undergone the light irradiation lowers the coercive force.Type: ApplicationFiled: November 17, 2004Publication date: May 26, 2005Inventors: Masaya Sakaguchi, Tatsuaki Ishida
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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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Publication number: 20050052767Abstract: A self-servo reference signal including a timing pattern and an oblique phase pattern is transferred in advance on a magnetic disk 1 by magnetic printing. A phase difference detection section 13 detects a phase difference between the two patterns to detect the position of a magnetic head 2. A burst signal generated by a record signal generation section 14 is recorded in a region of the magnetic disk 1 where no self-servo reference signal is recorded. A track pitch calculation section 11 determines a relationship between the reproduction output of the burst signal detected by a reproduction signal processing section 12 and the phase difference detected by the phase difference detection section 13, thus calculating an optimum data track pitch.Type: ApplicationFiled: September 2, 2004Publication date: March 10, 2005Inventors: Keizo Miyata, Hiroshi Kohso, Makoto Kimura, Tatsuaki Ishida
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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: 6858329Abstract: A master disc capable of conducting a preformat recording by a magnetic transcription without causing any unevenness over an entire magnetic disc is provided. The master disc is provided with a radial land portion where an array of ferromagnetic thin films is formed and a concave portion against the land portion. The land portion and the concave portion are formed such that the land portion is joined with the surface of the magnetic disc when the present magnetic disc is overlapped on the magnetic disc, and that the concave portion is not contacted with the surface of the magnetic disc, and also that a space surrounded by the surface of the magnetic disc and the concave portion is open to air at a peripheral end portion of the magnetic disc.Type: GrantFiled: March 29, 2001Date of Patent: February 22, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Taizou Hamada, Hideyuki Hashi, Tatsuaki Ishida, Nobuyuki Komura, Yasuaki Ban, Keizo Miyata, Kiyokazu Tohma
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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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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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Photomask, method of generating resist pattern, and method of fabricating master information carrier
Patent number: 6821869Abstract: A recess for deaeration is formed in the surface of a resist film by using the photolithography technique, a photomask is allowed to come into contact with projections for close contact on both sides or around the recess for deaeration, and evacuation is performed via the recess for deaeration, thereby enhancing close contact between the photomask and the projections for close contact. With the configuration, a resist pattern having an accurate recess while preventing diffraction of light is formed.Type: GrantFiled: May 7, 2002Date of Patent: November 23, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Terumi Yanagi, Nobuyuki Komura, Tatsuaki Ishida, Keizo Miyata -
Patent number: 6785070Abstract: A magnetic transcription device for transcribing information signals of a master information carrier in a magnetic recording medium by applying a magnetic field generated by magnetic field generating means to a contact body obtained by contacting the master information carrier having a base on which ferromagnetic bodies corresponding to the information signals are formed with a magnetic recording medium having a ferromagnetic layer, wherein the magnetic recording medium includes driving means for adjusting a distance between the magnetic field generating means and the contact body while rotating the magnetic field generating means relative to the contact body.Type: GrantFiled: December 3, 2001Date of Patent: August 31, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kouji Taniguchi, Kaoru Matsuoka, Taizou Hamada, Hideyuki Hashi, Yasuaki Ban, Tatsuaki Ishida
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Patent number: 6781777Abstract: A high-level region and a low-level region are formed on a surface of a nonmagnetic base member, in which high-level region is formed a ferromagnetic thin film pattern which corresponds to a preformat information signal, in such a structure that a flow promoting shape of such a shape (e.g., smooth curved shape, polygonal shape) that inhibits the stagnation of a flow of a detergent to promote the flow in order to prevents sticking and residing of foreign matter contained in the detergent is formed at an area where the detergent is liable to stagnate in the high-level region, i.e. at an inner radial portion of a disk-shaped mater information carrier.Type: GrantFiled: October 23, 2001Date of Patent: August 24, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Keizo Miyata, Hideyuki Hashi, Tatsuaki Ishida
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Publication number: 20040109252Abstract: 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: ApplicationFiled: November 20, 2003Publication date: June 10, 2004Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Hideyuki Hashi, Taizou Hamada, Tatsuaki Ishida, Kiyokazu Tohma
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Publication number: 20040100710Abstract: 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: ApplicationFiled: November 20, 2003Publication date: May 27, 2004Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Hideyuki Hashi, Taizou Hamada, Tatsuaki Ishida, Kiyokazu Tohma