Patents by Inventor Hideki Saga
Hideki Saga 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: 6608806Abstract: A method for recording information is disclosed in which an information recording medium is irradiated with a recording energy beam power-modulated into at least a record power level and a record-ready power level lower than the record power level. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion. Also, only in the case where the energy beam is modulated by the power lower in power level than the record-ready power level after the last pulse of the energy beam pulse train including at least one pulse for forming a mark portion and the mark portion is followed by a space portion of a predetermined length, the particular radiation energy of low power level is reduced as compared with when the mark portion is followed by a space potion of a different length.Type: GrantFiled: October 16, 2002Date of Patent: August 19, 2003Assignee: Hitachi, Ltd.Inventors: Makoto Miyamoto, Tsuyoshi Toda, Masatoshi Ohtake, Motoyasu Terao, Junko Ushiyama, Keikichi Andoo, Yumiko Anzai, Akemi Hirotsune, Tetsuya Nishida, Hideki Saga
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Publication number: 20030123333Abstract: A method for reproducing information on a recording medium includes irradiating electromagnetic energy or light to the recording medium from one side with respect to the recording medium, applying a recording magnetic field to an electromagnetic energy or light irradiated position on the recording medium from the one side of irradiating electromagnetic energy or light, and detecting magnetic leakage flux emerging from the recording medium from the one side of irradiating electromagnetic energy or light.Type: ApplicationFiled: December 17, 2002Publication date: July 3, 2003Inventors: Hideki Saga, Hiroaki Nemoto, Hirofumi Sukeda, Masahiko Takahashi, Kimio Nakamura, Yohji Maruyama, Hiroshi Ide, Takehiko Hamaguchi
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Patent number: 6560168Abstract: An information recording apparatus using a recording medium which holds information by reversed magnetic domains on a perpendicular magnetic recording film includes an irradiation unit for applying electromagnetic energy or light onto the recording medium, and a magnetic flux detection unit for detecting magnetic leakage flux emerging from the recording medium, the magnetic flux detection unit being disposed on the same side as the irradiation unit with respect to the recording medium. As a result, both side recording of the recording medium can be conducted.Type: GrantFiled: December 12, 2000Date of Patent: May 6, 2003Assignee: Hitachi, Ltd.Inventors: Hideki Saga, Hiroaki Nemoto, Hirofumi Sukeda, Masahiko Takahashi, Kimio Nakamura, Yohji Maruyama, Hiroshi Ide, Takehiko Hamaguchi
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Patent number: 6545954Abstract: A high-speed large capacity file system is built in which the track density is improved by applying a highly precise magnetic domain width control technique to a light pulse-irradiated magnetic field modulation magnetooptical disk device which can be overwritten and is suitable for the improvement of the bit density. For the purpose, bipolar magnetic domains having edges of positive and negative polarities with respect to the direction of movement of a light spot are formed and the recording condition is optimized. Normal recording is carried out on the basis of the result of the optimization of the recording condition.Type: GrantFiled: February 25, 2002Date of Patent: April 8, 2003Assignee: Hitachi, Ltd.Inventors: Hirofumi Sukeda, Hideki Saga
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Patent number: 6529467Abstract: A method for recording information is disclosed in which an information recording medium is irradiated with a recording energy beam power-modulated into at least a record power level and a record-ready power level lower than the record power level. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion. Also, only in the case where the energy beam is modulated by the power lower in power level than the record-ready power level after the last pulse of the energy beam pulse train including at least one pulse for forming a mark portion and the mark portion is followed by a space portion of a predetermined length, the particular radiation energy of low power level is reduced as compared with when the mark portion is followed by a space potion of a different length.Type: GrantFiled: December 21, 2001Date of Patent: March 4, 2003Assignee: Hitachi, Ltd.Inventors: Makoto Miyamoto, Tsuyoshi Toda, Masatoshi Ohtake, Motoyasu Terao, Junko Ushiyama, Keikichi Andoo, Yumiko Anzai, Akemi Hirotsune, Tetsuya Nishida, Hideki Saga
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Patent number: 6529466Abstract: An information recording apparatus for recording data by applying energy to a recording medium to form thereon local physical changes of the medium includes a total energy irradiating amount discriminating unit for discriminating a total energy irradiating amount of each mark and each space when data is recorded, and a recording energy irradiating unit for switching between at least two levels of the total energy irradiating amount during a mark non-forming period, in accordance with results discriminated by the total energy irradiating amount discriminating unit. The at least two levels may be at least two mutually different levels.Type: GrantFiled: December 18, 2001Date of Patent: March 4, 2003Assignees: Hitachi, Ltd., Hitachi Maxell, Ltd.Inventors: Hideki Saga, Hirofumi Sukeda, Takehiko Yorozu
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Publication number: 20030039192Abstract: A method for recording information is disclosed in which an information recording medium is irradiated with a recording energy beam power-modulated into at least a record power level and a record-ready power level lower than the record power level. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion. Also, only in the case where the energy beam is modulated by the power lower in power level than the record-ready power level after the last pulse of the energy beam pulse train including at least one pulse for forming a mark portion and the mark portion is followed by a space portion of a predetermined length, the particular radiation energy of low power level is reduced as compared with when the mark portion is followed by a space potion of a different length.Type: ApplicationFiled: October 16, 2002Publication date: February 27, 2003Inventors: Makoto Miyamoto, Tsuyoshi Toda, Masatoshi Ohtake, Motoyasu Terao, Junko Ushiyama, Keikichi Andoo, Yumiko Anzai, Akemi Hirotsune, Tetsuya Nishida, Hideki Saga
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Patent number: 6512726Abstract: An information recording apparatus for recording data by applying energy to a recording medium to form thereon local physical changes of the medium includes a space length discriminating unit for discriminating a space length of a space in a channel data sequence when data is recorded, and a recording energy irradiating unit for generating at least two recording waveforms when successive spaces having a same length in the channel data sequence are recorded, in accordance with results discriminated by the space length discriminating unit. The at least two recording waveforms may be at least two mutually different recording waveforms.Type: GrantFiled: December 18, 2001Date of Patent: January 28, 2003Assignees: Hitachi, Ltd., Hitachi Maxell, Ltd.Inventors: Hideki Saga, Hirofumi Sukeda, Takehiko Yorozu
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Patent number: 6442120Abstract: An optical reproduction method for reproducing information includes intermittently irradiating light to a moving optical medium, detecting reflected light from the moving optical medium while the light is irradiated intermittently when a moving distance of a light spot of the intermittently irradiated light on the moving optical medium is smaller than a diameter of the light spot, processing information based on the detected reflected light utilizing a differential operation, and obtaining a reproduction signal based on the differential operation.Type: GrantFiled: January 18, 2001Date of Patent: August 27, 2002Assignee: Hitachi, Ltd.Inventors: Harukazu Miyamoto, Hideki Saga, Seiji Yonezawa
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Patent number: 6430132Abstract: An information recording apparatus capable of forming a fine mark reliably and highly precisely through compensation for thermal interference and heat accumulation. The information recording apparatus is provided with a recording energy irradiating unit for generating at least two recording waveforms when marks of the same length or spaces of the same length in a channel data sequence are recorded. The information recording apparatus constructed as above can realize highly reliable recording/reproducing operations and can be made compact at a low cost with a large storage capacity.Type: GrantFiled: November 16, 2000Date of Patent: August 6, 2002Assignees: Hitachi, Ltd., Hitachi Maxell, Ltd.Inventors: Hideki Saga, Hirofumi Sukeda, Takehiko Yorozu
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Patent number: 6414912Abstract: A high-speed large capacity file system is built in which the track density is improved by applying a highly precise magnetic domain width control technique to a light pulse-irradiated magnetic field modulation magnetooptical disk device which can be overwritten and is suitable for the improvement of the bit density. For the purpose, bipolar magnetic domains having edges of positive and negative polarities with respect to the direction of movement of a light spot are formed and the recording condition is optimized. Normal recording is carried out on the basis of the result of the optimization of the recording condition.Type: GrantFiled: April 17, 2000Date of Patent: July 2, 2002Assignee: Hitachi, Ltd.Inventors: Hirofumi Sukeda, Hideki Saga
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Publication number: 20020075764Abstract: A high-speed large capacity file system is built in which the track density is improved by applying a highly precise magnetic domain width control technique to a light pulse-irradiated magnetic field modulation magnetooptical disk device which can be overwritten and is suitable for the improvement of the bit density. For the purpose, bipolar magnetic domains having edges of positive and negative polarities with respect to the direction of movement of a light spot are formed and the recording condition is optimized. Normal recording is carried out on the basis of the result of the optimization of the recording condition.Type: ApplicationFiled: February 25, 2002Publication date: June 20, 2002Inventors: Hirofumi Sukeda, Hideki Saga
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Publication number: 20020071361Abstract: An optical reproduction apparatus includes a light source which irradiates irradiation light onto a recording medium, the irradiation light being reflected by the recording medium to produce reflection light, a modulator which repetitively pulse modulates the irradiation light to produce irradiation light pulses, a photodetector which detects reflection light from the recording medium at more than two timings during each of the irradiation light pulses, and outputs detection signals respectively representative of the reflection light detected at the more than two timings during each of the irradiation light pulses, and an operation circuit which performs an operation between the detection signals outputted from the photodetector during each of the irradiation light pulses.Type: ApplicationFiled: February 15, 2002Publication date: June 13, 2002Inventors: Harukazu Miyamoto, Hideki Saga, Seiji Yonezawa
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Patent number: 6404716Abstract: An information recording apparatus capable of forming a fine mark reliably and highly precisely through compensation for thermal interference and heat accumulation. The information recording apparatus is provided with a recording energy irradiating unit for generating at least two recording waveforms when marks of the same length or spaces of the same length in a channel data sequence are recorded. The information recording apparatus constructed as above can realize highly reliable recording/reproducing operations and can be made compact at a low cost with a large storage capacity.Type: GrantFiled: November 16, 2000Date of Patent: June 11, 2002Assignees: Hitachi, Ltd., Hitachi Maxell, Ltd.Inventors: Hideki Saga, Hirofumi Sukeda, Takehiko Yorozu
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Publication number: 20020054556Abstract: A method for recording information is disclosed in which an information recording medium is irradiated with a recording energy beam power-modulated into at least a record power level and a record-ready power level lower than the record power level. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion. Also, only in the case where the energy beam is modulated by the power lower in power level than the record-ready power level after the last pulse of the energy beam pulse train including at least one pulse for forming a mark portion and the mark portion is followed by a space portion of a predetermined length, the particular radiation energy of low power level is reduced as compared with when the mark portion is followed by a space potion of a different length.Type: ApplicationFiled: December 21, 2001Publication date: May 9, 2002Applicant: Hitachi, Ltd.Inventors: Makoto Miyamoto, Tsuyoshi Toda, Masatoshi Ohtake, Motoyasu Terao, Junko Ushiyama, Keikichi Andoo, Yumiko Anzai, Akemi Hirotsune, Tetsuya Nishida, Hideki Saga
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Publication number: 20020041558Abstract: An information recording apparatus for recording data by applying energy to a recording medium to form thereon local physical changes of the medium includes a space length discriminating unit for discriminating a space length of a space in a channel data sequence when data is recorded, and a recording energy irradiating unit for generating at least two recording waveforms when successive spaces having a same length in the channel data sequence are recorded, in accordance with results discriminated by the space length discriminating unit. The at least two recording waveforms may be at least two mutually different recording waveforms.Type: ApplicationFiled: December 18, 2001Publication date: April 11, 2002Inventors: Hideki Saga, Hirofumi Sukeda, Takehiko Yorozu
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Publication number: 20020041553Abstract: An information recording apparatus for recording data by applying energy to a recording medium to form thereon local physical changes of the medium includes a total energy irradiating amount discriminating unit for discriminating a total energy irradiating amount of each mark and each space when data is recorded, and a recording energy irradiating unit for switching between at least two levels of the total energy irradiating amount during a mark non-forming period, in accordance with results discriminated by the total energy irradiating amount discriminating unit. The at least two levels may be at least two mutually different levels.Type: ApplicationFiled: December 18, 2001Publication date: April 11, 2002Inventors: Hideki Saga, Hirofumi Sukeda, Takehiko Yorozu
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Patent number: 6343056Abstract: A method for recording information is disclosed in which an information recording medium is irradiated with a recording energy beam power-modulated into at least a record power level and a record-ready power level lower than the record power level. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion. Also, only in the case where the energy beam is modulated by the power lower in power level than the record-ready power level after the last pulse of the energy beam pulse train including at least one pulse for forming a mark portion and the mark portion is followed by a space portion of a predetermined length, the particular radiation energy of low power level is reduced as compared with when the mark portion is followed by a space potion of a different length.Type: GrantFiled: February 2, 2001Date of Patent: January 29, 2002Assignee: Hitachi, Ltd.Inventors: Makoto Miyamoto, Tsuyoshi Toda, Masatoshi Ohtake, Motoyasu Terao, Junko Ushiyama, Keikichi Andoo, Yumiko Anzai, Akemi Hirotsune, Tetsuya Nishida, Hideki Saga
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Publication number: 20010043538Abstract: A method for recording information is disclosed in which an information recording medium is irradiated with a recording energy beam power-modulated into at least a record power level and a record-ready power level lower than the record power level. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion. Also, only in the case where the energy beam is modulated by the power lower in power level than the record-ready power level after the last pulse of the energy beam pulse train including at least one pulse for forming a mark portion and the mark portion is followed by a space portion of a predetermined length, the particular radiation energy of low power level is reduced as compared with when the mark portion is followed by a space potion of a different length.Type: ApplicationFiled: February 2, 2001Publication date: November 22, 2001Applicant: Hitachi, Ltd.Inventors: Makoto Miyamoto, Tsuyoshi Toda, Masatoshi Ohtake, Motoyasu Terao, Junko Ushiyama, Keikichi Andoo, Yumiko Anzai, Akemi Hirotsune, Tetsuya Nishida, Hideki Saga
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Patent number: 6288981Abstract: In an optical recording and magnetic-head reproducing system, the reproduced output is prevented from starting to decrease, upon the length of record bits getting shorter, in the range of the bit length larger than reproducing resolution of a magnetic reproducing head. When data are recorded magneto-optically on a magnetic recording medium, the radius of curvature of arcs constituting the boundary of recorded magnetic domains is made as large as possible so that the shape of the recorded spot may be substantially rectangular. As a result, it becomes possible to improve the efficiency of magnetic reproduction, and high-output as well as high-SN-ratio reproduction at high linear recording density can be achieved.Type: GrantFiled: July 18, 2000Date of Patent: September 11, 2001Assignee: Hitachi, Ltd.Inventors: Kazuetsu Yoshida, Hiroaki Nemoto, Hideki Saga