Patents by Inventor Akio Okamuro
Akio Okamuro 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: 7858167Abstract: A rewritable optical recording medium including: a substrate having a guide groove formed thereon, a phase-change type recording layer, a portion in a crystalline state of the phase-change type recording layer corresponds to an unrecorded or erased state, and a portion in an amorphous state of the phase-change type recording layer corresponds to a recorded state, so that an amorphous mark corresponding to the recorded state is formed upon irradiation with a recording laser beam. The phase-change type recording layer contains Sb as a main component, and further contains Ge and/or Te, a content of Ge is from 1 atomic % to 30 atomic %, and a content of Te is from 10 atomic % to 30 atomic %, and in the phase-change type recording layer, Sb/Te is at least 4.5, and the atomic ratio of Ge to Te is from 1:3 to 1:20.Type: GrantFiled: March 12, 2007Date of Patent: December 28, 2010Assignee: Mitsubishi Kagaku Media Co., Ltd.Inventors: Takashi Ohno, Masae Kubo, Michikazu Horie, Masaaki Mizuno, Hiroyuki Hoshino, Akio Okamuro
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Patent number: 7609603Abstract: A rewritable optical recording medium includes a substrate and a phase-change type recording layer. A portion in a crystalline state corresponds to an unrecorded or erased state, and a portion in an amorphous state correspond to a recorded state, to record EFM modulated information by forming amorphous marks by irradiating the recording layer with a recording laser beam, and the recording is carried out by irradiating a recording laser beam having a wavelength of about 780 nm through an optical system having a numerical aperture NA of 0.5 or 0.55, at 24-times velocity or 32-times velocity of the reference velocity.Type: GrantFiled: March 12, 2007Date of Patent: October 27, 2009Assignee: Mitsubishi Kagaku Media Co., Ltd.Inventors: Takashi Ohno, Masae Kubo, Michikazu Horie, Masaaki Mizuno, Hiroyuki Hoshino, Akio Okamuro
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Patent number: 7313070Abstract: The present invention provides CD-RW which makes high velocity recording at a level of at least 24-times velocity possible, rewritable DVD which makes high velocity recording at a level of at least 6-times velocity possible, and a recording method therefor, while maintaining interchangeability with conventional CD-RW standards and rewritable DVD standards. A rewritable optical recording medium comprising a substrate and a phase-change type recording layer, wherein a portion in a crystalline state corresponds to an unrecorded or erased state, and a portion in an amorphous state correspond to a recorded state, to record EFM modulated information by forming amorphous marks by irradiating the recording layer with a recording laser beam, and wherein recording is carried out by irradiating a recording laser beam having a wavelength of about 780 nm through an optical system having a numerical aperture NA of 0.5 or 0.Type: GrantFiled: July 14, 2004Date of Patent: December 25, 2007Assignee: Mitsubishi Kagaku Media Co., Ltd.Inventors: Takashi Ohno, Masae Kubo, Michikazu Horie, Masaaki Mizuno, Hiroyuki Hoshino, Akio Okamuro
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Publication number: 20070253318Abstract: An optical recording medium includes a substrate having phase pits, a reflective layer that reflects a light beam emitted to the substrate and the phase pits, and a reflectivity reducing layer that reduces the reflectivity of the reflective layer on a light-incident side of the reflective layer. A dielectric layer is formed as the reflectivity reducing layer so that a refractive index varies. In another variation, a metal layer is used as the reflectivity reducing layer, which is formed of a metal film with a higher refractive index than that of the reflective layer.Type: ApplicationFiled: July 28, 2006Publication date: November 1, 2007Inventors: Tetsuo Hosokawa, Akio Okamuro
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Publication number: 20070237060Abstract: A rewritable optical recording medium including: a substrate having a guide groove formed thereon, a phase-change type recording layer, a portion in a crystalline state of the phase-change type recording layer corresponds to an unrecorded or erased state, and a portion in an amorphous state of the phase-change type recording layer corresponds to a recorded state, so that an amorphous mark corresponding to the recorded state is formed upon irradiation with a recording laser beam. The phase-change type recording layer contains Sb as a main component, and further contains Ge and/or Te, a content of Ge is from 1 atomic % to 30 atomic %, and a content of Te is from 10 atomic % to 30 atomic %, and in the phase-change type recording layer, Sb/Te is at least 4.5, and the atomic ratio of Ge to Te is from 1:3 to 1:20.Type: ApplicationFiled: March 12, 2007Publication date: October 11, 2007Applicant: Mitsubishi Kagaku Media Company Ltd.Inventors: Takashi Ohno, Masae Kubo, Michikazu Horie, Masaaki Mizuno, Hiroyuki Hoshino, Akio Okamuro
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Publication number: 20070159945Abstract: A rewritable optical recording medium includes a substrate and a phase-change type recording layer. A portion in a crystalline state corresponds to an unrecorded or erased state, and a portion in an amorphous state correspond to a recorded state, to record EFM modulated information by forming amorphous marks by irradiating the recording layer with a recording laser beam, and the recording is carried out by irradiating a recording laser beam having a wavelength of about 780 nm through an optical system having a numerical aperture NA of 0.5 or 0.55, at 24-times velocity or 32-times velocity of the reference velocity.Type: ApplicationFiled: March 12, 2007Publication date: July 12, 2007Applicant: Mitsubishi Kagaku Media Co., Ltd.Inventors: Takashi OHNO, Masae KUBO, Michikazu HORIE, Masaaki MIZUNO, Hiroyuki HOSHINO, Akio OKAMURO
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Patent number: 7001655Abstract: An optical recording medium simultaneously having higher recording characteristics and storage stability than ever, is obtained. An optical recording medium comprising at least a phase change recording layer, a first diffusion preventing layer, a second diffusion preventing layer and a protective layer formed in this order on a substrate, characterized in that the first diffusion preventing layer and the second diffusion preventing layer comprise a non-gas element and nitrogen and/or oxygen as the main components, the non-gas element in each of the first diffusion preventing layer and the second diffusion preventing layer, is the same, and the content (atomic %) of nitrogen and/or oxygen contained in the second diffusion preventing layer, is larger than the content (atomic %) of nitrogen and/or oxygen contained in the first diffusion preventing layer.Type: GrantFiled: December 1, 2004Date of Patent: February 21, 2006Assignees: Mitsubishi Chemical Corporation, Mitsubishi Kagaku Media Co., Ltd.Inventors: Kenjirou Kiyono, Jun Kanehira, Akio Okamuro
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Publication number: 20040248036Abstract: The present invention provides CD-RW which makes high velocity recording at a level of at least 24-times velocity possible, rewritable DVD which makes high velocity recording at a level of at least 6-times velocity possible, and a recording method therefor, while maintaining interchangeability with conventional CD-RW standards and rewritable DVD standards.Type: ApplicationFiled: July 14, 2004Publication date: December 9, 2004Applicant: MITSUBISHI CHEMICAL CORPORATIONInventors: Takashi Ohno, Masae Kubo, Michikazu Horie, Masaaki Mizuno, Hiroyuki Hoshino, Akio Okamuro
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Patent number: 6430116Abstract: A magneto-optical recording medium having a writing layer, a switching layer and a readout layer on a substrate, wherein a magnetization direction corresponding to information is written in the writing layer, and the magnetization direction of the writing layer is transferred to the readout layer by a magnet static coupling force from the writing layer at a temperature of at least room temperature, and wherein the writing layer is composed of a plurality of layers which are made of alloys of a rare earth metal and a transition metal and which are exchange-coupled one another, including a layer having rare earth metal dominant magnetization at room temperature and a layer having transition metal dominant magnetization at room temperature.Type: GrantFiled: May 5, 2000Date of Patent: August 6, 2002Assignee: Mitsubishi Chemical CorporationInventors: Toshifumi Kawano, Akio Okamuro
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Patent number: 5389455Abstract: A medium includes a readout layer, a memory layer, an adjusting layer for an exchange coupling force .sigma..sub.W, and a writing layer, and can perform an over-write operation upon radiation of a modulated laser beam. The readout layer essentially consists of GdFeCo, the memory layer essentially consists of TbFeCo, the adjusting layer essentially consists of GdFeCo, and the writing layer essentially consists of DyFeCo. The C/N ratio of the medium exceeds 53 dB. The C/N ratio is a value obtained when a plurality of mark.sup.H having a period of 1.6 .mu.m are written, and are read out so that medium noise is maximized as compared to other noise components.Type: GrantFiled: September 21, 1992Date of Patent: February 14, 1995Assignee: Nikon CorporationInventors: Jun Saito, Tetsuo Hosokawa, Akio Okamuro, Hiroyuki Matsumoto, Haruhisa Iida, Satomi Kokai, Hideki Akasaka