Patents by Inventor Naomasa Nakamura
Naomasa Nakamura 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: 7011876Abstract: There is provided an optical recording medium capable of preventing cross erase and increasing its recording density. The optical recording medium includes: a reflecting film; a first transparent film provided on the reflecting film; a first semitransparent film provided on the first transparent film; a second transparent film provided on the first semitransparent film; a recording film provided on the second transparent film, the recording film being capable of reversibly changing an atomic arrangement; and a third transparent film provided on the recording film. The first semitransparent film has a complex refractive index of n?ik satisfying relationships of 0<n<1 and 1<k, and a product of a thickness d (nm) of the first semitransparent film and an extinction coefficient k of the complex refractive index is d×k?44.Type: GrantFiled: October 4, 2004Date of Patent: March 14, 2006Assignee: Kabushiki Kaisha ToshibaInventors: Sumio Ashida, Keiichiro Yusu, Katsutaro Ichihara, Naomasa Nakamura, Noritake Ohmachi
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Publication number: 20060007846Abstract: An optical information recording medium of this invention includes a substrate, a light incident surface, a first reflecting layer formed between the substrate and the light incident surface, a second reflecting layer formed between the first reflecting layer and the light incident surface and stacked on the first reflecting layer, the second reflecting layer being made of the same material as that of the first reflecting layer, and a phase change optical recording layer formed between the second reflecting layer and the light incident surface, the phase change optical recording layer transiting between a crystal state and an amorphous state when irradiated with a light beam.Type: ApplicationFiled: August 5, 2005Publication date: January 12, 2006Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Naomasa Nakamura, Keiichiro Yusu, Sumio Ashida, Katsutaro Ichihara
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Publication number: 20050227178Abstract: A recording material for a medium used for the recording film of a write-once type information recording disk equipped with a transparent resin substrate on which concentric or spiral grooves were formed and a recording film which was formed on the grooves, characterized in that it is formed by one organic coloring matter having an anion portion and a coloring matter portion in which the maximum absorption wavelength zone exists at a longer wavelength side than the wavelength of short wavelength laser beam irradiated on the recording film and forms a record mark on the recording film by irradiation of the short wavelength laser beam, and the record mark has a higher optical reflection coefficient than the optical reflection coefficient of the recording film before irradiation of the short wavelength laser beam. This material realizes so-called Low to High property.Type: ApplicationFiled: April 12, 2005Publication date: October 13, 2005Applicants: KABUSHIKI KAISHA TOSHIBA, HAYASHIBARA BIOCHEMICAL LABORATORIES, INC.Inventors: Seiji Morita, Koji Takazawa, Naoki Morishita, Naomasa Nakamura, Yasushi Aizawa, Yoshinori Koyama
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Publication number: 20050226135Abstract: A write-once information recording disk has a transparent substrate having concentric or spiral grooves formed therein, and a recording film formed on the grooves on the transparent substrate, wherein the recording groove has an anion portion and a pigment portion, being formed of one organic pigment of which maximum absorption wavelength region from the wavelength of short wavelength laser light to be emitted to the recording film is present at the longer wavelength side, a recording mark is formed on the recording film by irradiation with short wavelength laser light, and the recording mark has a higher light reflectivity than the light reflectivity of the recording film before irradiation with the short wavelength laser light. Therefore, the write-once type optical disk has a so-called low-to-high characteristic, that is, the reflectivity is higher after recording than before recording.Type: ApplicationFiled: April 12, 2005Publication date: October 13, 2005Applicants: KABUSHIKI KAISHA TOSHIBA, HAYASHIBARA BIOCHEMICAL LABORATORIES, INC.Inventors: Seiji Morita, Koji Takazawa, Naoki Morishita, Naomasa Nakamura, Yasushi Aizawa, Yoshinori Koyama
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Publication number: 20050219995Abstract: A write-once optical disk comprises a transparent resin substrate having a concentrically or spirally shaped groove and a land formed thereon, and a recording film formed on the groove and the land of the transparent resin substrate, a recording mark being formed by emission of a short-wavelength laser light beam. In addition, a light reflectivity of the recording mark portion formed by emission of the short wave laser light beam is higher than a light reflectivity obtained before emission of the short wavelength laser light beam, and a depth of the groove is in the range of 50 to 80 nm.Type: ApplicationFiled: March 25, 2005Publication date: October 6, 2005Inventors: Seiji Morita, Koji Takazawa, Naoki Morishita, Naomasa Nakamura
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Publication number: 20050219996Abstract: A write-once optical disk comprises a transparent resin substrate having a concentrically or spirally shaped groove and a land formed thereon, and a recording film formed on the groove and the land of the transparent resin substrate, a recording being formed on the medium by emission of a short-wavelength laser beam. Light reflectivity of the recording mark portion formed by emission of the short-wavelength laser light is set so as to be higher than the light reflectivity obtained before emission of the short-wavelength laser light, and the groove wobbles in a predetermined amplitude range.Type: ApplicationFiled: March 25, 2005Publication date: October 6, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Seiji Morita, Koji Takazawa, Yasuaki Ootera, Naoki Morishita, Naomasa Nakamura
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Publication number: 20050219997Abstract: A write-once information recording medium comprises a transparent resin substrate having a concentrically or spirally shaped groove and a land formed thereon, and a recording firm formed on the groove and the land of the transparent resin substrate, a recording mark being formed on the medium by emission of a short wavelength laser light, the recording medium having an L to H feature in which a light reflectivity of the recording mark portion formed by the emission of the short wavelength laser light is higher than a light reflectivity obtained before the emission of the short wavelength laser light.Type: ApplicationFiled: March 25, 2005Publication date: October 6, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Seiji Morita, Koji Takazawa, Naoki Morishita, Naomasa Nakamura
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Patent number: 6944116Abstract: An optical information recording medium of this invention includes a substrate, a light incident surface, a first reflecting layer formed between the substrate and the light incident surface, a second reflecting layer formed between the first reflecting layer and the light incident surface and stacked on the first reflecting layer, the second reflecting layer being made of the same material as that of the first reflecting layer, and a phase change optical recording layer formed between the second reflecting layer and the light incident surface, the phase change optical recording layer transiting between a crystal state and an amorphous state when irradiated with a light beam.Type: GrantFiled: March 22, 2002Date of Patent: September 13, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Naomasa Nakamura, Keiichiro Yusu, Sumio Ashida, Katsutaro Ichihara
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Publication number: 20050128917Abstract: A disk has a burst cutting area (BCA) formed by a crystalline portion and an amorphous portion, and the disk is an optical disk (L-H medium) in which the reflectance of the crystalline portion is lower than that of the amorphous portion. The width Wcry of the crystalline portion in the BCA is lower than half the data period Wdat. Therefore, the average level of a BCA reproduction signal is unchanged regardless of whether the optical disk is an H-L medium or an L-H medium, so that focus control and reproduction of a BCA code can be performed even if a parameter of a circuit is a default.Type: ApplicationFiled: November 23, 2004Publication date: June 16, 2005Inventors: Akihito Ogawa, Naomasa Nakamura, Noritake Oomachi, Keiichiro Yusu
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Publication number: 20050112499Abstract: A phase-change optical recording medium has a recording film that brings about reversible phase-change between a crystalline phase and an amorphous phase upon irradiation with light and an interface film formed in contact with at least one surface of the recording film and comprising hafnium (Hf), silicon (Si), oxygen (O) and carbon (C).Type: ApplicationFiled: October 26, 2004Publication date: May 26, 2005Inventors: Tsukasa Nakai, Sumio Ashida, Keiichiro Yusu, Takayuki Tsukamoto, Noritake Oomachi, Naomasa Nakamura, Urara Ichihara
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Publication number: 20050106353Abstract: A phase-change optical recording medium has a first information layer including a phase-change optical recording film arranged in a position close to the light incident side, a second information layer including another phase-change optical-recording film arranged in a position remote from the light incident side and an interlayer separating film arranged between the first information layer and the second information layer, in which at least one of the first information layer and the second information layer includes a noise reduction film in contact with the interlayer separating film. The noise reduction film is formed of SiOx (1?x?2) or SiOC.Type: ApplicationFiled: October 29, 2004Publication date: May 19, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tsukasa Nakai, Sumio Ashida, Keiichiro Yusu, Takayuki Tsukamoto, Noritake Oomachi, Naomasa Nakamura, Katsutaro Ichihara, Urara Ichihara
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Publication number: 20050042408Abstract: There is provided an optical recording medium capable of preventing cross erase and increasing its recording density. The optical recording medium includes: a reflecting film; a first transparent film provided on the reflecting film; a first semitransparent film provided on the first transparent film; a second transparent film provided on the first semitransparent film; a recording film provided on the second transparent film, the recording film being capable of reversibly changing an atomic arrangement; and a third transparent film provided on the recording film. The first semitransparent film has a complex refractive index of n?ik satisfying relationships of 0<n<1 and 1<k, and a product of a thickness d (nm) of the first semitransparent film and an extinction coefficient k of the complex refractive index is d×k?44.Type: ApplicationFiled: October 4, 2004Publication date: February 24, 2005Applicant: Kabushiki Kaisha ToshibaInventors: Sumio Ashida, Keiichiro Yusu, Katsutaro Ichihara, Naomasa Nakamura, Noritake Ohmachi
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Publication number: 20050025035Abstract: A phase-change optical recording medium has a phase-change recording film to which recording and erasure can be reversibly performed by irradiation with light, and at least one dielectric film formed of a SiOC film containing Si, O and C, and having a carbon concentration within a range of between 0.1 and 30 atomic %.Type: ApplicationFiled: June 29, 2004Publication date: February 3, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tsukasa Nakai, Sumio Ashida, Keiichiro Yusu, Takayuki Tsukamoto, Noritake Oomachi, Naomasa Nakamura, Urara Ichihara
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Patent number: 6842419Abstract: An optical information recording medium includes a substrate, first information recording layer, and second information recording layer. The first information recording layer includes a recording film, first dielectric film whose complex index has a real part n1, second dielectric film whose complex index has a real part n2, and third dielectric film whose complex index has a real part n3. Relationships n1>n2 and n3>n2 are satisfied.Type: GrantFiled: March 22, 2002Date of Patent: January 11, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Naomasa Nakamura, Sumio Ashida, Keiichiro Yusu, Katsutaro Ichihara, Noritake Oomachi
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Patent number: 6805935Abstract: There is provided an optical recording medium capable of preventing cross erase and increasing its recording density. The optical recording medium includes: a reflecting film; a first transparent film provided on the reflecting film; a first semitransparent film provided on the first transparent film; a second transparent film provided on the first semitransparent film; a recording film provided on the second transparent film, the recording film being capable of reversibly changing an atomic arrangement; and a third transparent film provided on the recording film. The first semitransparent film has a complex refractive index of n−k satisfying relationships of 0<n<1 and 1<k, and a product of a thickness d (nm) of the first semitransparent film and an extinction coefficient k of the complex refractive index is d×k≦44.Type: GrantFiled: March 21, 2003Date of Patent: October 19, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Sumio Ashida, Keiichiro Yusu, Katsutaro Ichihara, Naomasa Nakamura, Noritake Ohmachi
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Patent number: 6800224Abstract: A production process of an optical disk, wherein when a layer of an ultra violet rays curing resin which constitutes a portion of the optical disk is formed, a comi-transparent film of a metal is formed an a molded substrate on which a pattern was transcribed and this molded substrate is used as a semi-transparent stamper, and the production of an optical disk with two layers at one side is made easy thereby.Type: GrantFiled: September 17, 2001Date of Patent: October 5, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Yasuaki Ootera, Naomasa Nakamura
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Publication number: 20040121261Abstract: A phase-change optical recording medium includes a phase-change optical recording film that permits reversible phase change between a crystalline phase and an amorphous phase upon irradiation with light, and an interface film formed of hafnium oxide, or a mixture of hafnium oxide and at least one oxide selected from the group consisting of cerium oxide, titanium oxide and zirconium oxide, and formed in contact with at least one surface of the phase-change optical recording film.Type: ApplicationFiled: November 21, 2003Publication date: June 24, 2004Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Sumio Ashida, Takayuki Tsukamoto, Keiichiro Yusu, Katsutaro Ichihara, Noritake Ohmachi, Naomasa Nakamura, Nobuhisa Yoshida
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Publication number: 20040076908Abstract: A phase change optical recording medium according to an embodiment of this invention includes a substrate, a reflecting layer which reflects a light beam, a phase change recording layer which is arranged between the substrate and the reflecting layer and changes between a crystalline state and an amorphous state when irradiated with the light beam, a first dielectric layer which is arranged between the substrate and the reflecting layer, and a second dielectric layer which is arranged between the substrate and the first dielectric layer and has a thermal conductivity lower than that of the first dielectric layer.Type: ApplicationFiled: October 6, 2003Publication date: April 22, 2004Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Noritake Oomachi, Katsutaro Ichihara, Keiichiro Yusu, Sumio Ashida, Naomasa Nakamura, Takayuki Tsukamoto
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Publication number: 20040022987Abstract: There is provided an optical recording medium capable of preventing cross erase and increasing its recording density. The optical recording medium includes: a reflecting film; a first transparent film provided on the reflecting film; a first semitransparent film provided on the first transparent film; a second transparent film provided on the first semitransparent film; a recording film provided on the second transparent film, the recording film being capable of reversibly changing an atomic arrangement; and a third transparent film provided on the recording film. The first semitransparent film has a complex refractive index of n−k satisfying relationships of 0<n<1 and 1<k, and a product of a thickness d (nm) of the first semitransparent film and an extinction coefficient k of the complex refractive index is d×k≦44.Type: ApplicationFiled: March 21, 2003Publication date: February 5, 2004Applicant: Kabushiki Kaisha ToshibaInventors: Sumio Ashida, Keiichiro Yusu, Katsutaro Ichihara, Naomasa Nakamura, Noritake Ohmachi
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Publication number: 20030161257Abstract: An optical disk exhibits enhanced overwrite overwrite characteristics and cross-erase suppression. An optical disk includes a flattening layer formed on a substrate; a reflective layer formed on the flattening layer; a phase-change optical recording layer formed on the reflective layer, the recording layer being changeable between crystalline and amorphous states, portions of the recording layer to become the crystalline state exhibiting reflectivity lower than other portions of the recording layer to become the amorphous state; a plurality of dielectric layers stacked on the recording layer, at least two of the dielectric layers having different optical constants; and a light absorbing layer formed at one location selected from a location between the recording layer and the lowermost layer of the dielectric layers, a location between any of two adjacent layers of the dielectric layers, and a location on the uppermost layer of the dielectric layers.Type: ApplicationFiled: February 26, 2003Publication date: August 28, 2003Applicant: Kabushiki Kaisha ToshibaInventors: Keiichiro Yusu, Sumio Ashida, Naomasa Nakamura, Noritake Oomachi, Katsutaro Ichihara