Patents by Inventor Naoto Hirosaki

Naoto Hirosaki 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).

  • Patent number: 7608862
    Abstract: A light emitting device comprises at least two lead wires, a light emitting element that is disposed on an end portion of at least one of said lead wires and connected electrically with the end portion and the other lead wire, and a phosphor that absorbs at least part of the light emitted from said light emitting element and emanates light having different wavelengths from the wavelength of the light emitted from said light emitting element, wherein the excitation spectrum of said phosphor has a flat region in a wavelength range including a primary wavelength of the light from said light emitting element.
    Type: Grant
    Filed: March 1, 2005
    Date of Patent: October 27, 2009
    Assignees: Fujikura Ltd., National Institute for Materials Science
    Inventors: Ken Sakuma, Koji Omichi, Naoto Hirosaki
  • Patent number: 7597821
    Abstract: One preferred embodiment according to the present invention, there is provided an oxynitride phosphor and a light emitting device using the same that is able to reduce production costs and chromaticity shifts. The phosphor is represented by a general formula of (Ca1-zYz)x(Si, Al)12(O, N)16:Eu2+y, and has a main phase of substantially an alpha SiAlON crystal structure, wherein the value z is larger than 0 and smaller than 0.15.
    Type: Grant
    Filed: August 29, 2005
    Date of Patent: October 6, 2009
    Assignees: Fujikura Ltd., National Institute For Materials Science
    Inventors: Ken Sakuma, Naoki Kimura, Naoto Hirosaki
  • Patent number: 7598194
    Abstract: It is aimed at providing an oxynitride powder, which is suitable for usage as a phosphor, is free from coloration due to contamination of impurities, and mainly includes a fine ?-sialon powder. An oxynitride powder is produced by applying a heat treatment in a reducing and nitriding atmosphere, to a precursor compound including at least constituent elements M, Si, Al, and O (where M is one element or mixed two or more elements selected from Li, Mg, Ca, Sr, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), thereby decreasing an oxygen content and increasing a nitrogen content of the precursor.
    Type: Grant
    Filed: April 22, 2005
    Date of Patent: October 6, 2009
    Assignee: National Institute for Materials Science
    Inventors: Naoto Hirosaki, Takayuki Suehiro
  • Publication number: 20090236969
    Abstract: This invention provides a blue phosphor, which has higher blue brightness and larger half-value width in an emission spectrum as compared with the conventional rare earth-activated sialon phosphor and has better durability as compared with the conventional oxide phosphor. The phosphor comprises a metal element M, wherein M represents Ce, dissolved as a solid solute in a nitride or oxynitride crystal having a ?-type Si3N4 crystal structure, an AlN crystal structure, or an AlN polytype structure, and emits fluorescence having a peak in a wavelength region of 450 nm to 500 nm upon exposure to light from an excitation source.
    Type: Application
    Filed: March 20, 2006
    Publication date: September 24, 2009
    Applicant: NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventor: Naoto Hirosaki
  • Patent number: 7573190
    Abstract: The present invention provides a white light emitting diode for emitting white light with warmness at a higher luminance, and an intermediate color light emitting diode satisfying light emission with diversified color tones at a higher luminance. A fluorescent material which emits yellowish red or red light and has a CaAlSiN3 crystal phase including, dissolved therein in a solid state, one or more element(s) selected from Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. The fluorescent material is mixed with another fluorescent material emitting green, yellowish green, or yellow light, and the mixed phosphor is combined with a semiconductor light emitting element for emitting bluish purple or blue light, to fabricate a white light emitting diode which efficiently emits a warm white light with a high efficiency.
    Type: Grant
    Filed: February 15, 2005
    Date of Patent: August 11, 2009
    Assignee: National Institute for Materials Science
    Inventors: Naoto Hirosaki, Ken Sakuma, Kyota Ueda, Hajime Yamamoto
  • Patent number: 7564065
    Abstract: The present invention provides in one embodiment a light emitting device that has a high efficacy even in a range of low color temperatures, a long-term reliability, and an improved color rendering property. In addition, the present invention provides in another embodiment a lighting apparatus using such a light emitting device. In the light emitting device, a mixture of a first phosphor material that emits yellow green, yellow or yellow orange light and a second phosphor material that emits light having a longer wavelength than the first phosphor material, for example, yellow orange or orange light is used as a phosphor. The first phosphor material is represented by a general formula Cax(Si, Al)12(O, N)16:Euy2+ and a main phase thereof has an alpha-SiAlON crystal structure.
    Type: Grant
    Filed: March 22, 2005
    Date of Patent: July 21, 2009
    Assignees: Fujikura Ltd., National Institute for Materials Science
    Inventors: Ken Sakuma, Naoto Hirosaki
  • Publication number: 20090167153
    Abstract: The present invention aims at providing a white light emitting diode lamp (a bullet type light emitting diode lamp or a chip-type light emitting diode lamp to be mounted on a substrate) and light emitting device with warmness at a higher luminance, and an intermediate color light emitting diode lamp and light emitting device satisfying light emission in diversified color tones at a higher luminance. The solving means resides in adoption of at least including a semiconductor light emitting element, and a plurality of fluorescent materials that absorb part or whole of light emitted from the semiconductor light emitting element, and emit fluorescence at a wavelength different from that of the absorbed light, wherein the plurality of fluorescent materials comprise a phosphor mainly composed of a CaAlSiN3 crystal phase.
    Type: Application
    Filed: August 8, 2008
    Publication date: July 2, 2009
    Applicant: NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventors: Naoto Hirosaki, Ken Sakuma, Kyota Ueda, Hajime Yamamoto
  • Publication number: 20090153028
    Abstract: A fluorescent substance includes a crystal of nitride or oxy-nitride having a ?-type Si3N4 crystal structure having Eu+2 solid-dissolved into it and emitting a fluorescent light having a peak within a range of 500 nm to 600 nm in wavelength by being irradiated with an excitation source. The fluorescent substance further includes another crystalline or amorphous compound different from the nitride or oxy-nitride crystal and a quantity of the nitride or oxy-nitride crystal contained in the fluorescent substance is 50 wt % or more.
    Type: Application
    Filed: January 22, 2009
    Publication date: June 18, 2009
    Applicant: NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventor: Naoto HIROSAKI
  • Publication number: 20090146549
    Abstract: An LED with a semiconductor light emitting element that emits a blue or a blue-violet light, and a fluorescent material that absorbs some or all of the light emitted from the element and emits a fluorescent light of a wavelength different from the absorbed light. The fluorescent material is a mixed fluorescent material obtained by mixing a first fluorescent material that emits a blue-green or a green light, a second fluorescent material that has a peak emission wavelength longer than that of the first fluorescent material and emits a green or a yellow-green light, a third fluorescent material that has a 1 peak emission wavelength longer than that of the second fluorescent material and emits a yellow-green, a yellow or a yellow-red light, and a fourth fluorescent material that has a peak emission wavelength longer than that of the third fluorescent material and emits a yellow-red or a red light.
    Type: Application
    Filed: February 11, 2009
    Publication date: June 11, 2009
    Applicants: FUJIKURA LTD., NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventors: Naoki KIMURA, Ryuji Suzuki, Ken Sakuma, Naoto Hirosaki
  • Patent number: 7544310
    Abstract: A green fluorescent substance of the invention is higher in luminance of green than a conventional rare-earth activated sialon fluorescent substance and more excellent in durability than a conventional oxide fluorescent substance. The fluorescent substance is obtained by solid-dissolving Eu into a nitride or oxy-nitride crystal having a ?-type Si3N4 crystal structure, and emits a fluorescent light having a peak within a range of 500 nm to 600 nm in wavelength by being irradiated with an excitation source.
    Type: Grant
    Filed: March 9, 2005
    Date of Patent: June 9, 2009
    Assignee: National Institute for Materials Science
    Inventor: Naoto Hirosaki
  • Patent number: 7540977
    Abstract: The present invention aims at providing a chemically stabilized inorganic phosphor, among oxynitride phosphors including alkaline earths, which oxynitride phosphor emits orange or red light at longer wavelengths at higher luminance than conventional sialon phosphors activated by rare earths. The present invention further aims at providing a light emitting instrument based on the phosphor, for a lighting instrument excellent in color rendering property and for an image displaying apparatus excellent in durability. The solving means resides in provision of a fundamental phosphor comprising: a composition on a pseudo-ternary phase diagram including AO (A is one kind or two or more kinds of element(s) selected from Mg, Ca, Sr, and Ba; and AO is oxide of A), Si3N4, and SiO2 as end members, respectively, and satisfying all of the following conditions: in a composition formula, pAO-qSi3N4-rSiO2(p+q+r=1), 0.1?p?0.95??(1), 0.05?q?0.9??(2), and 0?r?0.
    Type: Grant
    Filed: September 16, 2005
    Date of Patent: June 2, 2009
    Assignee: National Institute for Materials Science
    Inventors: Naoto Hirosaki, Rong-Jun Xie
  • Publication number: 20090129052
    Abstract: An illuminator includes a light emitting light source and a fluorescent substance. The fluorescent substance includes a crystal of nitride or oxy-nitride having a ?-type Si3N4 crystal structure having Eu+2 solid-dissolved into it and emitting a fluorescent light having a peak within a range of 500 nm to 600 nm in wavelength by being irradiated with an exciting light.
    Type: Application
    Filed: December 16, 2008
    Publication date: May 21, 2009
    Applicant: NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventor: Naoto Hirosaki
  • Publication number: 20090121608
    Abstract: Disclosed are violet, blue, and green phosphors having excellent durability and high luminance. Specifically disclosed is a phosphor which contains a metal element M (M is at least one element selected from among Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm and Yb) for constituting a metal ion, which is solid-solubilized in an AlON crystal, an AlON solid solution crystal or an inorganic crystal having the same crystal structure as AlON. The phosphor is capable of emitting fluorescence having a peak in the wavelength range from 300 nm to 700 nm. Also disclosed is a method for producing such a phosphor. Further disclosed are an illuminating device and an image display each containing such a phosphor.
    Type: Application
    Filed: February 22, 2007
    Publication date: May 14, 2009
    Inventors: Rong-Jun Xie, Naoto Hirosaki
  • Patent number: 7525245
    Abstract: A fluorescence emitting device is provided using a phosphor emitting a light by bombardment of an electron beam and having excellent luminance lifetime. The electron beam excited phosphor comprises a solid solution prepared by an AlN crystal or AlN solid solution crystal formed with at least Eu, Si and oxygen represented by the composition formula Eua Alb Sic Nd Oe [Wherein a+b+c+d+e=1, and a, b, c, d and e satisfy the following conditions: 0.00001?a?0.1 0.4?b?0.55 0.001?c?0.1 0.4?d?0.55 0.001?e?0.1].
    Type: Grant
    Filed: April 10, 2006
    Date of Patent: April 28, 2009
    Assignees: Futaba Corporation, National Institute for Materials Science
    Inventors: Kiyoshi Tamura, Naoto Hirosaki
  • Publication number: 20090091237
    Abstract: A fluorophor which comprises as a main component, an ? type sialon crystal containing at least Li, A element (wherein A represents one or more elements selected from among Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Er, Tm and Yb), M element (wherein M represents one or more metal elements except Li and the A element), Si, Al, oxygen and nitrogen. The fluorophor has an a type sialon crystal structure which is represented by the general formulae: (Lix1, Ax2, Mx3)(Si12?(m+n)Alm+n)(OnN16?n) 1.2?x1?2.4 (1) 0.001?x2?0.4 (2) and 0?x3?1.0 (3), and has a luminescence peak at a wavelength in the range of 400 to 700 nm. The above phosphor is reduced in the lowering of brightness, and can be suitably used for a white LED and the like.
    Type: Application
    Filed: June 28, 2006
    Publication date: April 9, 2009
    Applicant: NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventors: Naoto Hirosaki, Rong-Jun Xie, Mamoru Mitomo
  • Publication number: 20090085465
    Abstract: A fluorophor comprising, as a main component, an ?-type sialon crystal which contains at least an A element (wherein A represents one or more elements selected from among Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Er, Tm and Yb), an M element (wherein M represents one or more elements selected from among Li, Na, Mg, Ca, Y, La, Gd and Lu), Si, Al, oxygen and nitrogen, and is represented by the general formulae: (Mx, Ay)(Si12?(m+n)Alm+n)(OnN16?n) (1) m=?M×x+?A×y (2) 0.2?x?2.4 (3) 0.001?y?0.4 (4) and 0.5×m<n?4 (5). The fluorophor is reduced in the lowering of brightness, and is useful for a white color LED and the like.
    Type: Application
    Filed: June 28, 2006
    Publication date: April 2, 2009
    Applicant: NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventors: Naoto Hirosaki, Rong-Jun Xie, Mamoru Mitomo
  • Publication number: 20090066230
    Abstract: A phosphor which emits light having high brightness, serves as an excellent orange or red phosphor whose light brightness is less decreased when exposed to an excitation source contains a crystal phase having the chemical composition expressed by the general formula [1]: (1?a?b)(Ln?pMII?1?pMIII?MIV?N3)·a(MIV?(3n+2)/4NnO)·b(AMIV?2N3)??[1] wherein Ln? represents a metal element selected from the group consisting of lanthanoids, Mn, and Ti; MnII? represents a divalent metal element except the Ln? element; MIII? represents a trivalent metal element; MIV? represents a tetravalent metal element; A represents a metal element selected from the group consisting of Li, Na, and K; 0<p?0.2; 0?a, 0?b, a+b>0, 0?n, and 0.002?(3n+2)a/4?0.9.
    Type: Application
    Filed: May 24, 2006
    Publication date: March 12, 2009
    Applicants: Mitsubishi Chemical Corporation, Ind Admin Ins NATIONAL INSTITUTE FOR MATERIALS SCI
    Inventors: Naoto Hirosaki, Takatoshi Seto, Naoto Kijima
  • Publication number: 20090057611
    Abstract: A green phosphor that exhibits a green luminance higher than those of conventional rare-earth-activated sialon phosphors, having durability higher than those of conventional oxide phosphors, and that emits light by ultraviolet or visible light. There is provide a phosphor comprising a crystal of oxynitride or nitride with ?-type Si3N4 crystal structure and, solid dissolved therein, Eu, which phosphor emits a fluorescence having a peak at a wavelength falling within the wavelength region of 500 to 600 nm upon excitation source irradiation. The luminous intensity within the wavelength region of 500 to 600 nm is high, so that the phosphor is excellent as a green phosphor.
    Type: Application
    Filed: March 20, 2006
    Publication date: March 5, 2009
    Applicant: NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventor: Naoto Hirosaki
  • Publication number: 20090050845
    Abstract: A ? type Sialon fluorescent substance is disclosed that is capable of achieving enhanced brightness of a white light emitting diode using blue to ultraviolet light as a light source. In the fluorescent substance which contains not less than 90% by mass of a ? type Sialon composition represented by general formula: Si6-zAlzOzN8-z as a host material wherein z is not less than 0.24 and not more than 0.42, Eu is present dissolved in solid solution as a luminescent center at a content of 0.05 to 0.2% by atom. The ? type Sialon fluorescent substance is preferably in the form of a powder having an average particle size of not less than 1 ?m and not more than 20 ?m. A white LED of good luminescent characteristics can be obtained by using a blue or ultraviolet light emitting diode as a excitation light source in combination with a fluorescent substance that emits yellow or red light.
    Type: Application
    Filed: May 10, 2006
    Publication date: February 26, 2009
    Applicants: NATIONAL INSTITUTE FOR MATERIALS SCIENCE, DENKI KAGAKU KOGYO KABUSHIKI KAISHA
    Inventors: Naoto Hirosaki, Hideyuki Emoto, Masahiro Ibukiyama
  • Patent number: 7494606
    Abstract: The invention provides an oxynitride phosphor represented by a composition formula M1?aCeaSibAlcOdNe, wherein M denotes La or a compound of which main component is La and sub-component is at least one kind of element selected from the group consisting of Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu; the a that represents a composition ratio of Ce is a real number satisfying 0.1?a?1; the b that represents a composition ratio of Si is a real number satisfying b=(6?z)×f; the c that represents a composition ratio of Al is a real number satisfying c=(1+z)×g; the d that represents a composition ratio of O is a real number satisfying d=z×h; the e that represents a composition ratio of N is a real number satisfying e=(10?z)×i; the z is a real number satisfying 0.1?z?3; the f is a real number satisfying 0.7?f?1.3; the g is a real number satisfying 0.7?g?3; the h is a real number satisfying 0.7?h?3; the i is a real number satisfying 0.7?i?1.
    Type: Grant
    Filed: February 22, 2006
    Date of Patent: February 24, 2009
    Assignees: Sharp Kabushiki Kaisha, National Institute for Materials Science
    Inventors: Kohsei Takahashi, Naoto Hirosaki