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).

  • Publication number: 20110121234
    Abstract: A green phosphor for emitting light, a spectrum of which is sharp, in an ultraviolet and visible light region, which has higher green light brightness than the conventional rare earth-activated sialon phosphor and has higher durability than the conventional oxide phosphor, is provided. The phosphor being characterized in that Al and a metal element M (here, M is Eu) are incorporated into a crystal of a nitride or oxynitride having a ?Si3N4 crystal structure as a solid solution, the content of oxygen in the crystal does not exceed 0.8% by mass, and that the phosphor emits a visible light having a luminescence peak wavelength in the range of 450 nm to 650 nm upon exposure to an excitation source is provided. This luminescence spectrum has a sharp spectrum shape. A manufacturing method of the phosphor, a lighting device and an image display device utilizing the phosphor are also provided.
    Type: Application
    Filed: December 7, 2006
    Publication date: May 26, 2011
    Inventor: Naoto Hirosaki
  • Patent number: 7947198
    Abstract: The present invention aims at providing a chemically stabilized inorganic phosphor which emits orange light or red light at wavelengths longer than the conventional rare-earth activated sialon phosphor and which has a higher luminance.
    Type: Grant
    Filed: June 23, 2005
    Date of Patent: May 24, 2011
    Assignee: National Institute for Materials Science
    Inventor: Naoto Hirosaki
  • Patent number: 7910023
    Abstract: According to the invention, a highly crystalline ?-sialon is synthesized to emit highly intense light and a white LED showing an excellent color rendering characteristic is provided by shifting emitted light to the short wavelength side (blue shift). Such an ?-sialon is designed so as to be expressed by general formula (Lix, Cay, Euz) (Si12?(m+n)Alm+n) (OnN16?n) wherein the numerical ranges of x, y, z, m and n are respectively 0<x<2.0, 0<y<2.0, 0<z?0.5 (provided that 0.3?x+y+z?2.0), 0<m?4.0 and 0<n?3.0.
    Type: Grant
    Filed: April 27, 2006
    Date of Patent: March 22, 2011
    Assignee: National Institute for Materials Science
    Inventors: Rong-Jun Xie, Mamoru Mitomo, Naoto Hirosaki, Yoshinobu Yamamoto
  • Patent number: 7906040
    Abstract: An ?-sialon is offered which is represented by general formula: (M1)X(M2)Y(Si, Al)12(O, N)16 (wherein M1 represents one or more elements selected from the group which consists of Li, Mg, Ca, Y and lanthanoid (except La and Ce) and M2 represents one or more elements selected from the group which consists of Ce, Pr, Eu, Tb, Yb and Er and wherein 0.3<X+Y<1.5 and 0<Y<0.7), the ?-sialon containing from 30 ppm to 1% of fluorine as an impurity. By making primary particles of the ?-sialon 1 to 10 ?m in average particle size, an ?-sialon phosphor can be obtained reproducibly, stably and in a large quantity. Especially, if containing 30 to 200 ppm of impurity fluorine, the ?-sialon phosphor can exhibit an excellent emission characteristic as a white fluorescent matter.
    Type: Grant
    Filed: June 14, 2005
    Date of Patent: March 15, 2011
    Assignees: National Institute for Materials Science, Denki Kagaku Kogyo Kabushiki Kaisha
    Inventors: Mamoru Mitomo, Naoto Hirosaki, Hideyuki Emoto, Masahiro Ibukiyama
  • Patent number: 7892451
    Abstract: Disclosed is a phosphor containing a nitrogen element, a compound having a garnet structure and an activator. The activator is composed of at least one element selected from the group consisting of Ce, Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb and Mn.
    Type: Grant
    Filed: April 21, 2005
    Date of Patent: February 22, 2011
    Assignees: Sumitomo Chemical Company, Limited, Independent Administrative Institution National Institute for Materials Science
    Inventors: Naoto Hirosaki, Takayoshi Ezuhara, Susumu Miyazaki
  • Patent number: 7846351
    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: Grant
    Filed: March 20, 2006
    Date of Patent: December 7, 2010
    Inventor: Naoto Hirosaki
  • Publication number: 20100283381
    Abstract: A JEM phase phosphor having superior luminous efficiency is obtained, and a light emitting device is provided, which includes first and second phosphors and in which fluorescence from the first phosphor is not much absorbed by the second phosphor, with the JEM phase phosphor used as a first phosphor. The first phosphor is the JEM phase phosphor having optical absorption of at most 30% at a wavelength in a relation of complementary color to the emission wavelength of the first phosphor. In the light emitting device having a combination of the first phosphor and the second phosphor emitting fluorescence of longer wavelength than the first phosphor, the first phosphor has optical absorption at the emission wavelength of the second phosphor of at most 30%.
    Type: Application
    Filed: September 6, 2006
    Publication date: November 11, 2010
    Inventors: Kohsei Takahashi, Naoto Hirosaki
  • Patent number: 7825580
    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 formula: (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: Grant
    Filed: June 28, 2006
    Date of Patent: November 2, 2010
    Assignee: National Institute for Materials Science
    Inventors: Naoto Hirosaki, Rong-Jun Xie, Mamoru Mitomo
  • Patent number: 7815817
    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: Grant
    Filed: March 20, 2006
    Date of Patent: October 19, 2010
    Assignee: National Institute for Materials Science
    Inventor: Naoto Hirosaki
  • Patent number: 7780872
    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: Grant
    Filed: January 22, 2009
    Date of Patent: August 24, 2010
    Assignee: National Institute for Materials Science
    Inventor: Naoto Hirosaki
  • Publication number: 20100200874
    Abstract: The invention is a phosphor which includes a phosphor material having a composition represented by a general formula: M(0)aM(1)bM(2)x?(vm+n)M(3)(vm+n)?yOnNz?n, wherein M(0) is one or more elements selected from Li, Na, Be, Mg, Ca, Sr, Ba, Sc, Y, La, Gd and Lu; M(1) is one or more activators selected from Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm and Yb; M(2) is one or more elements selected from Si, Ge, Sn, Ti, Hf and Zr; M(3) is one or more elements selected from Be, B, Al, Ga, In, Tl and Zn; O is oxygen; N is nitrogen; and an atomic ratio of M(0), M(1), M(2), M(3), O and N is adjusted to satisfy the following: x, y and z satisfy 33?x?51, 8?y?12 and 36?z?56; a and b satisfy 3?a+b?7 and 0.001?b?1.2; m and n satisfy 0.8·me?m?1.2·me and 0?n?7 in which me=a+b; and v satisfies v={a·v(0)+b·v(1)}/(a+b) (wherein v(0) is a valence of M(0) ion and v(1) is a valence of M(1) ion). The invention also relates to a method for producing the phosphor and a light-emitting device using the phosphor.
    Type: Application
    Filed: September 1, 2008
    Publication date: August 12, 2010
    Applicant: National Institute for Materials Science
    Inventors: Kousuke Shioi, Naoto Hirosaki, Hisayuki Miki
  • Publication number: 20100164367
    Abstract: The present invention provides a fluorescent substance exhibiting higher brightness as compared to conventional fluorescent substances, a method for producing the same, and a light-emitting device using such a fluorescent substance. Specifically, the fluorescent substance comprises an ?-sialon crystal structure having the same crystal structure with an ?-type silicon nitride crystal, which includes at least an M(0) element (where M(0) represents one or two elements selected from Sr and La), an M(1) element (where M(1) represents one or more elements selected from Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm and Yb), Si, Al, and nitrogen.
    Type: Application
    Filed: May 1, 2008
    Publication date: July 1, 2010
    Inventors: Kousuke Shioi, Naoto Hirosaki
  • Patent number: 7713443
    Abstract: An object of the present invention is to provide an inorganic phosphor, particularly, an oxynitride phosphor containing alkaline earths which has a higher luminance than that of conventional sialon phosphors activated with a rare earth, and is chemically stable. By baking a raw material mixture containing at least silicon nitride powder, M element containing inorganic substance, and A element containing inorganic substance at a temperature range of 1200° C. to 2200° C. in a nitrogen atmosphere, a phosphor comprising an inorganic composition containing at least M Element, A Element, silicon, oxygen, and nitrogen (wherein M Element is one or two or more elements selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb, A Element is one or two or more elements selected from the group consisting of Mg, Ca, Sr, and Ba) and containing at least crystal having the same crystal structure as that of A2Si5N8 and A element-containing crystal is obtained.
    Type: Grant
    Filed: January 25, 2006
    Date of Patent: May 11, 2010
    Assignee: National Institute For Materials Science
    Inventors: Naoto Hirosaki, Rong-Jun Xie
  • Publication number: 20100072498
    Abstract: According to the invention, a highly crystalline ?-sialon is synthesized to emit highly intense light and a white LED showing an excellent color rendering characteristic is provided by shifting emitted light to the short wavelength side (blue shift). Such an ?-sialon is designed so as to be expressed by general formula (Lix, Cay, Euz) (Si12-(m+n)Alm+n) (OnN16-n) wherein the numerical ranges of x, y, z, m and n are respectively 0<x<2.0, 0<y<2.0, 0<z?0.5 (provided that 0.3?x+y+z?2.0), 0<m?4.0 and 0<n?3.0.
    Type: Application
    Filed: April 27, 2006
    Publication date: March 25, 2010
    Applicant: National Institute For Materials Science
    Inventors: Rong Jun Xie, Mamoru Mitomo, Naoto Hirosaki, Yoshinobu Yamamoto
  • Publication number: 20100072881
    Abstract: A SiAlON phosphor represented by a general formula (1) Lup(Si, Al)12(O, N)16:Euq??(1) wherein at least a main phase has an alpha SiAlON crystal structure; and 0.25?p?0.65.
    Type: Application
    Filed: September 17, 2009
    Publication date: March 25, 2010
    Applicants: Fujikura Ltd., National Institute for Materials Science
    Inventors: Ken Sakuma, Naoto Hirosaki
  • Patent number: 7678294
    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: Grant
    Filed: December 16, 2008
    Date of Patent: March 16, 2010
    Assignee: National Institute for Materials Science
    Inventor: Naoto Hirosaki
  • Publication number: 20100039020
    Abstract: A blue fluorescent material having excellent durability and a high luminance, especially one emitting a high-luminance light by the action of electron rays. The fluorescent material comprises inorganic crystals having a crystal structure which is an AlN crystalline, AlN polycrystalline, or AlN solid-solution crystalline structure. It is characterized in that the inorganic crystals contain at least europium in solution and have an oxygen content of 0.4 mass % or lower and that the fluorescent material emits fluorescence derived from divalent europium ions upon irradiation with an excitation source. More preferably, the fluorescent material contains a given metallic element and silicon. Also provided are a process for producing the fluorescent material and an illuminator including the blue fluorescent material.
    Type: Application
    Filed: January 11, 2008
    Publication date: February 18, 2010
    Inventor: Naoto Hirosaki
  • Publication number: 20090272995
    Abstract: An epoxy resin composition for optical semiconductor element encapsulation includes an epoxy resin (Component (A)) mainly containing an epoxy compound represented by a specific structural formula (1), a curing agent (Component (B)), and at least one of an oxynitride phosphor and a nitride phosphor (Component (C)). Therefore, the phosphor component (C) is uniformly dispersed in the epoxy resin composition without segregation. Thus, the resin composition serves as an excellent optical semiconductor element encapsulation material which has an adequate light diffusion property and a high light transmittance and permits a reduction in internal stress. Therefore, a light emitting diode element encapsulated with the epoxy resin composition is capable of stably emitting light, and satisfactorily performs its functions.
    Type: Application
    Filed: September 27, 2006
    Publication date: November 5, 2009
    Applicants: NITTO DENKO CORPORATION, NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventors: Hisataka Ito, Hideyuki Usui, Naoto Hirosaki
  • Patent number: 7611642
    Abstract: The present invention provides an oxynitride phosphor represented by a composition formula M(1)1-jM(2)jSibAlcOdNe (composition formula I) or a composition formula M(1)1-a-jM(2)jCeaSibAlcOdNe (composition formula II) and containing 50% or more of a JEM phase, and a light emitting device including a semiconductor light emitting element emitting an excited light, a first phosphor that is the oxynitride phosphor according to the present invention that absorbs the excited light and emits a fluorescence, and a kind or a plurality of kinds of second phosphor(s) that absorb(s) the excited light and emit(s) a fluorescence having a longer wavelength than the fluorescence emitted by the first phosphor. Thereby, a novel oxynitride phosphor being capable of highly efficiently emitting mainly a light having a wavelength of 510 nm or less and a light emitting device using the same can be provided.
    Type: Grant
    Filed: June 6, 2007
    Date of Patent: November 3, 2009
    Assignees: Sharp Kabushiki Kaisha, National Institute for Materials Science
    Inventors: Kohsei Takahashi, Naoto Hirosaki
  • Publication number: 20090267482
    Abstract: A blue phosphor, which has excellent durability and high brightness, and in particular a blue phosphor in a powder state, which can realize high-brightness luminescence upon exposure to an electron beam, are provided. The phosphor being characterized by comprising at least europium incorporated as a solid solution into an inorganic crystal having a crystal structure of an AlN crystal or an AlN solid solution crystal, wherein the phosphor emits divalent europium-derived fluorescence having a peak at a wavelength in the range of 430 nm to 500 nm upon exposure to an excitation source, is provided. In this case, it is more preferable that a predetermined metal element and silicon are incorporated therein. And a manufacturing method to manufacture such phosphor is also provided. Further, a lighting device comprising such blue phosphor is provided.
    Type: Application
    Filed: December 7, 2006
    Publication date: October 29, 2009
    Inventor: Naoto Hirosaki