Patents by Inventor Kohsei Takahashi
Kohsei Takahashi 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: 11641009Abstract: A light-emitting device including a solid-state light source that emits light having a peak wavelength in the range of 480 nm or less and a fluorescent film that covers the solid-state light source and includes at least one kind of phosphor, wherein the fluorescent film includes at least one kind of near-infrared phosphor that is excited by light from the solid-state light source, has a peak wavelength in the range exceeding 700 nm, and has an emission spectrum with a full width at half maximum of 100 nm or more in a range including the peak wavelength.Type: GrantFiled: June 12, 2019Date of Patent: May 2, 2023Assignees: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY, PHOENIX ELECTRIC CO., LTD., NATIONAL INSTITUTE FOR MATERIALS SCIENCEInventors: Takashi Fukuda, Tetsuya Gouda, Yuta Sakimoto, Naoto Hirosaki, Kohsei Takahashi
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Publication number: 20210249569Abstract: A light-emitting device including a solid-state light source that emits light having a peak wavelength in the range of 480 nm or less and a fluorescent film that covers the solid-state light source and includes at least one kind of phosphor, wherein the fluorescent film includes at least one kind of near-infrared phosphor that is excited by light from the solid-state light source, has a peak wavelength in the range exceeding 700 nm, and has an emission spectrum with a full width at half maximum of 100 nm or more in a range including the peak wavelength.Type: ApplicationFiled: June 12, 2019Publication date: August 12, 2021Applicants: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY, PHOENIX ELECTRIC CO., LTD., NATIONAL INSTITUTE FOR MATERIALS SCIENCEInventors: Takashi FUKUDA, Tetsuya GOUDA, Yuta SAKIMOTO, Naoto HIROSAKI, Kohsei TAKAHASHI
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Patent number: 9711686Abstract: Provided is a light-emitting device that has a high emission efficiency, excellent stability and temperature properties, and that generates light having a high color rendering property sufficient for practical use. This semiconductor light-emitting device comprises a semiconductor light-emitting element that emits blue light, a green phosphor that absorbs the blue light and emits green light, and an orange phosphor that absorbs the blue light and emits orange light, and is characterized in that the orange phosphor is an Eu-activated ?-SiAlON phosphor having an emission spectrum peak wavelength within a range of 595 to 620 nm.Type: GrantFiled: March 22, 2016Date of Patent: July 18, 2017Assignee: SHARP KABUSHIKI KAISHAInventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga
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Patent number: 9631140Abstract: In a light-emitting device, a 50%-area average diameter of primary particles of a Eu-activated ? SiAlON fluorescent material is 10 ?m or more, a scattering probability of scattering materials at a peak wavelength of excitation light emitted from an excitation light source is 0.1 mm?1 or more and 0.5 mm?1 or less, and the Eu-activated ? SiAlON fluorescent material is entrapped inside a transparent member in a dispersed state together with the scattering materials.Type: GrantFiled: December 19, 2013Date of Patent: April 25, 2017Assignee: SHARP KABUSHIKI KAISHAInventors: Kenichi Yoshimura, Hiroshi Fukunaga, Masamichi Harada, Kohsei Takahashi
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Patent number: 9570655Abstract: Provided is a light-emitting device that has a high emission efficiency, excellent stability and temperature properties, and that generates light having a high color rendering property sufficient for practical use. This semiconductor light-emitting device (1) comprises a semiconductor light-emitting element (2) that emits blue light, a green phosphor (14) that absorbs the blue light and emits green light, and an orange phosphor (13) that absorbs the blue light and emits orange light, and is characterized in that the orange phosphor is an Eu-activated ?-SiAlON phosphor having an emission spectrum peak wavelength within a range of 595 to 620 nm.Type: GrantFiled: January 5, 2012Date of Patent: February 14, 2017Assignee: SHARP KABUSHIKI KAISHAInventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga
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Publication number: 20160223147Abstract: Provided is a light emitting device with effectively improved color rendering properties. A light emitting device 1 includes: a light source 2 that emits light having the maximum intensity at a predetermined wavelength; a first phosphor (yellow phosphor) 51 that absorbs the light emitted by the light source 2 and outputs fluorescent light having the maximum intensity at a first wavelength which is longer than the predetermined wavelength; and a second phosphor (red phosphor) 52 that absorbs the light emitted by the light source 2 and outputs fluorescent light having the maximum intensity at a second wavelength which is longer than the first wavelength. An absolute value of wavelength dependency of an optical absorption rate of the second phosphor 52 at the first wavelength is set to not more than 0.6%/nm. Accordingly, the color rendering properties of the light emitted by the light emitting device 1 can be effectively improved.Type: ApplicationFiled: March 21, 2016Publication date: August 4, 2016Inventors: Kenichi YOSHIMURA, Kohsei TAKAHASHI, Hiroshi FUKUNAGA, Masatsugu MASUDA
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Publication number: 20160204311Abstract: Provided is a light-emitting device that has a high emission efficiency, excellent stability and temperature properties, and that generates light having a high color rendering property sufficient for practical use. This semiconductor light-emitting device comprises a semiconductor light-emitting element that emits blue light, a green phosphor that absorbs the blue light and emits green light, and an orange phosphor that absorbs the blue light and emits orange light, and is characterized in that the orange phosphor is an Eu-activated ?-SiAlON phosphor having an emission spectrum peak wavelength within a range of 595 to 620 nm.Type: ApplicationFiled: March 22, 2016Publication date: July 14, 2016Inventors: Kenichi YOSHIMURA, Kohsei TAKAHASHI, Hiroshi FUKUNAGA
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Patent number: 9322529Abstract: Provided is a light emitting device with effectively improved color rendering properties. A light emitting device 1 includes: a light source 2 that emits light having the maximum intensity at a predetermined wavelength; a first phosphor (yellow phosphor) 51 that absorbs the light emitted by the light source 2 and outputs fluorescent light having the maximum intensity at a first wavelength which is longer than the predetermined wavelength; and a second phosphor (red phosphor) 52 that absorbs the light emitted by the light source 2 and outputs fluorescent light having the maximum intensity at a second wavelength which is longer than the first wavelength. An absolute value of wavelength dependency of an optical absorption rate of the second phosphor 52 at the first wavelength is set to not more than 0.6%/nm. Accordingly, the color rendering properties of the light emitted by the light emitting device 1 can be effectively improved.Type: GrantFiled: April 2, 2012Date of Patent: April 26, 2016Assignee: SHARP KABUSHIKI KAISHAInventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga, Masatsugu Masuda
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Patent number: 9279079Abstract: A method of manufacturing a first phosphor of which emission spectrum shape well matches with a color filter of three primary colors of light, a light-emitting device including the first phosphor, and an image display apparatus including the light-emitting device are provided. The light-emitting device includes a semiconductor light-emitting element emitting excitation light and the first phosphor absorbing the excitation light and emitting green light. The first phosphor contains a solid solution of aluminum element and a metal element M selected from the group consisting of Mn, Ce and Eu in crystals of an oxynitride having a ?-type Si3N4 crystal structure, an amount of oxygen in the crystals being not higher than 0.8 mass %.Type: GrantFiled: May 29, 2008Date of Patent: March 8, 2016Assignees: SHARP KABUSHIKI KAISHA, NATIONAL INSTITUTE FOR MATERIALS SCIENCEInventors: Kohsei Takahashi, Masamichi Harada, Naoto Hirosaki
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Publication number: 20150357529Abstract: In a light-emitting device, a 50%-area average diameter of primary particles of a Eu-activated ? SiAlON fluorescent material is 10 ?m or more, a scattering probability of scattering materials at a peak wavelength of excitation light emitted from an excitation light source is 0.1 mm?1 or more and 0.5 mm?1 or less, and the Eu-activated ? SiAlON fluorescent material is entrapped inside a transparent member in a dispersed state together with the scattering materials.Type: ApplicationFiled: December 19, 2013Publication date: December 10, 2015Inventors: Kenichi YOSHIMURA, Hiroshi FUKUNAGA, Masamichi HARADA, Kohsei TAKAHASHI
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Patent number: 8928005Abstract: A semiconductor light-emitting device that is high in luminous efficiency and that emits light which is high in color rendering property includes a semiconductor light-emitting element that emits blue light; a green fluorescent substance that absorbs the blue light and emits green light; and an orange fluorescent substance that absorbs the blue light and emits orange light, fluorescence emitted by the green fluorescent substance and the orange fluorescent substance having an emission spectrum that has a peak wavelength of not less than 540 nm and not more than 565 nm and that satisfies the relation of 0.70>PI(90)/PI(MAX)>0.55, where PI(MAX) represents an emission intensity at the peak wavelength, and PI(90) represents an emission intensity at a wavelength 90 nm longer than the peak wavelength.Type: GrantFiled: July 2, 2010Date of Patent: January 6, 2015Assignees: Sharp Kabushiki Kaisha, Independent Administrative Institution, National Institute for Materials ScienceInventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga, Naoto Hirosaki
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Patent number: 8901591Abstract: There is realized a light-emitting device that emits, with high efficiency, white light with excellent color rendering index. A light-emitting device (1) of the present invention is a light-emitting device (1) for emitting white light, including at least a light-emitting element (2) for emitting blue light, an orange fluorescent material (13) which absorbs the blue light so as to emit orange light, and a green fluorescent material (14) which absorbs the blue light so as to emit green light, the orange fluorescent material (13) being a Ce-activated CaAlSiN3 fluorescent material in a solid solution crystal form in which Ce and oxygen are dissolved in a crystal having a composition of cCaAlSiN3.(1?c)LiSi2N3 where 0.2?c?0.8, and the orange fluorescent material (13) containing 2 weight % or more of Ce.Type: GrantFiled: July 15, 2011Date of Patent: December 2, 2014Assignees: Sharp Kabushiki Kaisha, National Institute for Materials ScienceInventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga, Naoto Hirosaki
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Publication number: 20140233209Abstract: Provided is a light emitting device with effectively improved color rendering properties. A light emitting device 1 includes: a light source 2 that emits light having the maximum intensity at a predetermined wavelength; a first phosphor (yellow phosphor) 51 that absorbs the light emitted by the light source 2 and outputs fluorescent light having the maximum intensity at a first wavelength which is longer than the predetermined wavelength; and a second phosphor (red phosphor) 52 that absorbs the light emitted by the light source 2 and outputs fluorescent light having the maximum intensity at a second wavelength which is longer than the first wavelength. An absolute value of wavelength dependency of an optical absorption rate of the second phosphor 52 at the first wavelength is set to not more than 0.6%/nm. Accordingly, the color rendering properties of the light emitted by the light emitting device 1 can be effectively improved.Type: ApplicationFiled: April 2, 2012Publication date: August 21, 2014Applicant: SHARP KABUSHIKI KAISHAInventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga, Masatsugu Masuda
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Patent number: 8674392Abstract: Disclosed is a light-emitting device that exhibits good color rendering and highly efficiently emits white light in an incandescent bulb color range. The semiconductor light-emitting device (1) of the present invention includes: a semiconductor light-emitting element (2) that emits blue light; a green phosphor (14) that absorbs the blue light and emits green light; and an orange phosphor (13) that absorbs the blue light and emits orange light. The orange phosphor (13) produces an emission spectrum having a peak at a wavelength of equal to or greater than 590 nm but equal to or less than 630 nm and having a full width at half maximum of 130 nm or greater at the peak, the full width at half maximum of the emission spectrum of the orange phosphor (13) being broader than a full width at half maximum of an emission spectrum of the green phosphor (14). The orange phosphor (13) exhibits an absorptance having a peak wavelength of 420 nm or greater. ABS(530) and ABS(MAX) satisfy a relation, ABS(530)/ABS(MAX)<0.Type: GrantFiled: January 27, 2011Date of Patent: March 18, 2014Assignee: Sharp Kabushiki KaishaInventors: Kenichi Yoshimura, Hiroshi Fukunaga, Kohsei Takahashi, Naoto Hirosaki
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Publication number: 20130285104Abstract: Provided is a light-emitting device that has a high emission efficiency, excellent stability and temperature properties, and that generates light having a high color rendering property sufficient for practical use. This semiconductor light-emitting device (1) comprises a semiconductor light-emitting element (2) that emits blue light, a green phosphor (14) that absorbs the blue light and emits green light, and an orange phosphor (13) that absorbs the blue light and emits orange light, and is characterized in that the orange phosphor is an Eu-activated ?-SiAlON phosphor having an emission spectrum peak wavelength within a range of 595 to 620 nm.Type: ApplicationFiled: January 5, 2012Publication date: October 31, 2013Applicant: SHARP KABUSHIKI KAISHAInventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga
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Publication number: 20130277698Abstract: There is realized a light-emitting device that emits, with high efficiency, white light with excellent color rendering index. A light-emitting device (1) of the present invention is a light-emitting device (1) for emitting white light, including at least a light-emitting element (2) for emitting blue light, an orange fluorescent material (13) which absorbs the blue light so as to emit orange light, and a green fluorescent material (14) which absorbs the blue light so as to emit green light, the orange fluorescent material (13) being a Ce-activated CaAlSiN3 fluorescent material in a solid solution crystal form in which Ce and oxygen are dissolved in a crystal having a composition of cCaAlSiN3ยท(1?c)LiSi2N3 where 0.2?c?0.8, and the orange fluorescent material (13) containing 2 weight % or more of Ce.Type: ApplicationFiled: July 15, 2011Publication date: October 24, 2013Inventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga, Naoto Hirosaki
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Publication number: 20130207146Abstract: There is realized a light-emitting device that emits, with high efficiency, white light with excellent color rendering index in a lamp color region. A light-emitting device (1) of the present invention is a light-emitting device (1) for emitting white light in a lamp color region, including at least a light-emitting element (2) for emitting blue light, an orange fluorescent material (13) which absorbs the blue light so as to emit orange light, and a red fluorescent material (14) which absorbs the blue light so as to emit red light, the orange fluorescent material (13) being a Ce-activated CaAlSiN3 fluorescent material in a solid solution crystal form in which Ce and oxygen are dissolved in a crystal having a composition of cCaAlSiN3.(1?c)LiSi2N3 where 0.2?c?0.8.Type: ApplicationFiled: July 15, 2011Publication date: August 15, 2013Applicant: Sharp Kabushiki KaishaInventors: Kenichi Yoshimura, Kohsei Takahashi, Hiroshi Fukunaga, Naoto Hirosaki
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Publication number: 20120319155Abstract: Disclosed is a light-emitting device that exhibits good color rendering and highly efficiently emits white light in an incandescent bulb color range. The semiconductor light-emitting device (1) of the present invention includes: a semiconductor light-emitting element (2) that emits blue light; a green phosphor (14) that absorbs the blue light and emits green light; and an orange phosphor (13) that absorbs the blue light and emits orange light. The orange phosphor (13) produces an emission spectrum having a peak at a wavelength of equal to or greater than 590 nm but equal to or less than 630 nm and having a full width at half maximum of 130 nm or greater at the peak, the full width at half maximum of the emission spectrum of the orange phosphor (13) being broader than a full width at half maximum of an emission spectrum of the green phosphor (14). The orange phosphor (13) exhibits an absorptance having a peak wavelength of 420 nm or greater. ABS(530) and ABS(MAX) satisfy a relation, ABS(530)/ABS(MAX)<0.Type: ApplicationFiled: January 27, 2011Publication date: December 20, 2012Applicants: INDEPENDENT ADMINISTRATIVE INSTITUTION, NATIONAL INSTITUTE FOR MATERIALS SCIENCE, SHARP KABUSHIKI KAISHAInventors: Kenichi Yoshimura, Hiroshi Fukunaga, Kohsei Takahashi, Naoto Hirosaki
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Publication number: 20120162573Abstract: A liquid crystal display including a backlight and a filter, the backlight including a light-emitting device having a light-emitting element emitting blue light, and a green phosphor and a red phosphor absorbing a part of primary light emitted from the light-emitting element and emitting first secondary light and second secondary light, respectively, the green phosphor being a ?-type SiAlON phosphor containing Eu and Al dissolved in a crystal of a nitride or an oxynitride having a ?-type Si3N4 crystal structure, and the filter including filters for colors of red (R), green (G), blue (B) and yellow (Y), respectively, arranged in a plane for subpixels provided in each pixel of the liquid crystal display, which attains excellent color reproducibility (NTSC ratio) and high luminance, can be provided.Type: ApplicationFiled: August 26, 2010Publication date: June 28, 2012Inventors: Kohsei Takahashi, Masanori Watanabe, Tetsuya Hanamoto, Masatsugu Masuda, Kenji Terashima
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Publication number: 20120139409Abstract: A headlamp 1 includes: a semiconductor laser 2, which emits laser light; and a light-emitting section 5, which includes at least either a fluorescent material sintered body obtained by sintering an oxynitride fluorescent material or a fluorescent material sintered body obtained by sintering an oxynitride fluorescent material and a nitride fluorescent material and which produces fluorescence upon receiving laser light emitted by the semiconductor laser 2. This allows the headlamp 1 to quickly radiate heat generated in the light-emitting section outward, thus bringing about an effect of preventing the light-emitting section from rising in temperature when irradiated with high-power and high-density laser light.Type: ApplicationFiled: December 6, 2011Publication date: June 7, 2012Applicant: SHARP KABUSHIKI KAISHAInventors: Katsuhiko KISHIMOTO, Kohsei Takahashi