Patents by Inventor Hideto Sugawara
Hideto Sugawara 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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Publication number: 20030209720Abstract: An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circle over (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circle over (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circle over (3)} an Al layer as a high-reflection electrode, {circle over (4)} a Ti layer having a barrier function, and {circle over (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.Type: ApplicationFiled: April 17, 2003Publication date: November 13, 2003Applicant: Kabushiki Kaisha ToshibaInventors: Haruhiko Okazaki, Hideto Sugawara
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Publication number: 20030205714Abstract: There are provided a semiconductor light emitting device wherein the variation in tone in each device is small and the variation in tone due to deterioration with age is also small, and a method for manufacturing the same. The semiconductor light emitting device includes an active layer for emitting primary light having a first wavelength by current injection, and a light emitting layer excited by the primary light for emitting secondary light having a second wavelength different from said first wavelength, wherein the primary light and the secondary light are mixed to be outputted.Type: ApplicationFiled: April 17, 2003Publication date: November 6, 2003Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hideto Sugawara, Koichi Nitta, Hirohisa Abe, Kuniaki Konno, Yasuo Idei
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Publication number: 20030201449Abstract: A semiconductor light-emitting device, including a first substrate of a first conductivity type, a first bonding layer provided on the first substrate and consisting essentially of a GaP material of the first conductivity type, a second bonding layer provided on the first bonding layer, coincident with the first bonding layer in the planar direction of the crystal, having the first conductivity type, and consisting essentially of a material represented by a formula InxGayP, where 0≦x, y≦1, and x+y=1, and a light-emitting layer comprising a first cladding layer, an active layer, and a second cladding layer, which are successively provided on the second bonding layer, each of the active layer and first and second cladding layers consisting essentially of a material represented by a formula InxGayAlzP, where x+y+z=1, and 0≦x, y, z≦1.Type: ApplicationFiled: May 5, 2003Publication date: October 30, 2003Inventors: Ryo Saeki, Hideto Sugawara, Yukio Watanabe, Tamotsu Jitosho
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Patent number: 6627521Abstract: There is disclosed a semiconductor light emitting element formed by selective growth and being high in light emitting efficiency, in which at least one GaN-based layer grown by ELO is stacked/formed on a sapphire substrate, and a fluorescent substance for converting an ultraviolet light to a visible light is contained in a selective growth mask material layer for use in this case. Since this fluorescent substance converts the ultraviolet light to the visible light, a binding efficiency of the ultraviolet light to the fluorescent substance is enhanced in either one of a center light emitting type and UV light emitting type of light emitting elements. By further containing the fluorescent substance into a passivation film, the efficiency is further enhanced.Type: GrantFiled: October 28, 2002Date of Patent: September 30, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Chisato Furukawa, Hideto Sugawara, Nobuhiro Suzuki
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Publication number: 20030138976Abstract: A nitride compound semiconductor light-emitting device having a stack of layers including an active layer for a light emitting device and a method of manufacturing the device is disclosed. The method includes the steps of growing a first layer on a substrate at a first temperature to obtain an incomplete crystalline structure including both indium and aluminum and having the composition expressed as InXAlYGa1-X-YN(0≦X≦1, 0≦Y≦1). The method grows a cap layer on the first layer to cover the first layer, with growth of the cap layer proceeding at a second temperature substantially equal to or below the first temperature. The first layer is heat treated at a third temperature above the first temperature to cause the incomplete crystalline structure to crystallize and to create areas of differing compositions, thus changing the first layer to an active layer. The material of the cap layer is selected to be heat stable during the heat-treating step.Type: ApplicationFiled: January 30, 2003Publication date: July 24, 2003Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Hideto Sugawara
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Patent number: 6590233Abstract: The semiconductor light emitting device has the first semiconductor light emission element 13 for emitting color light in the first wave length range, the second semiconductor light emission element 14 for emitting color light in the second wave length range, the frame electrode 11 for mounting the first and second semiconductor light emission elements, and the package 19 for molding them together. The first semiconductor light emission element 13 is composed of an InGaAlP series material having an active layer 34 composed of a plurality of composite luminous layers 54, 55, 56, and 57 for emitting color light with a different wavelength. Luminescence spectra from the plurality of luminous layers are partially overlapped with each other. Each of the plurality of composite luminous layers 54, 55, 56, and 57 is further composed of a plurality of luminous layers 58 for emitting color light with substantially the same wavelength.Type: GrantFiled: August 28, 2001Date of Patent: July 8, 2003Assignee: Kabushiki Kasiha ToshibaInventor: Hideto Sugawara
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Patent number: 6586773Abstract: A semiconductor light-emitting device, including a first substrate of a first conductivity type, a first bonding layer provided on said first substrate and consisting essentially of a GaP material of the first conductivity type, a second bonding layer provided on the first bonding layer, coincident with the first bonding layer in a crystal orientation, having the first conductivity type, and consisting essentially of a material represented by a formula InxGayP, where 0≦x, y≦1, and x+y=1, and a light-emitting layer comprising a first cladding layer, an active layer, and a second cladding layer, which are successively provided on the second bonding layer, each of the active layer and first and second cladding layers consisting essentially of a material represented by a formula InxGayAlzP, where x+y+z=1, and 0≦x, y, z≦1.Type: GrantFiled: October 31, 2001Date of Patent: July 1, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Ryo Saeki, Hideto Sugawara, Yukio Watanabe, Tamotsu Jitosho
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Patent number: 6576933Abstract: There are provided a semiconductor light emitting device wherein the variation in tone in each device is small and the variation in tone due to deterioration with age is also small, and a method for manufacturing the same. The semiconductor light emitting device includes an active layer for emitting primary light having a first wavelength by current injection, and a light emitting layer excited by the primary light for emitting secondary light having a second wavelength different from said first wavelength, wherein the primary light and the secondary light are mixed to be outputted.Type: GrantFiled: March 9, 2001Date of Patent: June 10, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Hideto Sugawara, Koichi Nitta, Hirohisa Abe, Kuniaki Konno, Yasuo Idei
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Patent number: 6548834Abstract: A semiconductor light emitting element is proposed that improves a light extraction efficiency without requiring any complicated processes and techniques. The semiconductor light emitting element includes an active layer for emitting first light by current injection, and a light absorbing and emitting section for absorbing a part of the first light and for emitting second light having a greater peak wavelength than the first light. A difference in peak wavelength between the first light and the second light is in a range in which a spectrum of a mixture of the first and second light maintains a unimodal characteristic or is smaller than 0.9 times a half width of the spectrum of the first light.Type: GrantFiled: January 25, 2002Date of Patent: April 15, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Hideto Sugawara, Koichi Nitta, Ryo Saeki, Katsufumi Kondo, Masanobu Iwamoto
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Patent number: 6538265Abstract: A nitride compound semiconductor light-emitting device having a stack of layers including an active layer for a light emitting device and a method of manufacturing the device is disclosed. The method includes the steps of growing a first layer on a substrate at a first temperature to obtain an incomplete crystalline structure including both indium and aluminum and having the composition expressed as InXAlYGa1−X−YN (0≦X≦1, 0≦Y≦1). The method grows a cap layer on the first layer to cover the first layer, with growth of the cap layer proceeding at a second temperature substantially equal to or below the first temperature. The first layer is heat treated at a third temperature above the first temperature to cause the incomplete crystalline structure to crystallize and to create areas of differing compositions, thus changing the first layer to an active layer. The material of the cap layer is selected to be heat stable during the heat-treating step.Type: GrantFiled: September 13, 1999Date of Patent: March 25, 2003Assignee: Kabushiki Kaisha ToshibaInventor: Hideto Sugawara
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Patent number: 6504181Abstract: There is disclosed a semiconductor light emitting element formed by selective growth and being high in light emitting efficiency, in which at least one GaN-based layer grown by ELO is stacked/formed on a sapphire substrate, and a fluorescent substance for converting an ultraviolet light to a visible light is contained in a selective growth mask material layer for use in this case. Since this fluorescent substance converts the ultraviolet light to the visible light, a binding efficiency of the ultraviolet light to the fluorescent substance is enhanced in either one of a center light emitting type and UV light emitting type of light emitting elements. By further containing the fluorescent substance into a passivation film, the efficiency is further enhanced.Type: GrantFiled: December 20, 2000Date of Patent: January 7, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Chisato Furukawa, Hideto Sugawara, Nobuhiro Suzuki
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Patent number: 6479836Abstract: According to the invention, there is provided a semiconductor light emitting device comprising: a contact layer formed of a nitride semiconductor; and a p-side electrode provided in contact with a surface of the contact layer, the contact layer having a superlattice including an alternative stacked structure of first nitride semiconductor layers having a wider bandgap and second nitride semiconductor layers having a narrower bandgap, the first semiconductor layers being selectively doped with a p-type dopant.Type: GrantFiled: August 18, 2000Date of Patent: November 12, 2002Assignee: Kabushiki Kaisha ToshibaInventors: Nobuhiro Suzuki, Hideto Sugawara
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Publication number: 20020139984Abstract: A semiconductor light emitting element is proposed that improves a light extraction efficiency without requiring any complicated processes and techniques. The semiconductor light emitting element includes an active layer for emitting first light by current injection, and a light absorbing and emitting section for absorbing a part of the first light and for emitting second light having a greater peak wavelength than the first light. A difference in peak wavelength between the first light and the second light is in a range in which a spectrum of a mixture of the first and second light maintains a unimodal characteristic or is smaller than 0.9 times a half width of the spectrum of the first light.Type: ApplicationFiled: January 25, 2002Publication date: October 3, 2002Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hideto Sugawara, Koichi Nitta, Ryo Saeki, Katsufumi Kondo, Masanobu Iwamoto
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Publication number: 20020117674Abstract: The semiconductor light emitting device has the first semiconductor light emission element 13 for emitting color light in the first wave length range, the second semiconductor light emission element 14 for emitting color light in the second wave length range, the frame electrode 11 for mounting the first and second semiconductor light emission elements, and the package 19 for molding them together. The first semiconductor light emission element 13 is composed of an InGaAlP series material having an active layer 34 composed of a plurality of composite luminous layers 54, 55, 56, and 57 for emitting color light with a different wavelength. Luminescence spectra from the plurality of luminous layers are partially overlapped with each other. Each of the plurality of composite luminous layers 54, 55, 56, and 57 is further composed of a plurality of luminous layers 58 for emitting color light with substantially the same wavelength.Type: ApplicationFiled: August 28, 2001Publication date: August 29, 2002Inventor: Hideto Sugawara
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Publication number: 20020110947Abstract: When a plurality of semiconductor layers including a nitride compound layer containing indium are stacked on a substrate, materials of layers above the indium containing nitride compound layer are limited to specific compounds, or their growth temperatures are limited within a predetermined range, to suppress thermal deterioration of the nitride compound layer containing indium or deterioration of the interface and to thereby grow a high-quality semiconductor light emitting element using nitride compound semiconductors.Type: ApplicationFiled: April 18, 2002Publication date: August 15, 2002Applicant: KABUSHIKI KAISHA TOSHIBA.Inventors: Hideto Sugawara, Masayuki Ishikawa
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Publication number: 20020088985Abstract: A semiconductor light emitting element, semiconductor light emitting device or image display device includes a wavelength converter for converting a wavelength into another, optical reflector having a wavelength selectivity and a light absorber having a wavelength selectivity, which are disposed in a predetermined positional relation, to prevent external leakage of primary light and to extract secondary light made by wavelength-converting the primary light with a very high efficiency. By using a semiconductor light emitting element for ultraviolet emission, or by combining it with a fluorescent material or any other appropriate material having a wavelength converting function, various kinds of applications, such as illuminator, having a remarkably long-life light source can be made. The semiconductor light emitting element preferably has a emission wavelength near 330 nm, and preferably uses BGaN in its light emitting layer.Type: ApplicationFiled: October 23, 2001Publication date: July 11, 2002Applicant: Kabushiki Kaisha ToshibaInventors: Satoshi Komoto, Koichi Nitta, Nobuhiro Suzuki, Kuniaki Konno, Hideto Sugawara, Chisato Furukawa
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Publication number: 20020079506Abstract: A semiconductor light emitting element, semiconductor light emitting device or image display device includes a wavelength converter for converting a wavelength into another, optical reflector having a wavelength selectivity and a light absorber having a wavelength selectivity, which are disposed in a predetermined positional relation, to prevent external leakage of primary light and to extract secondary light made by wavelength-converting the primary light with a very high efficiency. By using a semiconductor light emitting element for ultraviolet emission, or by combining it with a fluorescent material or any other appropriate material having a wavelength converting function, various kinds of applications, such as illuminator, having a remarkably long-life light source can be made. The semiconductor light emitting element preferably has a emission wavelength near 330 nm, and preferably uses BGaN in its light emitting layer.Type: ApplicationFiled: October 24, 2001Publication date: June 27, 2002Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Satoshi Komoto, Koichi Nitta, Nobuhiro Suzuki, Kuniaki Konno, Hideto Sugawara, Chisto Furukawa
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Patent number: 6399963Abstract: When a plurality of semiconductor layers including a nitride compound layer containing indium are stacked on a substrate, materials of layers above the indium containing nitride compound layer are limited to specific compounds, or their growth temperatures are limited within a predetermined range, to suppress thermal deterioration of the nitride compound layer containing indium or deterioration of the interface and to thereby grow a high-quality semiconductor light emitting element using nitride compound semiconductors.Type: GrantFiled: March 6, 2001Date of Patent: June 4, 2002Assignee: Kabushiki Kaisha ToshibaInventors: Hideto Sugawara, Masayuki Ishikawa
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Publication number: 20020053681Abstract: In a light emitting element using nitride compound semiconductors, an active layer made of a mixed crystal containing In additionally contains at least Al or B as a component of the mixed crystal to improve the thermal resistance of the crystal and the reliability of the element characteristics. Thus, the semiconductor light emitting element has a sufficient lifetime and permits the emission wavelength to be freely selected from a wider wavelength range including blue, green and orange.Type: ApplicationFiled: November 2, 2001Publication date: May 9, 2002Applicant: Kabushiki Kaisha ToshibaInventors: Hideto Sugawara, Koichi Nitta
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Publication number: 20020050601Abstract: A semiconductor light-emitting device, including a first substrate of a first conductivity type, a first bonding layer provided on the first substrate and consisting essentially of a GaP material of the first conductivity type, a second bonding layer provided on the first bonding layer, coincident with the first bonding layer in the planar direction of the crystal, having the first conductivity type, and consisting essentially of a material represented by a formula InxGayP, where 0≦x, y≦1, and x+y=1, and a light-emitting layer comprising a first cladding layer, an active layer, and a second cladding layer, which are successively provided on the second bonding layer, each of the active layer and first and second cladding layers consisting essentially of a material represented by a formula InxGayAlzP, where x+y+z=1, and 0≦x, y, z≦1.Type: ApplicationFiled: October 31, 2001Publication date: May 2, 2002Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Ryo Saeki, Hideto Sugawara, Yukio Watanabe, Tamotsu Jitosho