Abstract: A light-emitting device includes an optical member including first and second light emitting elements, first and second light condenser portions, and a light guide portion. The first light condenser portion is disposed at a position corresponding to the first light-emitting element, and condenses a portion of light emitted from the first light-emitting element. The second light condenser portion surrounds the first light condenser portion, and condenses a portion of the light that is not incident to the first light condenser portion among the light emitted from the first light-emitting element. The light guide portion is disposed at a periphery of the second light condenser portion and at a position corresponding to the second light-emitting element, and guides light emitted from the second light-emitting element by causing total reflection in an interior of the light guide portion.

Abstract: An object of the present invention is to provide a GaN crystal long in light emission lifetime by time-resolved photoluminescence measurement and provide high-quality GaN crystal and GaN substrate that have few specified crystal defects affecting the light emission lifetime. A gallium nitride crystal having a light emission lifetime by time-resolved photoluminescence measurement, of 5 ps or more and 200 ps or less, and satisfying at least one of the following requirement (i) and requirement (ii): (i) an FWHM in a 004 diffraction X-ray rocking curve is 50 arcsec or less at least one position of the crystal; and (ii) a dislocation density is 5×106 cm?2 or less.

Abstract: Provided is a method of producing a silicon compound material, including the steps of: storing a silicon carbide preform in a reaction furnace; supplying a raw material gas containing methyltrichlorosilane to the reaction furnace to infiltrate the preform with silicon carbide; and controlling and reducing a temperature of a gas discharged from the reaction furnace at a predetermined rate to subject the gas to continuous thermal history, to thereby decrease generation of a liquid or solid by-product derived from the gas.

Abstract: A light-emitting device includes an optical member including first and second light emitting elements, first and second light condenser portions, and a light guide portion. The first light condenser portion is disposed at a position corresponding to the first light-emitting element, and condenses a portion of light emitted from the first light-emitting element. The second light condenser portion surrounds the first light condenser portion, and condenses a portion of the light that is not incident to the first light condenser portion among the light emitted from the first light-emitting element. The light guide portion is disposed at a periphery of the second light condenser portion and at a position corresponding to the second light-emitting element, and guides light emitted from the second light-emitting element by causing total reflection in an interior of the light guide portion.

Abstract: A light-emitting device includes an optical member including first and second light emitting elements, first and second light condenser portions, and a light guide portion. The first light condenser portion is disposed at a position corresponding to the first light-emitting element, and condenses a portion of light emitted from the first light-emitting element. The second light condenser portion surrounds the first light condenser portion, and condenses a portion of the light that is not incident to the first light condenser portion among the light emitted from the first light-emitting element. The light guide portion is disposed at a periphery of the second light condenser portion and at a position corresponding to the second light-emitting element, and guides light emitted from the second light-emitting element by causing total reflection in an interior of the light guide portion.

Abstract: A light-emitting device includes a concentrator, a first tubular body surrounding the concentrator, one or more first light-emitting elements disposed at a position corresponding to the concentrator, and a plurality of second light-emitting elements. The first tubular body is transparent. The first tubular body has a plurality of recesses formed in an end portion of the first tubular body. Portions of the first tubular body between the recesses form light guide portions. The plurality of second light-emitting elements are disposed at positions corresponding to a plurality of the light guide portions.

Abstract: A light-emitting device includes a concentrator, a first tubular body surrounding the concentrator, one or more first light-emitting elements disposed at a position corresponding to the concentrator, and a plurality of second light-emitting elements. The first tubular body is transparent. The first tubular body has a plurality of recesses formed in an end portion of the first tubular body. Portions of the first tubular body between the recesses form light guide portions. The plurality of second light-emitting elements are disposed at positions corresponding to a plurality of the light guide portions.

Abstract: A light-emitting device includes an optical member including first and second light emitting elements, first and second light condenser portions, and a light guide portion. The first light condenser portion is disposed at a position corresponding to the first light-emitting element, and condenses a portion of light emitted from the first light-emitting element. The second light condenser portion surrounds the first light condenser portion, and condenses a portion of the light that is not incident to the first light condenser portion among the light emitted from the first light-emitting element. The light guide portion is disposed at a periphery of the second light condenser portion and at a position corresponding to the second light-emitting element, and guides light emitted from the second light-emitting element by causing total reflection in an interior of the light guide portion.

Abstract: Provided is a method of producing a silicon compound material, including the steps of: storing a silicon carbide preform in a reaction furnace; supplying a raw material gas containing methyltrichlorosilane to the reaction furnace to infiltrate the preform with silicon carbide; and controlling and reducing a temperature of a gas discharged from the reaction furnace at a predetermined rate to subject the gas to continuous thermal history, to thereby decrease generation of a liquid or solid by-product derived from the gas.

Abstract: A mixed gas containing a precursor gas, an additive gas and a carrier gas is supplied to a preform stored in an electric furnace, and silicon carbide is deposited by chemical vapor deposition or chemical vapor phase impregnation to form a film. The preform includes multiple fiber bundles, and the fiber bundles include multiple fibers. This heat-resistant composite material includes a ceramic fiber preform impregnated with silicon carbide, and producing the composite material involves a step in which silicon carbide is deposited between the fibers to integrate the fibers which configure the fiber bundles, and a step in which silicon carbide is deposited between the fiber bundles to integrate the fiber bundles. Hereby, uniformity of embedding and growth rate of the silicon carbide film are both attained.

Abstract: In the present embodiment, in the production of a heat-resistant composite material resulting from impregnating a ceramic fiber preform with silicon carbide, a mixed gas containing starting material gas, an additive gas, and a carrier gas is supplied to a substrate having a minute structure such as a preform stored in an electric furnace, silicon carbide is deposited to form a film by means of a chemical vapor deposition method or a chemical vapor infiltration method, and the film formation growth speed and embedding uniformity are controlled by means of the amount of additive gas added to the starting material gas, the starting material gas contains tetramethylsilane, and the additive gas contains a molecule containing chlorine such as methyl chloride or hydrogen chloride. The film formation growth speed and embedding uniformity of the silicon carbide are both achieved.

Abstract: In the present embodiment, in the production of a heat-resistant composite material resulting from impregnating a ceramic fiber preform with silicon carbide, a mixed gas containing starting material gas, an additive gas, and a carrier gas is supplied to a substrate having a minute structure such as a preform stored in an electric furnace, silicon carbide is deposited to form a film by means of a chemical vapor deposition method or a chemical vapor infiltration method, and the film formation growth speed and embedding uniformity are controlled by means of the amount of additive gas added to the starting material gas, the starting material gas contains tetramethylsilane, and the additive gas contains a molecule containing chlorine such as methyl chloride or hydrogen chloride. The film formation growth speed and embedding uniformity of the silicon carbide are both achieved.

Abstract: A mixed gas containing a precursor gas, an additive gas and a carrier gas is supplied to a preform stored in an electric furnace, and silicon carbide is deposited by chemical vapor deposition or chemical vapor phase impregnation to form a film. The preform includes multiple fiber bundles, and the fiber bundles include multiple fibers. This heat-resistant composite material includes a ceramic fiber preform impregnated with silicon carbide, and producing the composite material involves a step in which silicon carbide is deposited between the fibers to integrate the fibers which configure the fiber bundles, and a step in which silicon carbide is deposited between the fiber bundles to integrate the fiber bundles. Hereby, uniformity of embedding and growth rate of the silicon carbide film are both attained.