Abstract: A wavelength conversion member comprises: a substrate; and a wavelength conversion layer. The wavelength conversion layer contains a first phosphor and a second phosphor. The second phosphor has a higher thermal conductivity than the first phosphor. In the wavelength conversion layer, a volume of the second phosphor is larger than a volume of the first phosphor. The wavelength conversion layer includes a first portion and a second portion. The first portion is located closer to the substrate than the second portion, and is in direct contact with the second portion. Thicknesses of the first portion and the second portion are equal to each other. A volume V11 of the first phosphor in the first portion, a volume V12 of the second phosphor in the first portion, a volume V21 of the first phosphor in the second portion, and a volume V22 of the second phosphor in the second portion satisfy V11/V12<V21/V22.

Abstract: A light source includes a semiconductor light emitting device; and a wavelength converter. The wavelength converter includes: a substrate; a phosphor layer disposed on the substrate; and a light reflective layer disposed on the substrate so as to surround the phosphor layer. The phosphor layer includes phosphor particles and a first matrix material in which the phosphor particles are dispersed. The light reflective layer includes inorganic compound particles and a second matrix material in which the inorganic compound particles are dispersed. The inorganic compound particles have a refractive index higher than that of the first matrix material. The first matrix material has a refractive index higher than that of the phosphor particles. The phosphor particles have a refractive index higher than that of the second matrix material.

Abstract: A light source device includes: a semiconductor light-emitting element; a converging optical system which converges the excitation light emitted from the semiconductor light-emitting element; and a wavelength conversion element to which the excitation light is emitted. The wavelength conversion element includes: a first wavelength conversion region where main light enters; and a second wavelength conversion region which is disposed in the surrounding region of the first wavelength conversion region and where the excitation light excluding the main light enters. The wavelength conversion efficiency in the second wavelength conversion region is lower than the wavelength conversion efficiency in the first wavelength conversion region.

Abstract: A wavelength conversion member, comprises: a substrate; a first wavelength conversion layer on the substrate, the first wavelength conversion layer containing a first phosphor and a first matrix; and a second wavelength conversion layer containing a second phosphor, first inorganic particles, and a second matrix. The first phosphor and the second phosphor convert at least part of the excitation light incident on the second main surface into first light having longer wavelengths than the excitation light. The first light is emitted from the second main surface of the second wavelength conversion layer. A volume Vp1 of the first phosphor, a volume Vw1 of the first wavelength conversion layer, a volume Vp2 of the second phosphor, and a volume Vw2 of the second wavelength conversion layer satisfy Vp1/Vw1>Vp2/Vw2.

Abstract: A wavelength converter comprises: phosphor particles; and a matrix that is located between the phosphor particles and comprises zinc oxide crystallites. Pores are included in at least one of the zinc oxide crystallites.

Abstract: A wavelength conversion element includes a support member having a supporting surface, and a wavelength converter disposed above the supporting surface. The wavelength converter contains first fluorescent particles which absorb excitation light and generate fluorescence (second radiation light), and a transparent binder which bonds the first fluorescent particles, and has a joint surface facing supporting surface, and an incident surface disposed opposite to the joint surface, the excitation light entering the incident surface. The excitation light and fluorescence are emitted from the incident surface. The wavelength converter includes projections. At least part of the projections is disposed on the incident surface. The first fluorescent particles are partially exposed from vertices of the projections.

Abstract: The present disclosure aims to enhance controllability of a lighting apparatus and increase durability. A lighting apparatus includes a light source; a condenser that converges first light emitted from the light source onto a predetermined focal position of a wavelength conversion element as converged light; the wavelength conversion element that receives the converged light and emits second light at an emission point; and a projection lens that projects the second light as projection light. The lighting apparatus changes the focal position of the condenser lens to change the emission point of the second light to the projection lens, thereby being capable of projecting the second light in any direction.

Abstract: A projection apparatus of the present disclosure includes a light-emitting element for emitting excitation light, a wavelength converter for receiving the excitation light, converting the excitation light into light of a different wavelength, and emitting the converted light as radiation light, and an optical filter for receiving the radiation light. The optical filter reflects long-wavelength light of wavelengths longer than wavelengths of the radiation light. With this configuration, the optical filter reflects long-wavelength light of wavelengths longer than wavelengths of the radiation light, thus being able to prevent the wavelength converter from being irradiated with long-wavelength light, and being able to prevent deterioration of the wavelength converter.

Abstract: A phosphor includes, as a main component, a compound represented by a general formula (3-a)YO3/2.aCeO3/2.(5-b)AlO3/2.bGaO3/2.cKO1/2.dPO5/2, where a, b, c and d satisfy 0.12?a?0.18, 1.50?b?3.00, 0.01?c?0.08, and 0.01?d?0.08.

Abstract: A lamp includes: first and second semiconductor light-emitting elements adapted to emit excitation light; a wavelength conversion element adapted to convert the excitation light into light having a peak wavelength different from that of the excitation light; and a concave mirror adapted to reflect the excitation light emitted from the semiconductor light-emitting elements to the wavelength conversion element and reflect the light from the wavelength conversion element toward an outside of the lamp. A distance y1 from an optical axis of the first semiconductor light-emitting element to an optical axis of the concave mirror satisfies (D+Dphos)/2?y1?4f, and a distance y2 from an optical axis of the second semiconductor light-emitting element to the optical axis of the concave mirror satisfies 4f<y2?R.

Abstract: A wavelength conversion member comprises: a substrate; and a wavelength conversion layer. The wavelength conversion layer contains a first phosphor and a second phosphor. The second phosphor has a higher thermal conductivity than the first phosphor. In the wavelength conversion layer, a volume of the second phosphor is larger than a volume of the first phosphor. The wavelength conversion layer includes a first portion and a second portion. The first portion is located closer to the substrate than the second portion, and is in direct contact with the second portion. Thicknesses of the first portion and the second portion are equal to each other. A volume V11 of the first phosphor in the first portion, a volume V12 of the second phosphor in the first portion, a volume V21 of the first phosphor in the second portion, and a volume V22 of the second phosphor in the second portion satisfy V11/V12<V21/V22.

Abstract: A wavelength conversion member, comprises: a substrate; a first wavelength conversion layer on the substrate, the first wavelength conversion layer containing a first phosphor and a first matrix; and a second wavelength conversion layer containing a second phosphor, first inorganic particles, and a second matrix. The first phosphor and the second phosphor convert at least part of the excitation light incident on the second main surface into first light having longer wavelengths than the excitation light. The first light is emitted from the second main surface of the second wavelength conversion layer. A volume Vp1 of the first phosphor, a volume Vw1 of the first wavelength conversion layer, a volume Vp2 of the second phosphor, and a volume Vw2 of the second wavelength conversion layer satisfy Vp1/Vw1>Vp2/Vw2.

Abstract: A wavelength conversion member includes a substrate, a dichroic mirror layer, an SiO2 layer, a ZnO layer, and a phosphor layer, which are sequentially stacked from the substrate. The dichroic mirror layer reflects at least part of light incident from the above. The phosphor layer includes a plurality of phosphors and ZnO between the phosphors.

Abstract: An illumination apparatus of the disclosure includes a semiconductor light-emitting element and a light conversion element. The semiconductor light-emitting element has a first optical waveguide and a second optical waveguide. The light conversion element has a first light converter and a second light converter. A first emitted light emitted from first optical waveguide enters the first light converter and a second emitted light emitted from the second optical waveguide enters the second light converter. First power applied to the first optical waveguide and second power applied to the second optical waveguide are independent.

Abstract: A light source includes a semiconductor light emitting device; and a wavelength converter. The wavelength converter includes: a substrate; a phosphor layer disposed on the substrate; and a light reflective layer disposed on the substrate so as to surround the phosphor layer. The phosphor layer includes phosphor particles and a first matrix material in which the phosphor particles are dispersed. The light reflective layer includes inorganic compound particles and a second matrix material in which the inorganic compound particles are dispersed. The inorganic compound particles have a refractive index higher than that of the first matrix material. The first matrix material has a refractive index higher than that of the phosphor particles. The phosphor particles have a refractive index higher than that of the second matrix material.

Abstract: A wavelength converter comprises: phosphor particles; and a matrix that is located between the phosphor particles and comprises zinc oxide crystallites. Pores are included in at least one of the zinc oxide crystallites.

Abstract: A hydrogen gas inspection method includes: converting first light having a first wavelength to second light having a second wavelength longer than the first wavelength by using a phosphor, the first light being emitted from a semiconductor light emitting device; irradiating a space to be inspected with the second light; and determining whether hydrogen gas is present in the space utilizing Raman scattered light generated by the hydrogen gas irradiated with the second light.

Abstract: A wavelength conversion member includes: a heat conducting layer; a sapphire substrate having a third surface directly contact with a second surface of the heat conducting layer and the fourth surface opposite to the third surface; and a phosphor layer having a fifth surface directly contact with the fourth surface and a sixth surface opposite to the fifth surface, the phosphor layer including phosphor. At least one of an area of a first surface and an area of the second surface of the heat conducting layer is at least 2800 times as large as an area of the sixth surface of the phosphor layer. At least one of an area of the third surface and an area of the fourth surface of the sapphire substrate is at least two times as large as the area of the sixth surface of the phosphor layer.

Abstract: The present invention provides an oxynitride silicate fluorescent substance capable of output a light having a high luminance even when irradiated by an exciting light having a high energy density. The present invention is a yellow fluorescent substance represented by a chemical formula (Ba1-x-y-z,Srx)aSibOcNd:Eu2+y,Y3+z (0.9?a?1.1, 1.9?b?2.1, 1.9?c?2.1, 1.9?d?2.1, 0?x?1, 0<y<0.01, and 0?z<0.01).

Abstract: The present disclosure aims to enhance controllability of a lighting apparatus and increase durability. A lighting apparatus includes a light source; a condenser that converges first light emitted from the light source onto a predetermined focal position of a wavelength conversion element as converged light; the wavelength conversion element that receives the converged light and emits second light at an emission point; and a projection lens that projects the second light as projection light. The lighting apparatus changes the focal position of the condenser lens to change the emission point of the second light to the projection lens, thereby being capable of projecting the second light in any direction.