To provide an oxide fluorescent material that has a light emission peak wavelength in a wavelength range of from red light to near infrared light. The oxide fluorescent material has a composition encompassed in a compositional formula represented by the following formula (1):

(Li.sub.1-tM.sup.1.sub.t).sub.u(Ga.sub.1-vM.sup.2.sub.v).sub.5O.sub.w:Cr.sub.x,Ni.sub.y,M.sup.3.sub.z,  (1)

wherein in the formula (1), M.sup.1 represents at least one kind of an element selected from the group consisting of Na, K, Rb, and Cs; M.sup.2 represents at least one kind of an element selected from the group consisting of B, Al, Sc, In, and a rare earth element; M.sup.3 represents at least one kind of an element selected from the group consisting of Si, Ge, Sn, Ti, Zr, Hf, Bi, V, Nb, and Ta; and t, u, v, w, x, y, and z each satisfy 0≤t≤1.0, 0.7≤u≤1.6, 0≤v<1.0, 7.85≤w≤11.5, 0.05≤x≤1.2, 0≤y≤0.5, 0.25<x+y≤1.2, y<x, and 0≤z≤0.5.

A metallic structure for an optical semiconductor device, including a base body having disposed thereon at least in part metallic layers in the following order; a nickel or nickel alloy plated layer, a gold or gold alloy plated layer, and a silver or silver alloy plated layer, wherein the silver or silver alloy plated layer has a thickness in a range of 0.001 μm or more and 0.01 μm or less.

A light emitting assembly comprising at least one of each of a solid state device and a thermal radiation source, couplable with a power supply constructed and arranged to power the solid state device and the thermal radiation source, to emit from the solid state device a first, relatively shorter wavelength radiation, and to emit from the thermal radiation source non-visible infrared radiation, and a down-converting luminophoric medium arranged in receiving relationship to said first, relatively shorter wavelength radiation, and the infrared radiation, and which in exposure to said first, relatively shorter wavelength radiation, and infrared radiation, is excited to responsively emit second, relatively longer wavelength radiation. In a specific embodiment, monochromatic blue or UV light output from a light-emitting diode is down-converted to white light by packaging the diode and the thermal radiation device with fluorescent or phosphorescent organic and/or inorganic fluorescers and phosphors in an enclosure.

A phosphor element includes: a phosphor part having an incident face for excitation light, an opposing face opposing the incident face, and a side face, the phosphor part converting at least a part of the excitation light incident onto the incident face into a fluorescence and emitting the fluorescence from the incident face; an integral low refractive index layer on the side face and opposing face of the phosphor part and having a refractive index lower than that of the phosphor part; and an integral reflection film covering a surface of the low refractive index layer. The area of the incident face of the phosphor part is larger than the area of the opposing face.

The invention provides a lighting device comprising a plurality of solid state light sources and an elongated ceramic body having a first face and a second face defining a length (L) of the elongated ceramic body, the elongated ceramic body comprising one or more radiation input faces and a radiation exit window, wherein the second face comprises the radiation exit window, wherein the plurality of solid state light sources are configured to provide blue light source light to the one or more radiation input faces and are configured to provide to at least one of the radiation input faces a photon flux of at least 1.0*10.sup.17 photons/(s.Math.mm.sup.2), wherein the elongated ceramic body comprises a ceramic material configured to wavelength convert at least part of the blue light source light into at least converter light, wherein the ceramic material comprises an A.sub.3B.sub.5O.sub.12:Ce.sup.3+ ceramic material, wherein A comprises one or more of yttrium (Y), gadolinium (Gd) and lutetium (Lu), and wherein B comprises aluminum (Al).

A wavelength conversion device includes a matrix containing inorganic material, a phosphor embedded in the matrix, and filler particles embedded in the matrix and containing resin material. This wavelength conversion device prevents the phosphor from falling.

A light emitting diode package includes: a housing; a light emitting diode chip arranged in the housing; a wavelength conversion unit arranged on the light emitting diode chip; a first fluorescent substance distributed inside the wavelength conversion unit and emitting light having a peak wavelength in the cyan wavelength band; and a second fluorescent substance distributed inside the wavelength conversion unit and emitting light having a peak wavelength in the red wavelength band, wherein the peak wavelength of light emitted from the light emitting diode chip is located within a range of 415 nm to 430 nm.

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.

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.

Embodiments include luminescent phosphor compounds that include one or more emitting ions and one or more disturbing ions, and methods for their production. An emitting ion in the compound may be characterized by a first decay time constant when the emitting ion is undisturbed. However, a corresponding disturbing ion in the compound, which is different from the emitting ion, causes the emitting ion to have a pre-defined, target disturbed decay time constant that is greater than zero and less than the first decay time constant. An embodiment of an authentication system is configured to measure the decay time constant of a phosphor compound applied to an article, and to determine whether the decay time constant corresponds to a phosphor compound that includes a particular disturbing ion (e.g., in order to determine whether or not the article is authentic).