An object is to provide a new type of near-infrared ray-emitting phosphor which exhibits excellent emission intensity. A near-infrared ray-emitting phosphor is represented by a general formula, (Y, Lu, Gd).sub.3-x-y (Ga,Al,Sc).sub.5O.sub.12:(Cr.sub.x,(Yb,Nd).sub.y) (0.05<x<0.3, 0≤y<0.3).

Disclosed is a blue to white light conversion device, comprising: a light conversion subassembly comprising at least one light conversion layer, sandwiched between two light transmitting members, wherein the light conversion layer comprises a light conversion material comprising phosphors and/or quantum dots; at least one light diffusing subassembly neighboring the light conversion subassembly; and a top frame and a bottom frame surrounding the light diffusing subassembly and light conversion subassembly, respectively.

A light emitting diode (LED) assembly includes an LED light source having a first light output with a characteristic spectrum and at least one phosphor through which the first light output passes. The phosphor includes the quaternary compound M-Li—Al—O, where M is Ba, Sr, or Ca, activated by Eu.sup.2+ or Ce.sup.3+.

A ceramic composition is provided. The ceramic composition includes a corundum phase, and a CeAl.sub.11O.sub.18 phase. A ratio of an amount of substance of the CeAl.sub.11O.sub.18 phase with respect to a total amount of substance of the ceramic composition is not lower than 0.5 mol % and not higher than 5 mol %.

A phosphor and a light source device having the phosphor having a high internal quantum yield by enabling a large Ce amount, capable of shifting the fluorescence wavelength of yellow fluorescence to the long wavelength side, having satisfactory heat quenching resistance, and excellent in blue light transmittance. The phosphor includes a Ce:YAG single crystal having a Ce amount of 0.7 parts by mole or more when the total amount of Y and Ce is 100 parts by mole.

A color wheel according to an embodiment of the present invention comprises: a basic fluorescent body having a basic light-emitting wavelength; and at least one modified fluorescent body having at least one light-emitting wavelength different from the basic light-emitting wavelength, wherein the basic fluorescent body comprises Y.sub.3Al.sub.5O.sub.12 and the modified fluorescent body comprises Y.sub.3(Ga.sub.xAl.sub.(1-x)).sub.5O.sub.12:Ce in which gallium is doped on the basic fluorescent body

A method for preparing a wavelength converting film is disclosed. The method comprising mixing at least one phosphor, a polysiloxane and optionally an organic solvent, thereby preparing a mixture, placing the mixture on a substrate, pre-curing the mixture on the substrate, thereby preparing a wavelength converting film. Furthermore, a wavelength converting film is disclosed, a method for preparing a light-emitting device and a light-emitting device.

A light emission device including a light emitting element having a light emission peak wavelength in a range of 400 nm or more and 490 nm or less; and a fluorescent member including a first fluorescent material having a light emission peak wavelength in a range of 510 nm or more and less than 580 nm, a second fluorescent material having a light emission peak wavelength in a range of 580 nm or more and 680 nm or less and a full width at half maximum of 15 nm or more and 100 nm or less, and a third fluorescent material having a light emission peak wavelength in a range of 600 nm or more and 650 nm or less and a full width at half maximum of 14 nm or less, and having a melanopic ratio (MR) value in a specified range at a certain correlated color temperature.

The present invention relates to a phosphor plate including a sintered body including (Y.sub.1-x-y, Gd.sub.x, Ce.sub.y).sub.3Al.sub.5O.sub.12 particles and Al.sub.2O.sub.3 particles, in which 0.07≤x≤0.11 and 0.010≤y≤0.015 are satisfied, the (Y.sub.1-x-y, Gd.sub.x, Ce.sub.y).sub.3Al.sub.5O.sub.12 particles in the sintered body has an average particle diameter of 4 μm or more and 6 μm or less, the (Y.sub.1-x-y, Gd.sub.x, Ce.sub.y).sub.3Al.sub.5O.sub.12 particles has a concentration of 20 vol % or more and 30 vol % or less with respect to a total amount 100 vol % of the (Y.sub.1-x-y, Gd.sub.x, Ce.sub.y).sub.3Al.sub.5O.sub.12 particles and the Al.sub.2O.sub.3 particles, a ratio of an average particle diameter of the Al.sub.2O.sub.3 particles to the average particle diameter of the (Y.sub.1-x-y, Gd.sub.x, Ce.sub.y).sub.3Al.sub.5O.sub.12 particles is 1 or more and 2 or less, and the sintered body has a total thickness of 150 μm or more and 250 μm or less.

Provided is a wavelength conversion member in which the following are dispersed in a thermoplastic resin: a LuYAG fluorescent material that is represented by (Y.sub.1-α-βLu.sub.αCe.sub.β).sub.3Al.sub.5O.sub.12 (in which α is a positive number between 0.3-0.8 inclusive and β is a positive number between 0.01-0.05 inclusive), that emits yellow-green light as a result of excitation by blue light, and that has a diffraction peak within a range in which the diffraction angle 2θ in X-ray diffraction by the K.sub.α1 line of Cu is 52.9° to 53.2° inclusive; and a KSF fluorescent material that is represented by K.sub.2(Si.sub.1-xMn.sub.x)F.sub.6 (in which x is a positive number between 0.001 and 0.3 inclusive) and that emits red light as a result of excitation by blue light. The content of the KSF fluorescent material in the wavelength conversion member is 1 to 5 times the content of the LuYAG fluorescent material by mass ratio. The wavelength conversion member makes it possible to provide a light-emitting device that has small color deviation, that is suitable as a lighting device, that emits white light, and that has good color rendering properties in a color temperature range of 4,000-6,500K, i.e., the color temperature range from white to daylight color.