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).

Provided is a method for producing a fluoride phosphor. The method includes: providing a first solution containing an element M.sup.1 containing at least one selected from the group consisting of group 13 elements, manganese, and fluorine, a second solution containing an element M.sup.2 containing at least one selected from the group consisting of group 4 elements and group 14 elements, and a third solution containing at least one selected from the group consisting of alkali metal elements; and adding the second solution and the third solution to the first solution at substantially the same time.

Phosphors include a CaAlSiN.sub.3 family crystal phase, wherein the CaAlSiN.sub.3 family crystal phase comprises at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb.

A fluoride phosphor, comprising fluoride particles having an average particle size of 0.1 μm to 7 μm and a maximum particle size of 1 μm to 18 μm, wherein a ratio of the maximum particle size with respect to the average particle size is higher than 1. The fluoride particles have a composition containing an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements; an alkali metal; Mn; and F. In the composition, when the number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 but less than 0.2, the number of moles of the element M is more than 0.8 but less than 1, and the number of moles of F is more than 5 but less than 7.

A white light emitting device comprises: an LED that generates excitation light of wavelength from 420 nm to 480 nm; and photoluminescence materials that generate light with a peak emission wavelength from 500 nm to 650 nm comprising a broadband phosphor, and a manganese-activated narrowband red fluoride phosphor with a peak emission wavelength from 628 nm to 640 nm and a full width at half maximum of less than 30 nm. The device generates white light with a selected color temperature from 2200K to 6500K, a General Color Rendering Index, CRI Ra, of at least 80, and a Duv (Delta u, v) from 0.0060 to 0.0170 for the selected color temperature and wherein the device has an LER (Luminous Efficacy of Radiation) of at least 320 lm/W.sub.opt.

Systems and methods to provide multiple channels of light to form a blended white light output, the systems and methods utilizing recipient luminophoric mediums to alter light provided by light emitting diodes. The predetermined blends of luminescent materials within the luminophoric mediums provide predetermined spectral power distributions in the white light output.

An image detector for a radiation-based imaging technique is disclosed. The image detector may comprise a detector material on a substrate. The detector material may be an optically active material represented by the following formula (I) (M′).sub.8 (M″M′″).sub.6O.sub.24(X,X′).sub.2:M″″ Further is disclosed the use of the image detector and the use of the optically active material represented by the formula (I).

A phosphor plate includes a plate-like composite including a base material and a phosphor contained in the base material, in which the base material contains spinel, the phosphor includes a phosphor containing a Si element, and in an X-ray diffraction pattern of the phosphor plate using a Cu-Kα ray, in a case in which peak intensity corresponding to the spinel having a diffraction angle 2θ in a range of 36.0° or more and 37.4° or less is set to 1, total intensity of peaks having a diffraction angle 2θ in a range of 32.5° or more and 34.5° or less satisfies 0.5 or less.

Provided is a method for producing a phosphor, using a nitride raw material, that gives a high-reliability (Sr,Ca)AlSiN.sub.3-based nitride phosphor at a productivity higher than before. The method comprises a mixing step of mixing raw materials and a calcining step of calcining the mixture obtained in the mixing step and, in producing the phosphor having a crystalline structure substantially identical with that of (Sr,Ca)AlSiN.sub.3 crystal as the host crystal, a strontium nitride containing SrN, Sr.sub.2N, or the mixture thereof as the main crystalline phase, as determined by crystalline phase analysis by powder X-ray diffractometry, and having a nitrogen content of 5 to 12 mass % is used as part of the raw materials.

A method of producing a light transmissive element includes providing a holding member including an upper surface and a plurality of holes, each of the plurality of holes having at least one inner lateral surface that is a substantially smooth surface and an opening in the upper surface of the holding member; filling the plurality of holes with a wavelength conversion member containing fluorescent particles and a light transmissive member such that the wavelength conversion member is in contact with the inner lateral surface of each of the plurality of holes; molding the wavelength conversion member; and taking out the wavelength conversion member from the holding member after the molding of the wavelength conversion member.