A phosphor powder contains an EU-activated β-type sialon phosphor particles. When a median diameter in the phosphor powder having not been subjected to an ultrasonic homogenizer treatment is set as D1 and a median diameter in the phosphor powder having been subjected to an ultrasonic homogenizer treatment is set as D2, 1.05≤D1/D2≤1.70. A dispersion liquid in which 30 mg of the phosphor powder is uniformly dispersed in 100 ml of a 0.2% concentration of a sodium hexametaphosphate aqueous solution is added to a columnar container of which a bottom surface has an inner diameter of 5.5 cm. Then, the dispersion liquid is irradiated with ultrasonic waves for 3 minutes at a frequency of 19.5 kHz, and an output of 150 W, in a state where a cylindrical tip, which has an outer diameter of 20 mm, of an ultrasonic homogenizer is immersed in the dispersion liquid in ≥1.0 cm.

A phosphor may have the empirical formula: (AB).sub.1+x+2yAl.sub.11−x−y(AC).sub.xLi.sub.yO.sub.17:E, where 0<x+y<11; x>0; AC=B, Ga, In, or combinations thereof; AB=Na, K, Rb, Cs, or combinations thereof; and E=Eu, Ce, Yb, Mn, or combinations thereof. The phosphor may be used in conversion LED components.

The present disclosure provides methods for generating tunable white light with controllable circadian energy performance. The methods use a plurality of LED strings to generate light with color points that fall within blue, yellow/green, red, and cyan color ranges, with each LED string being driven with a separately controllable drive current in order to tune the generated light output. Different light emitting modes can be selected that utilize different combinations of the plurality of LED strings in order to tune the generated white light. One or more of the LED strings can have ultraviolet or violet LEDs.

A premixed photoluminescent composition and related hardened form and method of forming joints for pavers or stones. The premixed photoluminescent composition comprises solid aggregates; a photoluminescent particulate component adapted to emit light when photoexcited; and a binder. When in contact with an activator, oxygen or water, the binder is adapted to harden into a water-resistant binder matrix that bonds the solid aggregates and embeds the photoluminescent particulate component. In use, the water-resistant binder matrix has a transparency allowing transmission of at least a portion of the light emitted by the photoluminescent particulate component.

A phosphor powder composed of α-sialon phosphor particles containing Eu. The phosphor powder has an ammonium ion concentration C.sub.A of the phosphor powder of equal to or more than 15 ppm and equal to or less than 100 ppm, which is determined from the following extracted ion analysis. (Extracted Ion Analysis A) 0.5 g of a phosphor powder is added to 25 ml of distilled water in a polytetrafluoroethylene (PTFE)-made container with a lid and held at 60° C. for 24 hours, and then a total mass M.sub.A of ammonium ions included in an aqueous solution obtained by removing a solid content from the solution by filtration is determined using ion chromatography. Then, C.sub.A is determined by dividing M.sub.A by the mass of the phosphor powder.

A luminophore may have the general empirical formula X.sub.3A.sub.7Z.sub.3O.sub.11:E, where: X=Mg, Ca, Sr, Ba, and/or Zn; A=Li, Na, K, Rb, Cs, Cu, and/or Ag; Z=Al, Ga, and/or B; and E=Eu, Ce, Yb, and/or Mn.

A light emitting device includes a first light source containing a first light emitting element, and a second light source containing a second light emitting element and a second fluorescent material, the first light source emits light in a region that is demarcated in a chromaticity diagram of the CIE 1931 color coordinate system by a first straight line connecting a first point having x,y of 0.280,0.070 in the chromaticity coordinate and a second point having x,y of 0.280,0.500 in the chromaticity coordinate, a second straight line connecting the second point and a third point having x,y of 0.013,0.500 in the chromaticity coordinate, a purple boundary extending from the first point toward a direction in which x decreases in the chromaticity coordinate, and a spectrum locus extending from the third point toward a direction in which y decreases in the chromaticity coordinate, in a light emission spectrum, a light emission intensity ratio I.sub.PM/I.sub.PL of a light emission intensity I.sub.PM at a wavelength of 490 nm with respect to a light emission intensity I.sub.PL at a maximum light emission peak wavelength of the first light emitting element is in a range of 0.22 or more and 0.95 or less, the second light source emits light having a color deviation duv from a blackbody radiation locus in a range of −0.02 or more and 0.02 or less measured according to JIS Z8725 with a correlated color temperature in a range of 1,500 K or more and 8,000 K or less in a chromaticity diagram of the CIE 1931 color coordinate system, and the light emitting device emits mixed color light of light emitted from the first light source and light emitted from the second light source.

A premixed photoluminescent composition and related hardened form and method of forming joints for pavers or stones. The premixed photoluminescent composition comprises solid aggregates; a photoluminescent particulate component adapted to emit light when photoexcited; and a binder. When in contact with an activator, oxygen or water, the binder is adapted to harden into a water-resistant binder matrix that bonds the solid aggregates and embeds the photoluminescent particulate component. In use, the water-resistant binder matrix has a transparency allowing transmission of at least a portion of the light emitted by the photoluminescent particulate component.

The present invention discloses a red light and near-infrared light-emitting material and a light-emitting device. The red light and near-infrared light-emitting material contains a compound represented by a molecular formula, xA.sub.2O.sub.3.Math.yIn.sub.2O.sub.3.Math.bR.sub.2O.sub.3, wherein the element A is Sc and/or Ga; the element R is one or two of Cr, Yb, Nd or Er and necessarily includes Cr; and 0.001≤x≤1, 0.001≤y≤1, 0.001≤b≤0.2, and 0.001≤b/(x+y)≤0.2. The light-emitting material can be excited by a technically mature blue light source to emit light with a high-intensity wide-spectrum or multiple spectra. Compared with existing materials, the light-emitting material has higher luminescent intensity. The light-emitting device uses an LED chip to combine an infrared light-emitting material and a visible light light-emitting material. In this way, the same LED chip can emit near-infrared light and visible light at the same time, which greatly simplifies the packaging process and reduces the packaging cost.

The present invention discloses a red light and near-infrared light-emitting material and a light-emitting device. The red light and near-infrared light-emitting material contains a compound represented by a molecular formula, xA.sub.2O.sub.3.yIn.sub.2O.sub.3.bR.sub.2O.sub.3, wherein the element A is Sc and/or Ga; the element R is one or two of Cr, Yb, Nd or Er and necessarily includes Cr; and 0.001≤x≤1, 0.001≤y≤1, 0.001≤b≤0.2, and 0.001≤b/(x+y)≤0.2. The light-emitting material can be excited by a technically mature blue light source to emit light with a high-intensity wide-spectrum or multiple spectra. Compared with existing materials, the light-emitting material has higher luminescent intensity. The light-emitting device uses an LED chip to combine an infrared light-emitting material and a visible light light-emitting material. In this way, the same LED chip can emit near-infrared light and visible light at the same time, which greatly simplifies the packaging process and reduces the packaging cost.