The present invention relates to a method of identifying and/or distinguishing materials by means of luminescence, wherein at least one luminescent substance is incorporated into the material and/or applied onto the material and the luminescence behaviour of the substance is analysed after excitation by means of radiation, and the use thereof for identifying and/or sorting and/or recycling and/or authenticating and/or performing a quality check and/or formulation check on materials.

A transparent complex oxide sintered body is manufactured by sintering a compact in an inert atmosphere or vacuum, and HIP treating the sintered compact, provided that the compact is molded from a source powder based on a rare earth oxide: (Tb.sub.xY.sub.1-x).sub.2O.sub.3 wherein 0.4x0.6, and the compact, when heated in air from room temperature at a heating rate of 15 C./min, exhibits a weight gain of at least y% due to oxidative reaction, y being determined by the formula: y=2x+0.3. The sintered body has a long luminescent lifetime as a result of controlling the valence of Tb ion.

Persistent infrared (IR) phosphors are disclosed. In an embodiment a phosphor has the general formula: M1.sub.(mk)Ga.sub.(2nxyz)M2.sub.pO.sub.(rm+3n+2p):xSb.sup.3+,yM3,zD,kM4, wherein M1 is chosen from magnesium, calcium, barium, strontium, zinc, scandium, yttrium, lanthanum, gadolinium, lutetium, or bismuth, or combinations thereof; M2 is chosen from silicon, germanium, tin, titanium, zirconium, or combinations thereof; M3 is chosen from magnesium, aluminum, indium, scandium, or combinations thereof; M4 is chosen from praseodymium, neodymium, samarium, europium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or combinations thereof; D is chosen from chromium, iron, nickel, manganese, or cobalt, or combinations thereof; and wherein 1m4; 1n3; 0p5; 0.0002x2n; 0y2n; 0.0001z0.1; 0k0.1; and r is selected from 1, 1.5, 2, 2.5, and 3.

A fast-decaying, dense phosphor having relatively high light emission is described. Through a combination of material selection, growth and deposition technique, phosphor thin films are made that preserve the necessary light output when used in thin-films, unlike common fast phosphors, such as P-46, P-47, and also have an afterglow that decays much faster than common bright phosphors, such as P-43. Use of the phosphor is described in applications where acquiring many frames/images very quickly is required.

A process for detecting oil or lubricant contamination in a manufactured product, the process comprising adding a fluorescent taggant to oils or lubricants contained in processing machinery for said product, conveying said product past an infrared detection apparatus, irradiating said product with infrared radiation from said detection apparatus as it passes the detection apparatus, and detecting infrared radiation emitted from said irradiated product.

Embodiments include articles, authentication methods and apparatus, and article manufacturing methods. An article includes a substrate with a first luminescent taggant, and an extrinsic feature with a second luminescent taggant, which is positioned proximate a portion of the article surface. The first and second taggants produce emissions in overlapping emission bands as a result of exposure to excitation energy. Above the extrinsic feature, the substrate and extrinsic feature emissions combine in the overlapping emission band to produce confounded emissions that are distinguishable from the substrate emissions taken alone. An authentication system determines whether, in a region corresponding to a substrate-only region of an authentic article, emissions having first emission characteristics are detected in the overlapping emission band. The system also determines whether, in a region corresponding to an extrinsic feature region of an authentic article, the confounded emissions are detected in the overlapping emission band.

Disclosed herein is a method including manufacturing a powder having a composition of formula (1),

M.sup.1.sub.aM.sup.2.sub.bM.sup.3.sub.cM.sup.4.sub.dO.sub.12(1) where O represents oxygen, M.sup.1, M.sup.2, M.sup.3, and M.sup.4 represents a first, second, third, and fourth metal that are different from each other, where the sum of a+b+c+d is about 8, where a has a value of about 2 to about 3.5, b has a value of 0 to about 5, c has a value of 0 to about 5 d has a value of 0 to about 1, where b and c, b and d, or c and d cannot both be equal to zero simultaneously, where M.sup.1 is a rare earth element comprising gadolinium, yttrium, lutetium, scandium, or a combination of thereof, M.sup.2 is aluminum or boron, M.sup.3 is gallium, and M.sup.4 is a dopant; and heating the powder to a temperature of 500 to 1700 C. in an oxygen containing atmosphere to manufacture a crystalline scintillator.

A fast-decaying, dense phosphor having relatively high light emission is described. Through a combination of material selection, growth and deposition technique, phosphor thin films are made that preserve the necessary light output when used in thin-films, unlike common fast phosphors, such as P-46, P-47, and also have an afterglow that decays much faster than common bright phosphors, such as P-43. Use of the phosphor is described in applications where acquiring many frames/images very quickly is required.

An inspection station for detecting oil or lubricant contamination in a manufactured product, the inspection station having (a) a conveyor for advancing manufactured product, and (b) an infrared detection apparatus, including (i) a high intensity infrared light source for directing at the manufactured product, and (ii) a high speed NIR spectrometer sensor tuned to detect an emitted signal from a taggant disposed in the oil or lubricant.

A light-emitting ceramic that includes a pyrochlore type compound that contains 0.01 mol % or more of Bi with respect to 100 mol % of ABO.sub.W, and one co-added element selected from the group consisting of Mg, Ca, Zn, Sr, Ba, Sc, Ga, In, Yb, and Lu. The A site contains at least one selected from the group consisting of La, Y, and Gd in a total amount of 80 mol % or more, B contains at least Sn, and W is a positive number for maintaining electrical neutrality.