A method for manufacturing a phosphor powder of the present invention, in which the phosphor powder contains an inorganic compound in which Eu as an activator is solid-soluted in a crystal represented by Ba.sub.26Si.sub.51O.sub.2N.sub.84 or in an inorganic crystal having the same crystal structure as the crystal represented by Ba.sub.26Si.sub.51O.sub.2N.sub.84, the method including: a mixing step of mixing a raw material containing each element constituting the inorganic compound to obtain a raw material mixture blended such that b=51 and a/b>(26?c)/51 are satisfied when molar ratios of Ba, Si, and Eu in the raw material mixture are respectively a, b, and c; a firing step of firing the raw material mixture to obtain a fired product; and a cleaning treatment step of subjecting the fired product to an acid treatment and/or a water treatment.

A phosphor includes, as a main component, a compound represented by a general formula (3-a)YO.sub.3/2.aCeO.sub.3/2.(5-b)AlO.sub.3/2.bGaO.sub.3/2.cKO.sub.1/2.dPO.sub.5/2, where a, b, c and d satisfy 0.12a0.18, 1.50b3.00, 0.01c0.08, and 0.01d0.08.

The present invention discloses a nitrogen-containing luminescent particle, characterized in that a structure of the nitrogen-containing luminescent particle is divided into an oxygen poor zone, a transition zone, and an oxygen rich zone from a core to an outer surface of the particle depending on an increasing oxygen content, the oxygen poor zone being predominantly a nitride luminescent crystal or oxygen-containing solid solution thereof, the transition zone being predominantly a nitroxide material, the oxygen rich zone being predominantly an oxide material or oxynitride material; the nitride luminescent crystal or oxygen-containing solid solution thereof has a chemical formula of M.sub.m-m1A.sub.a1B.sub.b1O.sub.o1N.sub.n1:R.sub.m1, the nitroxide material has a chemical formula of M.sub.m-m2A.sub.a2B.sub.b2O.sub.o2N.sub.n2:R.sub.m2, the oxide material or oxynitride material has a chemical formula of M.sub.m-m3A.sub.a3B.sub.b3O.sub.o3N.sub.n3:R.sub.m3. The nitrogen-containing luminescent particle and the nitrogen-containing illuminant of the present invention have good chemical stability, good aging and light decay resistance, and high luminescent efficiency, and are useful for various luminescent devices. The manufacturing method of the present invention is easy and reliable, and useful for industrial mass production.

A raised pavement marker (RPM) is sized and configured to comply with Department of Transportation requirements and includes a main body with a top side, opposite angled side faces, opposite ends and a bottom surface structured to be bonded to a road surface. A sheet substrate is coated on a top surface with multiple layers of a photoluminescent composition containing one or more rare earth materials that emits a highly visible glowing light in dark or near dark conditions for at least 6 hours when fully charged. The sheet substrate is inserted within a recessed pocket on the top side of the RPM with the photo-luminescent top surface facing up and is covered by a transparent acrylic lens that is electronically welded to the main body to provide an integral one piece sealed structure. The opposite angled side faces may be fitted with prismatic reflective lenses.