The invention provides a lighting unit comprising a light source, configured to generate light source light and a particulate luminescent material, configured to convert at least part of the light source light into luminescent material light, wherein the light source comprises a light emitting diode (LED), wherein the particulate luminescent material comprises particles comprising cores, said cores comprising a phosphor comprising M.sub.xM.sub.2-2xAX.sub.6 doped with tetravalent manganese, wherein M comprises an alkaline earth cation, M comprises an alkaline cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, at least comprising silicon, wherein X comprises a monovalent anion, at least comprising fluorine, and wherein the particles further comprise a metal phosphate based coating, wherein the metal of the metal phosphate based coating is selected from the group consisting of Ti, Si and Al.

A phosphor plate including: a complex containing an -sialon phosphor and a sintered body containing spinel represented by a general formula M.sub.2xAl.sub.4-4xO.sub.6-4x (where M represents at least one of Mg, Mn, and Zn, and 0.2<x<0.6). In addition, there is provided a light emitting device including: a group III nitride semiconductor light emitting element; and the phosphor plate provided on one surface of the group III nitride semiconductor light emitting element. Further, there is provided a method for manufacturing the phosphor plate.

The present invention provides a functional material, its preparation method, a three-dimensional display raster and a display device, which belongs to the display technical field and can solve the pollution problem in current three-dimensional display devices. The functional material includes an inorganic mixed powder with a modified layer, the inorganic mixed powder comprising boron oxide, sodium oxide, lithium oxide, zirconium oxide, aluminum oxide, zinc oxide, titanium oxide, silicon dioxide, calcium oxide, silver complexes, silver phosphate, silver nitrate, tourmaline, silver thiosulfate, carbon nanotubes, aluminum sulfate, manganese, manganese oxide, iron, iron oxide, cobalt, cobalt oxide, nickel, nickel oxide, chromium, chromium oxide, copper, copper oxide, magnesium oxide, boron carbide, silicon carbide, titanium carbide, zirconium carbide, tantalum carbide, molybdenum carbide, boron nitride, chromium nitride, titanium nitride, zirconium nitride, aluminum nitride, chromium boride, Cr.sub.3B.sub.4, titanium boride, zirconium boride, tungsten disilicide, titanium disilicide and the like; the modified layer being generated by a reaction of a dianhydride and a diamine.

A light source using a light-converting material, in particular for the conversion of collimated or focused light, which does not operate solely on the principle of geometric concentration as known from the prior art, but which reflects light away from the interface between the surface of the conversion body (1) and the surroundings due to the high refractive index of the conversion body (1), possibly by means of an applied reflective layer. The light source uses the high refractive index and high transmittance of the phosphor material as the properties necessary to direct the light in the desired direction directly by the conversion body (1) itself. The light source emits collimated or focused intense secondary light, or a homogenised mix of primary and secondary light, or it may transmit supplementary light.