EFFICIENTLY GENERATING WHITE LIGHT WITH GOOD COLOUR RENDITION OF ILLUMINATED OBJECTS

摘要

1346461 Luminescent materials; electroluminescence WESTINGHOUSE ELECTRIC CORP 27 May 1971 17521/71 Heading C4S [Also in Division H1] An electrical device for generating white light comprises three components having emissions in the respective wavelength regions 515 to 570 nm., 588 to 630 nm., and 430 to 485 nm. The device may be a fluorescent tube, an electrodeless discharge tube or an electroluminescent device which may be combined with light-emitting junctions. The emissions may be either of the band or line types or combinations thereof. Numerous examples of combinations of phosphors suitable for fluorescent tubes are disclosed. A suitable phosphor for an electroluminescent device is a mixture of copper-activated zinc sulphide, copper and manganese-activated zinc sulphide, and either copper-activated zinc selenide or copperactivated zinc-mercuric chloride. In a combination of an electroluminescent device 48, 52 and light-emitting junctions 50 one or two of the components can be provided by the junctions, e.g. silicon carbide or Ga(P, Sb) junctions, the electroluminescent material providing the other two or one components. The device may be surrounded by a light scattering material, e.g. magnesium 56 coated on a cup-shaped member 54. In an electrodeless tube energized by an R.F.-fed surrounding coil the components are provided by thulium, terbium and europium, or the iodides thereof.