ABSTRACT
In the lamp industry, the term “light” is expanded to include the near ultraviolet and infrared regions. Phosphor, in the form of a fine powder, is applied as a uniform coating onto the inside surface of the lamp tube, resulting in a very efficient light source. The method of application requires that, from a practical standpoint, the phosphor used for coating must be a powder. Possibly the first useful application of a phosphor was by Thomas A. Edison in a patent applied for in 1896, granted in 1907, covering a short vacuum tube coated on the inside with blue emitting calcium tungstate phosphor. In the initial period of phosphor manufacture, the fired cake was milled to a powder and shipped to the lamp plant. The typical phosphor is produced by thoroughly mixing a number of components containing the required elements, and firing them at the temperature required to initiate a reaction that will result in the desired crystal structure.
