Lamps Using Fluorescence[^1]

One of the greatest achievements in recent years in the field of light sources is fluorescent lamps, which have been produced for some time now by the firm Mazda.

In these lamps the primary source of radiation is a discharge in mercury vapor mixed with argon, taking place between electrodes made of coiled tungsten wire coated with a layer that readily emits electrons. The ultraviolet radiation of the mercury discharge excites the fluorescence of a phosphor deposited on the inner surface of the lamp bulb. By selecting the phosphor material it becomes possible to obtain light of almost any spectral composition, both monochromatic and of mixed tones. In particular, in this way it has proved possible to obtain the closest approximation to daylight.

Another very important merit of these lamps is that their efficiency proves to be higher than that of any colored light sources that have existed up to the present time.

N. Khlebnikov, Moscow

Literature

1. Journ. Appl. Phys., 10, XII, 1939.