Abstract
Recently, sterilization due to the ultraviolet rays is popularized in place of the polluted water sterilization by chlorine addition which has a bad influence on the ecosystem in the lower reaches of the river. We developed the electrode-less lamp device of the long life, big output which met such use a little in front. The examination to decline was done in that development reducing the voltage across to an exciting coil to prevent the phenomenon for a surface that to turn black from the time when a lamp was early. We improved the phenomenon which turned black in the early time of the surface of the lamp, and learned to provide a long life lamp as that result.
