| 摘要 |
PURPOSE:To make it possible to make a light emission strength constant while operation and make a light acting period constant without increasing the cost of a lighting circuit of a light source by making the light emission strength constant by controlling the steam pressure of light emitting material. CONSTITUTION:For a light source 1 having inactive gas and light emitting material enclosed, its light emission strength decreases gradually while operation. For the decrease of light emission strength while operation, the steam pressure is increased gradually corresponding to decrease of the light emission strength while operation so as to make the light emission strength constant while operation by using the change of light emission strength by change of the steam pressure of the light emitting material until the steam pressure is increased up to a steam pressure corresponding to the maximum light emission strength by the steam pressure of the light source. The light emission strength can thus be constant while operation, and an acting time using the light wavelength effect can be constant during the life of the light source 1. |
