| 摘要 |
PURPOSE:To provide an inexpensive transitable light source apparatus capable of serving as a main illumination by controlling an electric power for heating a cathode, and varying a light emitting ratio of mercury vapor and inactive gas. CONSTITUTION:An electric power for heating a cathode 2 is controlled. At the time of lighting without heating the cathode 2, an electron having energy equivalent to a cathode falling voltage is flown from the cathode 2 into a space. The energy is enough to ionize and energize inactive filled gas. And further, the filled pressure of the inactive gas is far higher than a mercury vapor pressure. Accordingly, in a lamp, light emission caused by the inactive gas tends to be stronger. Meanwhile, at the time of lighting while heating the cathode 2, the cathode falling voltage is low because a temperature at the cathode 2 is high. consequently, flying energy of the electron is reduced so that a ratio of ionizing and energizing the inactive gas is also reduced. Therefore, the light emission ratio of the mercury vapor and the inactive gas can be varied, and thus, light emitting color of the lamp can be changed. |
