| 摘要 |
PURPOSE:To freely adjust the quantity of light by passing a high frequency current through a coil so as to light a discharge tube after reducing pressure within the discharge tube by a pressure adjusting means, and raising pressure of gases in the discharge tube while increasing power supplied to the coil so as to increase the quantity of light. CONSTITUTION:While a closing valve 8 is closed and a closing valve 11 is opened, a pump 6 is operated so that gases in a discharge tube 1 are sucked into a reservoir 9. When pressure within the discharge tube 1 reaches to the range of 10<-2> to 10<-1>Torr the closing valve 8 is opened and the closing valve 11 closed and gases are circulated through a closed circuit A in the direction of the arrow. Then a high-frequency current is passed through a coil 2 so that the discharge tube 1 is lighted. As the output of a high-frequency power source 3 is increased, the closing valve 11 is gradually opened and pressure of the gases circulating through the closed circuit A is raised and then the temperature of plasma inside the discharge tube 1 is raised and the quantity of light of the discharge tube is increased accordingly. Thereby a desired quantity of light is obtained. |
