| 摘要 |
PURPOSE:To obtain a necessary amount of light required for exposing within a constant period, irrespective of a change of rising characteristic of light flux by providing a means which detects and integrates the light from electrodeless discharge lamp and by controlling a switch connected to the charging capacitance by such integrated value. CONSTITUTION:The microwave generated by a magnetron 1 propagates within a waveguide and is radiated to the cavity 4, forming a microwave field within the cavity 4. The rare gas of discharge lamp 6 discharges by such microwave field and the light having the particular luminous spectrum depending on the kind of metal gas is emitted. However, the time for obtaining a constant amount of light t1 changes due to fluctuation in manufacturing of discharge lamp 6, ambient temperature environment and restarting condition. Accordingly, an optical output Aa from the electrodeless discharge lamp 6 is detected and such output and the other optical output B are integrated (with time) from the strating period. When an integral value of output A and BXT become equal (time T), the switch Ts is opened. Thereby, if the rising characteristic changes like A' in the figure, any effect is given to the required time t and it can be made constant for the required total amount of light indicated by the area OBoBt1.t1. |
