| 摘要 |
PURPOSE:To always maintain metal vapor amount in a laser tube in an optimum state and to oscillate multiple colors for a long period of time by controlling the temperature of metal reservoir on the basis of a current flowing to an auxiliary anode for blowing back the metal vapor. CONSTITUTION:A direct current is supplied from a constant-current source 21 through a ballast resistor to auxiliary anodes 9 provided at both ends of a laser tube 1 for blowing back metal vapor. The voltages of the anodes 9 are applied to a detector 22 for both the voltages to be averaged, compared with a preset reference voltage, and the compared output is applied to a heater driver 23, thereby controlling the current of a heater 8. That is, if the voltages of the anodes 9 are constant, the currents flowing to the anodes become constant, and the current of the heater 8 is so controlled that the voltages of the anodes 9 detected by the detector 22 become equal to the reference voltage. Thus, the evaporation amount can be so controlled that the metal vapor amount in the tube 1 become constant, thereby operating it in an optimum operating state for a long period of time. |
