Microwave excitation gas laser oscillating apparatus

Abstract

Based on an oscillation ON/OFF signal and an output state instruction signal output to a high-voltage generating circuit ( 101 ) from a power supply control apparatus ( 301 ), heater voltage applied from a heater circuit ( 201 ) to a heater of a magnetron ( 2 ) is controlled depending on whether the magnetron ( 2 ) is stopped from oscillating or is continuously or intermittently operating. The heater voltage of the magnetron ( 2 ) measured during the intermittent operation is controlled to be higher than that measured during the continuous output and to be lower than that measured while the oscillation is stopped, thereby reducing the change in temperature of the heater and providing a lower limit temperature at which the magnetron ( 2 ) can oscillate stably. This configuration increases the service life of the magnetron ( 2 ) used for a microwave excitation laser.

1 . A microwave excitation gas laser oscillating apparatus comprising a discharge tube that excites a gas by means of discharge to generate a laser light; a magnetron that supplies microwaves to said discharge tube; and a microwave power supply apparatus for supplying power to said magnetron, wherein 
 said microwave power supply apparatus has a heater circuit for applying heater voltage to the heater of said magnetron; and a high-voltage generating circuit for applying a high voltage between the anode and cathode of said magnetron, and    said heater circuit controls the heater voltage output to said magnetron from the heater circuit depending on whether the magnetron is stopped from oscillating or providing a continuous output or an intermittent output.    
     
     
         2 . A microwave excitation gas laser oscillating apparatus according to  claim 1 , wherein said heater circuit is configured so that the heater voltage measured while the magnetron is providing a continuous output is lower than that measured while the oscillation of the magnetron is stopped.  
     
     
         3 . A microwave excitation gas laser oscillating apparatus according to  claim 1 , wherein said heater circuit is configured so that the heater voltage measured while the magnetron is providing an intermittent output is lower than that measured while the oscillation of the magnetron is stopped.  
     
     
         4 . A microwave excitation gas laser oscillating apparatus according to  claim 1 , wherein said heater circuit is configured so that the heater voltage measured while the magnetron is providing an intermittent output is higher than that measured while the magnetron is providing a continuous output and is lower than that measured while the oscillation of the magnetron is stopped.  
     
     
         5 . A microwave excitation gas laser oscillating apparatus comprising a discharge tube that excites a gas by means of discharge to generate a laser light; a magnetron that supplies microwaves to said discharge tube; and a microwave power supply apparatus for supplying power to said magnetron, wherein 
 said microwave power supply apparatus comprises: 
 a heater circuit for applying heater voltage to the heater of said magnetron;  
 a high-voltage generating circuit for applying a high voltage between the anode and cathode of said magnetron; and  
 an abnormal-voltage detecting circuit for detecting abnormal oscillation of the magnetron through abnormal voltage generated in an abnormal-voltage-detecting winding provided in a step-up transformer constituting the high-voltage generating circuit.  
   
     
     
         6 . A microwave excitation gas laser oscillating apparatus according to  claim 5 , wherein the abnormal-voltage detecting circuit has a display function for generating an abnormality alarm signal if abnormal voltage lasts over a set period of time.  
     
     
         7 . A microwave excitation gas laser oscillating apparatus comprising a discharge tube that excites a gas by means of discharge to generate a laser light; a magnetron that supplies microwaves to said discharge tube; and a microwave power supply apparatus for supplying power to said magnetron, wherein 
 said microwave power supply apparatus comprises: 
 a heater circuit for applying heater voltage to the heater of said magnetron;  
 a high-voltage generating circuit for applying high voltage between the anode and cathode of said magnetron; and  
 an abnormal-voltage detecting circuit for detecting a defect in the heater section of the magnetron by detecting abnormal voltage through a heater-voltage-detecting monitor winding provided in a heater transformer constituting said heater circuit.  
   
     
     
         8 . A microwave excitation gas laser oscillating apparatus comprising a discharge tube that excites a gas by means of discharge to generate a laser light; a magnetron that supplies microwaves to said discharge tube; and a microwave power supply apparatus for supplying power to said magnetron, wherein 
 said microwave power supply apparatus comprises: 
 a heater circuit for applying heater voltage to the heater of said magnetron;  
 a high-voltage generating circuit for applying high voltage between the anode and cathode of said magnetron;  
 a current detecting element that detects current flowing between the anode and cathode of the magnetron; and  
 an abnormal-current detecting circuit which operates, when detecting that the current value of the current detecting element is abnormal, to stop the operation of only the abnormal microwave power supply.  
   
     
     
         9 . A microwave excitation gas laser oscillating apparatus according to  claim 8 , further comprising a plurality of microwave power supply apparatuses and magnetrons.  
     
     
         10 . A microwave excitation gas laser oscillating apparatus comprising a discharge tube that excites a gas by means of discharge to generate a laser light; a magnetron that supplies microwaves to said discharge tube; and a microwave power supply apparatus for supplying power to said magnetron, wherein 
 said microwave power supply apparatus comprises: 
 a heater circuit for applying heater voltage to the heater of said magnetron;  
 a high-voltage generating circuit for applying high voltage between the anode and cathode of said magnetron;  
 abnormal-oscillation detecting means for detecting abnormal oscillation of the magnetron; and  
 a heater voltage instructing circuit which operates, when the abnormal-oscillation detecting means detects abnormal oscillation of the magnetron, to gradually increase the heater voltage, store in the heater circuit a heater voltage at which the abnormal oscillation stops, and output an instruction signal for operation at that heater voltage.  
   
     
     
         11 . A microwave excitation gas laser oscillating apparatus according to  claim 10 , wherein the abnormal-oscillation detecting means comprises an abnormal-voltage detecting circuit for detecting abnormal oscillation of the magnetron through abnormal voltage generated in the abnormal-voltage-detecting winding provided in the step-up transformer constituting the high-voltage generating circuit.