| 摘要 |
PURPOSE:To miniaturize a current control element and thereby to reduce the cost therefore by improving the anode starting voltage starting characteristic and by reducing the load voltage of the control element immediately after the device is lighted up. CONSTITUTION:Before a laser tube 4 is lighted up, the output V0 of anode voltage dividing resistors 18 and 19 is equivalent to the output of a DC supply source 1. A switch 21 being closed, the output is amplified 14 through comparison with te reference voltage VS2 set 13 at a level higher than V0 and thereby a motor cylinder 16 is driven 15. Then, the bellows of a gas reservoir 17 is compressed and thereby the gas pressure of the laser tube 4 is raised. When the swtich 21 is opened simultaneously with the lighting-up of the tube 4, the anode current flows to a resistor 3, the output voltage Vm1 is turned into Vm2 through DC amplificaton 10 and amplifed 14 through comparison with the output V0 of the anode voltage dividing resistors 18 and 19 and thereby the belows is expanded to adjust the gas pressure. Therefore, the anode voltage is kept at a prescribed value with the improved anode voltage starting characteristic of the laser tube and the load voltage of the current control element 2 is kept below the prescribed value in the course from just after the lighting-up to the stationary state. Accordingly, the breakdown voltage of the current control element can be selected to be low, thereby the miniaturization and reduction of cost of the device are enables and also stable laser oscillation is obtained. |
