| US 7,586,969 B2 | ||
| Method for discriminating anomaly in gas composition and discharge excitation type gas laser oscillator | ||
| Akira Egawa, Yamanashi (Japan); Minoru Ando, Yamanashi (Japan); and Hajime Ikemoto, Yamanashi (Japan) | ||
| Assigned to Fanuc Ltd, Yamanashi (Japan) | ||
| Filed on Dec. 11, 2007, as Appl. No. 12/267. | ||
| Claims priority of application No. 2006-337141 (JP), filed on Dec. 14, 2006. | ||
| Prior Publication US 2008/0144681 A1, Jun. 19, 2008 | ||
| Int. Cl. H01S 3/03 (2006.01) | ||
| U.S. Cl. 372—61 [372/55; 372/57] | 4 Claims |
| 1. Method for discriminating an anomaly in gas composition of a laser gas excited by discharge in a discharge tube of a laser
oscillator, said method comprising:
detecting an actual output current value of a high-frequency power supply unit supplying power to said discharge tube at an
arbitrary pressure lower than high pressure during steady-state operation, at a start of said laser oscillator, after said
laser gas begins discharge excitation at a pressure lower than said high pressure during said steady-state operation;
comparing said detected actual output current value with a normal output current value that has been detected when said gas
composition of said laser gas is normal at the same pressure as said actual output current value is detected; and
discriminating, if a difference between said actual output current value and said normal output current value is equal to
or greater than a preset value, that said gas composition of said laser gas is abnormal.
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