| 摘要 |
An excimer laser device which is capable of keeping the rotational speed of a fan constant and uniformizing a laser gas flow between main discharge electrodes even when the pressure of a laser gas filled in a casing varies. The excimer laser device includes a casing filled with a laser gas; a pair of main discharge electrodes disposed in the casing for producing an electric discharge to discharge-pump the laser gas at a high repetition rate; a fan for producing a high-speed laser gas flow between the main discharge electrodes; bearings, the fan having a rotatable shaft rotatably supported by the bearings; a motor for actuating the fan; a rotational speed detecting device for detecting a rotational speed of the fan; and control device for controlling at least one of a voltage and a frequency to be supplied to the motor based on the rotational speed of the fan detected by the rotational speed detecting device, thereby to control the rotational speed of the fan at a constant level.
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