| 摘要 |
PROBLEM TO BE SOLVED: To provide a plurality of prisms in a band-narrowed module accurately and readily in an enclosure. SOLUTION: A plurality of prisms 23a, 23b and 23c are all provided on one substrate 33 and set in an enclosure 20a of a band-narrow module 20. In the band-narrowed module 20, which contains an optical element for band narrowing or monitoring excimer laser light or a monitoring-module enclosure 20a, an inlet port 38 through which purging gas flows in and anoutlet port 39 through which the purging gas flows out are provided. An exhaust pipe which is bent at the intermediate part is connected to this outlet port 39. |
