EXTINCTION DEVICE

摘要

PURPOSE:To finely adjust an extinction amount by changing the incident angle of a member having a multilayer reflection preventing film. CONSTITUTION:The multilayer reflection preventing film 13 having angle dependency or a thin film coating member 11 where the multilayer reflection film is formed, and a driving means (step motor) 15 for tilting the thin film coating member are provided on a synthetic quartz substrate 12 excellent in light transmission. By inclining the member 11 from the incident angle position having the maximum reflectance against incident light by the driving means 15, the transmissivity or the reflectance of the member 11 is changed to optionally and finely adjust extinction rate.