| 摘要 |
PURPOSE: An optical device is provided to decrease deterioration in optical characteristics of optical members irradiated with UV rays. CONSTITUTION: This UV optical device is equipped with optical members irradiated with UV rays. A part or the whole optical members are disposed in a casing(9) having a gas inlet and a gas outlet, and dry air with less than 5000 ppm water content (volume ratio) is introduced through the gas inlet(10) into the casing(9) to blow to at least such optical members that deterioration in the optical characteristics causes serious problems to the members. Thus, changes in the optical members with time can be suppressed.
|
