Shapiro and Shapiro
Projection optical apparatus
 A projection optical apparatus comprises illuminating means providing for an illuminating light beam, a projection optical system including optical elements disposed across the illuminating light beam and having an imaging plane, and detecting mean including temperature sensor means provided on at least one of the optical elements and producing an output corresponding to the temperature of the one optical element. 
Nippon Kogaku K. K.
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G03F G02B G03F G02B G03F G03F
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Makoto Takeshi Kiyoyuki Akikazu Hideo
Uehara Asami Muramatsu Tanimoto Mizutani