Lens barrel having deformed optical element, and projection aligner including same

摘要

A lens barrel includes an optical element having a light-transmissive surface which is deformed by own weight thereof and/or by being supported, and a plurality of protrusive parts which support the optical element. The plurality of protrusive parts are disposed in such a way as to enable the light-transmissive surface of the optical element to be deformed symmetrically with respect to a plane which includes an optical axis.