Optical path length compensating optical system in

专利名称：Optical path length compensating optical

system in an alignment apparatus

发明人：Makoto Uehara,Kazumasa Endo,Susumu

Mori,Shuhei Takagi,Yukio Kakizaki

申请号：US06/5953申请日：19860813公开号：US04723846A公开日：19880209

摘要：An optical path length compensating device comprises a first objective havingone focus coincident with a two-dimensional plane and provided for movement along thetwo-dimensional plane, a second objective having one focus coincident with a

predetermined focal plane, first and second reflecting means provided in the optical pathbetween the first objective and the second objective for movement along the opticalpath, the first reflecting means including at least one reflecting surface for turning theoptical path from the first objective by a predetermined angle in a plane parallel to thetwo-dimensional plane, the second reflecting means including at least one pair ofreflecting surfaces for directing the light from the first reflecting means to the secondobjective, means for moving the first objective and the first reflecting means in operativeassociation with each other, and means for moving the second reflecting means so thatthe other focus of the first objective and the other focus of the second objective arecoincident with each other.

申请人：NIPPON KOGAKU K. K.

代理机构：Shapiro and Shapiro

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