| 摘要 |
A position detecting system for detecting relative positional relationship between first and second objects disposed opposed to each other, includes a first mark formed on the first object and provided by a physical optic element, a second mark formed on the second object and provided by a physical optic element, a light projecting portion for projecting onto the first object a radiation beam having a predetermined light intensity distribution, a light detecting portion for detecting first light diffracted by the first mark and diffracted by the second mark, and second light diffracted by at least one of the first and second marks at a diffraction order different from that of the first light, an adjusting device for adjusting the position of incidence of the radiation beam upon the first object on the basis of first and second signals, of signals detected by the light detecting portion, corresponding to the first and second lights, respectively, and a determining portion for determining the relative positional relationship between the first and second objects on the basis of the detection of the first and second signals by the light detecting portions.
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