| 摘要 |
PROBLEM TO BE SOLVED: To simply and highly accurately detect or confirm a focusing state in an exposure equipment.SOLUTION: By projecting a pattern array PT constructed by a bar shape patterns PL1 to PL4 while moving a stage 12 to a shading part 40 to which slits ST1 to ST6 is formed, a light quantity signal is outputted from a photosensor PD. Thus, it is determined whether or not the focusing state is maintained based on an amplitude ratio M obtained by the light quantity signal.SELECTED DRAWING: Figure 8 |
