| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect a relative positional shift between a plurality of structures even in a narrow place. SOLUTION: A laser beam output from a linear beam regression type laser sensor 22 is passed through a slit 26, and reflected by a reflecting plate 24. The laser beam reflected by the reflecting plate 24 is passed through the slit 26 again to be returned to the linear beam regression type laser sensor 22. A variation of received beam luminous energy in the laser sensor 22 with respect to a set value, and a positional change error by shielding the beam by the slit 26 are detected when a position is changed in either of the structures 21, 23 or when positions are changed in the both, and when exceeding an allowance value in constitution. The relative displacement between the two structures 21, 23 is detected by this manner. COPYRIGHT: (C)2004,JPO&NCIPI |
