| 摘要 |
PROBLEM TO BE SOLVED: To prevent displacement signals of respective beams from merging with each other in a scanning objective area, and to provide a wide effective scanning width. SOLUTION: This displacement measuring instrument uses a light scanning device for launching a plurality of beamsαandβdifferent in incident angles to a deflector for changing the progressing direction of light, and is equipped with a screening means 12 for screening the other beamα(β) to prevent the beam from irradiating a measuring object 10 when one beamβ(α) irradiates the object 10. By this, only non-merged displacement signals is received by dispensing with simultaneous irradiation of the beamsαandβto the object 10. Further, a wide effective scanning width h is obtained, since a beamα(β) outside the scanning objective area H is screened that may affect a beamβ(α) by interfering with the beamβ(α) in the objective area H. COPYRIGHT: (C)2005,JPO&NCIPI
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