| 摘要 |
PROBLEM TO BE SOLVED: To provide a distance measurement apparatus and a distance measurement method for drastically reducing an influence of speckle without a degradation in the displacement sensitivity. SOLUTION: The distance measurement apparatus includes: an irradiation optical system 11 for irradiating a to-be-measured plane Wa with an irradiation light collected on a focus plane as an irradiation spot S; a reflection optical system 12 for collecting a reflection light reflected from the to-be-measured plane Wa on a confocal plane, and making it enter into a photodetector 13 through a pinhole 36 installed on the confocal plane of the collected reflection light; and a distance measurement means for detecting a displacement signal Esn based on the reflection light entering into the photodetector 13, and measuring a distance between the to-be-measured plane Wa based on the displacement signal Esn. The irradiation spot S for irradiating the to-be-measured plane Wa is elliptical. COPYRIGHT: (C)2008,JPO&INPIT
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