| 摘要 |
<p>In the present disclosures, in order to perform displacement measurement wherein optical resolution adjustment is possible, the effect is small with respect to mispositioning of the surface orientation of a diffraction grating, the configuration is simple, increased compactness is possible, and the inclination precision of an optical element has no effect, laser light (13) from a laser light source (12) is made into parallel light (15) by means of a collimator lens (14), is passed through a first diffraction grating (16), is allowed to proceed to a semi-transparent semi-reflective mirror (22), and a portion is reflected as first reversed light (L rev1) that passes through the first diffraction grating (16). The remainder of the parallel light (15) is allowed to proceed to a total reflection mirror (24) and is reflected as second reversed light (L rev2) that passes through the semi-transparent semi-reflective mirror (22) and the first diffraction grating (16). The amount of refracted light of a predetermined order that is of the first and second reversed light (L rev1, L rev2) and that results from the first diffraction grating is detected by a first optical sensor (28), and the amount of displacement is obtained from the interference band or a signal thereof corresponding to the amount of relative motion in the axial direction of the total reflection mirror (24) with respect to the semi-transparent semi-reflective mirror (22).</p> |
