| 摘要 |
PURPOSE:To enable the simple and easy detection of an angle of the inclination of a table by disposing photodetectors symmetrically to the optical axis of a projected light beam. CONSTITUTION:Photodetectors 40 and 42 are disposed in linear symmetry to the optical axis of a light beam projected onto the object 8 of detection of an angle by a projecting element 2 and a beam-radius restricting lens 4. Vectors of incidence on the detectors 40 and 42 are varied in accordance with the inclination of the plane 10 of this object 8, and when detection outputs of the detectors 40 and 42 are subjected to processing of division, the result of the division is varied, in accordance with an angle theta of inclination of the plane 10, from a value 1 obtained when there is no inclination. Thus, an angle of inclination of a table is detected simply and easily without using any special fitting jig or the like.
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