| 摘要 |
PROBLEM TO BE SOLVED: To reduce a detecting error of a reflected beam from a surface of a measured material to an inclination error of the surface of the measured material. SOLUTION: Lens systems 24, 26 constituting a lighting optical system mutually conjugates a surface light source part 23b that irradiates a lighting beam and a part around a lighted area on the surface of the measured material 2. The lens systems 24, 26 diagonally enter a pencil of rays into the surface of the measured material 2. The lens systems 27, 28 constituting a detecting optical system mutually conjugates a part around the lighted area on the surface of the measured material 2 and an incident end surface 29a of an optical fiber 29 that is an entrance pupil of a received-light sensor of a detecting part 30. |
