| 摘要 |
PROBLEM TO BE SOLVED: To enable an acquisition of an interference fringe image having an entire surface of a measured surface uniformly focused on, and shorten an entire length of a surface shape measurement device.SOLUTION: An optical system 3 is used in a surface shape measurement device 100 that measures a shape of a measured surface on the basis of an interference fringe to be formed by interfering measurement light reflected upon the measured surface with reference light reflected upon a reference surface, and the optical system 3 is an optical system that converts the measurement light into a wavefront having a predetermined shape and guides the converted measurement light to a measured surface 4. The optical system 3 is composed of, in order far from the measured surface 4, a first lens L1, a second lens L2 having a positive refractive power, and a third lens L3 having a positive refractive power, and the first lens L1 is a meniscus lens with a convex shape on an opposite side of the measured surface 4. |
