Optical device and inspection method

Abstract

An optical device for inspecting a to-be-inspected surface having a riblet structure in which projections each extending in a first direction are provided in a second direction intersecting the first direction is configured to include a condensing optical system that irradiates an irradiation region on the to-be-inspected surface with light from a light source and that condenses light reflected by the irradiation region; and a photodetector that has a photosensitive surface disposed on a plane different from a plane conjugate to the to-be-inspected surface with respect to the condensing optical system, and that detects intensity distribution of the light condensed by the condensing optical system.

Dependencies are inferred from the claim text.