Interference fringe inspection apparatus, interference fringe inspection method, and inspection method using interference fringes

摘要

PROBLEM TO BE SOLVED: To provide a light source device capable of emitting monochromatic light, for example, monochromatic light close to the emission line spectrum of a low pressure sodium lamp. SOLUTION: It comprises a light source 12 comprising a discharge tube containing mercury, a first optical filter 13 and a second optical filter 14 sequentially arranged in front of the light source, and a light diffusing plate. One optical filter 13 has an optical characteristic that blocks a spectral component in a wavelength range shorter than one peak wavelength of light generated from the light source, and the second optical filter 14 has a peak wavelength of light generated from the light source. The light source device 10 is configured to have an optical characteristic that blocks a spectral component in a longer wavelength range and diffuses light transmitted through the first optical filter 13 and the second optical filter 14 by a light diffusion plate. [Selection] Figure 1