| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical system having coaxial illumination that suppresses doubling of an image and aberrations caused by insertion of a beam splitter in a path of non-parallel light rays.SOLUTION: An optical system includes a light source unit that emits diffusive light rays, a thin film that reflects the diffusive light rays from the light source unit, and a first lens group that irradiates the light reflected by the thin film as parallel light. The optical system may preferably include a filter that is to be located between the light source unit and the thin film to make uniform irradiation by reducing light intensity of a portion of the diffusive light rays emitted by the light source unit relative to light intensity of the remaining portion thereof. |
