CPC A61B 1/0684 (2013.01) [A61B 1/00096 (2013.01); A61B 1/0615 (2013.01); A61B 1/0623 (2013.01); A61B 1/07 (2013.01)] | 15 Claims |
1. An illumination optical system for use with an endoscope including an insertion portion configured to be inserted into a subject, the illumination optical system comprising:
an optical element including an incident surface through which light enters as incident light and an emission surface configured to emit the light as illumination light,
the emission surface includes a diffusion region configured to diffuse the light emitted,
the diffusion region includes a plurality of concave portions and a plurality of peripheral regions, the plurality of concave portions and the plurality of peripheral regions being arrayed on the emission surface,
each of the plurality of concave portions includes a plurality of total reflection surfaces inclined with respect to the emission surface, each of the plurality of total reflection surfaces being configured to totally reflect the incident light,
at least one of the plurality of total reflection surfaces is inclined at a first angle with respect to the emission surface,
each of the plurality of peripheral regions is formed so as to entirely surround the plurality of total reflection surfaces, and includes a transmission surface configured to transmit and emit:
reflected light totally reflected by the plurality of total reflection surfaces after passing through the incident surface, and
the incident light not totally reflected by the plurality of total reflection surfaces after passing through the incident surface.
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