| 摘要 |
Providing a sighting device having a simple structure, being easy to manufacture and free from parallax. A sighting device comprises, in order from a target object side, a positive meniscus lens having a convex surface facing the target object and a negative meniscus lens having a convex surface facing the target object, wherein the surface of said positive meniscus lens that faces away from said target object or the surface of said negative meniscus lens that faces toward said target object is adapted to constitute a semi-transparent reflection surface or a wavelength selective reflection surface, and a point source is provided at a focal point of a catadioptric optical system constituted by said semi-transparent reflection surface or said wavelength selective reflection surface and a refracting surface of the negative meniscus lens having with the convex surface facing said target object, the refracting surface facing away from said target object side.
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