| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical element capable of relaxing restrictions in design and to miniaturize an image pickup optical system using the optical element by giving wavelength selectivity that unnecessary wavelength light is removed to a reflection surface having curvature. SOLUTION: In the optical element obtained by integrally forming plural reflection surfaces having the curvature, at least one of the reflection surfaces is coated with material absorbing the unnecessary wavelength light and transmitting necessary wavelength light and also coated with a reflection film. For example, the optical element 1 is constituted to have solid shape obtained by integrally forming an incident and emitting surface and plural reflection surfaces having the curvature on the surface of a transparent body. The element 1 is constituted of two refractive surfaces and five reflection surfaces, that is, a concave refractive surface R1, a concave mirror R2, a convex mirror R3, a concave mirror R4, a convex mirror R5, a convex mirror R6 and a concave refractive surface R7 in order from an object side. The mirror R2 is constituted of a reflection mirror transmitting the unnecessary wavelength light and reflecting the necessary light from object light.
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