摘要 |
A compact optical system for microscope, endscope and binoculars capable of providing a clear image of minimal distortion even at a wide field angle. The optical system is a decentered optical system. Curved surfaces constituting the optical system include at least one rotationally asymmetric surface having no axis of rotational symmetry in or out of the surface. To correct rotationally asymmetric aberrations due to decentration by the rotationally asymmetric surface, the following condition is satisfied:where FX is the focal length in the X-direction of the optical system, and FXn is the focal length in the X-direction of a portion of the rotationally asymmetric surface on which an axial principal ray strikes.
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