Nikon Corporation

Kouichi Ohshita

Mami Muratani

Akihiko Obama

The object is to provide an optical system with a wavelength selecting device. According to one aspect of the present invention, an optical system with a wavelength selecting device includes, in order from an object along an optical axis, an objective optical system composed of optical elements having refractive power and an aperture stop, a no-power optical group composed of optical elements having no refractive power, and an imaging device. The no-power optical group includes the wavelength selecting device for making short wavelength light be selectively substantially non-transparent. The wavelength selecting device preferably satisfies the predetermined conditional expressions.

Optical system with wavelength selecting device

The object of the present invention is to provide an eyepiece lens having a large pupil diameter of 10 mm or more, securing higher magnification, equipped with a high quality diopter adjustment function at low cost. The eyepiece lens includes, in order from an eye point side EP, a negative meniscus lens Lhaving a concave surface facing to the eye point side EP, a double convex lens L, and a negative lens L. Diopter of the eyepiece lens is adjusted by moving the double convex lens Lalong an optical axis. At least one surface of the double convex lens Lhas an aspherical surface having positive refractive power getting weaker in accordance with increase in a distance to the surface from the optical axis, and given conditional expressions are satisfied.

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Tokyo, Japan

Kouichi Ohshita