OPTICAL ELEMENT, ITS MANUFACTURING METHOD, LENS UNIT USING IT AND ELECTRONIC EQUIPMENT USING IT

摘要

PROBLEM TO BE SOLVED: To prevent lowering of translucency of an optical element, a lens unit and electronic equipment or the like using the element.

SOLUTION: The optical element is equipped with a lens 4 and an optical filter 5 provided at least on one surface of the lens 4. Product of a refractive index and film thickness of the optical filter 5 is made to become smaller from a center of the lens 4 toward its outer periphery. Since optical path length in the optical filter 5 can be made equal both at a central part and at an outer peripheral part of the lens 4 thereby, wavelengths other than desired wavelength can be intercepted and only transmissivity of the desired wavelength can be kept high. Thus there is no need for providing a multilayer film and translucency can be raised as much.

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