OPTICAL SYSTEM, IMAGING DEVICE, AND ENDOSCOPE SYSTEM

Abstract

An optical system includes an image forming optical system with a first and a second lens group, and forms an image of light from a subject on each of a visible light imaging element and an infrared light imaging element. The system also includes a separation optical system that separates an optical path of light passing through the image forming optical system into at least two optical paths. The first lens group includes a plurality of cemented lenses formed by bonding a lens having positive refractive power and a lens having negative refractive power, in which when αp is an average linear expansion coefficient of the lens having positive refractive power at 100° C. to 300° C. and αn is an average linear expansion coefficient of the lens having negative refractive power at 100° C. to 300° C., the following conditional formula |1−αp/αn|<0.2 is satisfied.

CPC Classifications