Patent ID: 9417429
Filing Date: 2016-08-16
CPC Classification: G02B,G11B

Claim Text:
1. An image pick-up apparatus comprising: an imaging optical system including a plurality of lenses and a diaphragm arranged between the lenses, the imaging optical system forming an image on an image surface, the image surface being curved; and an image sensor that detects the image formed on the image surface, wherein the imaging optical system includes a front lens group including lenses disposed on an object side with respect to the diaphragm; and a rear lens group including lenses disposed on the image surface side with respect to the diaphragm; wherein a lens surface among lens surfaces in the front lens group has a highest power surface of the front lens group, and a lens surface among lens surfaces in the rear lens group has a highest power surface of the rear lens group, the lens surface having the highest power surface of the front lens group and the lens surface having the highest power surface of the rear lens group are concentric surfaces; and wherein the front lens group includes a plano-concave lens whose light-exiting-side surface has a concave surface and whose light-incident-side surface has power φr that satisfies a following expression: where φo is power of the entire imaging optical system.