Patent ID: 10698183

Abstract:
The object-side surface of a negative lens element closest to the object side within a first lens group includes a paraxial convex surface and a peripheral surface having a curvature less than that of the paraxial surface. The image-side surface of a last lens element of a second lens group includes a paraxial concave surface and a peripheral surface having an inflection point changing from positive to negative values. 0.10<La/TL<0.31, and 0.35<Bh<0.70 are satisfied; La: distance from the object-side surface of the negative lens element, closest to the object side, to an axial light-bundle restriction diaphragm closest to the object side; TL: distance from the object-side surface of this negative lens element to an imaging surface; Bh: height to an inflection point on the image side of the lens element closest to the image side divided by the effective radius thereof.