Patent ID: 9042025
Filing Date: 2015-05-26
Classification: G02B

Abstract:
1. An eyepiece optical system substantially consisting of, in order from an object side: a first lens having a positive refractive power with an observation-side lens surface being a convex surface; a second lens having a negative refractive power and having a meniscus shape with a concave surface facing the object side; and a third lens having a positive refractive power with an observation-side lens surface having a smaller radius of curvature than a radius of curvature of an object-side lens surface, wherein each of the first lens, the second lens and the third lens consists of a single lens, and the conditional expressions (1), (2) and (3) below are satisfied at the same time: where f1 is a focal length of the first lens, f3 is a focal length of the third lens, f is a focal length of the entire lens system, and TL is a distance along an optical axis from an object-side lens surface of the first lens to the observation-side lens surface of the third lens, and wherein the conditional expression (4) below is satisfied: where 2ω is a maximum angle of view at a total angle of view.