Patent ID: 6104543
Filing Date: 2000-08-15
Classification: G02B

Abstract:
An eyepiece optical system comprising a first lens group comprising a negative single meniscus lens element having a convex surface on the side of a user's eye, and a second lens group having positive power as a whole, in this order from an object;wherein an intermediate image formed by an objective optical system is positioned between said first lens group and said second lens group;wherein said second lens group comprises a positive single meniscus lens element having a convex surface on the side of a user's eye, and a cemented sub-lens group having positive power as a whole in this order from said object, and said cemented sub-lens group comprising a positive lens element and a negative lens element; andwherein the following conditions are satisfied:-15<f.sub.1 /f.sub.e <-3.5-10<f.sub.1 /f.sub.2 <-3.0whereinf.sub.1 designates the focal length of said first lens group;f.sub.2 designates the focal length of said second lens group; andf.sub.e designates the focal length of the entire lens system.