| 摘要 |
A wide-angle eyepiece lens having an angle of view greater than 60 DEG comprises, in order from the object end, a first lens group including a positive power meniscus lens element with a concave object side surface, an overall negative power second lens group including a doublet comprising, in order from the object side, a negative power lens element and a positive power lens element, and an overall positive power third lens group, and satisfies the following conditions: 1.2<f1/f<3.5 3<-f2/f 0.010<1/ upsilon 2N-1/ upsilon 2P 1<|R3/f|where f is the overall focal length of the eyepiece lens; f1 is the overall focal length of the first lens group; f2 is the overall focal length of the second lens group; upsilon 2N is the Abbe number of the negative power lens element of the second lens group; upsilon 2P is the Abbe number of the positive lens element of the second lens group; R3 is the curvature of radius of the foremost object side surface of the second lens group.
|
