Patent ID: 8503113

Claim:
A relay lens for an imaging system having a main lens, the main lens having a pupil plane, the relay lens, in the order from the subject side to the image side thereof, comprising: a first lens of negative refractive power, wherein the first lens has a first subject-side surface facing the subject side of the imaging system and a first image-side surface concave towards the image side of the imaging system, the first subject-side surface is a plane; and a second lens of positive refractive power, wherein the second lens has a second subject-side surface convex towards the subject side of the imaging system and a second image-side surface convex towards the image side of the imaging system; wherein, the first lens comprises a first principal plane and a second principal plane from the subject side to the image side thereof; the second lens comprises a third principal plane and a fourth principal plane from the subject side to the image side thereof; wherein, the relay lens satisfies the following formulas: 0.53<|ƒ1/ƒ2|<0.57; 1.54<ν1/ν2<3.11; 0.22<D1/D2<0.65, wherein f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, D1 is the distance between the second principal plane of the first lens and the third principal plane of the second lens, D2 is the distance between the fourth principal plane of the second lens and the pupil plane.