Patent ID: 6028713
Filing Date: 2000-02-22
Classification: G02B

Abstract:
A compact lens including a three lens element structure arranged along an optical axis, said compact lens comprising, in order from the object side:a front lens group of positive refractive power, said front lens group consisting of only two lens elements having refractive power, said two lens elements being a negative lens element with a concave surface on the object side and a biconvex lens element having surfaces of different refractive power with a surface of stronger curvature on the object side; anda rear lens group having a negative refractive power and comprising a negative meniscus lens element with its concave surface on the object side;wherein the following conditional equations are satisfied0.90<L/f<1.050.18<D.sub.4 /f<0.36whereL is the on-axis distance from the compact lens element surface nearest the object side to the image plane of the compact lens,f is the focal length of the compact lens, andD.sub.4 is the on-axis surface spacing between the front lens group and the rear lens group;wherein each of said two lens elements in the front lens group has at least one surface that is aspheric, and wherein the following conditional equation is satisfied:0.02<D.sub.2 /f<0.07where D.sub.2 is the distance between said two lens elements in the front lens group.