US 7,321,475 B2 | ||
Image pick-up lens system | ||
Zhuo Wang, Beijing (China); Min-Qiang Wang, Beijing (China); Ying-Bai Yan, Beijing (China); Guo-Fan Jin, Beijing (China); and Ji-Yong Zeng, Beijing (China) | ||
Assigned to Tsing Hua University, Beijing (China); and Hon Hai Precision Industry Co., Ltd., Tu-Cheng, Taipei Hsien (Taiwan) | ||
Filed on Sep. 30, 2004, as Appl. No. 10/954,726. | ||
Claims priority of application No. 2004 1 0027254 (CN), filed on May 15, 2004. | ||
Prior Publication US 2005/0254147 A1, Nov. 17, 2005 | ||
This patent is subject to a terminal disclaimer. | ||
Int. Cl. G02B 9/04 (2006.01); G02B 13/18 (2006.01) |
U.S. Cl. 359—793 [359/717; 359/738] | 6 Claims |
1. An image pick-up lens system comprising:
an aperture stop;
a biconvex first lens; and
a meniscus-shaped second lens having a concave surface on a side of an object;
wherein the aperture stop, the first lens and the second lens are aligned in that order from the object side to an image side,
the first lens is aspheric on both convex surfaces thereof, the second lens has at least one aspheric surface, and the following
conditions are satisfied;
0.6<f1/f<0.7, (1)
1<T/f<1.56, (2)
0.45<R2/R1<1; and (3)
1.2<d/R2<2.1, (4)
wherein f1 is a focal length of the first lens, f is a focal length of the system, T is a length from the aperture stop to
an image pick-up surface of the image side, R1 is an absolute value of a radius of curvature of the first lens on the object side, R2 is an absolute value of a radius of curvature of the first lens on the image side, and d is a thickness of the first lens.
|