| US 7,515,351 B2 | ||
| Inverse telephoto with correction lenses | ||
| Chun Shan Chen, Taichung (Taiwan); and Hsiang Chi Tang, Taichung (Taiwan) | ||
| Assigned to Largan Precision Co., Ltd., Taichung (Taiwan) | ||
| Filed on Nov. 28, 2007, as Appl. No. 11/946,836. | ||
| Claims priority of application No. 96124474 A (TW), filed on Jul. 05, 2007. | ||
| Prior Publication US 2009/0009887 A1, Jan. 08, 2009 | ||
| Int. Cl. G02B 15/14 (2006.01) | ||
| U.S. Cl. 359—680 [359/761; 359/793] | 18 Claims |
| 1. An inverse telephoto with correction lenses comprising five lens elements with refractive power, from the object side to
the image side:
a first lens element with negative refractive power having a concave image-side surface;
a second lens element with positive refractive power having a convex image-side surface;
a third lens element with a convex object-side surface;
a fourth lens element with a concave image-side surface;
a fifth lens element with positive refractive power having a convex image-side surface, at least one of surfaces of the fifth
lens element being aspheric; and
an aperture stop located between the first lens element and the second lens element;
in the optical lens system, at least three of the surfaces of the first, second, third, fourth and fifth lens elements are
aspheric;
an object to be photographed is imaged on an electronic sensor, a total track length of the optical lens system is TTL, an
image height of the optical lens system is ImgH, and they satisfy the relation:
TTL/ImgH<4.75.
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