| US 7,463,433 B2 | ||
| Optical lens assembly | ||
| Hsiang Chi Tang, Taichung (Taiwan) | ||
| Assigned to Largan Precision Co., Ltd., Taichung (Taiwan) | ||
| Filed on Oct. 12, 2006, as Appl. No. 11/549,102. | ||
| Claims priority of application No. 95128678 A (TW), filed on Aug. 04, 2006. | ||
| Prior Publication US 2007/0236812 A1, Oct. 11, 2007 | ||
| Int. Cl. G02B 9/10 (2006.01) | ||
| U.S. Cl. 359—795 [359/717; 359/736; 359/793] | 9 Claims |
| 1. An optical lens assembly comprising two plastic lenses with refractive power: from the object side to the image side:
a first lens with positive refractive power, a front surface and a rear surface of the first lens being convex and aspherical,
a refractive index N1 of the first lens satisfies the relation: 1.6>N1>1.5, a focal length of the first lens is f1, and a focal length of optical system is f, and they satisfy the relation: f/f1>2.0;
a second lens with negative refractive power, a front surface of the second lens being concave, a rear surface of the second
lens being convex, and both the front and rear surfaces being aspherical, a refractive index N2 of the second lens satisfies the relation: N2>1.55;
wherein an aperture is located in front of the first lens for controlling the brightness of the optical system;
the focal length of the second lens is f2, and the focal length of optical system is f, and they satisfy the relation: |f/f2|<1.0.
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