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Imaging lens
 
   
Document Number
US Patent 7388721
Issued Date
June 17, 2008
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Abstract
An imaging lens (100) comprising, arranged sequentially from the object side, a positive-meniscus first lens (1) with its convex plane facing the object side, a negative-power-meniscus second lens (2), and a positive-power third lens (3), the second and third lenses (2, 3) functioning as correction lenses. The first lens (1) has a strong power, and both the second and third lenses (2, 3) are aspherical on opposite planes. When the synthetic focal distance of the imaging lens is f, the focal distance of the first lens f1, the distance from the incident surface on the object side to the imaging surface of the first lens (1) .SIGMA.d, and the Abbe number of the second lens d2, the following conditional expressions are satisfied. 0.50<f1/f<1.5 (1) 0.50<.SIGMA.d/f<1.5 (2) 50> d2 (3). Accordingly, a small, low-cost imaging lens capable of high-quality imaging can be realized.
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Number of Claims:
3
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Published
June 17, 2008
Application Number
11/639,096
Filed
December 14, 2006
US Classification
359/716   359/689 359/690 359/785
Int'l Classification
G02B   13/18   (20060101)  
Examiner
Assistant Examiner
Parent Case
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional of U.S. patent application Ser. No. 10/532,382, filed Apr. 21, 2005, now U.S. Pat. No. 7,251,083.
USPTO Field of Search
359/687   359/689   359/690   359/713   359/714   359/715   359/716   359/758   359/766   359/773   359/774   359/780   359/785   359/792  
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