| 摘要 |
A compact short back focus imaging lens system with two lenses is revealed and includes along the optical axis from an object side to an image side: an aperture stop, a first lens with positive refractive power that is a meniscus aspherical lens with convex surface facing the object side, a second lens with negative refractive power that is a meniscus aspherical lens with convex surface facing the image side, an IR cut-off filter and an image sensor. Moreover, the following conditions are satisfied by the imaging lens system: - 0.3 ≤ f 1 f 2 ≤ - 0.01 0.25 ≤ bf TL ≤ 0.4 wherein f1 is focal length of the first lens, f2 is focal length of the second lens, bf is back focal length of the imaging lens system, and TL (overall length) is the distance from the aperture stop to the image plane. Thus, the imaging lens system of the present invention has short back focal length effects and reduced overall length so as to achieve the requirement of minimized volume for mobile phones or mini-cameras.
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