| 摘要 |
A five-lens image lens system is revealed. The five-lens image lens system includes a first lens group with a negative power and a second lens group with a positive power. Along an optical axis in order from an object plane to an image plane, the first lens group includes a negative first lens and a negative second lens while at least one of optical surfaces of the first lens and the second lens is an aspherical optical surface. The second lens group includes a positive third lens, a positive fourth lens, and a negative fifth lens from the object plane to the image plane while an image-side lens surface of the positive fourth lens is glued with an object-side lens surface of the negative fifth lens. The image lens system satisfies the following conditions: 2R2>R4>R2, 2|F12|<|F34|, and Vd1>Vd2, Vd4>Vd5; wherein R2, R4 respectively represent curvature radius of the image-side lens surface of the negative first lens and the negative second lens; f12, f34 respectively represent focal length of the negative first lens and the negative second lens; Vd1, Vd2, Vd4, Vd5 respectively are Abbe numbers of the first lens, the second lens, the fourth lens, and the fifth lens. Thus the image lens system has features of wide viewing angle, small Fno, high brightness, high resolution, and effectively minimized length (through the lens, TTL). Therefore, the applications and effects of the image lens system are improved and especially suitable for lens of EDR (Event Data Recorder) of car safety systems.
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