| 摘要 |
An aspherical single lens of compact construction and good image-forming performance which is obtained by shaping the first surface into such an aspherical configuration the curvature radius of which increases gradually toward the periphery from the center while satisfying the following conditions: 0.42<q<1.3 (a) and 0.5(f-1)<d<1.2f (b) wherein, q=-r1/r2, r1 is the curvature radius in the vicinity of the optical axis of the first surface, r2 is the curvature radius of the second surface, f is the focal length and d is the thickness of the lens.
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