| 摘要 |
An image-forming lens, of the retro-focus type, having only two lens elements is disclosed. By making the object-side of the first lens element, in order from the object side, be a convex surface, and by satisfying two specified conditions, an image forming lens having a wide image angle, low distortion, and with a sufficiently large back focus for insertion of other optical components between the lens and the image plane is achieved, while simultaneously providing a compact and low-cost lens construction. By making at least one surface of each lens element be aspherical, a high-quality image is provided. In the preferred embodiments disclosed, both surfaces of each lens element are made aspherical.
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