| 摘要 |
PURPOSE:To obtain an image-forming lens which has aberrations compensated well and has such wide field angle that it can be applied to a photographic lens or the like, by using a medium having a refractive index distribution and constituting a lens system with a small number of lenses. CONSTITUTION:This lens system is formed with two lenses consisting of a medium whose refractive index is changed continuously in accordance with the distance from the optical axis. The first lens arranged in the object side has such concave shape that the thickness is smallest on the optical axis and is increased according as going away from the optical axis, and further, the first lens has a meniscus shape whose concave is directed to the image side. The second lens arranged in the image side has a concave shape, and the image-side face of the second lens is plane or a concave. The first and the second lenses have the refractive index distribution where the refractive index is highest on the optical axis and is reduced gradually according as going away from the optical axis. |
