| 摘要 |
PURPOSE:To obtain a wide-field-angle photographic lens which has various aberrations compensated excellently by isuing two distributed index lenses. CONSTITUTION:This lens consists of two lenses which vary in refractive index continously with the distance from the optical axis. The 1st lens arranged at an object field side is thickest on the optical axis, and becomes thinner and thinner according to the distance from the optical axis, and the refractive index distribution has the largest refractive index on the optical axis and decreases in refractive index according to the distance from the optical axis. The 2nd lens arranged at the image field side is thickest on the optical axis and increases in thickness according to the distance from the optical axis, and its refractive index distribution has the maximum refractive index on the optical axis and decreases in refractive index according to the ditance from the optical axis. The 1st and the 2nd lens both have positive power; and the object-field side surface of the 1st lens is convex to the object field side and the object-field side of the 2nd lens is concave to the object field side. |
