ES383463A1 - Symmetrical copying lens system - Google Patents

Abstract

A system of symmetrical lenses for copies of the Split Dagor type that has an aperture not greater than F (4.5) that increases the image formed in this regard between IX and 1.6X, said lens system being corrected for spherical aberration and Chromatic aberration including secondary color, lateral and longitudinal chromaticism, coma, astigmatism, distortion and field curvature comprising: (a) a front composite component including lens elements I, II and III between the plane of the object and the diaphragm; (b) a posterior composite component including IV, V, and VI lens elements between the diaphragm and the imaging plane; (c) the two outer lens elements I and VI being of equal positive power and being symmetrically positioned around the diaphragm, the two inner lens elements III and IV being of equal positive power and being positioned adjacent to the diaphragm symmetrically around it, and the lens elements II and V being of equal negative power, the lens element II being placed between the lens elements I and III and glued to the lens element I and the lens V between lens elements IV and VI and glued to lens element VI; (d) providing the numerical values relating to the construction data of the lens system in a table below, in which R1 to R10 represent the radii of curvature of successive lens surfaces, and the minus sign (-) used in relation to it means that the radius of the designated surface has its center of curvature located on the input side of the lens system with respect to the vertex of said surfaces: (see graph) in which Nd and v are absolute values for the refractive index and Abbe number of the glass, respectively, from which the lens elements are manufactured. (Machine-translation by Google Translate, not legally binding)