| 摘要 |
965,015. Optical objectives. ISCO OPTISCHE WERKE G.m.b.H. March 19, 1962 [May 9, 1961], No. 10355/62. Heading G2J. The objective has an angle of field of about 80 degrees and comprises a dispersing system, formed by a meniscus lens I, and a meniscus doublet II, and separated by an air span d 5 greater than the equivalent focal length, which is less than the back focal length, from a convergent lens system in which there is a convergent doublet III, a convergent meniscus IV, a divergent lens V and a convergent doublet VI. In the objective, the powers D 1 , D 2 and D 3 of the three cemented surfaces are such that:- The divergent lens V has an axial thickness greater than 10% of the equivalent focal length. Specification 816,898 is referred to.
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