Title: Symmetrical type four-component lens system

Abstract: A symmetrical type four-component lens system comprises, in the direction of incidence of light, a first lens component, a second lens component, a stop, a third lens component and a fourth lens component. Each lens component is a combination of a positive and a negative lens element, the concave surface of each element facing the stop. The surfaces of the first and fourth components facing the stop have shorter radii of curvature than the surfaces of the second and third components facing away from the stop. The first and fourth components have greater focal lengths than the second and third components. The second and third components satisfy certain conditions relating to the materials forming them.

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Inventors: Kawakami, Tadashi (Tokyo, JA)

Application Number: 447678
Filing Date: 1974-03-04
Publication_date: 1976-03-02
Assignee: Nippon Kogaku Kabushiki Kaisha (Tokyo, JA)
Primary Class(es): 359/772
Other Classes:
US Patent Ref:

2713809	Jul, 1955	Cook	350/220.
3672748	Jun, 1972	Doi et al.	350/220.

Other Refs:
Primary Examiner: Corbin, John K.
Assistant Examiner:
Attorney: Shapiro and Shapiro