Lens structure

US3992078A · kind A · utility

Assignee

• The Rank Organisation Limited

Inventors

• David Freeman · Tampa, US
• Brian Blandford · London, GB

Key dates

• Filing date: May 6, 1975
• Grant date: Nov 16, 1976
• Expiry date: May 6, 1995

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B13/14
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An optical objective for the infra-red wave band, comprising front and rear simple positive lens elements each made of Germanium, said elements being axially spaced by a distance S lying between 0.8F and 1.2F, the rear surfaces of said elements being plane or convex to the front with radii of curvature greater than 10F and the front surface of each element being convex to the front with a radius of curvature less than the radius of curvature of its rear surface.