Apochromat type objective lenses
US4854686A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 5, 1988 |
| Grant date | Aug 8, 1989 |
| Priority date | — |
| Expiry date | May 5, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B9/34
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An apochromat type objective lenses, which is applied to an astronomical telescope; a telephoto lens for cameras or the like, comprising a semiapochromatic first lens system synthesized lens composed of two lenses in one group consisting of a convex lens and a concave lens, and an achromatic second lens system synthesized lens composed of two lenses in one group consisting of a concave lens and a convex lens, which is arranged in a spaced apart relation behind the semiapochromatic first lens system; the first and second lens systems being fulfilled with the condition below: ##EQU1## where, f, f: the focal length of the first and second lens systems, PA1 K, K: the proportion of the residual secondary chromatic aberration of the first and second lens systems, and PA1 L: the mutual spacing between respective lens systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.