Wide band color correcting infrared lens system
US4999005A · kind A · utility
Inventor
Key dates
| Filing date | Oct 19, 1988 |
| Grant date | Mar 12, 1991 |
| Priority date | — |
| Expiry date | Oct 19, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/146
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An infrared refractive lens triplet having color correcting properties for radiation within the 3 to 13 micrometer spectral band. In certain embodiments of the invention the triplet is capable of simultaneously focusing radiation in the 3-5 micrometer and the 8-12 micrometer atmospheric windows for imaging about a single focal plane. In these embodiments one lens comprises germanium and another is formed of materials selected from the group consisting of sulfides and selenides of zinc and combinations thereof. A third lens is a glass characterized by chromic properties corresponding approximately to EQU 40<V<46 EQU with EQU V=(N.sub.D -1)/(N.sub.13 -N.sub.3), wherein: PA1 N.sub.D is the refractive index at 8 micrometers, PA1 N.sub.13 is the refractive index at 13 micrometers, and PA1 N.sub.3 is the refractive index at 3 micrometers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.