Telescopic camera
US5071238A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 1989 |
| Grant date | Dec 10, 1991 |
| Priority date | — |
| Expiry date | Nov 8, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B9/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is a lens system for a telescopic camera comprised of a primary lens, a secondary lens and a tertiary lens. The primary lens is a positive lens having a convex front surface and an aspheric back surface which define an optical axis. The secondary lens is a negative lens which has a concave front surface and a concave back. The front surface of the secondary lens is positioned at a predetermined fixed distance adjacent to the back surface of the primary lens and centered with respect to the optical axis. The tertiary lens is a field flattening lens having a convex front surface and a convex back surface. The front surface of the tertiary lens is positioned at a predetermined fixed distance adjacent to the back surface of the secondary lens, wherein the primary, secondary and tertiary lenses have surfaces shaped to focus on an object viewed such that a field of view of about 4.2.degree. is produced, and said lens system is capable of capturing approximately 94% of all incident photons within the optical axis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.