Variable magnification observation optical system
US9709780B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 1, 2014 |
| Grant date | Jul 18, 2017 |
| Priority date | — |
| Expiry date | May 1, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0025
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
These variable-magnification observation optical systems are provided with an objective system, an erecting system, and an eyepiece system. In order from the object side, the objective system has a positive first lens group, a positive second lens group, and a negative third lens group. In order from the object side, the eyepiece system has a positive fourth lens group and a positive fifth lens group. The erecting system is located between the first and second lens groups. In order from the object side, the fifth lens group has the following, with air gaps in between: a negative meniscus lens element, the concave surface of which faces the object side; a negative meniscus lens element, the convex surface of which faces the object side; and a biconvex positive lens element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.