Objective optical system and endoscope using same
US9063340B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 2014 |
| Grant date | Jun 23, 2015 |
| Priority date | — |
| Expiry date | Apr 30, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B9/34
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An objective optical system includes: a negative first lens group; an aperture stop; and a positive second lens group, provided in this order from an object side. The first lens group includes a first lens, which is a negative single lens, and a cemented lens formed by cementing a positive lens and a negative lens together, provided in this order from the object side. The second lens group includes a fourth lens, which is a positive single lens, and a cemented lens formed by cementing a positive lens and a negative lens together, provided in this order from the object side. The objective optical system satisfies Conditional Formula (1): f1/f<1.1, wherein f1 is the focal length of the lens provided most toward the object side, and f is the focal length of the entire lens system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.