Objective optical system for endoscope
US9939627B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 8, 2017 |
| Grant date | Apr 10, 2018 |
| Priority date | — |
| Expiry date | May 8, 2037 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/18
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An objective optical system for endoscope includes, a first group having a positive refractive power, an aperture stop, and a second group having a positive refractive power, wherein the first group includes a first lens having a negative refractive power, and a second lens having a positive refractive power, the second group includes a cemented lens, and the cemented lens includes a third lens having a positive refractive power and a fourth lens having a negative refractive power, and the following conditional expressions (1), (2), (3), (4), (7) and (9) are satisfied:0.13≤La/Lb≤0.17 (1),−2.7≤f4/f≤−2.2 (2),−0.7≤(ne2×f2)/(ne4×f4)≤0 (3),2.5≤νd3/νd4≤3.5 (4)−2.6≤r2o/rcc≤−2 (7), and−1.2≤r2i/f2≤−0.9 (9).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.