Objective lens system for an endoscope
US4867546A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1988 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Mar 14, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/06
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An objective lens system for an endoscope comprising a front lens unit, a stop, and a rear lens unit wherein the front lens unit comprises a lens component arranged that the surface on the object side thereof is formed as an aspherical surface having portions whose curvature is made gradually stronger as they are farther from the optical axis or a lens component arranged that the surface on the image side thereof is formed as an aspherical surface having portions whose curvature is made gradually weaker as they are farther from the optical axis, and the rear lens unit comprises a lens component arranged that the surface on the image side thereof is formed as an aspherical surface having portions whose curvature is made gradually stronger as they are farther from the optical axis or a lens component arranged that the surface on the object side thereof is formed as an aspherical surface having portions whose curvature is made gradually weaker as they are farther from the optical axis, the objective lens system for an endoscope being arranged that distortion and curvature of field are corrected favorably.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.