Objective for an endoscope
US4806001A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 1987 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Jan 28, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B23/243
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An objective for an endoscope comprising, in the order from the object side, a first lens unit I having negative refractive power, a second lens unit II having positive refractive power, a third lens unit III having positive refractive power, an aperture stop S arranged between the front end of the second lens unit and rear end of the third lens unit and a fourth lens group IV comprising a lens component which has a concave surface on the object side, the four unit objective for an endoscope being arranged so that the overall length is short, outer diameter of the objective is small, angle of view is wide, intensity of light in the marginal portion is high, and distortion is corrected favourably.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.