Inverse triplet lens assemblies
US6414802B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 1, 2000 |
| Grant date | Jul 2, 2002 |
| Priority date | — |
| Expiry date | Dec 1, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/04
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Objective lenses employing three lens units U1, U2, U3 having a negative (or weak positive); positive; negative optical power configuration are disclosed. The lenses have a total field coverage of at least 50 degrees with a relative aperture of less than f/5. They employ small lens elements having aspherical surfaces and are designed for mass production, particularly using plastic optical materials. Designs for these lenses do not exist in all-spherical form, because the aberrations, particularly distortion, cannot be sufficiently corrected; however, by using a sufficient number of aspherical surfaces, not only can the aberrations be corrected to a higher degree than a conventional aspherized triplet design, but the sensitivity of the design to manufacturing deviations can also be minimized. Optionally, these lenses can include a fourth lens unit U4 which provides an extended pupil, which is desirable when the lens is used with a digital light sensor
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.