Three-element photographic objective with reduced tolerance sensitivities
US7477461B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 2006 |
| Grant date | Jan 13, 2009 |
| Priority date | — |
| Expiry date | Feb 18, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/021
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention is a compact lens system for use as a wide-field photographic objective with small format digital image sensors having a pixel dimension less than 0.010 mm. The f-number of the lens system is 2.9740, and the effective focal length of the system is 3.85 mm. The full angular field of view of the lens system is 61 degrees, and the chief ray incidence angles on the image plane are less than 18 degrees. The system comprises three plastic lenses, each having two aspheric surfaces. At least one of the aspheric surfaces in the system is coated with a multilayer infrared cut-off filter for blocking infrared wavelengths from the image sensors. The lens system has a reduced sensitivity to manufacturing tolerances, particularly lateral misalignment of optical elements and surfaces.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.