Fresnel lens
US5151826A · kind A · utility
13Cited by
2References
7Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 8, 1991 |
| Grant date | Sep 29, 1992 |
| Priority date | — |
| Expiry date | Mar 8, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/193
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A fresnel lens in which each of the facets is so dimensioned and configured that the distance between the facet and a focal point of the lens is (n+k) .lambda. where n is an integer, .lambda. is the wavelength of the radiation passing through the lens, and k is a fraction between 0 and 1 which is substantially constant for any facet over the entire face of the lens. Preferably the lens comprises a plurality of zones, each comprising a number of facets, the integer n being constant for each facet of each said zone, but being different for facets of different zones.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.