Dual grooved Fresnel lens for overhead projection
US5803568A · kind A · utility
4Cited by
5References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 1, 1996 |
| Grant date | Sep 8, 1998 |
| Priority date | — |
| Expiry date | Aug 1, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B3/08
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A Fresnel lens is optimized for an overhead projector by increasing its transmission efficiency through a balancing of loses due to riser blockage and surface reflection and by introducing coma in the Fresnel lens which reduces the size of the projected image of the light source filament.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.