Fresnel lens and projection display device using one such lens
US8009354B2 · kind B2 · utility
1Cited by
6References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 7, 2005 |
| Grant date | Aug 30, 2011 |
| Priority date | — |
| Expiry date | Dec 9, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/74
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A Fresnel lens comprises at least one first prism and one second prism. Each prism has a first side and a second side which forms with a main axis an angle greater than that formed by the first side and the main axis. Conventionally, the second side of the first prism collimates the light received from a light source in line with the main axis. In order to improve the optical effectiveness, the second side of the second prism transmits the light received from the source in a first direction slightly different from the main axis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.