Solar powered lamp having a cover containing a fresnel lens structure
US5228772A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 9, 1991 |
| Grant date | Jul 20, 1993 |
| Priority date | — |
| Expiry date | Aug 9, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S136/291
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A solar powered light comprises a cover containing a fresnel lens structure (also referred to as a fresnel lens cover) which is disposed directly above and adjacent to a photovoltaic cell thereof. The fresnel lens cover comprises a continuous and smooth outer surface and a prismatic inner surface having a plurality of prismatic means arranged in concentric circles to bend incoming radiation, especially at high angles of incidence, such as during winter months or at the beginning or end of a day, toward an optical axis thereof. The prisms have different thicknesses and are arranged in different angular configurations to accomplish the desired bending at each point of the cover. In a preferred embodiment, additional prismatic means are formed on a peripheral portion of the outer surface to cover a photodetector used for sensing the absence of light and triggering circuitry to turn on the solar powered lights.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.