Illuminating device
US8118457B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 20, 2010 |
| Grant date | Feb 21, 2012 |
| Priority date | — |
| Expiry date | Dec 20, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H20/855
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An illuminating device includes a light source and a light receiving surface, first and second light exit surfaces. When a point at the edge of the light emitting surface is P2 and an axis which passes through a center P1 of a light emitting surface and is perpendicular to the light emitting surface is an optical axis, the optical element has a hollow around the optical axis. The first light exit surface is such that x coordinate of a point most distant from the optical axis on the first light exit surface is at least 1.5 times x coordinate of P2, that in 80% or more of an area in which x coordinate of a point is at least the x coordinate of another point P3, an angle of incidence of light emitted at P1 is at least the critical angle and that in 80% or more of an area in which x coordinate of a point is equal to or smaller than x coordinate of another point P4, an angle of incidence of light emitted at P2 is smaller than the critical angle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.