Illumination unit using LED and image projecting apparatus employing the same
US7182497B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 2005 |
| Grant date | Feb 27, 2007 |
| Priority date | — |
| Expiry date | Aug 31, 2025 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF21Y2115/10
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An illumination unit is provided which includes a glass rod including a parabolic reflection surface, a light incident surface facing the parabolic reflection surface, a concave portion formed inwardly in the light incident surface at a position of a focal point of the parabolic reflection surface, and a light guide portion facing the parabolic reflection surface and having a rectangular section. An LED module is disposed at the focal point of the parabolic reflection surface and emitting light to the parabolic reflection surface through the concave portion. A surface of the light guide portion parallel to the light incident surface is stepped from the light incident surface in a direction in which the rectangular section of the light guide portion decreases.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.