Optical element and illumination device using the same
US9200777B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 2012 |
| Grant date | Dec 1, 2015 |
| Priority date | — |
| Expiry date | May 7, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H20/855
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An illumination device for planar light sources gives uniform illumination on an illuminated plane. A of lengthwise direction and length of breadthwise direction are different from each other. The illumination device includes a planar light source and an optical element including a light receiving surface for receiving light form the planar light source and a light exiting surface. A shape of the planar light source is symmetric with respect to x-axis and y-axis and a length of the shape in x-axis direction is shorter than length of the shape in y-axis direction; the center of the planar light source is set as the origin and two axes orthogonal to each other are selected as x-axis and y-axis. Assuming that the maximum value of x-coordinate of the planar light source is a and the maximum value of y-coordinate of the planar light source is b, the following relationships hold:
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.