Neon-tube substitute using light-emitting diodes
US8256918B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 2008 |
| Grant date | Sep 4, 2012 |
| Priority date | — |
| Expiry date | Jul 10, 2029 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF21Y2115/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A tubular luminaire efficiently utilizes the light of a line of high-brightness unlensed LEDs to reproduce the homogeneous appearance of a neon tube. The transparent tube has an annular cross-section suitable for cost-effective manufacturing by extrusion. The LEDs are mounted in a line on a circuit board that can be positioned either inside or outside the tube. Their light shines into a cylindrical groove, thereby entering within the material of the tube. Above the groove, the wall of the tube has a spiral shape that reflects the light laterally so that it stays within the annular tube for a considerable path length. Volume scattering by a low density of scattering inclusions causes the light to escape as a homogenous glow. Alternatively, mild surface scattering from the inside surface can be used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.