Method of manufacturing an electrode-less incandescent bulb
US8702465B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 2012 |
| Grant date | Apr 22, 2014 |
| Priority date | — |
| Expiry date | Jul 13, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J65/044
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The manufacture of an electrodeless bulb involves one end of a tube closed off, and a first neck is formed in the tube close to the closed end. A second neck is formed in the tube, close to the still open end; a metal halide pellet of known size is dropped into the tube and the tube is evacuated. With the vacuum being maintained heat is applied to the closed end, causing the metal halide pellet to sublime and with it the impurities. The impurities are drawn off, the vacuum being maintained and the metal halide condenses in the tube between the necks. Once the tube is cool, the evacuation is discontinued and the tube is refilled with noble gas and the quartz tube is sealed off at the second neck.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.