Incandescent halogen lamp with protective envelope coating
US4256988A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 26, 1978 |
| Grant date | Mar 17, 1981 |
| Priority date | — |
| Expiry date | Dec 26, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01K1/32
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention relates to electric incandescent lamps having a gas fill containing halogen. The internal surface of the lamp envelope and optionally also the exposed surface of internal components of the lamp are protected from attack by halogens including fluorine by a continuous imperforate coating composed of a metal oxide resistant to halogen attack. In order to achieve the necessary degree of continuity of the coating the oxide is formed in situ from a compound of the metal deposited as a solution on the surface. The preferred oxide is alumina, the other oxides of polyvalent and transition metals, including metals of the lanthanide series may be used. The coatings are preferably formed from solutions of halides of the metals in polar organic solvents such as methanol. The invention prolongs the life of lamps provided with the protective coating and enable such resistant and possibly cheaper materials to be employed for certain lamp components.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.