Compact incandescent coiled coil filament
US4683397A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 14, 1986 |
| Grant date | Jul 28, 1987 |
| Priority date | — |
| Expiry date | Apr 14, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01K1/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
This invention provides an improved compact fine wire incandescent lamp filament and method for making such having a primary mandrel ratio in the range of about 1.40 to about 4.00 and a secondary mandrel ratio which is greater than or equal to the primary mandrel ratio. The improved filament design exhibits an increase in compactness and retains or increases structural rigidity while exhibiting minimal sag when the filament is incorporated into an incandescent lamp of the tungsten halogen type variety. The compact coiling method is particularly useful in designing compact filaments for high voltage applications where it is desirable to eliminate the use of rectifying means to lower the effective voltage across the filament.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.