Lamp filament configuration for use in a drum lens
US4175244A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1978 |
| Grant date | Nov 20, 1979 |
| Priority date | — |
| Expiry date | Sep 11, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01K1/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The improvement in a filament system in a lamp for use in a drum lens of a navigational light in which a plurality of vertically positioned similar filaments are spaced about but away from a vertical axis adapted to be placed at the focal point of the lens. The filaments are positioned in a horizontal plane relative to each other whereby no more than two filaments are aligned in any horizontal direction. In using four filaments, three of the filaments are positioned at the corners of a horizontal square and the fourth filament is positioned outside of tne unoccupied corner of the square and in line with the diagonal of the square through the unoccupied corner thereby minimizing shadowing of one filament by other filaments in any horizontal direction. The vertical height of the filaments are short, such as approximately ten millimeters thereby confining the beam spread from the lens and the filaments are positioned close to the center of the square for minimizing defocusing of the light passing through the lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.