Effect of Filament Length on Performance of 300mm Closed Top Drum Lens,

摘要

The 300mm closed top drum lens,produced by the Corning Glass Company,was designed for a point source of light placed at the lens'center. Since actual light sources are not ideal point sources,but are usually vertical tightly coiled filaments,it was desired to determine the performance of the lens as the filament size was varied. A number of standard marine aids to navigation lamps was examined,and twelve lamps with graded filament lengths were used to measure the lens-to-bare-lamp candlepower ratio provided by the 300mm lens. (Modified author abstract)