Effect of Filament Length on Performance of Drum Lenses,

摘要

The peak beam candlepower of a lens-lamp combination depends upon the size and shape of the lamp filament. This relationship can be stated in terms of the variation of lens-to-lamp candlepower ratio with lamp filament length. Previous tests showed that the lens-to-lamp ratio increases with decreasing filament length. These previous tests were made with filaments having lengths from about 6millimeters to 3.6millimeters. In this report,measurements of lens to lamp ratios are presented for filaments having lengths of from 6millimeters to 2.5millimeters. These measurements are given for a 200millimeter pressed glass drum lens, 300millimeter pressed glass closed top drum lens,and a 375millimeter cut-glass drum lens. (Modified author abstract)