Negative Test Method as an Aid in Condenser Design

A new method is outlined for testing the performance of a projecting system including light sources, condensing, and projecting lenses. The usual conditions are reversed, the light source being replaced by a dark target possessing identical dimensions and surrounded by a lighted area. Under such conditions perfection of adjustment is indicated by a uniformly dark screen. Any departure from correct adjustment is indicated by the presence of light patches. A new two lens condensing system is described which gives a gain of approximately 50 per cent in the screen brightness. The effect upon screen brightness of various factors such as spherical aberration in the condensing lens and lack of correct adjustment of the component parts of the system is discussed.

Print ISSN

0096-6460

Published

1922-05

Content type

Original Research

DOI

10.5594/J12455