The Function of the Condenser in the Projection Apparatus

Light radiates from every point of a source in all directions. If we had a very intense, and at the same time cold, point-shaped source, projection would be possible without any additional optical apparatus. Supposing we have such a source s separated by the distance d from a stencil t and at a distance D from the projection screen, the size of the image on the screen would be $\frac{\mathrm{D}}{\mathrm{d}}$ times the actual size of the Stencil or, differently expressed, the magnification $\mathrm{M}+\mathrm{M}=\frac{\mathrm{D}}{\mathrm{d}}$. The magnification may be changed in two ways: (a) By keeping the projection distance D constant and varying the distance between source and stencil. (b) By keeping the distance d the same and varying the projection distance.

Print ISSN

0096-6460

Published

1918-11

Content type

Original Research

DOI

10.5594/J17996