An Optical System for the Reproduction of Sound from 35-mm. Film
An optical system has been designed and tested for use in 35-mm. sound reproducers. It is the slitless type, and gives a scanning image that is 0.001 inch wide when used with an exciter lamp having a coil diameter of 0.055 inch. A toric lens is used to form a curved-line image of the filament of the lamp. This curved image is then re-imaged by a highly corrected objective lens of numerical aperture 0.28. The objective lens has inherent curvature of field, but this curvature is compensated by the curvature of the line-image formed by the toric lens so that the final image is flat. The toric lens also acts as a condenser lens to throw an image of the filament into the objective lens. Careful tests of samples show that the final image is flat, straight, and of uniform width and intensity.
- Print ISSN
- 0097-5834
- Published
- 1938-07
- Content type
- Original Research
- DOI
- 10.5594/J14652