Apparatus for illuminating medical diagnostic imaging film with enhanced viewability

摘要

View box apparatus is provided for illuminating a film containing a medical diagnostic image for radiologic observation and study. A light source is contained within the view box, at one end thereof, and a transparent plate is positioned at the other end for supporting the imaging film. A panel of material is positioned in the box between the light source and the transparent plate to diffuse light from the source, and one or more layers of a microprism film is positioned between the diffuser panel and the imaging film. The microprism film layer reflects light rays which are incident thereon at an angle less than a critical angle back into the view box, so that such light rays do not pass through the microprism film to illuminate the imaging film. Light rays incident upon the microprism film which are greater than the critical angle are refracted by the microprism film, to provide light for illuminating the imaging film having a solid angle which is much less than the solid angle of light from the diffuser. Accordingly, the microprism film serves to substantially reduce scatter, and thereby significantly improves resolution and contrast for an observer of the imaging film.