| 摘要 |
A photochromic projection system wherein indicia appearing on a cathode ray tube, and forming an opaque image on an ultraviolet-sensitive film positioned against the end face of the cathode ray tube, is imaged upon a viewing screen after passing through a transparent map. A pair of dichroic filters are used both of which reflect yellow and green radiation so that only the yellow and green portion of the radiation from an external illuminating source for the film is reflected to the film. The red and blue portion of the source radiation is transmitted through one of the dichroic filters and reflected from a mirror through the second dichroic filter where it is recombined with the yellow and green light reflected from the face of the cathode ray tube and from the second dichroic filter to provide an image in white light which then is directed through the transparent map onto the viewing screen.
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