| 摘要 |
<PICT:1005072/C4-C5/1> In an optical information display apparatus, such as for producing a trace, representing the course of a moving object, superimposed on a map, a photochromic film 24, Fig. 2, is used which is normally in a clear transmissive state but is rendered light absorptive by ultraviolet light, and the composite image produced on the film 24 is projected by a lens system 26 on the screen 12. To increase the persistency of the traces on the photochromic film 24, the latter is enclosed in a refrigerated chamber and a number of such films may be mounted on a disc for selective interposition into the beam. The apparatus is described in detail in Division G2. Specification 930,355 is referred to. |
