| DIG 439 |  | CONVERSION SCREENS FOR THE CONVERSION OF THE SPATIAL DISTRIBUTION OF X-RAYS OR PARTICLE RADIATION INTO VISIBLE IMAGES (e.g., fluoroscopic screens) [G21K-4/00] *** (photographic processes using X-ray intensifiers G03C-5/17; discharge tubes comprising luminescent screens H01J-1/62; cathode-ray tubes for X-ray conversion with optical output H01J-31/50) |