Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens (photographic processes using X-ray intensifiers G03C5/17; discharge tubes comprising luminescent screens H01J1/62; cathode ray tubes for X-ray conversion with optical output H01J31/50)

Filing statistics

CPC G21K 4/00 belongs to the parent subclass G21K, which recorded 13,768 patent applications worldwide between 2013 and 2023. Annual filings declined from 1,483 in 2013 to 927 in 2023 (-37%), peaking at 1,598 applications in 2014. The most active applicants in class G21 are CHINA GENERAL NUCLEAR POWER CORPORATION (1,383 applications), WESTINGHOUSE ELECTRIC CORPORATION (1,347 applications) and KOREA ATOMIC ENERGY RESEARCH INSTITUTE (1,303 applications).

Source: EPO PATSTAT, worldwide filings