Ernst Ruska

German physicist (1906 to 1988) who, as a doctoral student under Max Knoll at the Technische Hochschule Berlin, helped build the first electron microscope in 1931 and achieved resolution beyond that of light microscopy by 1933; he was associated with Siemens from 1937 to 1955, where he helped mass-produce the instrument, and was awarded half of the 1986 Nobel Prize in Physics for the invention.