How many electron microscopes are there in the world?

I would guess around 50,000 - including industrial tools. Every semiconductor plant, university and research institute have tens of EM tools. read more

Electron microscopes are used when the specimens are too small for optical microscopes as they have wavelengths around 100,000 times shorter than visible light and can achieve magnification levels of up to 10,000,000x. read more

Two years later, in 1933, Ruska built an electron microscope that exceeded the resolution attainable with an optical (light) microscope. Moreover, Reinhold Rudenberg, the scientific director of Siemens-Schuckertwerke, obtained the patent for the electron microscope in May 1931. read more