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Joined 2026-09-21 Message
Incoming links: Ernst Ruska
Ernst Ruska and Max Knoll developed electron optics while improving the writing spot of a cathode-ray oscilloscope.[ref]
The Development of the Electron Microscope and of Electron Microscopy by Ernst Ruska. Ruska, Nobel lecture, §C; RMP reprint pp. 628–629
A structured object tests image formation more strongly than a single bright spot: each feature must retain its own image position.On 7 April 1931, a cold cathode source and two short magnetic coils imaged aperture grids at . A platinum grid preceded the first coil; a bronze grid preceded the second. The fluorescent screen showed one-stage grid images and the first grid reimaged through both stages. Comparing these patterns tested successive image formation, not merely beam concentration. Heating could destroy even metal grids. This prototype did not establish resolution beyond an optical microscope.[ref]
The Development of the Electron Microscope and of Electron Microscopy by Ernst Ruska. Ruska, §E, Figs. 2–3; RMP reprint p. 630: dated one-stage and two-stage comparison
In 1933, Ruska measured focal lengths at with a pole-piece lens, then built an instrument giving -fold magnification.[ref]
The Development of the Electron Microscope and of Electron Microscopy by Ernst Ruska. Ruska, §E, Figs. 4–5; RMP reprint p. 631
TU Berlin dates images surpassing conventional optical microscope resolution to 1933.[ref]Ernst Ruska by Technische Universität Berlin. TU Berlin, indexed historical biography: 1933 prototype surpassing light-microscope resolution
A fluorescent screen converts the spatial Electron distribution into visible light.[ref]
Transmission Electron Microscope (TEM) by JEOL. JEOL, The difference between Electron Beam and Light: fluorescent image readout
A collector reporting only total electric current would discard that spatial pattern. In a two-stage image relay, the first lens makes an intermediate real image; the second treats that image as its object. The diagram below illustrates this geometry with invented distances and an ideal beam. Max Knoll 2026-10-18
An electrical engineer who co-invented the electron microscope with Ernst Ruska.[ref]
https://collection.sciencemuseumgroup.org.uk/people/cp50265/max-knoll. Max Knoll, 1897–1969: occupation Electrical engineer; co-invention with physicist Dr Ernst Ruska
Nobel Prize in Physics in 1986 2026-10-18
Ernst Ruska received one half for fundamental work in electron optics and designing the first electron microscope. Gerd Binnig and Heinrich Rohrer received one quarter each for designing the scanning tunneling microscope.[ref]
The Nobel Prize in Physics 1986 by Nobel Prize Outreach. Individual official 1986 summary: Ruska one half for electron optics and the first electron microscope; Binnig and Rohrer one quarter each for scanning tunneling microscopy.
By Ernst Ruska. Nobel lecture delivered 8 December 1986; reprinted in Reviews of Modern Physics 59, 627–638 (1987), DOI 10.1103/RevModPhys.59.627.