The RCA Selectron -- US Patent 2,558,461 Selectron Electron Optics

Jan A. Rajchman, Radio Corporation of America
Applied: 28 December, 1949
Granted: 26 June, 1951



The '461 patent relates to the electron optics of the 256-bit planar type tube. '461 describes the geometry of electron emission from the faces of square cathodes. The beams are then guided along a 45 degree path and then through the addressing bars before becoming orthogonal. One goal is to use the emission efficiently, not unlike beam forming techniques used in "beam-power pentode" electron tubes. Another goal is to minimize the "line-of-sight" between cathode and storage element. This is necessary because the heavy ions and particles of cathode coatings will travel to the storage elements and destroy their secondary-electron emissive properties.


US Patent 2,558,461 -- Images on the left, text on the right

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