On Mon, May 2, 2016 at 2:21 PM, Paul Koning <[email protected]> wrote: > See https://en.wikipedia.org/wiki/Penetron. The idea is that there are two > layers, and a high voltage beam pokes through the first to activate the > second. > I think Tektronix made monitors of this type, but apparently GE invented > them. I remember hearing about that technology in the 1970s; I never > actually saw one in the wild (from any manufacturer).
I'd never heard it called a "Penetron" before; I'm not sure if that was a trademark (perhaps of GE), but the generic term was "beam penetration CRT". I've never seen the DEC VR20, but I have an HP 1338A color XY display that uses this technology to produce multicolor displays with red, green, and yellow. Although the technology was invented for color TV, I've never seen a beam penetration CRT with any blue phosphor. I hadn't heard of it being used in Tektronix oscilloscopes, but I'm not surprised. They also used it in the DAS9120 series logic analyzers, with the DAS9129 mainframe being the color display versions of the more common DAS9100, and in the later 1241 logic analyzer. As with the HP 1338A, the colors are red, green, and yellow.
