Nice LAB11 brochure.

Eric Smith spacewar at
Mon May 2 23:48:34 CDT 2016

On Mon, May 2, 2016 at 2:21 PM, Paul Koning <paulkoning at> wrote:
> See  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.

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