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Colour CRT development

 
Nuvistor
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Was this the forerunner of the single electron gun, stripe phosphor CRT. From PT Jan 1962.

C3DB5825 C526 4AF4 A721 98964A93C65A

 

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Topic starter Posted : 26/02/2018 8:38 pm
Katie Bush
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I'll bet it was an interesting project to work on! - I'm just visualising a single electron beam and trying to imagine the beam being turned on/off at the correct intensity for the correct length of time at the correct time to ensure that only the intended colour(s) of phosphor were energised. I can also imagine getting the phosphors equally matched, to all emit an equal/correct luminosity, would be something of a challenge.

One thing intrigues me.... With the reference to "Zebra" are we to assume the colours were laid down in stripes that ran all the way from top to bottom of the screen? Or were they laid out more along the lines of a slot mask PIL tube? In groups of three stripes that overlapped with the groups above and below?

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Posted : 26/02/2018 9:23 pm
Nuvistor
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I was thinking of continuous stripes from top to bottom, or side to side for that matter but an interesting point.

Thats the only information I have found, but will look further if I have time.

A lot more information on Wikipedia, not had chance to read it.

https://en.m.wikipedia.org/wiki/Beam-index_tube

 

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Topic starter Posted : 26/02/2018 9:51 pm
Till Eulenspiegel
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Beam index CRT.   Various proposals were tried and tested, Appletube, Zebratube etc.                                                                                                   https://visions4netjournal.com/indextron/

I do remember there was a topic on Radiofil about this type of tube.

Till Eulenspiegel.

 

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Posted : 26/02/2018 10:09 pm
Cathovisor
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I see Frank has already posted a link but as soon as I saw the piece I thought "ah, beam-indexing tube".

The major advantage was the much greater efficiency as energy was not lost passing the beam through the shadow mask, but would have been offset by the complexity of multiplexing that single gun with R, G and B signals and getting the timing right. For the record, that's how a B+K 467 works - it multiplexes the HT feeds.

It is fascinating to see that some small beam-indexing tubes made it to production.

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Posted : 26/02/2018 10:12 pm