Author Topic: using CRT electron beam for something other then display?  (Read 28010 times)

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Online coppercone2Topic starter

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using CRT electron beam for something other then display?
« on: February 25, 2024, 07:29:24 am »
So the CRT allows you to control a electron beam on a grid.

Rather then exciting phosphor, can you use it for some other purpose? there are many uses of electron beams.

https://en.wikipedia.org/wiki/Electron-beam_technology

Assuming you can highly modify a CRT

I imagined like sawing open a television with a diamond saw so you can put the front on a hinge with some kinda vacuum gasket and put stuff in there

also it would be good part of men in black or something if they find some aliens misusing TV's like that. they don't use that to watch the game, slick
« Last Edit: February 25, 2024, 07:43:41 am by coppercone2 »
 

Offline wasedadoc

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Re: using CRT electron beam for something other then display?
« Reply #1 on: February 25, 2024, 08:13:22 am »
Before solid state image sensors were developed, for about 50 years all TV cameras used tubes employing electron beam scanning. Search using terms such as "image orthicon", "vidicon" and "Plumbicon".
 
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Offline Andy Chee

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Re: using CRT electron beam for something other then display?
« Reply #2 on: February 25, 2024, 08:35:20 am »
can you use it for some other purpose?
You can use it to make some interesting youtube videos:

 

Offline JustMeHere

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Re: using CRT electron beam for something other then display?
« Reply #3 on: February 25, 2024, 08:39:06 am »
can you use it for some other purpose?
You can use it to make some interesting youtube videos:


Why do I feel like I'm on the Black Mesa Compound tram?
 

Offline tggzzz

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There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Online coppercone2Topic starter

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Re: using CRT electron beam for something other then display?
« Reply #5 on: February 25, 2024, 09:46:31 am »
i mean can you make a manufacturing machine out of it some how. the page I listed has alot of process, as interesting as those are,

Like milling etc

I am guessing the focus is too poor to do small things, and power is well too low for welding (is it? its in a vacuum after all). But something like coatings, chemistry, materials prep (some kind of macro structures that require more focus then essentially putting them over a vat of boiling metal in a vacuum). Vacuum soldering with electron beam?
« Last Edit: February 25, 2024, 09:50:08 am by coppercone2 »
 

Online mikeselectricstuff

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Re: using CRT electron beam for something other then display?
« Reply #6 on: February 25, 2024, 09:52:03 am »
a-d converter : http://electricstuff.co.uk/glassadc.html

Another one was for TV pattern generators - similar to a camera tube but with a fixed pattern target
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Online tooki

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Re: using CRT electron beam for something other then display?
« Reply #7 on: February 25, 2024, 12:17:07 pm »
 

Offline jonpaul

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Re: using CRT electron beam for something other then display?
« Reply #8 on: February 25, 2024, 12:53:01 pm »
Numeric 0..9 readout, Nimo, 1960s

ENIAC 1949..1953 data storage

TRW 1960s streak camera image converter

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Offline wasedadoc

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Re: using CRT electron beam for something other then display?
« Reply #9 on: February 25, 2024, 04:30:01 pm »
Also standard for decades was the "flying spot scanner" for televising  film and slides.  A full brightness raster on the CRT faceplate, focussed onto the celluloid and then through optical colour filters to photomultipliers providing the video RGB signals.

https://en.wikipedia.org/wiki/Flying-spot_scanner
 

Online tooki

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Re: using CRT electron beam for something other then display?
« Reply #10 on: February 25, 2024, 04:32:00 pm »
Numeric 0..9 readout, Nimo, 1960s

Also standard for decades was the "flying spot scanner" for televising  film and slides.  A full brightness raster on the CRT faceplate, focussed onto the celluloid and then through optical colour filters to photomultipliers providing the video RGB signals.

Those both work by exciting phosphor, which is expressly NOT what the OP wants to learn about.
 

Offline Alex Eisenhut

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Re: using CRT electron beam for something other then display?
« Reply #11 on: February 25, 2024, 04:42:35 pm »
https://en.wikipedia.org/wiki/IBM_1360

"Data was written to the chips using an electron gun, similar to the operation of a television tube."
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Offline tggzzz

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Re: using CRT electron beam for something other then display?
« Reply #12 on: February 25, 2024, 04:49:44 pm »
The Eidophor and Talaria:
http://www.earlytelevision.org/Yanczer/eidophor.html

I forgot eidophors.

I saw one once in ~1985, at London Zoo. There was a conference about this newfangled thing, object oriented programming. One of the talks showed building a GUI plus application (in LISP, of course) on the fly, the first time I had seen anything like that.

The projector was an black and white eidophor, which I expect was adequate with "natural" images. But with rectangular bars and text it was, um, suboptimal. The oil film couldn't cope with sharp edges blocks, and any change anywhere in the picture caused the rest to wobble.

But nobody cared; the content was eye-opening.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Online tooki

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Re: using CRT electron beam for something other then display?
« Reply #13 on: February 25, 2024, 04:59:31 pm »
Nice! I wonder if there exist any working Eidophor units anywhere in the world. I’d love to see that crazy piece of engineering!

(I finally got to see a Linotype this summer, after wanting to see one for decades. Then this summer I saw two different ones, one day apart, one of them working!)
 

Offline MarkT

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Re: using CRT electron beam for something other then display?
« Reply #14 on: February 25, 2024, 06:00:02 pm »

I imagined like sawing open a television with a diamond saw so you can put the front on a hinge with some kinda vacuum gasket and put stuff in there

BANG!!!

No, don't do that.  Watch this video on reconditioning TV tubes first: 
 

Offline tggzzz

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Re: using CRT electron beam for something other then display?
« Reply #15 on: February 25, 2024, 06:09:53 pm »

I imagined like sawing open a television with a diamond saw so you can put the front on a hinge with some kinda vacuum gasket and put stuff in there

BANG!!!

No, don't do that.  Watch this video on reconditioning TV tubes first: 

Yeah. Don't cut the ugly bit off a Tek 465 CRT.



Often there is an easily snappable nipple inside the pins at the end of the tune.
https://entertaininghacks.wordpress.com/2016/03/09/rescuing-a-broken-tektronix-465-crt/

There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline Gyro

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Re: using CRT electron beam for something other then display?
« Reply #16 on: February 25, 2024, 06:54:47 pm »
I imagined like sawing open a television with a diamond saw so you can put the front on a hinge with some kinda vacuum gasket and put stuff in there

The other problem is that the emissive coating on the cathode will be destroyed as soon as it comes into contact with air. In manufacture, it is coated with chemical salts and then the final forming is done under vacuum.
Best Regards, Chris
 

Offline p.larner

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Re: using CRT electron beam for something other then display?
« Reply #17 on: February 25, 2024, 07:30:57 pm »
i thought electron beams needed a vacume to travel,so whats going on in the linked vid?
 

Offline TimFox

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Re: using CRT electron beam for something other then display?
« Reply #18 on: February 25, 2024, 08:29:24 pm »
Electron beams travel better In vacuum.
High-energy beams can be useful in air, so long as the window between the source (in a vacuum chamber) and air is thin enough, or a “differentially pumped” exit aperture is used.
In air, the range for an electron, depending on how you define it, is roughly 2 mm at 1 keV, but about 10 m at 1 MeV.
Thus, energetic electrons from an electron accelerator can be used in radiation therapy, avoiding the low efficiency of Bremsstrahlung to produce x-ray photons (which have longer range in matter than massive electrons or ions).
 

Offline SiliconWizard

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Re: using CRT electron beam for something other then display?
« Reply #19 on: February 25, 2024, 09:06:38 pm »
Can we use a CRT as a giant triode?
 

Offline Gyro

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Re: using CRT electron beam for something other then display?
« Reply #20 on: February 25, 2024, 09:12:38 pm »
Well a large screen one would take 25kV or so, but the cathode, and possible cathode current, is tiny. So not giant, no.
Best Regards, Chris
 

Online coppercone2Topic starter

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Re: using CRT electron beam for something other then display?
« Reply #21 on: February 25, 2024, 09:25:03 pm »
I imagined like sawing open a television with a diamond saw so you can put the front on a hinge with some kinda vacuum gasket and put stuff in there

The other problem is that the emissive coating on the cathode will be destroyed as soon as it comes into contact with air. In manufacture, it is coated with chemical salts and then the final forming is done under vacuum.

I would imagine so long you keep it dry its OK? Guess you would need a dry box to load this up.

how strong are those electrons anyway. can it say weld foil possibly? say 0.001. In open air for a tig beam that is something like an amp, supposedly. A TV beam is something like 100uA. 0.0001 vs 1. But how much less do you need in a vacuum on thin material. It says EBW uses 50mA to 1A typically.

So you need 500x overload on the beam gun. I guess that process is out.
« Last Edit: February 25, 2024, 09:28:32 pm by coppercone2 »
 

Offline cosmicray

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Re: using CRT electron beam for something other then display?
« Reply #22 on: February 25, 2024, 09:27:38 pm »
Back in the dark ages, of 1987-1988, I saw a piece of kit, that was apparently a very custom build. It read 9-track computer tapes, with print page images, then used a CRT beam (of some type) to directly imprint 35mm film. The film was then developed, and used to make printing plates. The plates were put on offset presses to print books containing television ratings, which were then express shipped out to advertising agencies and networks. It was a very refined system, with lots of disparate parts. The internet has likely demolished it.
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Offline Alex Eisenhut

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Re: using CRT electron beam for something other then display?
« Reply #23 on: February 25, 2024, 09:30:13 pm »
Back in the dark ages, of 1987-1988, I saw a piece of kit, that was apparently a very custom build. It read 9-track computer tapes, with print page images, then used a CRT beam (of some type) to directly imprint 35mm film. The film was then developed, and used to make printing plates. The plates were put on offset presses to print books containing television ratings, which were then express shipped out to advertising agencies and networks. It was a very refined system, with lots of disparate parts. The internet has likely demolished it.

Sounds like a kind of photo typesetter.
https://en.wikipedia.org/wiki/Phototypesetting
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Offline TimFox

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Re: using CRT electron beam for something other then display?
« Reply #24 on: February 25, 2024, 09:35:04 pm »
Going back to the 1970s, Celco made relatively small screen CRTs with superb focusing that could resolve 10,000 lines.  They were used either with high-end lenses or optical contact to expose 35 mm or 2.25 inch film.
Celco still exists, mainly working with cinema applications.
 


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