Author Topic: How a color picture tube (CRT) is manufactured.  (Read 4120 times)

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Online BrianHGTopic starter

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How a color picture tube (CRT) is manufactured.
« on: November 05, 2022, 02:24:01 am »
It's amazing that even this far back in the past, how mass automated and precise most of the manufacturing process which has already been achieved to make such a refined product.  Just the shadow mask itself with it's required not only microscopic precision, but also the unique cavity shape on both sided of the metal which is required to prevent angular bleed from the electron gun is a marvel of ingenuity.

Yes, they even show how the color phosphor is applied to the tube. (SKIP TO 4:00 where it truly begins)

« Last Edit: November 09, 2022, 04:58:53 am by BrianHG »
 
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Offline pcprogrammer

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Re: How a color picture tube (CRT) is manufactured.
« Reply #1 on: November 05, 2022, 07:45:14 am »
Very interesting. Also the division between what woman and man did in the process. The small fiddly stuff done by woman and the coarse by man :)

Offline unknownparticle

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Re: How a color picture tube (CRT) is manufactured.
« Reply #2 on: November 05, 2022, 05:20:33 pm »
Saw this yesterday, probably the best video of the construction and working description of a colour CRT I've ever seen.  To think this was everyday technology and manufacturing for over 60 years, although it was incredibly technical and complex, and yet it has now virtually disappeared. All that combined knowledge and skill, gone forever.
DC coupling is the devils work!!
 
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Online LaserSteve

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Re: How a color picture tube (CRT) is manufactured.
« Reply #3 on: November 05, 2022, 05:31:56 pm »
The plant engineering is superb. Pay for the line workers must have been decent too.  A sense of humor there too, with the convergence scene.

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Steve
"When in doubt, check the Byte order of the Communications Protocol, By Hand, On an Oscilloscope"

Quote from a co-inventor of the PLC, whom i had the honor of working with recently.
 

Offline PartialDischarge

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Re: How a color picture tube (CRT) is manufactured.
« Reply #4 on: November 05, 2022, 06:16:24 pm »
Philips had wonderful labs in Eindhoven dedicated amongst others to digital signal processing for audio and video.  One of my fav books on discrete time signal processing is from them:

« Last Edit: November 05, 2022, 06:23:06 pm by PartialDischarge »
 

Online tom66

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Re: How a color picture tube (CRT) is manufactured.
« Reply #5 on: November 05, 2022, 07:16:00 pm »
Quite a beautiful art building those tubes.  I almost miss it with newer panel technologies, though the art has changed somewhat from hand assembly to creating a machine that can produce a 24 million subpixel display with nearly no defects consistently for very competitive prices.
 

Online coppice

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Re: How a color picture tube (CRT) is manufactured.
« Reply #6 on: November 05, 2022, 07:24:04 pm »
Philips had wonderful labs in Eindhoven dedicated amongst others to digital signal processing for audio and video.  One of my fav books on discrete time signal processing is from them:
Philips had a pretty uneven approach to DSP. They produced a line of pretty nice DSP chips in the late 80s, then almost immediately killed them. They then repeated this process multiple times. I used that first generation of chips. It was pretty good for its time. If they had fleshed out the range they might have had a success on their hands.

 

Online RJSV

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Re: How a color picture tube (CRT) is manufactured.
« Reply #7 on: November 06, 2022, 04:10:23 am »
   Are you implying, the whole Football game / beer / barbeque ritual (boring...hmm), that whole market dynamic is what funded COLOR TVs and kick-started the whole, modern electronics marketplace ?
 

Offline eti

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Re: How a color picture tube (CRT) is manufactured.
« Reply #8 on: November 06, 2022, 04:22:54 am »
Thank you, this is fascinating, thank you very much for spending your time posting it, I very much appreciate it as an ex- TV and VCR repair apprentice from the 1990s.
 
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Offline Dundarave

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Re: How a color picture tube (CRT) is manufactured.
« Reply #9 on: November 06, 2022, 05:42:15 am »
It’s amazing that they could do all that at a price that would make a TV set reasonably affordable to the masses.  There were more hands and technology used in creating those tubes than there is in today’s fine watches at $30k a pop!
 

Offline eti

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Re: How a color picture tube (CRT) is manufactured.
« Reply #10 on: November 06, 2022, 06:51:07 am »
Bit of a weird intro… I was like “what’s this BS? I’m turning off if this intro is too long”

Also WHAT a dingy, depressing place to work. Well it’s either that or the film crew didn’t light it properly, and that hideous music… wow… One has to really want to watch it to get over that cheesy, ghastly racket.
« Last Edit: November 06, 2022, 07:12:42 am by eti »
 

Offline unknownparticle

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Re: How a color picture tube (CRT) is manufactured.
« Reply #11 on: November 06, 2022, 05:52:38 pm »
Thats how I feel about the majority of music of the last 15 or so years, it's like everyone uses the same template and just adds different, inane lyrics!

World was a different place back in the day of this Philips film.  Philips was always a bit strange though, I know, I used to work for them!
DC coupling is the devils work!!
 
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Offline pcprogrammer

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Re: How a color picture tube (CRT) is manufactured.
« Reply #12 on: November 06, 2022, 07:20:44 pm »
Such a documentary type of film might have been recorded on actual film and later transferred to some other medium for broadcasting. It was a different world back then. No cell phone with a HD camera to make the "crappy" movies you can see on youtube.

I actually liked the documentary for it's informational quality. Much better then what you see in "How it's made" for instance. And not that half arsed formatting you see in reality TV like "Border Patrol" where everything is chopped up in little bits and parts are repeated because you might have forgotten it in the three minutes the other bit was played.

Have worked for Philips too, long ago. For the business telephone exchange group. Was reeled in under the wrong pretenses. The manager sold it as a very technical job, were as it was just making the extension number programming for the exchanges sold. Left for a better job, both technical and money wise, within a year.

Online RJSV

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Re: How a color picture tube (CRT) is manufactured.
« Reply #13 on: November 06, 2022, 07:43:43 pm »
   Yes, thank you for posting that.
   I DID notice, (since the audio-visual qualities were mentioned), sounded like the audio had those periodic little 'crackles' like a PHONOGRAPH RECORD ??? Or, perhaps the audio track, on the older film copy, exhibits a similar low grade 'crackle'.
Either way, thanks.
 

Online BrianHGTopic starter

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Re: How a color picture tube (CRT) is manufactured.
« Reply #14 on: November 09, 2022, 04:49:14 am »
Even with such docus, and technical historical docs and formulas for the phosphor coatings, if we ever had to downgrade to CRTs, to re-engineer the manufacturing plant and procedures illustrated in this video would take over a decade, maybe 2, just to build the first one which can then be mass-manufactured.
 
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Online Gyro

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Re: How a color picture tube (CRT) is manufactured.
« Reply #15 on: November 09, 2022, 07:43:45 pm »
I was interested to see the profile of the shadowmask holes. I had always assumed that they were, well, just holes. The different size and profiling of the etching from each side, to avoid stray electrons bouncing down the 'length' of the holes, is really clever. Real attention to detail.

I once pulled a shadowmask out of an old tube. The mask itself was incredibly easy to dent with even a fairly gentle touch, but I was surprised that the frame could be held so firmly (and presumably repeatedly) by the bimetal strips onto the mounting pins in the faceplate, very good tolerancing. Also the hand applied foil shielding to prevent stray electrons from leaking around round the outside of the frame.
Best Regards, Chris
 
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Online coppice

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Re: How a color picture tube (CRT) is manufactured.
« Reply #16 on: November 09, 2022, 07:49:06 pm »
I was interested to see the profile of the shadowmask holes. I had always assumed that they were, well, just holes. The different size and profiling of the etching from each side, to avoid stray electrons bouncing down the 'length' of the holes, is really clever. Real attention to detail.
Real attention to the originals made by simpler methods sucking.
 

Online tom66

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Re: How a color picture tube (CRT) is manufactured.
« Reply #17 on: November 09, 2022, 08:17:04 pm »
I was interested to see the profile of the shadowmask holes. I had always assumed that they were, well, just holes. The different size and profiling of the etching from each side, to avoid stray electrons bouncing down the 'length' of the holes, is really clever. Real attention to detail.
Real attention to the originals made by simpler methods sucking.

Well, arguably Trinitron is a superior solution to the shadowmask, barring the requirement for the thin wire through the centre of the display.
 

Online coppice

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Re: How a color picture tube (CRT) is manufactured.
« Reply #18 on: November 09, 2022, 08:23:19 pm »
I was interested to see the profile of the shadowmask holes. I had always assumed that they were, well, just holes. The different size and profiling of the etching from each side, to avoid stray electrons bouncing down the 'length' of the holes, is really clever. Real attention to detail.
Real attention to the originals made by simpler methods sucking.

Well, arguably Trinitron is a superior solution to the shadowmask, barring the requirement for the thin wire through the centre of the display.
It took many years for Sony to get a Trinitron of any reasonable size to work well, and to the end a gentle tap on the case made the picture go crazy. The horizontal stabiliser wires were generally hard to see, but on some screens once you noticed them it was hard to look away.
 

Online Gyro

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Re: How a color picture tube (CRT) is manufactured.
« Reply #19 on: November 09, 2022, 08:55:45 pm »
I've always wanted to see a Trinitron mask first hand. The frame must be substantial to resist the pull of all those vertical wires, even if each one is minimally tensioned. I wonder if the horizontal support wires (yes, they can be irritating on a CAD monitor, as can the vibrations!) are threaded between the vertical ones or spot welded to each  - both sound unfeasibly difficult.
« Last Edit: November 09, 2022, 09:02:03 pm by Gyro »
Best Regards, Chris
 

Online BrianHGTopic starter

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Re: How a color picture tube (CRT) is manufactured.
« Reply #20 on: November 09, 2022, 09:23:27 pm »
SONY TRINITRON Television: HOW IT WAS MADE



I  think the Trinitron grill was also double sided optical exposed, then etched away.
Otherwise, for the date of the first available Trinitrons, it would have been too early in time to use more modern techniques like laser cutting and attaching wires would be impossible to maintain tension under temperature drift due to variances in length of such wires.
« Last Edit: November 09, 2022, 09:34:03 pm by BrianHG »
 
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Online Gyro

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Re: How a color picture tube (CRT) is manufactured.
« Reply #21 on: November 09, 2022, 09:51:51 pm »
Thanks for the video.

Yes, that makes much more sense - a lot less exciting than wires though.  :(
Best Regards, Chris
 

Offline james_s

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Re: How a color picture tube (CRT) is manufactured.
« Reply #22 on: November 09, 2022, 10:29:20 pm »
I've always wanted to see a Trinitron mask first hand. The frame must be substantial to resist the pull of all those vertical wires, even if each one is minimally tensioned. I wonder if the horizontal support wires (yes, they can be irritating on a CAD monitor, as can the vibrations!) are threaded between the vertical ones or spot welded to each  - both sound unfeasibly difficult.

I have dissected a couple of dead Triniton tubes over the years, somewhere I have some pictures. The frame is indeed substantial, in a 27" tube it is made out of square stock that is around 1" thick. The aperture grill is made from a thin sheet that is spot welded to the frame and has vertical slits etched down the length, they have the appearance of wires but if you look closely they are flat and part of the material around the edges. Depending on the size there are either one or two hair-thin wires stretched across the face of the grill, spot welded to leaf springs that are attached to the frame.
 

Online coppice

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Re: How a color picture tube (CRT) is manufactured.
« Reply #23 on: November 09, 2022, 10:56:04 pm »
I wonder how the flat screen CRT business really worked out? It seems they took years to perfect, so presumably a lot of investment went into them. They never really took over the market, so the volumes were limited compared to the preceding tubes. Then their market window started to close quite quickly, as other screen technologies took over.
 

Offline james_s

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Re: How a color picture tube (CRT) is manufactured.
« Reply #24 on: November 09, 2022, 10:59:39 pm »
It was just too little too late. The flat Trinitron displays looked great, I still have a 20" Sony SVGA monitor that I used for years. They achieved widespread use, but they came near the end of the CRT era so it's only natural that they didn't achieve more widespread use.
 


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