How a color picture tube (CRT) is manufactured. - Page 1
Forum section: electronics / general

author: BrianHG
author_rank: Super Contributor
timestamp: November 05, 2022, 02:24:01 am
content: 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)

author: pcprogrammer
author_rank: Super Contributor
timestamp: November 05, 2022, 07:45:14 am
content: 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

author: unknownparticle
author_rank: Frequent Contributor
timestamp: November 05, 2022, 05:20:33 pm
content: 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.

author: LaserSteve
author_rank: Super Contributor
timestamp: November 05, 2022, 05:31:56 pm
content: 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.Ultor Volts!Steve

author: PartialDischarge
author_rank: Super Contributor
timestamp: November 05, 2022, 06:16:24 pm
content: 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:

author: tom66
author_rank: Super Contributor
timestamp: November 05, 2022, 07:16:00 pm
content: 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.

author: coppice
author_rank: Super Contributor
timestamp: November 05, 2022, 07:24:04 pm
content: Quote from: PartialDischarge on November 05, 2022, 06:16:24 pmPhilips 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.

author: RJSV
author_rank: Super Contributor
timestamp: November 06, 2022, 04:10:23 am
content: 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 ?

author: eti
author_rank: Super Contributor
timestamp: November 06, 2022, 04:22:54 am
content: 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.

author: Dundarave
author_rank: Regular Contributor
timestamp: November 06, 2022, 05:42:15 am
content: 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!

author: eti
author_rank: Super Contributor
timestamp: November 06, 2022, 06:51:07 am
content: 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.

author: unknownparticle
author_rank: Frequent Contributor
timestamp: November 06, 2022, 05:52:38 pm
content: 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!

author: pcprogrammer
author_rank: Super Contributor
timestamp: November 06, 2022, 07:20:44 pm
content: 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.

author: RJSV
author_rank: Super Contributor
timestamp: November 06, 2022, 07:43:43 pm
content: 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 RECORDOr, perhaps the audio track, on the older film copy, exhibits a similar low grade 'crackle'.Either way, thanks.

author: BrianHG
author_rank: Super Contributor
timestamp: November 09, 2022, 04:49:14 am
content: 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.

author: Gyro
author_rank: Super Contributor
timestamp: November 09, 2022, 07:43:45 pm
content: 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.

author: coppice
author_rank: Super Contributor
timestamp: November 09, 2022, 07:49:06 pm
content: Quote from: Gyro on November 09, 2022, 07:43:45 pmReal attention to the originals made by simpler methods sucking.

author: tom66
author_rank: Super Contributor
timestamp: November 09, 2022, 08:17:04 pm
content: Quote from: coppice on November 09, 2022, 07:49:06 pmWell, arguably Trinitron is a superior solution to the shadowmask, barring the requirement for the thin wire through the centre of the display.

author: coppice
author_rank: Super Contributor
timestamp: November 09, 2022, 08:23:19 pm
content: Quote from: tom66 on November 09, 2022, 08:17:04 pmIt 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.

author: Gyro
author_rank: Super Contributor
timestamp: November 09, 2022, 08:55:45 pm
content: I've always wanted to see a Trinitron mask first hand. The frame must besubstantialto 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.

author: BrianHG
author_rank: Super Contributor
timestamp: November 09, 2022, 09:23:27 pm
content: SONY TRINITRON Television: HOW IT WAS MADEI 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.

author: Gyro
author_rank: Super Contributor
timestamp: November 09, 2022, 09:51:51 pm
content: Thanks for the video.Yes, that makes much more sense - a lot less exciting than wires though.

author: james_s
author_rank: Super Contributor
timestamp: November 09, 2022, 10:29:20 pm
content: Quote from: Gyro on November 09, 2022, 08:55:45 pmI 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.

author: coppice
author_rank: Super Contributor
timestamp: November 09, 2022, 10:56:04 pm
content: 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.

author: james_s
author_rank: Super Contributor
timestamp: November 09, 2022, 10:59:39 pm
content: 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.

author: MikeK
author_rank: Super Contributor
timestamp: November 09, 2022, 11:31:14 pm
content: Quote from: BrianHG on November 09, 2022, 09:23:27 pmI'm not sure why they credited Pittsburgh. The Sony plant was actually one county over in Westmoreland Co. I think that's Mt. Pleasant. But Pittsburgh is the nearest big city. It was previously the VW plant...making many VW Rabbits and even my [dearly departed] 1986 GTI.

author: tooki
author_rank: Super Contributor
timestamp: November 10, 2022, 12:17:27 am
content: Quote from: coppice on November 09, 2022, 10:56:04 pmHonestly, I wouldn’t say that they managed to perfect them. The corner sharpness of them, even with fancy dynamic focus, simply isn’t as good as curvier CRTs. Any deviation from a spherical surface leads to dot distortion, since the beam isn’t hitting perfectly perpendicularly. This distortion was exacerbated by the simultaneous push towards shorter tubes. If the tube could be 2 meters long, then it’d probably appear razor sharp, but with the short-neck tubes, it meant significant distortion of the dot in the corners. I believe they even used astigmatic beam lenses to try and compensate for this, but it couldn’t do it perfectly.As much as I admire the CRT, and enjoyed using them, I don’t think I’d want to go back, even if space and weight weren’t an issue.

author: james_s
author_rank: Super Contributor
timestamp: November 10, 2022, 12:22:06 am
content: I still think a good CRT looks great. I have a 27" Sony Trinitron XBR in my rec room, mostly it's used for vintage console games but I do use it for watching content sometimes and despite being 480i the picture is fantastic. It's *far* better than the specs would imply.I'm also a big fan of vector arcade games and for those there is no substitute for a CRT. Nothing can touch the dynamic range of the monochrome vector monitor used in Asteroids. A person that has only played that on an emulator has never really played it.

author: IDEngineer
author_rank: Super Contributor
timestamp: November 12, 2022, 04:37:51 pm
content: +1 for CRT vector displays. Nothing rastered nor masked can match their appearance.Did you ever play Gravitar? Vector perfection. I'd love to own one, but must be satisfied with my original Joust machine (which now needs debugging, sadly).

author: coppice
author_rank: Super Contributor
timestamp: November 12, 2022, 04:40:23 pm
content: Quote from: IDEngineer on November 12, 2022, 04:37:51 pmPenetron and Tektronix style storage screens could be really excellent. Other types of vector displays were not so great. Just trying to move the beam around fast enough to display anything complex could be a real problem.

author: james_s
author_rank: Super Contributor
timestamp: November 12, 2022, 06:17:07 pm
content: Quote from: IDEngineer on November 12, 2022, 04:37:51 pmI have a Black Widow that had been converted to Gravitar when I got it but I converted it back. I tried to like it but I just don't, I think Black Widow is a lot more fun. My favorite vector games in my collection are Tempest and Asteroids.

author: IDEngineer
author_rank: Super Contributor
timestamp: November 12, 2022, 07:58:01 pm
content: Funny story there... I could never get the "hang" of Tempest. But my wife was amazing at it.I really like Gravitar. Like Joust, it has an element of gravity and the additional realism that continuous thrust (engine in Gravitar, flapping wings in Joust) is required to offset that gravity. It felt more real to me in the way you had to control the ship. A lot of games (and TV shows, and Hollywood movies, and...) take shortcuts so I appreciate more true-to-life representations. Of course that kicks up the difficulty and I didn't have access to Gravitar long enough to get very good at it, which may be why I look back favorably - it's an itch that never got completely scratched!

author: james_s
author_rank: Super Contributor
timestamp: November 13, 2022, 01:47:47 am
content: Joust is ok, I don't own one though. Gravitar is just too hard, I never could get anywhere with it. Tempest is probably my favorite game of all time, my high score of 374k that I set around 20 years ago is still on mine. It's one of those games where you get "in the zone" and the world around you just fades away. Another of my favorites in my collection is Quantum, it was not popular at all when it came out and is quite rare because of that, it's a really unique game though and with a Motorola 68000 CPU it is quite powerful compared to the 8 bit CPUs used in most games of the era, it is the only vector game capable of drawing solid objects.Asteroids is easily the finest example of fully utilizing the capabilities of a monochrome vector monitor, the dynamic range is incredible and the gameplay is quite good too, the physics is absolutely top notch, it just feels good to play.

author: BrianHG
author_rank: Super Contributor
timestamp: November 13, 2022, 02:18:31 am
content: Quote from: james_s on November 13, 2022, 01:47:47 amYes, especially if you happen to have a perfectly focused and strong CRT, nothing could compete with the simplistic monochrome vector display of the original Asteroids.Though, I believe Joust was bitmap, not vector.Tempest's color vector display was also impressive to see.

author: james_s
author_rank: Super Contributor
timestamp: November 13, 2022, 04:04:22 am
content: Yes, Joust is definitely a raster game. It shares almost identical hardware with Defender, Stargate, Robotron, Sinistar and Bubbles. Of those, Robotron is the only one I have.

author: IDEngineer
author_rank: Super Contributor
timestamp: November 13, 2022, 04:10:21 am
content: Yes, Joust is raster. I brought it up because of how it uses gravity similar to Gravitar.

author: IDEngineer
author_rank: Super Contributor
timestamp: November 13, 2022, 05:15:27 am
content: I just looked up a video of Quantum, having never seen nor heard of it. Cool concept! The trackball would make it very interesting. I liked how they used a trackball in Marble Madness on the Amiga and would love trying it on Quantum.Might be interesting to duplicate Quantum as a touchscreen game on a phone or pad. I wrote a game for the iPhone years ago, a fun experience.