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The biggest CRT ever made: Sony's PVM-4300

(dfarq.homeip.net)
235 points rbanffy | 43 comments | 21 Jun 24 22:22 UTC | HN request time: 1.818s | source | bottom
1. MenhirMike ◴[22 Jun 24 21:33 UTC] No.40762400[source]▶
I'm kinda curious if CRT technology advanced to the point where a TV like that would've been possible at a better weight and price tag? I assume that CRT technology development stopped decades ago, but could we have e.g., replaced the heavy glass with some plastic-like material to save weight without compromising the picture? And are there any heavy components in the mechanism itself (Coils, Magnets?) that would have had alternatives?

I know it's just theorycrafting, but I do wonder what kind of CRT someone could've created if it wasn't for market economy forces.

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2. cesaref ◴[22 Jun 24 21:43 UTC] No.40762471[source]▶
I imagine much of the weight is for the tube to be strong enough to hold the vacuum without shattering. As the screen area increases, you need stronger electron sources, and higher HT to get the electrons to the phosphor. I think small 14 inch trinitrons are already using 20-30kV so I imagine the power supply and associated HT stuff will be quite scary in these larger sets.

There are all sorts of complex magnet arrangements to tune the beam to stay in focus across the image area, i don't know how that will scale with size, but it's probably more of a complexity when assembling the sets to calibrate the tubes.

replies(1): >>40764081 #
3. Animats ◴[22 Jun 24 22:05 UTC] No.40762611[source]▶
Here's the last gasp of thinner, bigger CRTs, in 2005.[1]

"Today, CRT markets are being threatened by flat-panel displays (FPDs) even though the screen quality of the CRT is one of the best of existing display devices. The depth of CRTs is one of its most important design factors to maintain its dominant position in the display market. Thus, a 32-in.-wide deflection-angle 125° CRT (tube length of 360 mm) has been developed, and mass production began in January 2005."

That was the Samsung Vixlim.[2] Apparently worked OK, but obsolete at launch.

Goes down in history as another last and greatest achievement of the wrong technology, along with the Doble steam car, the SS United States, 3-projector Cinerama, quadrophonic phonograph records, and the Olivetti Divisumma 24 mechanical four-function calculator.

[1] https://sid.onlinelibrary.wiley.com/doi/abs/10.1889/1.216683...

[2] https://www.reddit.com/r/crtgaming/comments/xgtmdw/does_anyo...

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4. joezydeco ◴[22 Jun 24 22:39 UTC] No.40762862[source]▶
The next big thing was supposed to be Field Emission Displays. Microscopic electron guns directly behind each phosphor. The big manufacturers experimented and tried getting it commercialized for decades, then pretty much gave up in the 2000s when LCDs got stupid cheap.

https://www.engineersgarage.com/field-emission-display/

replies(1): >>40763201 #
5. shrubble ◴[22 Jun 24 22:45 UTC] No.40762908[source]▶
The glass has to be thicker, thus more weight, to withstand implosion from the vacuum it is holding.
replies(1): >>40763155 #
6. NikkiA ◴[22 Jun 24 23:22 UTC] No.40763155[source]▶
Gorilla glass or sapphire glass might have enabled lighter tubes at a higher price, had CRTs retained popularity, but from what I can see, Corning never even considered it as a use case for Gorilla glass in their original 1960s attempt at development.
replies(1): >>40764390 #
7. Gare ◴[22 Jun 24 23:30 UTC] No.40763201[source]▶
There was also a brief reign of plasma TVs in-between, now almost a forgotten technology
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8. floam ◴[22 Jun 24 23:38 UTC] No.40763260{3}[source]▶
A good 720p plasma is still a great display to this day.
replies(1): >>40763481 #
9. perihelions ◴[22 Jun 24 23:55 UTC] No.40763349[source]▶
On top of the mechanical issues, CRT glass also functions as x-ray shielding, for which reason it is leaded (Pb). You can't really make that part lighter.

https://en.wikipedia.org/wiki/Cathode-ray_tube#Body

https://www.epa.gov/hw/frequent-questions-about-regulation-u...

(This isn't really an answer to the overall question—just a narrow observation of interest).

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10. phibz ◴[23 Jun 24 00:20 UTC] No.40763481{4}[source]▶
I have the second to last generation Panasonic plasmas. 42" 1080p display. At first the picture was amazing but over time it degraded slightly with what looks like subtle noise affecting the entire display. Solid colors have a faint shimmer of noise in them. As if white noise was blended with everything.

I still use it as a bedroom TV. I can barely lift it myself and it claims to use 450watts of power. It's certainly a lot. It's notably warm near it and will heat my room if I don't open the door.

Still the picture quality is very good at a distance. Only oled or micro led displays look better.

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11. pandaman ◴[23 Jun 24 00:58 UTC] No.40763702{5}[source]▶
This could be that you just noticed it? Panasonic plasma cells brightness is controlled by PWM off a 600 Hz carrier (it's even proudly advertised as "600 Hz!" on the TV box and stickers). While the number is quite big and stands out nicely against "240 Hz" advertised as refresh rate for the competing LCD TVs, it did not provide many different brightness levels per pixel (keep in mind that it's divided by 60 Hz or higher frame refresh) so those TVs were running temporal stochastic dithering to create more levels. If you looked closely at a new plasma TV screen it was very noisy with random pixels firing up at high frequency.
replies(1): >>40768010 #
12. xattt ◴[23 Jun 24 01:00 UTC] No.40763707{5}[source]▶
The heat! Many plasma displays had a faint heat you would feel on your face if you were near that I found uncomfortable. I am not sure if others felt the same.
replies(1): >>40764900 #
13. grishka ◴[23 Jun 24 01:24 UTC] No.40763829[source]▶
I remember reading somewhere that there was this wild prototype flat CRT where the electron gun was at the top, shooting down, and the beam did a 180 degree turn at the bottom before being deflected into the surface of the screen.
replies(2): >>40766027 #>>40766639 #
14. ddingus ◴[23 Jun 24 01:43 UTC] No.40763946{3}[source]▶
I have an HD plasma and it is fantastic. It is the very best living room display I have owned.

Like the CRT, it has glowing phosphors in a tube. Unlike the CRT, it is pixel addressable, where the CRT is basically not addressable, or maybe just field, frame and or line addressable. Of course the tradeoffs are well known. Resolution scaling on a CRT is rarely an issue, except when the dot mask is too coarse. It still looks great. It can be a major issue with pixel addressable displays, when uneven multiples are in play.

In my experience, a good plasma is right there with the CRT on color gamut and contrast, even does well on speed. Or can. Mine is 120Hz and does not lag more than a CRT does on 60Hz signals.

(If you want a fast one, get one of the 3D capable TV sets from that era. They have fast video processors and basically can run at least double the necessary frame rate. And if you have an nVidia GPU and good CAD software, you can even use one as a wall sized 3D display featuring a bunch of things an ordinary set will struggle with and large assembly visualization as well as technical surfacing being two use cases I found amazing.)

AMOLED looks like it may be the next plasma. I have one from Waveshare that is 10.5" and has 2560x1600 resolution. I wish it were bigger. It is fantastic! It has a much higher DPI than my plasma does and appears to not require a PWM cycling of pixels to get those hard to hit grey levels.

I am learning I like displays where the light is not filtered down to a color, instead is just emitted at the color. Micro LED could be another contender if they can get the dot pitch high enough.

All that said, I keep a few CRT displays. I really like them for retro computing and gaming.

replies(1): >>40765753 #
15. refurb ◴[23 Jun 24 02:03 UTC] No.40764081[source]▶
You’d be surprised how little glass is needed to be strong enough to withstand a near perfect vacuum.

I worked in a lab where we routinely held a few micro-torr of vacuum, which is about the limit for mechanical pumps. Cathode ray tubes are typically thousands or tens of thousands higher pressure.

We ran 1/4” wall thickness glass even in large flat stretches without issue.

I’m guessing the weight of large cathode ray tubes are more for durability than need for the vacuum inside.

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16. Aeolun ◴[23 Jun 24 02:13 UTC] No.40764135[source]▶
32 inch wide, 14.5 inch deep. Not bad. You could actually fit that on a 80cm desk.
17. MBCook ◴[23 Jun 24 02:50 UTC] No.40764349[source]▶
Oh I didn’t know that. Neat.
18. MBCook ◴[23 Jun 24 02:53 UTC] No.40764370{3}[source]▶
Despite its benefits over LCDs, it had no chance to compete on price. LCD prices just plummeted to far too fast.

OLED is the current equivalent (with perhaps QLED) and micro LED on the horizon.

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19. MBCook ◴[23 Jun 24 02:57 UTC] No.40764390{3}[source]▶
Would there be any point? Given the TV sizes of the 60s standard glass was probably more than strong enough, and the tube wouldn’t be very heavy.

No one would need to really think about until around 2000.

20. userbinator ◴[23 Jun 24 03:31 UTC] No.40764554[source]▶
I assume that CRT technology development stopped decades ago, but could we have e.g., replaced the heavy glass with some plastic-like material to save weight without compromising the picture?

Metal-cone CRTs were common in the early decades, and had a flatter screen than typical all-glass construction; here's the largest of those, a 30":

https://www.earlytelevision.org/dumont_30bp4.html

a TV using it cost almost $1800 in 1952 (equivalent to over $21k today):

https://www.earlytelevision.org/dumont_ra-119.html

I think metal-cone CRTs became unpopular due to the glass-to-metal seal not being as reliable, and difficulties with insulation (the whole cone is at the final accelerating voltage.)

21. ssl-3 ◴[23 Jun 24 04:22 UTC] No.40764767{3}[source]▶
How much did the flat sections bend or deflect under vacuum?
22. stevekemp ◴[23 Jun 24 04:52 UTC] No.40764900{6}[source]▶
I remember the heat.

I had a year of sickness, or so, back in the day. I decided I was gonna blow as much money as I could on the "best" TV setup. I bought a 42" plasma TV, and I sat it on the floor in my living room, in front of a window.

You could see the heat-haze above the screen, the air shimmering in front of the window, after it had been on for a while.

Lovely display, far too expensive, and far far too heavy, but for the five+ years I kept it I think I got my money's worth.

23. Karliss ◴[23 Jun 24 07:34 UTC] No.40765450{3}[source]▶
That's a bit misleading the level of vacum might differ by factor of 10000, but most of the force is still coming from atmosphere. For overall mechanical strength it doesn't matter that much if its 0.99 or 0.99999999999 atmospheres of pressure difference, temperature and other wheather changes are probably causing much bigger change in force applied to glass.
replies(1): >>40767001 #
24. ansgri ◴[23 Jun 24 08:39 UTC] No.40765753{4}[source]▶
microLED is the next plasma, with tiny non-organic LEDs. Organic LEDs have some problems with color gamut and (AFAIR) response time that make them inferior to plasma, whereas microLED, while still exotic, is being rapidly developed.

I've even worked on a color science-related project that attempted to use LG OLED TV as a poor man's reference display, and turns out they use a lot of tricks like dithering, heavy power limiting and low brightness resolution for each subpixel that make them look bad when pixel-peeping.

replies(1): >>40766210 #
25. guenthert ◴[23 Jun 24 09:17 UTC] No.40765952{3}[source]▶
Living room tv sets need to be child-save, unlike lab equipment.
26. ◴[23 Jun 24 09:31 UTC] No.40766027[source]▶
27. ddingus ◴[23 Jun 24 10:10 UTC] No.40766210{5}[source]▶
Ahhh, thanks for that. microLED was my first hope, until the AMOLED tech seemed to fill the gap for the smaller, high DPI, display use case at least. Nice to see the rapid dev going on.

Are there differences between OLED sources? I'm using Samsung AMOLED displays at present. I don't have access to an LG.

Do you have any thoughts on DPI for microLED?

I will definitely poke at the displays I have more to see what I can learn.

replies(1): >>40767461 #
28. throwaway2037 ◴[23 Jun 24 11:12 UTC] No.40766537[source]▶
This is an interesting point. Does anyone know how much lead would be in a 21 inch monitor?
replies(1): >>40766992 #
29. UncleSlacky ◴[23 Jun 24 11:31 UTC] No.40766639[source]▶
Yes, the Sinclair TV80 worked on that principle: https://en.wikipedia.org/wiki/TV80
replies(1): >>40767578 #
30. RetroSpark ◴[23 Jun 24 12:34 UTC] No.40766992{3}[source]▶
According to [0], about 1.2 kg (2.6 lbs). Surprisingly this is mostly in the neck and funnel of the tube - the screen itself uses different metals because lead would affect its optical performance.

[0] https://www.sciencedirect.com/science/article/pii/S187802961...

31. willis936 ◴[23 Jun 24 12:35 UTC] No.40767001{4}[source]▶
I don't think it's that misleading. At the end of the day you need a 14.696 psi negative pressure vessel. That isn't very dramatic. If you can confidently make something that works to 14.696 psi then you can be confident it will work at 14.65 or 14.5 psi.

The meat of the comment is that you don't need much material to withstand Earth's atmosphere compared to pressure vessel. It's a common misconception for folks who don't work with vacuums.

Having carried my share of heavy CRTs I can share that most of the weight is in the front glass. It needs to support the phosphor wire mesh and withstand the pokes and stabs of the world while not compromising the fragile thin-walled neck.

32. ansgri ◴[23 Jun 24 13:49 UTC] No.40767461{6}[source]▶
Sorry, cannot answer these questions competently. From my understanding, LG has monopoly on TV-scale OLED displays, so others big players in premium TV market (Sony and Samsung come to mind) bet on productizing uLED.
replies(1): >>40768214 #
33. grishka ◴[23 Jun 24 14:08 UTC] No.40767578{3}[source]▶
Nope, it's that, but folded in half. Found a mention of it (that I commented on, lol): https://mastodon.social/@tubetime/111219376410543899
34. phibz ◴[23 Jun 24 15:08 UTC] No.40768010{6}[source]▶
The level of noise went up dramatically after the first year. I read that this is part of the panel aging. It hasn't gotten worse since then. My two biggest gripes are high brightness areas don't work on large portions of the screen. A windows file browser is basically unusable.

The heat is probably what will eventually get me to replace it.

35. cubefox ◴[23 Jun 24 15:19 UTC] No.40768082[source]▶
"These wide-deflection CRTs attracted an extraordinary amount of attention even from end users in a variety of display shows last year and will help maintain the solid positions of CRTs in the coming era."
36. ddingus ◴[23 Jun 24 15:37 UTC] No.40768214{7}[source]▶
Well you improved my own lacking understanding, and with exemplary form. It is rare to see others share what you did. Thanks again.
37. cubefox ◴[23 Jun 24 15:41 UTC] No.40768249{4}[source]▶
The problem with MicroLED is that they remain very expensive to produce, so they may have no chance to compete on price, and the quality of OLED is getting better as well. Apple recently abandoned their MicroLED plans: https://www.yolegroup.com/strategy-insights/did-apple-just-k...
replies(1): >>40770274 #
38. MBCook ◴[23 Jun 24 20:14 UTC] No.40770274{5}[source]▶
Yeah, and we can’t make them small enough either. But it seems like the probable next big thing to me. Just gotta solve some issues.
replies(1): >>40773498 #
39. layer8 ◴[23 Jun 24 20:57 UTC] No.40770522{4}[source]▶
The death knell was that they couldn’t shrink the plasma cells enough to support 4K. LCD didn’t kill it, in the same sense that LCD doesn’t kill OLED.
40. kevinsync ◴[23 Jun 24 21:28 UTC] No.40770719{5}[source]▶
I had a Zenith 42" plasma (maybe Zenith Z42PX2D?) for about 10 years before the screen became insanely noisy and LG OLEDs hit the market. Really an amazing display though, at "tv distance" (6 to 8ft) the 852x480 resolution was not at all noticeable as "low resolution".

What I actually found was dog-shit quality video looked AMAZING on it, as did downsampled high-res video -- I had a media center pc hooked up via DVI, and off it went.

I replaced it with a 1080p 55" OLED in 2014 or 15 when it became unwatchable, and it's been incredible as well aside from very rare, short instances of judder.. As per my Zenith experience above, I figured lower-res (not 4k) would be better in the long run.

Curious to see how long it lasts, but it's still very bright and very good almost a decade later, no burn-in, no dead pixels, and it's on constantly.

41. medstrom ◴[23 Jun 24 22:17 UTC] No.40771068[source]▶
/r/crtgaming ... calling it, this the new hip before it's cool
42. cubefox ◴[24 Jun 24 07:56 UTC] No.40773498{6}[source]▶
But FED was also better than LCD, and it was still abandoned because of cost. The same thing could happen with MicroLED.
43. bzzzt ◴[24 Jun 24 08:09 UTC] No.40773562{5}[source]▶
> it claims to use 450watts of power.

I've still got a 42 inch GT60 plasma and while it certainly runs hot it's pulling about 140W on average so it's no space heater. It's become a bit more noisy, but not in a way that impacts viewing for me. After a while you don't see it anymore just like film grain...