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MenhirMike | 1 year ago

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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Animats|1 year ago

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...

Aeolun|1 year ago

32 inch wide, 14.5 inch deep. Not bad. You could actually fit that on a 80cm desk.

medstrom|1 year ago

/r/crtgaming ... calling it, this the new hip before it's cool

cubefox|1 year ago

"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."

perihelions|1 year ago

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).

throwaway2037|1 year ago

This is an interesting point. Does anyone know how much lead would be in a 21 inch monitor?

MBCook|1 year ago

Oh I didn’t know that. Neat.

joezydeco|1 year ago

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/

Gare|1 year ago

There was also a brief reign of plasma TVs in-between, now almost a forgotten technology

cesaref|1 year ago

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.

refurb|1 year ago

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.

userbinator|1 year ago

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.)

grishka|1 year ago

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.

shrubble|1 year ago

The glass has to be thicker, thus more weight, to withstand implosion from the vacuum it is holding.

NikkiA|1 year ago

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.