CRT w/ modern tech?

[CoolJosh3k]

New here and I hope to bring some interesting discussions to life.
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What would a high-end CRT be like if we build one from scratch using our much newer technology?

 

My first thought is about how fast would can draw a screen while keeping it at a high brightness. What max resolution?

 

Could we build one capable of showing a really wide colour gamut? What about making full use of 16bpc?

 

I can only dream of how low the latency could be. And what of the mostly absent motion blur effect.

[SolarNova]

29 minutes ago, CoolJosh3k said:

New here and I hope to bring some interesting discussions to life.
—

 

What would a high-end CRT be like if we build one from scratch using our much newer technology?

 

My first thought is about how fast would can draw a screen while keeping it at a high brightness. What max resolution?

 

Could we build one capable of showing a really wide colour gamut? What about making full use of 16bpc?

 

I can only dream of how low the latency could be. And what of the mostly absent motion blur effect.

 

It would blow the pants of current LCDs for sure, however it would also be way more expensive to produce, and as such since manufactuers are now far more used ot the current large margins of LCD production, they would want to keep that margin and thus the end result would be a hugely expensive price tag for the customers.

 

Also despite advances in efficiency, it would still be more power hungry than LCD, and again despite advance in miniaturization it would still be far more bulky than current displays.

 

In the end the image produce would be far superior BUT everything else about it would not meet the requirements of 'looking' modern.

 

The old king of CRTs, the FW900 is still today superior to the vast majority of LCD Monitors. Its primary drawbacks are its screen size, which while huge back in the day, is rather small by todays standard at 'just' 22".  In addition it lacks things like VRR. None the less a good example of a FW900 is considered superior to current LCDs for those that have experienced CRT displays, so a modern version would certainly trounce current LCDs.

 

Its not going to happen though.

 

 

EDIT: in regards to latency, there wouldn't be any. 'Effective' instant response. 'Effective' zero added input lag.

[CoolJosh3k]

It would be a niche market, but if it could do say 8K @ 480Hz there are a few rich gamers who’d be into that.

[Curufinwe_wins]

2 hours ago, SolarNova said:

 

Snip

It would be terrible. It probably wouldn't compete on resolution.

 

 It wouldn't be much more efficient than they were then at all (which was 170W for a tiny 22 inch screen). 

 

It would still be very loud and very low brightness. Electric sizzle, EMF, fuzz would all still be an issue.

 

Scaling size beyond say 50 inches would probably require multiple tubes and complex logic in drawing with them which might negate the benefits of input lag (after all the physical oleds themselves have effectively 0 input lag). (A single tube 50 inch CRT has a mandated 38 inch depth)

 

Furthermore, CRTs have inherently very poor gamma, which makes it extremely difficult to balance colors at more than one brightness. Almost all consumer CRTs had shit color reproduction particularly as brightness diminished.

 

People don't seem to understand that the majority of limits of CRTs were not technology, but physics. 

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Cathode Ray Tubes were invented in 1897. They have been used and perfected by science for decades. The technology itself was exceedingly mature, and advancements themselves very slow and primarily limited to adding active (and thus non-instaneous) electronic circuitry to the magnetic control of the of electrons towards their phosphors.

 

There haven't been crazy huge advances in non-actively cooled magnetic materials (unlike in actively cooled magnetics where we are 100s higher in performance than we were 2 decades ago).

[Curufinwe_wins]

1 hour ago, CoolJosh3k said:

It would be a niche market, but if it could do say 8K @ 480Hz there are a few rich gamers who’d be into that.

It can't.  The faster you move a cathode ray, the higher magnetic field you need need to move the yoke, in an exponential generation of waste heat. You could try to use more and more active cooling on the deflection coils, but then that makes the entire design even more complicated (without active cooling, you'd melt the attachment system between the coils and neck of the CRT. And probably everything else in it).

 

Also CRTs have a remarkably narrow range of acceptable operating conditions which limited their usage and mounting solutions even then. Generally tmin needed to be around 50 degrees F, and tmax was generally in the 100F range.

 

 

Jumbotrons used to be made with large arrays of individual uncontrolled (as in magnetically) single CRTs that functioned as single color subpixels. Obviously that system is remarkably inefficient compared to even panel LCDs or OLEDs/emissive LED technologies.

[CoolJosh3k]

But then with active cooling it “is” possible?

 

Well jumbotrons only used that method because it way the only way, right? Perhaps having 1 per per subpixel is the solution, while grouping the whole screen into what is effectively multiple crts? Overscan would be a serious issue if we did that though...

[Curufinwe_wins]

41 minutes ago, CoolJosh3k said:

But then with active cooling it “is” possible?

 

Well jumbotrons only used that method because it way the only way, right? Perhaps having 1 per per subpixel is the solution, while grouping the whole screen into what is effectively multiple crts? Overscan would be a serious issue if we did that though...

its *potentially maybe possible* but with cooling again one thing is that the laws of thermodynamics haven't changed in the last 15 years (Sony and Panasonic made high end CRTs until around 2010). Advances in cooling (generally) have been very slow and marginal.

 

Dramatically new cheap materials haven't taken over the market. About the most relevant new cooling tech has been skiving, but that doesn't even make more than a degree of difference between a Gen 3/4 cooler and a gen 7 with the same fans.

 

Point being, to the extent that active cooling is practical/possible today, it also would have been practical/possible then.

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You'd have to control overscan, EMF interference (at both ends of the tube), and curvature of the end screen cap, among many other issues. It **might** be possible, but it sure as hell isn't practical and would almost certainly be VERY expensive.

 

The resulting mosaic would also almost certainly have large positive (bad, going away from you) curvature if you wanted the screen to not look like a complex standing wave form. Which of course, is contrary to the current design goal of introducing negative curvature so as to make all parts of the FOV neutrally distant to your eyes and thus less distorted and easier look at.

[mariushm]

You can't really have both, you'll either have high refresh rate and small screen, or big screen and lower refresh rate.

 

Think of the electron gun that heats the phosphorus on crt screens like having a laser pointer in the center of the screen surface moving left to right, top to bottom, then resetting to top and doing same thing again.

If the surface is too big, the distances start to vary too much ... the time it takes for the laser pointer light to reach the surface in the corners is much longer than the time it would take for the light to reach the centers of the screen. 

The flatter the screen is, the bigger this difference...

See the crude image below ... think how easy it is to heat up evenly the whole corner square / rectangle ... if the electron gun is too close, the orange bit won't heat up as well as the red part because of the wall blocking the electrons

 

 

So the more horizontal pixels, the more difficult is to make a crt.

The more vertical pixels, the faster everything has to work because there's only so much time until the electron gun has to reheat the top pixel, otherwise you'll see screen flickering because the phosphorus cools down and pixels lose brightness.

 

[PeterVBelgium]

20 hours ago, CoolJosh3k said:

New here and I hope to bring some interesting discussions to life.
—

 

What would a high-end CRT be like if we build one from scratch using our much newer technology?

 

My first thought is about how fast would can draw a screen while keeping it at a high brightness. What max resolution?

 

Could we build one capable of showing a really wide colour gamut? What about making full use of 16bpc?

 

I can only dream of how low the latency could be. And what of the mostly absent motion blur effect.

i honestly think even with an high-end you'll get a raging headache 

[CoolJosh3k]

We solve the horizontal timing issue with a curved screen, but what about a curved mirror setup?

 

As I understand it, years ago there was work on amplifying the beam as needed. Or maybe I understand it all wrong. Here is an article: https://www.gizmodo.com.au/2015/08/a-century-old-device-may-be-the-future-of-electronics/

[Curufinwe_wins]

24 minutes ago, CoolJosh3k said:

We solve the horizontal timing issue with a curved screen, but what about a curved mirror setup?

 

As I understand it, years ago there was work on amplifying the beam as needed. Or maybe I understand it all wrong. Here is an article: https://www.gizmodo.com.au/2015/08/a-century-old-device-may-be-the-future-of-electronics/

Quote

The vacuum tubes of the future will run at higher frequencies and powers than the dinosaur tubes of yesteryear

From that article. That is more or less just scaling up their power. 

 

Also the issue for larger CRTs isn't the vacuum tube frequency (this is already many many kilohertz, sometimes as high as 100 kHz), it's that the higher power and frequency the vacuum tube gets, the more insanely powerful and complex the magnetic deflection coils get to focus and deflect the CRT beam into a recognizable image.

 

Assuming you have infinite magnetic deflection capabilities, frequency determines total permissible pixel count on the screen, and power dictates the brightness (more complicated and interrelated than just that, but you get the idea).

 

Unfortunately there is no infinite magnetic deflection capabilities for consumer devices. Unlike the military, you can't afford to supercool (LN2 etc) the deflector electromagnets (or other exotic solutions) to reach the insane fluxes required to shape the beam at ever higher power and frequency. Unlike the military you can't afford to have the CRT and deflection coils using kWs of power.

[CoolJosh3k]

It does take a good quality LCD to make the switch worth it.

[Curufinwe_wins]

2 hours ago, CoolJosh3k said:

It does take a good quality LCD to make the switch worth it.

Not really. Not if you have limited deskspace, or want to wall/cabinet mount, or you want something bigger than 27 inches, or if you don't want the loud buzz of CRTs in house.

 

CRTs are good at exactly one thing, input responsiveness (refresh and input lag), and not all of them were even good at that. 

 

It actually pisses me off how over-the-moon gaga Digital Foundry is over the exactly one good aspect of CRTs while ignoring literally all their other structural flaws. I say that as a very late adopter of LCDs. It's easy to say that a really good CRT is damn nice, when they forget how insanely expensive they were at the time and how absolute garbage normal consumer CRTs tended to be.

[straight_stewie]

There are a few problems with CRTs in modern applications:

1. It doesn't scale well with higher resolutions.
   1. There is a limit to how finely we can aim an electron beam
      1. The smaller the screen and the higher the resolution, the smaller the pixel, therefore the higher accuracy beam steering we need.
   2. As a result of which, higher resolutions will yield larger screen sizes, which makes CRTs deeper because in order to keep scan times (refresh rates) down we need to steer the electron beams less. The only way to do that is to decrease the angle the beam needs to change to reach the appropriate pixel. But then, there's a limit to that because the further away we put the beam emitter, the more lag there is between command to change the image and the image changing. This lag is very marginal, but still there.
   3. Scan times (refresh rates) are directly related to screen size, something not necessarily true for LCD screens.

[divito]

Kind of miss my 997DF but don't really see a way for them to be modernized well enough to be in use again. There are several limitations and specific advances that would need to happen to even try, as has been pointed out above.

 

I stayed on it for a very long time, only because of playing competitively and it being well before 120hz was a reliable thing for LCDs, when I finally switched over to a 2233RZ.