Author Topic: CRTs still being made?  (Read 4822 times)

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Online Dubbie

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CRTs still being made?
« Reply #50 on: December 10, 2017, 11:37:12 am »
How can someone still argue with a straight face that crt screens look better still? Maybe just when LCDs came out... but they have long been superseded. And before you ask, yes, I used to use $30k grade 1 Sony HD monitor, so I have a good point of comparison. I wouldn’t go back to CRT for anything. Now using a modern OLED and it looks beautiful.
 

Offline AutogolazzoJr

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Re: CRTs still being made?
« Reply #51 on: December 10, 2017, 12:31:29 pm »
CRTs are good for retro gaming, vector displays, and oscilloscopes. OLED blows away CRTs in every other application.
 

Offline james_s

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Re: CRTs still being made?
« Reply #52 on: December 12, 2017, 09:33:14 am »
I wish I had kept may Hantarex green screen monochrome monitor, I can't remember the model number but it was awsome, long persistance green much longer than P31. Would have been a nice tube for vector games, never mind  :palm:

P39?
Long persistence is actually not much use for games because it makes everything streaky. Just for fun I once tried a P39 green tube in the monitor of my Asteroids and it looked neat but not particularly useful. Most of these games used a fast enough draw speed that there is little or no visible flicker. Some of the later stuff like Star Wars had more flicker because there were so many vectors being drawn on the screen during some scenes.

Anyway those old monochrome monitors have increased significantly in value with the vintage computer collectors, they're hard to find these days.
 

Offline james_s

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Re: CRTs still being made?
« Reply #53 on: December 12, 2017, 09:45:10 am »
How can someone still argue with a straight face that crt screens look better still? Maybe just when LCDs came out... but they have long been superseded. And before you ask, yes, I used to use $30k grade 1 Sony HD monitor, so I have a good point of comparison. I wouldn’t go back to CRT for anything. Now using a modern OLED and it looks beautiful.

The same way some people argue that vinyl sounds better than CDs? It's subjective and what's "better" is not the same for everyone. I think it's pretty clear that some people perceive images and sound differently than others and certainly some value certain characteristics that others don't.

I use LCD in most things due to convenience, and LCD certainly has better geometry for a computer monitor but I definitely prefer the look of a good CRT, especially for video applications. The contrast ratio LCD is crap even on the good ones and the color is different, especially if you are anywhere outside the sweet spot for viewing position. Doesn't matter to you clearly and that's fine, but CRT looks better to me, especially on equal footing where resolution is the same. The 480i Sony XBR CRT I have in the basement produces a picture roughly on par with 1080p on the LCD upstairs despite the far lower resolution. This is especially true when watching older 480i analog content which looks awful on the LCD. I have modern equipment too, not top end but not cheap crap either.

OLED is very promising and indeed looks very CRT-like and natural to me. They are still fairly rare though and it remains to be seen how they perform with age. I've been waiting a long, long time now for OLED to deliver on its promises and *finally* it seems to be taking hold. I still worry that "the enemy of the best is good enough" will come into play and that LCD will eventually win out over OLED due to the fact that something 80% as good is adequate for 95% of people, especially when it's cheaper. Throughout my lifetime the vast majority of TVs I've seen people have are the cheapest big box store junk they could find, most people simply are not picky about picture quality. With the mass market low cost is king.

My main use of CRTs though is in vintage arcade and console games where LCD just looks completely wrong. Putting a modern LCD monitor in a 1981 Centipede arcade game is like putting the interior from a 2017 car in a 1957 Chevy, it just looks weird and out of place. Vector games inherently require a CRT due to their reliance on drawing the picture like an etch-a-sketch rather than scanning a raster.
« Last Edit: December 12, 2017, 09:50:12 am by james_s »
 

Offline chris_leyson

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Re: CRTs still being made?
« Reply #54 on: December 12, 2017, 09:46:17 am »
I think it must have been P39 as it was a much much brighter green than anthing else I had seen on a green screen monitor, and you're probably right about the long persistance, not much good for animated vector graphics. I never turned the brilliance all the way up or left the same image or text on the screen for long but I guess they must have suffered from screen burn.
 

Online Dubbie

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Re: CRTs still being made?
« Reply #55 on: December 12, 2017, 09:50:24 am »

 The 480i Sony XBR CRT I have in the basement produces a picture roughly on par with 1080p on the LCD upstairs despite the far lower resolution. This is especially true when watching older 480i analog content which looks awful on the LCD. I have modern equipment too, not top end but not cheap crap either.

I can see how this might be true with 480i content, but for reasonable HD content, it should be no contest.

Maybe I'm biased because I can't remember the last time I watched something that wasn't at least 720p.
 

Offline james_s

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Re: CRTs still being made?
« Reply #56 on: December 12, 2017, 09:54:35 am »
I think it must have been P39 as it was a much much brighter green than anthing else I had seen on a green screen monitor, and you're probably right about the long persistance, not much good for animated vector graphics. I never turned the brilliance all the way up or left the same image or text on the screen for long but I guess they must have suffered from screen burn.

I don't recall screen burn on the green monitors being any worse than others. Actually some of the worst for that were the amber monochrome screens, due largely to the fact that the amber phosphor is much less efficient at turning electrons into light. The P39 green also appears brighter because the very slightly yellowish green is right near the peak sensitivity of the human eye, it would look brighter even if it wasn't.

No CRT phosphor is immune to screen burn though, I've seen lots of old computer monitors and terminals with various menus burned into them and most of my arcade games have phosphor burn due to always displaying the same game. Some games were worse than this for others.
 

Offline chris_leyson

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Re: CRTs still being made?
« Reply #57 on: December 12, 2017, 09:55:45 am »
Nippon Electric Glass used to make CRTs or glass for CRTs and closed down their plant in Wales in 2005 to concentrate on LCD products. I think they opened a CRT plant in China around the same time ? If anyone is still making CRTs it's most likely a Chinese company.
« Last Edit: December 12, 2017, 09:58:01 am by chris_leyson »
 

Offline james_s

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Re: CRTs still being made?
« Reply #58 on: December 12, 2017, 09:59:05 am »
Speaking of screen burn, I think if OLED catches on we are going to see a lot of issues with those stupid @$@& network logos burning into the screens. This was a big problem back in the projection CRT and plasma days and now the logos seem to be larger and brighter than ever. As much as I like OLED it is definitely not immune to burn, especially if left at the retina-searing out of box settings intended to make it stand out on store displays.

I hate those logos!
 

Offline Cyberdragon

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Re: CRTs still being made?
« Reply #59 on: December 12, 2017, 04:43:13 pm »
Speaking of screen burn, I think if OLED catches on we are going to see a lot of issues with those stupid @$@& network logos burning into the screens. This was a big problem back in the projection CRT and plasma days and now the logos seem to be larger and brighter than ever. As much as I like OLED it is definitely not immune to burn, especially if left at the retina-searing out of box settings intended to make it stand out on store displays.

I hate those logos!

OLED screen burns?! :wtf: Well alot of modern phones and portable computers are going to have problems then, most of them are OLED now.

*researching* Apparently it's not permanent and will fade away with normal use. http://televisions.reviewed.com/features/what-to-know-about-oled-screen-burn-in-problems-causes-image-retention

Nippon Electric Glass used to make CRTs or glass for CRTs and closed down their plant in Wales in 2005 to concentrate on LCD products. I think they opened a CRT plant in China around the same time ? If anyone is still making CRTs it's most likely a Chinese company.

Most of them are Chinese, but I just posted a non-Chinese tube company earlier in this thread, so they do exist elsewhere.
« Last Edit: December 12, 2017, 04:50:37 pm by Cyberdragon »
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Offline james_s

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Re: CRTs still being made?
« Reply #60 on: December 13, 2017, 06:54:14 am »
Yes, OLED can suffer permanent burn.

https://www.rtings.com/tv/learn/permanent-image-retention-burn-in-lcd-oled

This should hardly be surprising as it's an emissive technology, each pixel being an individual light source which degrades slightly with use just like a CRT or plasma panel phosphor. If you have some pixels that are used heavily they will degrade at a higher rate than those which are not. Getting acceptable lifespan before brightness drops to an unacceptable level has been one of the big challenges holding up mass proliferation of OLED panels. It's not much of an issue with phones because they rarely display a static image for long periods of time and most people replace them every year or two anyway.

I'm still a big fan of OLED and I think the fantastic picture quality they are capable of producing is worth it but this is something people should be aware of. During normal use screen burn should not be a problem but bright static logos are torture on any kind of emissive display. They're torture on my eyes too, I can't even watch content that has them, it's like a blob of something on the screen that I can't wipe off, it's very distracting.
 

Offline coppice

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Re: CRTs still being made?
« Reply #61 on: December 13, 2017, 08:37:41 am »
OLED screen burns?! :wtf: Well alot of modern phones and portable computers are going to have problems then, most of them are OLED now.
The quoted lifetime of OLED panels was limited to a few hundred hours for several years. Burn in was a big issue, but these panels were considered adequate for things like phones - phone don't usually last very long, and few people keep the display on for much of the time. There were supposed to be some breakthroughs a while ago, which opened the field for 100k+ hour lifetimes, but who really knows? The obvious answer would be LG, as they are the only ones with deep experience of big TV panels. LG offer a 5 year warranty on their OLED TVs, but when a friend tried to get LG to define what the warranty actually covers, they were vague. They did indicate that a gradual colour shift would probably occur, that this would be correctable by tweaking, and was not considered a warranty claim issue. When probed about burn in they were evasive.
 

Offline james_s

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Re: CRTs still being made?
« Reply #62 on: December 13, 2017, 09:27:36 am »
That has always been the case. In the CRT and plasma days screen burn was not covered by warranty and OLED is going to be no different. Of course it's not something that a TV manufacture wants to talk about because many people will latch onto it as a defect in the product. I view it as a tradeoff one makes in exchange for the superb image quality. It's not uncommon for high performance equipment to require some degree of special care.
 

Online Berni

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Re: CRTs still being made?
« Reply #63 on: December 13, 2017, 05:28:16 pm »
Well the more modern CRTs have reduced the screen burn issue quite a bit, but im sure you can still get them to burn in if you blast them with a contrastful image at full brightness for a few days straight.

Then again for LCD the dead pixel issues from the old days is what manufacturers claimed as being normal. They could sell you a brand new monitor with a 2 or 3 dead pixels on it and not offer a replacement if you complain about it.
 

Offline james_s

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Re: CRTs still being made?
« Reply #64 on: December 14, 2017, 10:40:28 am »
I haven't noticed much difference in burn resistance between older and newer CRTs. Having worked on a lot of arcade games of from the earliest to the last of the CRT based games heavy screen burn is common. It's rare on home TVs but I have seen a lot of CRT projection and plasma TVs with news logos and ticker bars burned into them. These days virtually all TV channels have permanent logos, I'm not sure why anyone is willing to pay for content that is marred in that manner.
 

Offline coppice

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Re: CRTs still being made?
« Reply #65 on: December 14, 2017, 10:46:21 am »
I haven't noticed much difference in burn resistance between older and newer CRTs. Having worked on a lot of arcade games of from the earliest to the last of the CRT based games heavy screen burn is common. It's rare on home TVs but I have seen a lot of CRT projection and plasma TVs with news logos and ticker bars burned into them. These days virtually all TV channels have permanent logos, I'm not sure why anyone is willing to pay for content that is marred in that manner.
I don't think the rate of images burning into CRTs changed much over time. However, older CRTs, without a really effective ion trap, often burned a large blob in the centre of the screen.
 

Offline james_s

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Re: CRTs still being made?
« Reply #66 on: December 14, 2017, 10:55:05 am »
Those are *really* old CRTs, the aluminum layer they started applying to the back of the phosphor sometime around the 1950s blocked the ions. I've seen the older tubes that had the gun angled in the neck and a magnetic "ion trap" to deflect the beam back to the middle without deflecting the ions.
 

Offline coppice

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Re: CRTs still being made?
« Reply #67 on: December 14, 2017, 11:03:45 am »
Those are *really* old CRTs, the aluminum layer they started applying to the back of the phosphor sometime around the 1950s blocked the ions. I've seen the older tubes that had the gun angled in the neck and a magnetic "ion trap" to deflect the beam back to the middle without deflecting the ions.
The ions were trapped in the neck by an ion trap in the neck all through the life of the CRT. The aluminium coating gradually failed if the ion trap magnet was removed.
 

Offline james_s

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Re: CRTs still being made?
« Reply #68 on: December 14, 2017, 12:13:29 pm »
That's simply not true, CRTs have not had an ion trap in decades. If you look at the tubes that did the electron gun is pointed at a substantial angle in the neck and the ion trap is a separate magnet assembly that clamps onto the neck behind the deflection yoke to deflect the beam back toward the screen. Ions are not deflected by the magnetic field, that's why the ion burns only occurred in the center of the screen and that's how the ion trap worked. The magnet only deflected the electrons toward the screen and the ions harmlessly hit the side of the tube. Once the aluminized coating was developed in the 50s ion traps went away and tubes changed over to having straight guns that pointed directly at the screen. Quite a few earlier TVs got newer replacement tubes and the ion traps were removed. I have quite a lot of experience working with CRTs so this is something I'm very familiar with.

https://www.antiqueradio.org/art/Hoffman7M112RaulandCRTPatentDrawing.jpg
« Last Edit: December 14, 2017, 12:17:02 pm by james_s »
 

Offline T3sl4co1l

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Re: CRTs still being made?
« Reply #69 on: December 14, 2017, 05:36:09 pm »
I've seen classic tubes with ion trap magnets, they do indeed look kinda goofy inside, just as the patent drawing shows.

Ions are of course not completely undeflected, but the sensitivity is thousands of times weaker (because of the same difference in mass), which is close enough to zero for purposes of a few gauss and a few degrees.

Also, only negative ions are of interest here, because of course positive ions get sucked towards the cathode (and cause unpleasantness with the chemical purity and surface condition of the cathode, leading to degradation over time), which is interesting because you're often told that a molecule gets smacked by an electron and loses several in the process, but it's not an exclusive process, and sometimes they stick, and sometimes the molecule breaks (such is the case for water, even in the upper atmosphere) leaving fragments that go whichever way. :)

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