Author Topic: Why do backlight LEDs burn out and go blue?  (Read 19960 times)

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Offline james_s

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Re: Why do backlight LEDs burn out and go blue?
« Reply #50 on: November 11, 2021, 07:03:11 am »
Oh yes.  Every OLED display in history (so far) has been a short-lived POS.  TV screens are a newer application, but since LG did so well with their backlights, I can't wait to see the screen burn on the OLED models in a few years.

I know several different people with OLED TVs that are several years old and holding up well so far, they look absolutely fantastic too. They seem to hold up pretty well on the higher end smartphones too, but there are also a lot of lousy OLED displays that are notorious for failing.

The old CRT rear projection TVs were prone to screen burn too but it is not normally a problem with most content. Unfortunately all of the broadcast channels have those stupid logos in the corner now and I've seen those burn into displays. Those logos are the reason I stopped watching broadcast TV.
 
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Offline etiTopic starter

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Re: Why do backlight LEDs burn out and go blue?
« Reply #51 on: November 11, 2021, 07:31:06 am »
I have never and will never buy an OLED anything as long as I live. They exaggerate  the pros and hide/deny the cons until the cows come home. I’d rather have LCD than a half-hearted stop gap technology.
 

Online Zero999

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Re: Why do backlight LEDs burn out and go blue?
« Reply #52 on: November 11, 2021, 08:03:30 am »
I have never and will never buy an OLED anything as long as I live.
That's a very close minded statement. Technology improves all the time and the day might come when OLED displays become highly reliable and better performance than LEDs. You just don't know what will happen. I'm pretty sure some electric car owners, said the same thing about EVs in the past.
 
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Offline etiTopic starter

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Re: Why do backlight LEDs burn out and go blue?
« Reply #53 on: November 11, 2021, 08:10:14 am »
I have never and will never buy an OLED anything as long as I live.
That's a very close minded statement. Technology improves all the time and the day might come when OLED displays become highly reliable and better performance than LEDs. You just don't know what will happen. I'm pretty sure some electric car owners, said the same thing about EVs in the past.

They’ve had plenty long enough to improve - decades. They’re #%#% end of. The industry is moving away from OLED, I can’t recall what to, but this is a tacit admission of how crap they are in one terrible flaw where the colours burn in and one colour dies faster than the others. Good riddance.
« Last Edit: November 11, 2021, 08:12:16 am by eti »
 

Online Zero999

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Re: Why do backlight LEDs burn out and go blue?
« Reply #54 on: November 11, 2021, 08:24:37 am »
I have never and will never buy an OLED anything as long as I live.
That's a very close minded statement. Technology improves all the time and the day might come when OLED displays become highly reliable and better performance than LEDs. You just don't know what will happen. I'm pretty sure some electric car owners, said the same thing about EVs in the past.

They’ve had plenty long enough to improve - decades. They’re #%#% end of. The industry is moving away from OLED, I can’t recall what to, but this is a tacit admission of how crap they are in one terrible flaw where the colours burn in and one colour dies faster than the others. Good riddance.
So what? That means nothing. Electric cars were invented well over a century ago, before the cathode ray tube. You can't predict the future.
 

Offline PlainName

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Re: Why do backlight LEDs burn out and go blue?
« Reply #55 on: November 11, 2021, 09:04:32 am »
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Electric cars were invented well over a century ago, before the cathode ray tube. You can't predict the future.

If it takes oLED more than 100 years to get to the stage where eti stops hating them, I'd say that's beyond the entire future as far as we're concerned :)

The trouble is, as you say, we can't predict it. Electric cars stayed shit for maybe 95 of those years and it's only in the last few that they've become nearly a replacement for petrol/diesel. Still got a bit of a hurdle to leap, but maybe we'll end up changing to suit the technology instead. OTOH, LEDs have improved massively over a decade or so, IoT gone off like a rocket, etc.
 

Offline Cerebus

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Re: Why do backlight LEDs burn out and go blue?
« Reply #56 on: November 11, 2021, 12:12:54 pm »
I have never and will never buy an OLED anything as long as I live.
That's a very close minded statement. Technology improves all the time and the day might come when OLED displays become highly reliable and better performance than LEDs. You just don't know what will happen. I'm pretty sure some electric car owners, said the same thing about EVs in the past.

What do you expect? Have you ever seen eti express an opinion that wasn't set on a 'black/white' scale?  :)
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline Cerebus

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Re: Why do backlight LEDs burn out and go blue?
« Reply #57 on: November 11, 2021, 12:16:54 pm »
So what? That means nothing. Electric cars were invented well over a century ago, before the cathode ray tube. You can't predict the future.

[Fx: Peter Cook 'farty little man' voice**] "Did you know, that the electric automobile was in fact in common use before the petrol automobile?"*

* This is, in fact, true.

** For those who don't know what I'm on about:

« Last Edit: November 11, 2021, 12:20:35 pm by Cerebus »
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Online wraper

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Re: Why do backlight LEDs burn out and go blue?
« Reply #58 on: November 11, 2021, 12:17:36 pm »
I have never and will never buy an OLED anything as long as I live.
That's a very close minded statement. Technology improves all the time and the day might come when OLED displays become highly reliable and better performance than LEDs. You just don't know what will happen. I'm pretty sure some electric car owners, said the same thing about EVs in the past.

They’ve had plenty long enough to improve - decades. They’re #%#% end of. The industry is moving away from OLED, I can’t recall what to, but this is a tacit admission of how crap they are in one terrible flaw where the colours burn in and one colour dies faster than the others. Good riddance.
LOL, LG OLED TV in most cases last longer than LG LCD with failing backlight. Burn-in in most cases can be eliminated by running a compensation cycle for a few minutes. I'd say the most prominent downside is price rather than reliability.
 

Online Zero999

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Re: Why do backlight LEDs burn out and go blue?
« Reply #59 on: November 11, 2021, 12:43:33 pm »
So what? That means nothing. Electric cars were invented well over a century ago, before the cathode ray tube. You can't predict the future.

[Fx: Peter Cook 'farty little man' voice**] "Did you know, that the electric automobile was in fact in common use before the petrol automobile?"*

* This is, in fact, true.
Yes I knew that, but back then automobiles weren't yet mainstream, which wouldn't have happened so soon, had it not been for the massive improvements made to the internal combustion engine.
 

Offline IanB

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Re: Why do backlight LEDs burn out and go blue?
« Reply #60 on: November 11, 2021, 03:30:06 pm »
LOL, LG OLED TV in most cases last longer than LG LCD with failing backlight. Burn-in in most cases can be eliminated by running a compensation cycle for a few minutes. I'd say the most prominent downside is price rather than reliability.

Yes. Also, I was looking at a price sticker of nearly $1000 underneath a display TV, and realized it was not the price of the TV, but the price of a sound bar to pair up with the TV (which also cost nearly $1000).

In the old days you would buy a TV with integrated sound. Now, they are decoupled and you have to buy your sound separately.
 

Offline bdunham7

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Re: Why do backlight LEDs burn out and go blue?
« Reply #61 on: November 11, 2021, 03:34:42 pm »
LOL, LG OLED TV in most cases last longer than LG LCD with failing backlight.

That's a pretty low standard.  It is certainly possible that LG has perfected the OLED display and there won't be any issues, but given the track record of LG and the OLED in general, I'm not going to give them the benefit of the doubt quite yet.  The few years that they have been out isn't enough to convince me to replace my 14 year old plasma TV.  I like to keep things and a TV that only lasts 5 years would really irk me. 
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 
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Online wraper

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Re: Why do backlight LEDs burn out and go blue?
« Reply #62 on: November 11, 2021, 04:07:28 pm »
LOL, LG OLED TV in most cases last longer than LG LCD with failing backlight.

That's a pretty low standard.  It is certainly possible that LG has perfected the OLED display and there won't be any issues, but given the track record of LG and the OLED in general, I'm not going to give them the benefit of the doubt quite yet.  The few years that they have been out isn't enough to convince me to replace my 14 year old plasma TV.  I like to keep things and a TV that only lasts 5 years would really irk me.
Failing multimeter, coffee machine and similar small displays are not an indication of OLED TV reliability. They are out way more than a few years.
 

Offline bdunham7

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Re: Why do backlight LEDs burn out and go blue?
« Reply #63 on: November 11, 2021, 04:51:38 pm »
Failing multimeter, coffee machine and similar small displays are not an indication of OLED TV reliability. They are out way more than a few years.

OLED TVs have been out for 14 years, but those were rare, expensive and not very good.  Modern, mainstream 4K OLED TVs have been out about 4 years or so, AFAIK.  Here's an LG OLED with screen burn after about 4 years of use.  Go to 2:30 to skip the lower-time ones without burn.



A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline Ranayna

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Re: Why do backlight LEDs burn out and go blue?
« Reply #64 on: November 11, 2021, 05:40:20 pm »
In the old days you would buy a TV with integrated sound. Now, they are decoupled and you have to buy your sound separately.
They do still have integrated sound. But modern TVs have to be razor thin, and since decent sound needs physical volume, the inbuild speakers are mostly bad.
Well, now they can upsell their soundbars as well :D
 

Online wraper

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Re: Why do backlight LEDs burn out and go blue?
« Reply #65 on: November 11, 2021, 05:59:06 pm »
OLED TVs have been out for 14 years, but those were rare, expensive and not very good.  Modern, mainstream 4K OLED TVs have been out about 4 years or so, AFAIK.  Here's an LG OLED with screen burn after about 4 years of use.  Go to 2:30 to skip the lower-time ones without burn.
If he had manually ran compensation cycle, most likely those issues would be gone.
 

Offline bdunham7

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Re: Why do backlight LEDs burn out and go blue?
« Reply #66 on: November 11, 2021, 06:08:37 pm »
If he had manually ran compensation cycle, most likely those issues would be gone.

I've seen no success with screen-burn reduction apps in other devices--is there something special about the compensation cycle in an LG OLED?  Does it know somehow which pixels are weak?  Does it store calibration data?
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Online wraper

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Re: Why do backlight LEDs burn out and go blue?
« Reply #67 on: November 11, 2021, 06:17:59 pm »
If he had manually ran compensation cycle, most likely those issues would be gone.

I've seen no success with screen-burn reduction apps in other devices--is there something special about the compensation cycle in an LG OLED?  Does it know somehow which pixels are weak?  Does it store calibration data?
AFAIK it somehow measures the voltage on individual LEDs or something like that. IIRC there are repair threads on eevblog where after running it, visible burnout effects disappeared.
 

Offline james_s

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Re: Why do backlight LEDs burn out and go blue?
« Reply #68 on: November 11, 2021, 08:44:30 pm »
That's a very close minded statement. Technology improves all the time and the day might come when OLED displays become highly reliable and better performance than LEDs. You just don't know what will happen. I'm pretty sure some electric car owners, said the same thing about EVs in the past.

I have so far never paid money for a TV, but if I do ever buy one it will be OLED. The picture quality is simply stunning, no LCD can even come close. It's not like LCD TVs are some shining beacon of reliability either, right now I have two nice big LED lit LCD TVs in the back of my closet that have bad backlights. The 65" LCD that is my main TV is one I got for free because the LED backlight had failed. OLED TVs are already more reliable than a lot of LCD TVs.
 

Offline etiTopic starter

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Re: Why do backlight LEDs burn out and go blue?
« Reply #69 on: November 12, 2021, 01:13:52 am »
LOL, LG OLED TV in most cases last longer than LG LCD with failing backlight.

That's a pretty low standard.  It is certainly possible that LG has perfected the OLED display and there won't be any issues, but given the track record of LG and the OLED in general, I'm not going to give them the benefit of the doubt quite yet.  The few years that they have been out isn't enough to convince me to replace my 14 year old plasma TV.  I like to keep things and a TV that only lasts 5 years would really irk me.

2007 vintage Panny plasma here, given to us by a couple who were - ahem - "upgrading" - still going strong, daily use, MANY hours!
 

Offline etiTopic starter

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Re: Why do backlight LEDs burn out and go blue?
« Reply #70 on: November 12, 2021, 02:17:31 am »
Consumers are far too pampered and demanding, and I find people get overly obsessed with specs, display technologies etc, having swallowed and digested the marketing garbage, hook line and sinker. 😁

Quit the pixel peeping and just enjoy what you’ve got. The novelty of a new toy and all the things it can do, fade away and soon are forgotten once it transitions from “MY NEW TV!” into just “My TV”. I find this carries across the entire line of consumer gadgets too. Just use the thing and enjoy it - I don’t ever remember thinking “😱 Oh no! My blacks are too bright - it’s ruined my film - how can I possibly enjoy it now?!”

Reminds me of when my neighbour came back from the cinema, having watched a 3D film - he was extolling the virtues of how amazing it all was, how it jumped out at you, on and on… I said “yea that’s amazing but was the story any good?” - he was fixated on the novelty factor. In a similar vein, my Panasonic plasma isn’t even 720p, and yet it performs incredibly, and I never even think about that.
 

Offline PlainName

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Re: Why do backlight LEDs burn out and go blue?
« Reply #71 on: November 12, 2021, 12:59:09 pm »
Quote
In a similar vein, my Panasonic plasma isn’t even 720p

Is it colour?

Quote
he was extolling the virtues of how amazing it all was, how it jumped out at you, on and on… I said “yea that’s amazing but was the story any good?”

So you'd be OK watching stuff in B&W? I'm betting when colour TVs first came out there was someone asking, yeah but was the story any good?
 

Offline Cerebus

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Re: Why do backlight LEDs burn out and go blue?
« Reply #72 on: November 12, 2021, 01:28:26 pm »
So you'd be OK watching stuff in B&W? I'm betting when colour TVs first came out there was someone asking, yeah but was the story any good?

I (voluntarily) carried on watching TV in B&W into the 1990s. I rarely felt I missed out on anything without colour and with analogue SD the fact that the luminance signal had over twice the bandwidth of the chrominance signal meant that B&W was considerably crisper than colour. When you've only got at most 704 pixels in a line you need all the resolution you can get.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline PlainName

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Re: Why do backlight LEDs burn out and go blue?
« Reply #73 on: November 12, 2021, 02:54:43 pm »
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When you've only got at most 704 pixels in a line

But eti doesn't care about resolution...

I think all this shows is that different people have different appreciation of features. Resolution vs colour vs frame rate vs 3D vs power vs adverts vs ... well, there are lots of things you can trade off and we decide the balance that would suit us. Seems a bit silly to deride the choice of others when one has made one's own off-the-curve choice.
 

Offline macboy

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Re: Why do backlight LEDs burn out and go blue?
« Reply #74 on: November 12, 2021, 04:45:40 pm »
If he had manually ran compensation cycle, most likely those issues would be gone.

I've seen no success with screen-burn reduction apps in other devices--is there something special about the compensation cycle in an LG OLED?  Does it know somehow which pixels are weak?  Does it store calibration data?
Yes, it is special.
LG engineers determined that the forward voltage of the individual OLED pixels changes predictably with wear. So if you can measure the forward voltage, you know the state of that pixel and compensate. The modern OLED TV panels are engineered with a substantial headroom in maximum brightness output. As the each pixel ages, the TV applies compensation to boost the output to match original specifications. Eventually of course, it will run out of headroom and won't be able to boost some pixels any further, at which time light output will decrease and burn in will begin to show up. I've read they expect this will occur after approximately 100000 hours, or around 10 hours a day for 30 years. This technology has improved over the years (and didn't exist at first) so don't be surprised to hear of burn-in issues from people with old OLED panels. It's highly likely that modern OLED TVs (just like LCDs) will be replaced due to technological obsolescence or some non-panel fault far before the panel is worn out.
Even if my OLED TV only lasts 5 years, I will get another OLED to replace it. There is no other tech on the market that comes anywhere close to the picture quality. The picture uniformity is perfect; in fact, I now find it almost painful to watch any LCD TV due to the subtle non-uniformity (blotches, brighter edges, etc.) that most people don't even notice because it's so "normal"/common. The black levels and shadow detail of OLED are amazing. The best zone-lit LCDs have narrowed the gap but don't and can't match the performance.
 


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