How does OLED burn-in truly happen and why doesn't my phone show any signs of it?
Title almost says it all. OLED monitors are getting more and more affordable, but it's almost out of the picture when buying a monitor because of toolbars and HUD elements. I don't understand why monitors "burn-in", when I shine my LED flashlight or some LED xmas lights they won't simply start emitting the same light even when I turn them off. I know it's a dumb comparison, but still, what happens?
The other thing that I don't understand is the fact that I've never seen any signs of burn-in on anyone's phone. Alright, technically that's a lie, I did see some on a work phone (or two), that only had some chat app open, seemingly since ages, and the namebar was a bit burned-in, or something like that, as you'd guess I also didn't interact with that phone a lot. As as said above "but still," I've had my phone for a while now, so does my family and friends, some of us even doomscroll, and I've never seen any signs of burn-in on any (actually used) phone.
so, I can watch my background all day, but I should open my browser every like 3 hours press f11 twice and I'm safe? Ff I'm away just let the screensaver save my screen? In that case why would anyone ever worry about burn it, you almost have to do it intentionally. But if it's really dangerous, like I immerse myself into a youtube video, but it has the youtuber's pfp on the bottom right (does youtube still do that?), and it was hbomberguy's, am I just done, toasted, burnt-in?
OLEDs don't burn their image into anything. CRTs used to burn in right onto the screen making it impossible to fix without physically changing the "glass" (really the phosphor screen).
What happens is the OLED burns out unevenly, causing some areas to be weaker than others. That clearly shows when you try to show all the colors (white) because some areas can no longer get as bright as their neighboring areas. It is reminiscent of CRT burn-in. LCDs just have one big backlight (or multiple if they have zones) so unevenness from burnout in LCDs is rarely seen, though still a thing.
So, OLED manufacturers do things to avoid areas from burning out from staying on for too long like pixel shifting, reducing refresh rate, or dimming areas that don't change for a long time (like logos).
There is a secondary issue that looks like burn-in which is the panel's ability to detect how long a pixel has been lit. If it can't detect properly, then it will not give an even image. This is corrected every once in a while with "compensation cycles" but some panels are notorious for not doing them (Samsung), but once you do, it removes most commonly seen "burn-in".
You'd have to really, really leave the same image on your screen for months for it to have any noticeable in real world usage, at least with modern OLED TVs. You would normally worry more about the panel dimming too much over a long period of time, but I don't believe lifetime is any worse than standard LCD.
Most people replace their phones before it becomes an issue. Phones are often used for small amounts of time as people pick them up to reply to a message, browse the web for a bit or watch a video. Monitors are on for long durations and have more stationary UI elements, so they will suffer from burn-in much sooner.
Smartphones also benefit from vertical integration. Your iPhone for example knows it’s an iPhone and knows that the display uses OLED and exactly what its properties are, so it can use a mitigation to subtly vary the exact location of UI elements to help reduce the effect. Your desktop PC could do this in principle, but it doesn’t necessarily know the display technology with such certainty, so mitigations for one specific technology hasn’t been a priority on that platform.
Something I've noticed with my computer monitor is that it does this shifting thing. The usable resolution is 1440p, but the screen is actually a slightly higher resolution with maybe 10 extra pixels in each direction that it uses to very slowly bounce the display image around in like a very large DVD player screensaver.
My dad's Pixel 5 has some mad burn in. You can see the circles from his home screen icons across other apps. I've never had this happen personally, not sure how it happened to his.
Burn-in isn't a light being emitted when off, it's a light being dimmer when on.
An LED works by passing current between two different semiconductors. When an electron jumps over the "gap" between those two semiconductors, it releases a photon of a particular color (determined by the size of the gap). But over time, as an LED is used, the gap can be damaged (by heat, by vibration, etc); when this happens, fewer electrons can jump the gap and thus fewer electrons produce photons. Or the properties of the gap are changed so that they emit a slightly different wavelength photon. So if you leave a particular set of pixels on, producing light, for an extended time, those LEDs will degrade more than the rest of the screen, leading that area to be discolored or dimmer. This is burn-in.
Most of the time, that's fine, because the LEDs on your screen experience wear in a more-or-less uniform pattern. Your phone is somewhat less susceptible to this, since (1) you tend to have your phone screen off most of the time, (2) there aren't as many persistent HUD elements even when it's on, as every app has its own configuration of controls and UI elements, and (3) you tend to replace a phone more often than a monitor. When you replace your phone, it's probably more-or-less evenly dimmer overall than it was when you bought it, but since you don't have anything to compare it to, you won't know; with burn-in, though, that comparison is right next to the burned-in pixels.
By contrast, a computer monitor will typically be on for 8+ hours at a time, and persistent display elements are a part of every major operating system. If you're not using the LEDs in a panel more-or-less evenly, you'll end up with a persistent image.
Thanks, makes sense. But why don't monitors have an "emergency" protocol to let the LEDs rest a while if we can know what's the max stress that they can handle?
So instead of burning out, I'd get a pop up saying that I should do something, or it lowers the brightness in that area or smth.
(1) That would require more diagnostics than an LED on a monitor is able to provide at a reasonable cost, (2) if you're leaving the monitor on in a situation where burn-in is likely, you're probably not at the monitor when it matters, (3) monitors are a mission-critical piece of hardware, meaning that them turning themselves off (or even just turning off certain pixels) randomly is not a great idea, (4) it's probably the OS's job to decide when to turn off the monitor, as the OS has the context to know what's important and what isn't, and how long it's been since you've interacted with the device, and (5) it's in the monitor manufacturer's best interest for your monitor to get burn-in so that you have to replace it more often.
The actual answer is probably a combination of multiple things, but that's my guess.
Honestly, setting a screen timeout (or even a screen saver!) is the solution to this problem. So the problem was more or less solved in the early 80s.
People leave a tv on a 24h news channel with a logo that never moves. Or play a game that has certain elements of the GUI that never move. That’s how it happens most often, I think.
First of all, LED is not the same as OLED. The O stands for organic. They are more sensitive to stuff and break down over time sort of (maybe a really crappy explanation, someone with more knowledge please help), especially the blue color.
LEDs and OLEDs work the same way, the only difference is their composition. Standard LEDs use metals, OLEDs use organic compounds (which, yes, are more sensitive to breakdown over time, but come with the advantage of being smaller, lighter, more flexible, etc).
And actually, it's that size and flexibility that makes an OLED panel possible. An LED display is actually just a color LCD display with a white LED backlight; you need OLED to have the individual pixels generate their own light. Burn-in on a non-organic LED display would be a completely different thing (and is possible but rare).
It's a nitpick, but since we got out the important details, technically they're semimetals, or simple compounds with semimetalic properties.
An actual metal doesn't have the separation between electron bands necessary to support multiple different conduction regimes (i.e. the magic). Again, a nitpick.
It's only marginally more detailed on the chemistry, but conventional semiconductors (inorganic) are roughly like metal. Silicon is literally a shiny, meltable element, although it's more brittle than a true metal. Like metal, unless they react with something like in rusting, they're probably going to stay the same kind of metal. There's exceptions if you really abuse a piece of metal, but a laymen probably hasn't thought much about tempering and differences in crystal structure
Organic semiconducters are organic compounds, like a dye. Just as a dye can bleach or change over time, they can chemically change with a lot less outside help. This makes them prone to not working the same way after prolonged use. Blue and violet are the most energetic colours, so it makes sense the components emitting it would break down first. UV OLEDs would be even worse.
The reason we don't use arrays of inorganic LEDs as screens (yet) is that they're really picking hard and exacting to grow. The standard way to do it is grow a wafer which is about screen size, and then cut it up into tiny sections, only some of which will work, and each of which is worth something significant on it's own. OLED can be grown in less crazy conditions, more like just printing with ink, and Micro LED gets around the wafer problem by using a precise robot arm to handle, test and connect each sub-pixel individually.
Cool video i saw a few days ago about the challenges of making true microLED displays. These would become the unchallenged king of displays if it became economical to make them and wouldnt have any of these issues.
Just to tack on and expand on your first point: LED monitors are normally LCD displays but with LED backligthing, allowing for more zone control and it is more efficient both with space and energy usage.
For TV’s, burn in is becomming less of an issue due to software in newer models and improvements in the tech. The same goes for phones. Older OLED phones like the Pixel 2 I think, had issues with burn-in.
Rtings is actually doing a long term torture test as we write. They have also included some PC monitors for good meassure.
In general, the reason why it’s still not perfect for PC is that all office/daily use retains a static image on a large portion on your screen. Imagine a browser, Excel or program with a big static toolbar. This will cause issues even with pixel shift and refresh cycles. You can only move pixels so much without it affecting your experience.
If you were to only game or watch movies on it, it would likely never show signs of burn-in.
You'd have to have those pixels showing the same color for quite a long time, like months to years. We don't typically have our phones on that long, and with more modern OS versions, there aren't really that many things that stay on the screen anyway. What used to be burned in on phones were the navigation bar at the bottom. Gestures are default now. The icons at the top aren't actually static for long. And phone screens turn off after a few minutes. Dark mode being popular is a big help because the brightness of the screen is a factor.
All OLEDs can get burn in, we just don't have as many of the things that lead to burn in as before, plus a few things here and there meant to help alleviate it.
I'm away just let the screensaver save my screen?
Yup.
In that case why would anyone ever worry about burn it
Ignorance and the fact that you mostly hear about the people with problems not the ones who just bought their monitors and carried along with their lives.
Consider that almost everyone worrying about burn in has a phone with an OLED screen, that they're not worried about. What happened with phones will happen with TVs if they ever get cheap enough to really compete with LCD.
The caveat is that it actually doesn't matter unless you're only ever in that one app with the screen on. In reality, the majority of phone screens getting brun in are show models in stores and defective panels. But regardless, apps lead you more into fullscreen so you don't even have those at the bottom.
My pixel 3a had burn in after 3 years. It's the screen gui elements that rarely change that show the burn in. On android that's the message bar at the top and the white line task switch at the bottom.
I've been hearing "OLED burn in is better now" ever since I got my Galaxy Nexus 12 years ago. But it still seems to last only 3 years.
I don't have a way to share a picture of it, but my >6 year old phone has plenty of burn-in. The keyboard, a hamburger menu, a back arrow, are all clearly visible when the screen is bright/mostly white. It's an S9+, in case that is helpful info.
Oversimplified, lights fade over time; the ones you use more often fade faster.
The primary solution, if I understand it correctly, is jiggling. The image is altered slightly over time to change what pixels are illuminated and how so that one set is not left in the same configuration for too long. Like the ones beside each other are used in tandem and altered slightly to create the same effect. You're seeing an illusion made of quickly flashing red/green/blue/white(maybe) anyways, so it is just a more complicated type of control.
How long have you had your phone? I have seen it begin to happen around the three year mark on my Galaxy S8+ and my S20+. Slight ghosting of parts of the Wayz UI. My S23 Ultra hasn't yet, but still have a while on it.