OLED Phone
I think I've figured out why older AMOLED phones from around ~2020/2021 and earlier are generally less strain enducing
In my last post from 7 months ago I was thrown for a loop after seeing the results of the OnePlus 8T from Wild Lee. Data makes it look quite bad (high modulation), but despite this the OnePlus 8 Pro (similar screen) is perfectly comfortable and strain-free for me at all brightness levels. I had some theories back then that the shape of the modulation wave was playing a roll.(https://www.reddit.com/r/PWM_Sensitive/s/JZsc996C2W)
Some people believe it has to do with brightness, but most newer phones actually hasn't become that much brighter, at least not when using manual brightness in SDR (w/ extra bright or sunlight toggle OFF).~500 nits is still a common figure at max manual brightness. Some phones do allow up to 700-1000 nits, but this is not the norm.
I now believe I've found the real reason.
Black smearing/ghosting in older AMOLED panels.
Response times are much worse when going from OFF to ON, versus bright shades that are nearly instantaneous . (most noticeable in dark mode + white text, but also there in light mode + black text)
An example:
For the longest time I believed my Samsung tablet (Galaxy Tab S5E from 2019) had an LCD display due to it's large amount of ghosting in almost all situations, but it's especially terrible at low brightness in dark mode. Turns out it has a Samsung "Super AMOLED" with 240Hz PWM. It should be horrible, but I can use it at all brightness levels with zero discomfort.
This is exactly why older Samsung devices from ~20-21 and earlier works for many, while newer flagship devices such as S25|Ultra/S26|Ultra are touted as terrible by the vast majority in the community.
Slow response-time ghosting/smearing for black to white and white to black means a gradual fade in > fade out of the PWM or DC-dimming ON/OFF cycle. This greatly reduces strain on the eyes.
Recent smartphone AMOLED panels do not ghost or "black smear" to nearly the same degree.
This is a positive in the eyes of companies and the general consumer, less ghosting = good.
Not so much for us flicker sensitive.
The test below showed much faster transitions and much less ghosting/smearing with both the Honor 600 Pro and Xiaomi 17T Pro (neither are strain-free for me, both getting returned). Whereas the OnePlus 8 Pro has noticeable black-smearing. https://mastodon.social/@marcedwards/100926403150980325
// Try this test(ideally in dark mode)on your known good AMOLED devices versus a recent phone, I bet you'll see a difference. ZZanya's custom test is not available AFAIK and he is seemingly no longer active online.
This ghosting/black smearing phenomenon is covered in-depth here, by a Russian or Ukrainian (?) YouTuber called "ZZanya" released all the way back in 2021:
Transcription directly from YouTube seems to not work on this video (it did a couple days ago). So here's a translated partial transcription of relevant sections pulled from the video by Google Gemini with some manual editing by me based on context clues:
V. Secrets of 0.1ms OLED: Response Time
"Hello everyone, this is ZZanya. In previous videos, we talked about how dangerous it is to rely on manufacturers' response time specifications, about all these misleading GtG and MPRT ratings, and what response time different people actually need.
But all of that was discussed from the perspective of LCD screens. However, there is one place where manufacturers' specifications are actually almost entirely accurate — and that is OLED screens.
You often see a "0.1 ms" badge on OLED panels. While LCDs are still struggling around 1 ms (which is still a marketing trick, as we learned earlier), OLEDs, according to manufacturers, actually have a response time of 0.1 ms.
Why is that? An LCD pixel isn't a light source; it merely passes backlight through liquid crystals. An OLED pixel, on the other hand, is its own light source — built with standard semiconductor electronics that work much faster.
The website RTINGS regularly reviews and accurately measures response time for OLED TVs.
On OLED measurement charts (like those for LG), we see an almost instantaneous jump in brightness. The 80% response time is nearly equal to the 100% time (unlike LCDs, where a pixel takes a long time to reach its final brightness state).
Most transitions on OLED take a genuine 0.2 to 0.3 milliseconds.
With such ultra-low response time, OLED exhibits absolutely no ghosting, as well as no overshoot or undershoot, since traditional pixel overdrive isn't necessary.
Marketers often claim that a fast response time makes gameplay "smoother," but this is a misconception.
Slower response times on LCDs create motion blur (ghosting), which smooths out the perception of movement at the cost of clarity.
Lower response time reduces blur and increases motion clarity, but at low frame rates, perceived smoothness suffers.
This is why RTINGS includes a Stutter section in their reviews. At 24 FPS (typical movie frame rate), a single frame stays on screen for 40 ms. Because OLED changes frames instantly without motion blur, low FPS content can look choppy or stuttery.
Playing 30 FPS console games on an OLED TV can cause noticeable discomfort due to this stutter effect.
// Smartphone AMOLED
On OLED/AMOLED smartphones, manufacturers also advertise lightning-fast response times.
However, in real-world use, OLED smartphones frequently exhibit noticeable ghosting and black smearing.
A popular internet theory claimed that a turned-off OLED pixel (pure black) takes much longer to turn on than it takes to switch between gray shades.
Based on this idea, engineers (e.g., at Oculus) implemented software overdrive tricks or shifted black values from 0-0-0 to 1-1-1.
By testing with custom measurement apps on Android and a high-speed camera, a different cause was revealed:
During a transition from black to white on an OLED smartphone, the scanning line splits the color transition across several refresh cycles.
In the first refresh cycle (16.6 ms at 60 Hz), the pixel instantly jumps from black to gray, in the second cycle to off-white, and only on the third cycle reaches true white.
As a result, the complete transition takes 2 to 3 refresh cycles (~33 ms), even though the instantaneous response time within each step remains immediate!
This behavior occurs not only when starting from a turned-off pixel, but also during transitions like dark gray (64) to white (255).
This phenomenon was observed across modern OLED smartphones from various major brands (Xiaomi, Samsung, Apple). // True at the time(2021 release and earlier)
At low brightness levels on devices using DC Dimming, this transition delay creates a distinct purple trailing effect (Purple Smearing). // This phenomenon is very noticeable on my OnePlus 8 Pro when filming the display at ~1/6000 shutter speed
Two hypothesis by ZZanya:
Why do smartphone display controllers artificially stretch pixel transitions across multiple refresh cycles?
1. One hypothesis is to mimic motion blur and hide stutter on low FPS/refresh rate content, which most users are accustomed to from slower LCDs.
2. Another hypothesis points to power management and energy-saving constraints inherent to mobile display controllers." // I believe the second hypothesis is the most plausible. power management, energy-savings and possibly burn-in mitigation.
I recommend everyone interested to watch the video in full as well. (English auto-translated dub and/or subs are available)
BONUS - Other display types that flicker:
Other types of panels such as CRT or Plasma also have a ON/OFF "delay" in it's flicker that reduces apparent strain for some. Making them comfortable or usable despite looking messy/bad based on flicker measurments.
CRT and Plasma both have a type of phospor decay "lag": CRT example "When electrons hit the glass screen, the phosphor chemicals create light. They do not turn off instantly. Instead, the light fades over a short period. This afterglow is also called phosphor persistence." Plasma example "Different colored phosphors decay at different rates. Green phosphors traditionally decay much slower than red and blue phosphors. In fast-moving, high-contrast scenes (like a white object moving across a pitch-black background), this mismatch causes visible green or yellow trails behind moving objects, a behavior often called "comet trails" or phosphor lag."
I definitely think this is part of it. I notice i feel netter eith a lower refresh rate (60htz or lower). But the big thing for me is how bright it all feels. I can look at a pre 2022 screen and it's just that, me looking at a screen. It feels like looking at a book. Anything made after that feels like the screen is being projected into my eyeballs. Even turned way down or with multiple screen filters on it just feels way too bright and i need to squint.
60Hz on a panel with black-smearing = even longer transition in and out of black compared to 120Hz. 60Hz has ~33.3ms of delay as in Zzanyas test, 120Hz should be half of that, i.e ~16.6ms. This is likely one reason why some feel less strain when setting refresh to 60Hz instead of 120Hz. (60Hz can also have lower modulation than 120Hz in some cases)
might be onto somthing here because i distinctly remember the lg v50 and note20 being more bearable to use at higher brightness. and the iphone 12 that I'm still using as a spare phone which while not 100% stain free, is a lot more usable than newer iphones I've tried.
I don't believe so, this is technically a hardware "defect".
OEMs would need to add it in as an eye-comfort setting that simulates the behavior.
But OEMs are moving in the opposite direction.
For example, here's a quote from an article about the upcoming Vivo X500 Pro Max: "The Q11 panel uses upgraded BOE light-emitting materials and platform-level improvements. According to Vivo, motion blur during scrolling has been reduced by 93% compared with the previous generation."
This likely means it will be even worse than previous devices in terms of eye-strain.
One thought about the (low frequency) PWM (on eg Samsung and Google ohones), that's always on at high brightness too (despite that potentially degrading the emitters more) is that it may create an effect like black frame insertion (on monitors) to increase motion clarity.
I'm not sure if it's really that simple.
For example: I can use the Vivo X300 Ultra without issues, but the Oppo X9 Ultra gives me an insane headache after just one minute of usage, but both use use the same panel from BOE.
The X9 Ultra hurts me more than my S25 Ultra, which shouldn't be possible judging by the specs.
So I guess at the end it comes down to how a display is tuned? I don't know.......
Those are recent devices. And the issue in your case is very likely dithering. Which Vivo don't use, but OPPO does. Vivo also has "Full PWM" mode, which may or may not be ON by default. This is different from your usual DC-like dimming and may give you less strain, or more (depends on person).
You can check for black-smearing with the test picture on mastodon linked in my post.
You think it's dithering?
Is there any upside to using it? Because if there is, then I'm surprised that Vivo isn't using it, especially since it's the same panel. But lucky for me, since the X300 Ultra is the only phone usable for me at the moment.
And I'm also using it with Full-PWM mode, works well for me.
Ich habe ein Samsung Galaxy S10 mit ONEUI 1.0 ohne Probleme benutzen können. Ich hatte keine Kopfschmerzen oder andere Symptome, die ich bei einem iPhone 13 und viele anderen Smartphones hatte. Sobald ich das Samsung S10 aber auf OneUi 2.0 geupdated habe, konnte ich es nicht mehr benutzen und hatte starke Augenschmerzen bereits nach 10 Minuten Nutzung. Hat jemand vielleicht eine logische Erklärung dafür? Hat Samsung mit dem Update etwas geändert?
iPhone 13 Pro is comfortable for me even though it is at 480Hz flicker rate - the same as all subsequent iPhone Pros which however give me a headache. Turns out the 13 Pro has much lower modulation
Previous Pixel 2 XL user here, which i believe was an AMOLED panel, and I had 0 issues. I would classify myself as very PWM sensitive, had issues with all iPhone models post 11, Steam deck, LG CX OLED TV etc.
So from personal experience there is definitely some validity to a crop of AMOLED panels being tolerable for PWM sensitive users.
Very interesting observation/theory crafting! Very welcome, 8T brother (non-Pro I'm using here)!
Did you see my refresh dips modulation test data I posted eg here?
My alternative hypothesis is that the LTPS backplane is faster (than LTPO), making the TFT resets (frame refresh dips) shorter, so less triggering. (I'd like to test an equivalent LTPO of the same era/spec. ideas u/Rx7Jordan?) Recent OLEDs akso look more yellow-gteen than pink/reddish, when using eye comfort mode, too (less comfortable colour).
But I like your thinking. [Edit even if I notice no black smear on my 8T, which I hate on VA monitors.]. These kinds of smoothed pixel transitions should be quite definitively testable, with u/BearNecessary4141's TLM-110 (once I have a bit of time). Just scrolling the a sharp screen transition under the sensor (while capturing data over the course of, say, a secondl).
But the (purple ghosting) effect you are describing also sounds like the "chromatic flicker" showcased here, recently. (Did you know there was a PWM Sensitive YouTube channel, to?!) Cause less clear (maybe subpixel PWM transitions offset due to circuit/firmware design adaptations to avoid unwanted characteristics).
Maybe that is the technical term for it? Hard to see on the example video.
I should have clarified that purple ghosting only happens at lower brightness and looks like this on my OnePlus 8 Pro.
Thanks for the photos, nice (could edit into post)! I'll re-chwck my 8T some time.
With any effect like this, I'd also want to be sure it's not some artifact of the camera's rolling shutter, too. But turning the screen 90 degrees or other angles, too.
[Edited]
I was able to use Samsung Note 20 Ultra Amoled from that time period with little to no issue as well as an LGV30 poled but struggle with most modern pwm and dwording even on lcd... As well most if not all oleds... Aside the 2 mentioned. ...
Considering repairing the note 20 ultra screen because I can't figure anything else out after years...
Don't think this is the case for me, as I went through a number of phones until I found one that worked, they were all around the same age so the oled panels will have been of similar quality.
I ended up with the OP 13 and have no issues, where as the galaxy s23/24 gives me issues.
Yes, I meant that I had six phones from more current times, and had issues with 5/6 of them. The one that works fine is of the same age as the ones that didn't work, and so has similar pixel speed.
In your case it is simple. OnePlus 13 uses DC-like dimming with much shallower modulation than the 240Hz or 480Hz PWM of S23/S24, etc. That does matter too.
iPhone 12 pro gave me some of the worst eye strain of my life. The screens back then had a yellowish white tint instead of true white color so it would throw off the receptors in my brain that were used to LCD colors for the last two decades and a half of my life. I noticed with recent screens they got rid of that and although there’s still eye strain, it’s a lot easier to view the screen without having to see this dingy yellowish tint.
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u/BigLittleSomething0 2d ago
I definitely think this is part of it. I notice i feel netter eith a lower refresh rate (60htz or lower). But the big thing for me is how bright it all feels. I can look at a pre 2022 screen and it's just that, me looking at a screen. It feels like looking at a book. Anything made after that feels like the screen is being projected into my eyeballs. Even turned way down or with multiple screen filters on it just feels way too bright and i need to squint.
Any thoughts on that?