OLED Screens have severe PWM flicker in Dark Themes?

RomaRS

I found some worrisome behavior with an OLED screen in Zenbook 15 UM3504 OLED, the panel itself is ATNA56AC02-1 (SDC4180) . Here are some reviews of this panel from both notebookcheck and laptopmedia (the laptops themselves might be different but the screen is the same).

At brightness levels higher than 60% this panel is deemed to use DC dimming , i.e. I should be seeing only a thin brightness dip, which I do.

However, if I switch to dark theme in some applications (e.g. AMD Adrenaline, VS Code, MS Teams, etc.) , it looks like the pattern of flickering changes from a "dip" to a "peak".

I was able to capture this behavior on a phone cam which looks like flashes in slow-mo video recording. When OLED screen displays a lighter environment (e.g. light theme in the same application), this problem is not seen and indeed there is just a small running dip over the screen.

I think this would be better illustrated by a video (it's accelerated due to higher frame rate capture). Note this is not visible to the eye (only when filmed on camera). There are no such issues with lighter screen contents or light themed applications.

So it looks like the PWM pattern switches from "small brightness dip" to "big brightness peak" when switching from overall light to dark screen contents.

I am curious to see everyone's thoughts on it:

what might be causing it and is it general to all OLED screens?
could you check your OLED laptop and report if you have the same issue? I found the issue is most acutely reproduced in AMD Adrenaline Software, but it can be observed in any dark app (when it is opened) on top of lighter UI elements and the task bar.

DisplaysShouldNotBeTVs

RomaRS since each OLED pixel is self illuminating (an individual light for every dot, instead of a backlight behind the display) this also means that on very many OLED displays, PWM is used even to just control the shade of gray/the individual brightness itself used by that one pixel independent of the "relative" general backlight level

for example, that's why HDR on OLED displays is able to make one specific area bright while the rest remains dimmer. on many OLED "general screen backlight level" and "individual pixel color level" work in the same way, both use "per-pixel brightness control", unlike LCDs where the LCD layer is separate from the backlight layer.

meaning each individual pixel may have a different level of PWM (with darker pixels having higher flicker depth for the same reason dimmer screens use more PWM — with the one exception of "pure #000 black" which turns the pixel off) even if the whole screen is set to one backlight level

that's why I generally use light mode on my iPhone 14 Pro instead of dark mode (except for a pure black wallpaper and any apps that can actually use pure black with no large blocks of dark gray)

this is also why notebookcheck's PWM testing method is very flawed as they usually only test on one shade of color

RomaRS

DisplaysShouldNotBeTVs

Thank you very much, this was my hypothesis but this tells a lot about the low value of various TUV Flicker Free etc. certifications which even this screen has obtained. Presumably they test the screens in ideal conditions and are not a disinterested party.

Is there any way to tell if an OLED screen would exhibit this behavior at individual pixel level or not, or most likely all of them would? E.g. would this or this laptop/panel presumably have the same behavior? (maybe some other things that can reveal immediately the panel would have this issue)