willrs wrote: ↑28 Jun 2023, 19:45
I saw these two mentions of PWM dimming in LCD's resulting in repeated images and effecting motion fluidity. Does this also apply to OLED displays that use PWM dimming such as an iPhone display? And if so, what PWM frequencies would say a 60Hz OLED have to be at to avoid these?
The PWM dimming frequency of an iPhone is close or higher than the horizontal resolution of the device, so it's not as blatant as certain displays. Stroboscopics are more visible with fast motion that appears and then disappears off the edge of the screen in 1 second or less, and the iPhone screen is pretty small.
It varies from OLED to OLED. But the iPhone 14 OLED PWM frequency is 480Hz, and Huawei Mate 50 OLED PWM frequency is 1440Hz. While artifacts can be visible, keep in mind phone screens are very small, that scrolling means objects disappear off the edge of the screen very fast, so the stroboscopics aren't bothersome. At 480Hz, the PWM artifacts won't appear for 480 pixels/sec scrolling, and you'd have to be paying attention
while eyetracking the scroll, to see it.
Now, there's the indirect eyestrain from the PWM issues, but it's been fairly hard (for most people) to see the PWM artifacts on a small screen. Bigger screens are easier to see PWM artifacts on because things take a longer time to scroll over more pixels, and thus, you have more time to notice the PWM artifacts. But a phone screen held at arms length, and most people don't "eye-track the scroll" (because of just plain ugly 60Hz motion blur), so being bothered by PWM is less common on small screens and small-FOV displays, than it is for large displays and large-FOV displays (e.g. VR).
It is a pick-poison, but one does have to use a different PWM-strain ruler for both giant/large-FOV screens versus tiny phone screens.
One person may quickly eyestrain at 864Hz PWM on an ASUS PG248QE monitor from year 2013 when sitting close to it, but get zero eyestrain at 480Hz PWM on an iPhone 14 OLED held at arm's length -- depending on your PWM-sensitivity threshold. Everyone's threshold is different, for being bothered by PWM.