Not actually a problem for watch usability, but looks funny and takes away from the image of the pebble screen as a constant object. Can't vouch for how it affects phone usage.
In my projects, for any frequency above 800Hz flickering wasn't observable, but still created nausea and headaches. Above 8000Hz nausea and headaches were gone.
I'm extremely sensitive to refresh rates. I used to have two gigantic ViewSonic CRT monitors on my desk along with special Matrox video cards so that I could have high refresh rates.
60Hz gave me whacking migraines. 72Hz was fatiguing but didn't give me migraines. 80Hz+ and I was just fine.
I haven't had a migraine due to refresh rates on digital displays ever. Not even for incredibly slow displays.
You can see that even with LCD monitors. LCD monitors with a LED backlight will have a display refresh (ie. how often the pixels can change color) of, say, 60 Hz but the LED backlight might be run at 4 to 8 KHz (ie. how often the whole backlight turns on and off to give different brightness levels).
A 60Hz LED display is usually driven by a 4 or 8kHz refresh crystal.
Is there any objective research supporting this? I haven't heard of anyone doing simple blind testing or controlling for other factors.
To get 8-bit colors, with PWM, you need far higher refresh rates. For OLED, that’s 15.3 kHz minimum to get sRGB colors with PWM. If you only need to dim backlight, 4kHz is usually enough.
That’s all I can say about that.
That said, you were mentioning laptop displays, and the topic was OLED, that’s why I was mentioning why for OLED 60Hz is basically impossible.
And as the display of that Ideapad has around 50 brightness steps, you get a real refresh rate of about 1Hz. That’s insane.
As mentioned, I’ve tried this with the LEDs I’m using to light my room, and below a few kHz I get nausea, and so does the rest of my family.