The brightness of OLED screens is almost always lowered through pulse-width modulation (PWM). Put simply, the screen turns off and on very quickly to give the impression of a lower brightness. The on/off frequency is given in Hz.
If the frequency is too low, some experience a flicker at the lowest brightness, or that the screen is generally hard to look at and straining the eyes. Even if you don’t notice any direct problems yourself, you may have noticed that text is no longer as sharp and clear at the lowest brightness in a dark room.
A whole subreddit is about it problems people consider themselves experiencing off too low PWM dimming. Apple, Samsung, Google and Sony offer sad frequencies compared to Chinese manufacturers. The Pixel 10 series has a hidden setting that boosts the frequency, but the boost is only to a still-low 480 Hz (Accessibility > Adjust brightness for people with sensitive eyes).
Oneplus, Oppo, Xiaomi and other Chinese brands usually offer several thousand Hz – sometimes up to 4320 Hz – while SamsungApple and Google remain at a maximum of 480 Hz. TCL has an entire smartphone series (Nxtpaper) with full focus on eye comfort. As far as we know, Nothing is the only manufacturer in the West that has adopted high PWM. The mid-range Phone 4a Pro, for example, has 2160 Hz.
Sometimes Chinese phones also offer DC dimming as an option, which means that the brightness is reduced by lowering the current to the panel. The newly presented Xiaomi 17T Pro should offer DC and be completely flicker-free. That solution has previously brought other problems at really low brightness levels – including with the color reproduction – which is probably why it’s not standard.
With the iPhone 17 series, Apple actually offers for the first time option to turn off PWM for those who find it hard on the eyes. The brightness should then instead be lowered through DC dimming, although Apple does not mention the method.
Disables pulse width modulation to provide a different way to dim the OLED display, which can create a smoother display output at low brightness levels. Disabling PWM may affect low brightness display performance under certain conditions. – Apple
Many people read on their mobile phones in the dark before falling asleep. Having a panel that is pleasant to the eyes regardless of brightness is important for all bedside readers. It is high time for manufacturers to stop neglecting PWM and start offering high frequencies or DC as alternatives.
Has anyone noticed that the screen is hard to look at at the lowest brightness, or do you notice no difference?