Try the Brand New DC Brightness Control on Mi 9 - Mi 9/SE/T/T Pro/Lite - Mi Community

Dear Mi fans!

As we know, OLED panels have a lot of advantages. They have better color accuracy and contrasts and are thinner and brighter than traditional LCD panels. So now we can see a lot of smartphones with OLED panels on the market.

Most OLED panels use a technique called Pulse Width Modulation (PWM) for dimming its brightness. It is the most common way to adjust the brightness of an OLED display. This is different from DC dimming, which has been used by LCD panels to control its brightness levels. PWM is the easiest way to achieve high quality brightness control, but it maight make some users uncomfortable - such as flicker that may cause eye strain and headaches.

In order to better understand DC dimming, we first need to learn about PWM dimming.

What is PWM?

PWM stands for Pulse Width Modulation. It means you can vary the width of the light pulse to control the brightness of the display panel. On the PWM dimming display, the brightness adjustment depends on the screen stays on or off. The PWM dimming screen is not continuously lit up, but constantly on and off the screen. If you want to achieve a lower brightness, smartphone turn the display on and off in a very high frequency. This frequency is not perceived by the human eye, which usually sees anything that flickers faster than about 60Hz (60 times per seconds) as consistent. Some people, however, are much more sensitive to flicker.

At 100% brightness, you can see that the light is always on. When you lower the brightness to 50%, the panel alternates between on and off at equal intervals. However, when you further lower the brightness, the screen stays off for a longer time than it stays on. So, at extremely low levels of brightness, there is a obvious flicker effect.

What is DC Dimming?

DC dimming essentially controls the brightness by varying the power supplied to the circuit. Since Power = Voltage x Current, increasing or decreasing either of these inputs will vary the power supplied to the display panel, and thereby its brightness.

Smartphone manufacturers have become increasingly aware of the possible issues associated with PWM dimming. And now Xiaomi is going support DC-Dimming on Mi 9, which gives an option to people who suffer from PWM.