PWM dimming technology has stroboscopic problems, which is not good for eyes
OLED screens are self-illuminating pixels, and adjusting the current/voltage to change the brightness will also affect the color of the pixels.
What is DC dimming? DC means direct current. The OLED screen display is realized by RGB three self-luminous materials. The principle is similar to that of LED lights. The brightness of the screen is controlled by adjusting the input current/voltage of the LED lights. This is DC dimming.
What is PWM dimming? PWM is the abbreviation of Pulse Width Modulation. Under a fixed brightness, the perceived brightness is adjusted through the different ratio of the screen on and off time. The human eye has a characteristic that when seeing a rapidly changing image, it will be processed into a smooth image, which can be called the persistence of vision effect. PWM dimming uses this characteristic of the human eye to achieve the effect of adjusting the brightness of the display.
Source: DC-like dimming that is fading away
Looking at the information on the Internet, there is a saying that above a certain brightness threshold, the screen is dimmed with DC, and below the threshold, it is dimmed with PWM.
References:
1. What is DC Dimming & Why it's Important for AMOLED Smartphones?
2. In the future, OLED screen phones may not have DC dimming. Why do OLED screens insist on PWM dimming?
3. DC-like dimming gradually disappearing