It seems that mobile phones with LCD screens are becoming more and more difficult to find, at least from the perspective of protecting the eyes, this is undoubtedly a pity.
During the National Eyes Day (June 6), DxOMark released a long article detailing the problem of screen flickering.
Simply put, the reason why LCD is more eye-protecting than OLED is that it basically does not cause eye fatigue due to flicker. The fundamental reason is that the PWM dimming frequency of LCD starts from about 1000 Hz or higher, while the OLED screen Usually only 50500 Hz.
DxOMark explained that human eyes are sensitive to flicker up to 250 Hz, so OLED screens are more likely to cause eye fatigue than LCDs.
DxOMark said that even those who unconsciously perceive the flicker may react to it, such as headaches or eye fatigue after overusing the screen. These people can buy smartphones with LCD screens instead of OLED screens.
DxOMark measured in a professional laboratory, the PWM frequency of Xiaomi 10T Pro (Redmi K30S Extreme Edition) equipped with LCD screen reached 2360Hz, while Samsung S20U only had 241Hz and Huawei P40 Pro only 362Hz.
In addition, when the brightness of the OLED screen is very low, the duty cycle (the duration of the LED lighting in a cycle is called the duty cycle) is very short, and the flicker becomes more obvious at a lower PWM frequency. It can explain why reading text or watching videos in bed at night is more prone to headaches and more tired eyes than when watching the screen in brighter conditions.
PWM duty cycle at 25 percent , 50 percent , 75 percent and 100 percent perceptual brightness level
