Flickering refers to the continuous alternating switching on and off of the screen. Although we may not be aware of the flicker, physiologically, the eye does respond to it, and the iris expands and contracts in response to changes in brightness.
An involuntary physiological reaction can explain the cause of our headaches, especially after watching the screen for a long time. The eyes will feel tired because they are working hard. This is especially true when viewing the screen in the dark.
Unfortunately, flickering of mobile phone screens (especially OLED screens) is still a problem for many users. So why is my smartphone screen flickering?
The smartphone display hardware is based on LCD (Liquid Crystal Display) or OLED (Organic Light Emitting Diode) technology. The LCD itself does not emit light, but it uses a very bright LED as the backlight source. This compensates for the decrease in brightness caused by the low transmittance of the LCD panel. In contrast, in an OLED screen, each pixel itself can emit light.
To reduce the brightness of the screen, smartphone manufacturers use a technique called pulse width modulation (PWM). This way you can turn LEDs on and off with different pulse rates. However, we usually do not see the LED switching between on and off (by other words, flicker). Overall, we only experience screen blackout. The amount of dimming depends on the duration of the LED on and off. The longer the shutdown time, the darker the screen will appear.
OLED vs LCD
The flickering effect of OLED screens is usually more pronounced than LCDs. The PWM frequency range of an OLED screen is roughly 50-500 Hz, while an LCD display starts at around 1000 Hz and above. Since the human eye is usually sensitive to flicker up to 250Hz, it’s no surprise that OLED screens are more likely to cause eye fatigue than LCDs.
Some users might want to make friends with modern devices. Take a look at examples to prove this:
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Take a look at the current prices for LCD TVs: