Is your phone screen MAKING YOU ILL?
A flickering screen can cause headaches, nausea and other health problems. Robert Irvine explains the dangers of PWM and how to reduce its effects
If you’ve ever had a headache, felt dizzy or nauseous, or experienced blurred vision while using your phone, it might be due to pulse width modulation (PWM). This is a screen-dimming method many phone manufacturers use, which doesn’t actually dim your screen at all.
Instead, PWM rapidly turns your phone’s display on and off to fool your eyes and brain into perceiving that the screen is getting dimmer or brighter. When you decrease the brightness, the display continues to flash on and off hundreds of times per second but at a slightly lower frequency.
That difference between the screen being on for a split second then going off for a split second can be incredibly jarring to the brain. While PWM affects some phone users more than others, exposure to a strobing light can lead to health issues. It’s similar to the way a flickering fluorescent light can make you queasy.
How common a problem is PWM?
Smartphones have traditionally used direct-current (DC) dimming to control the brightness of their screens. This regulates the amount of voltage an LED panel receives, so the more power you supply, the brighter the LED. When you reduce that power, the screen dims.