Glossary A–ZLetter F
Flicker
Flicker is a rapid, periodic fluctuation in a screen's brightness that may be visible or go unnoticed.
It usually results from the way brightness is controlled. Many screens dim by switching the light on and off very quickly.
On LCD screens this affects the backlight, on LED walls the diodes themselves. If the frequency is high enough, the eye perceives a steady picture. Cameras are more sensitive: if you film an LED wall with a low refresh rate, stripes or moving bars appear in the video. Stages, sports venues and television studios therefore use LED walls with refresh rates in the range of several thousand hertz.
Some people react to flicker with headaches or fatigue, even if they do not consciously see it. At low brightness, flicker is often stronger because the dark phases become longer. Operators whose screens are filmed or hang at workplaces should look for flicker-free dimming or a high refresh rate in the data sheet and check the screen beforehand with a phone camera.