Screen Brightness

PWM Dimming and Screen Flicker

A screen set to 30 percent brightness does not necessarily emit a steady 30 percent of its maximum light. Some displays reduce average brightness by switching light output on and off rapidly. This technique is commonly called pulse-width modulation, or PWM. The switching can be too fast to look like ordinary visible blinking, yet it still changes the light reaching the eyes over time. The exact behavior varies by display technology, panel, brightness setting, and control electronics.