Pulse-Width Modulation, or PWM, is one of the ways display makers can use to adjust the display's brightness. PWM is considered to be an easy (or cost-effective) way to control the brightness, but it has serious drawbacks, such as flicker that may cause eye strain and headaches. In this article we'll discuss PWM and its effects on OLED displays.
PWM is easiest to understand in displays that use backlight, like LCDs. In LCDs that use PWM, the backlight is always on at its fullest brightness. If you want to achieve a lower brightness, you turn the display on and off in a very high frequency. This frequency is not perceived by the human eye, which usually sees anything that flickers faster than about 60Hz (60 times per seconds) as consistent. Some people, however, are much more sensitive to flicker.