PWM Flicker
Overview
PWM flicker is a visual artifact - flickering that some people can see - in certain displays.
Not all displays exhibit PWM flicker
Not all people are equally sensitive to flicker.
For a given display, one person may not detect the flicker, others might see it clearly.
Since not everyone can see it, we have use equipment (like a smartphone) to help us detect whether display has it.
Some people cannot see it but they are still affected by it
Naming and terminology
PWM stands for Pulse Width Modulation
You may see this referred to as "PWM dimming"
Background
Display panels have techniques to regulate their brightness levels:
PWM - Turning the entire display on and off rapidly. Ideally the frequency of turning the display on and off rapidly is so high that a viewer cannot see it.
DC dimming - Instead of turning off the display, less power is sent to the display.
What determines whether the flickering will be seen
The PWM frequency. The higher the frequency the less likely someone is to notice any flicker.
Variances in individuals eyes/brains - some people are just more sensitive to the effect
Headaches
Besides being visible and irritating, the flicker may produce headaches for some people. Some people say they cannot see the PWM flicker, but this still get the headaches caused by the PWM flicker.
Testing tablets for PWM flicker
How I measure for it: Measuring PWM flicker.
Resources
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