Decrease screen brightness below minimum level, by turning off individual pixels. This way the screen contrast is kept at the same level.
Save battery on newer AMOLED screens - they will turn off black pixels completely. Especially good for 4K screens - disable all those pixels you don't need!
Includes screen pattern editor and light sensor support for turning filter off automatically.
Screen pattern is shifted each 5 minutes to prevent uneven pixel wearout.

App sources available here:

Previous version with configurable notification available here:
From version Pixel Filter 2.2:
Quick settings tile for Android 7, by seizonsenryaku
All versions
February 19, 2017