All I know is turning the brightness control on my iPad all the way down to far left with lights out and in bed then just browsing boring stuff like news, Car and Driver, etc and it works like a sleeping pill for me. In about 15-20m of this and I can barely keep my eyes open.

Might be this minimized blue light effect as they suggest, or could just be a sort of recognized pattern/habit my brain now associates with bed. I don't know why, but it works for me. I'm getting sleepy now just thinking of it..