Sleep to the noise of fan sounds, but with a black, dark screen.
Fans create the best natural ambient white noise for sleep. Some fans are loud, some are low, and oscillate, but it’s the deep tones that relax us. In the hot summers, I often turn off my air conditioning so I can open the windows and work in front of a floor or window fan. The fan sounds help me focus by masking the distracting ambient sounds of the city.