Blue light from screens has little effect on how quickly you fall asleep: jeroensangers.com
@daviddelven True, bright light (1,000-2,000 lux) inhibits melatonin. But device screens emit only about 80-100 lux. At the other end of the scale, natural sunlight on a sunny day provides about 100,000 lux. The article I linked to does a very good job explaining the bright light hypothesis.