Cool-toned lights coming off your phone or computer screen are often considered types of light that will disrupt your sleep and trick your eyes into thinking it’s daytime. Many devices now have a night mode button that turns down the blue glow and replaces it with warmer lights, making it easier to fall asleep. A study conducted by the University of Manchester, however, is showing that the opposite may be true. During a study, the results showed that blue lights had less of an effect on mice than yellow-toned light.
Source: https://www.muscleandfitness.com/athletes-celebrities/news/blue-light