You have a Smartphone, you love it, you use it as much as possible, only if you knew the effect of its lights will you learn to keep the light rays to the barest minimum.
The blue lights that we have on our Smartphones are quite powerful, and they have been made to glow really bright that seeing the screens of our devices during a sunny day isn’t so hard. When using your devices at night, you come to see that the screens are so bright that they can even be used to search for a pin, and when we use them continuously, our eyes automatically adapt to them so well that a little increase or decrease in light quality is obvious.
Our brain knows that the daytime isn’t meant for sleeping, and it knows that when it’s nighttime, it’s time to sleep. The lights on these devices are so bright that they can easily confuse our brain into not knowing if it’s time for sleep or time to remain active.