Modern smartphones emit bright blue light, so even in the brightest sunny day you can see the screen.But, what happens at night when you are looking in your mobile screen? Well, your brain becomes very confused, and this light is associated with brightness of the sun.
This is very alarming fact, because the brain will stop producing melatonin, a hormone that is responsible for regulation of our sleep time. During the day is inactive , and around 9pm when the darkness come is increased in blood. This makes us sleepy. But when we are looking in the screen at night the light from it , confuse our brain, and that can be very bad for our health.
Here is the picture :