When darkness falls, the brain receives a signal that it is time to sleep so the sleep hormone is being discharged. If you are exposed to strong light source, during that moment, you will have a restless sleep. In terms of how to sleep, scientists are unanimous and say the sleep should take place in complete darkness.
When the sun rises and daylight appears the light receptors send to the brain a clear message that is it time to wake up.
Neurological studies have shown that sleep with the computer or TV turned on, or dimmed light, leads to bad mood. Restless dream that occurs from sleeping with the lights turned on can result in drowsiness, bad mood and difficulty waking up.
If you still cannot sleep without the TV being turned on, you can at least set the timer to turn it off in order to reduce or avoid consequences that might occur due to poor sleep.