Macbook screen goes black for a few seconds then reappears fine

The last two days my macbook screen has gone black for a few seconds then reappeared a few seconds later. Its as if it goes to sleep for a few seconds. The two times it has done this it has been charging. I have checked for hotspots but i have not activated any. I only bought the macbook air two months ago and have been really careful with it so i am confused.

any help? Please?

Thanks people.