Why does my laptop's monitor give off a green “flash”?

Question

I often hibernate my computer instead of shutting it down.

I've noticed that when my computer recovers from a hibernate, the laptop's screen flashes green (light green) for a second before the computer starts up.

I was wondering what causes the momentarily flash and if it is normal behavior which I shouldn't worry too much about?

Or is it signalling a problem with my laptop's monitor?

_{There doesn't seem to be anything wrong with the display other than the fact that it flashes green whenever I start it up.}