screen turns blue on macbook pro mid 2012

My mac's screen turns blue when i press at the top of the screen downwards and move the entire screen down (close position) and upright (open) again. It does not occur always but i am concerned that it might be indicative of something serious with the screen. Interestingly only the white portion of the screen is covered by blue and not any other color. This blue area goes away when i move the screen a bit. Has anyone has the same issue as the attached image?