Do I need to replace the screen or the screen data cable?

My MacBook Air Screen has a colour problem, when I connect it to an external display the colour is perfect and the image quality is amazing, but on the MacBook Air screen itself, the picture is extremely grainy, some what blurry, dim and the colour is off.

Also I should add that if a windows is open for a while, and then minimized, the window faintly lingers on in the background

I want to fix this issue, but I don't know where the issue stems from. Is it the screen itself, the display data cable or another issue I'm no aware off?

Any advice/knowledge/ideas related to my question is appreciated, if possible, a direct answer to my question, or method to find my answer is also great :D.

Pics below