Apple sources displays from multiple manufacturers, including companies that compete with it in other fields, for instance, Samsung, with whom Apple is locked in vicious competition (and legal fights) in the smartphone and tablet markets, also makes all iPad retina displays. Finding out who made the display on your laptop is a little trickier, since there are multiple possibilities. Go to System Preferences > Displays > Color, then highlight Color LCD and click Open Profile. This will bring up a table of information about your monitor; scroll down to line 17, which will offer a manufacturer number. A little judicious Google searching should match the number with a real company
My display, it turns out, is built by LG Display, which like Samsung is a South Korean company. My screen was probably built in South Korea, although the company also has module assembly plants in China and Poland.