As is the case with many different types of electronics, laptops sold by Dell, Sony, Toshiba, HP, Apple, etc. are not actually produced by the company at all. Rather, the companies source parts from many different manufacturers, and the final assembly occurs in one of only a few factories (Foxconn, Pegatron, etc.). Simply searching "Apple Suppliers 2011" will give you a list, published by Apple, of over 200 suppliers they use for their production.
The screens used by all major laptop brand are produced by only a hand full of laptop screen manufacturers, namely, LG/Philips, Samsung, AUO, ChiMei, Chunghwa, to name a few. These companies all supply many laptop brands, and the brands also use many different laptop screen manufacturers.
Two identical laptops from the same brand may use 2 different brands of screens, however both are built to the same specification and and are cross-compatible with each other. So as long as you match up your screen with the above 'compatibility check' you won't have any problems with compatibility. If you are having some trouble, then simply contact us, and we'll be happy to help you out!