How do I find out my iMac display panel's manufacturer?
It's an LG LM270WQ1 (SD)(F1).

One thread is here: https://discussions.apple.com/thread/5591164?tstart=0
And you can find replacement here: http://www.amazon.com/Apple-A1419-Screen-LM270WQ1-661-7169/dp/B00LEXN39W