Is this a display problem or graphics chip problem?

My iPhone screen has developed a large broken area (see attached photos). The area still responds perfectly to touch input, but obviously I can't see anything within the area. I've tried resetting and restoring the phone but it doesn't fix the problem.

Would a new LCD fix the problem or is the logic board itself broken?

Photos (The screen itself is has cracks in it, but these have been there for quite some time)

http://postimg.org/image/aoscg9im7/

http://s11.postimg.org/idkjk9s2b/DSCN159...