The iPhone 5’s design isn’t expected to change dramatically except for the back plate. A prototype at a Foxconn plant has been making rounds and one source talked with 9 To 5 Mac about the phone’s backing. The source said Apple would ditch the glass back found on the iPhone 5 and opt for metal. Issues with painting the glass white and scratches by iPhone owners were cited as the reason for a metal back by another Chinese Source:
According to a Chinese source, Apple is changing the rear part of iPhone 5 to aluminum which was used for first iPhone’s instead of glass or might adopt the design similar to iPod touch 4G, after facing lots of issues with white paint and scratches on rear glass surface, reported Taiwan’s Economic Daily News.
As of now it’s unknown if Apple will actually opt for metal over aluminum. Crafting the iPhone 5’s back out of aluminum would be a step back in the device’s design timeline — something Apple has very rarely done with any product — bringing its appearance closer to the original iPhone.
Metal would be a much more likely material as aluminum would require a plastic cover on the antenna to prevent signal loss. The iPhone 4 already has its antennas exposed and on the side making the case for aluminum arguable but from a design standpoint it would simply be a step backward. Metal is the more logical decision – it’s stronger and easier to color than glass.
A Potentially Larger Screen
One of the more prevalent rumors is the iPhone 5 sporting a larger edge-to-edge screen. The screen size is unknown but purported to be 4″ to compete with the larger Android phones on the market such as the Galaxy S and LG’s Optimus. However, the 4″ screen size is just an estimate.
Using a physically larger screen would present a number of problems such as changing the iPhone’s form factor, increasing the resolution to retain Retina Display status and thus frustrating developers who must rewrite their Apps to account for a resolution bump. Technically Apple could get away with using the same 960 x 480 resolution to still retain Retina Display status. However, the lowered Pixel Per Inch count would prevent Apple from labeling the iPhone 5’s screen a true Retina Display as it must be 300 PPI or higher.