updated 12:00 pm EDT, Fri August 3, 2012
Screen size remains most significant change
Although its screen size has grown, some other dimensions of the next iPhone have shrunk, according to ETrade Supply. The firm recently conducted measurements of what it claims is a front panel for the iPhone 5; it notes that the upcoming phone's screen should measure about 4.065 inches, versus 3.61 inches on the iPhone 4S. The panel is about 0.1mm thinner, though, and the Home button has shrunk by about 0.3mm. The area around the Home button has been reduced from 18mm to 15.4mm, and a similar reduction has taken place with the area around the earpiece.
ETrade also claims that the panel's glass seems to have better light transmittance, as well as improved scratch resistance. Apple is likely using a newer form of Corning's Gorilla Glass, which is mostly meant to reduce the likelihood of glass cracking or shattering.
Reducing some of the dimensions of the panel was likely essential to growing the screen's size without making the rest of the phone bigger, a problem found on many phones over the 4-inch mark. A thinner panel should also conceivably let Apple make the phone as a whole thinner, a recurring obsession for the company.