The biggest change, according to iSupply, is in the batter subsystem, where Apple went from a two-cell battery to a three-cell battery. Doing so allowed Apple to eliminate an injection-molded frame used to support the old battery, and the change resulted in a battery subsytem that is a mere 2.5mm thick, a 59% decrease from what would otherwise seem a tiny 6.1mm in the original iPad.
As noted in iFixIt’s teardown (and other teardowns published on the Internet), Apple also changed the way the display subsystem is assembled. Rather than using tabs, Apple now holds the display’s glass to the body of the iPad 2 with the help of a strong adhesive. This allowed Apple to entirely eliminate a stamped sheet metal frame from the iPad 2, which eliminated another .5mm when compared to the original iPad.
In addition, Apple is using a new touch screen overlay that is a stunning 25% thinner than the original iPad, taking this overlay from 0.8mm to 0.6mm. One more area was identified in the report: Apple reduced the amount of space between the case and the battery subsystem from 1.6mm to 1.3mm, a 19% decrease.
Apple hasn’t named the glass used in the device, but iSupply speculated that its a product from Asahi Glass Co. of Japan called Dragontail Glass. Asahi announced the new material at the same time the iPad 2 was announced, forming the foundation of iSupply’s speculation. The firm said that physical tests it performed on the glass in the iPad 2 found that it is more flexible than its predecessor, and said that this should increase its durability.
All of these improvements are small in real terms, yet huge in percentage terms, and they all add up to make the new iPad 2 thinner than the iPad, and thinner than any of the device’s competition. They are also a clear demonstration of how Apple looks at every single aspect of its products’ designs.