The next-generation iPhone, largely expected to launch in October, will reportedly have a slightly thinner, sharper display than previous iPhones, according to a new Wall Street Journal report. The improvement is due to "in-cell" technology, which integrates capacitive touch sensors into the display circuitry itself.
Apple's display suppliers are already mass-producing panels using in-cell technology, claimed sources for WSJ. An in-cell display doesn't require a separate touch digitizer layer, which is roughly half a millimeter thick. Removing the layer should consequently reduce the overall thickness of the device.
The improvement is similar to those Apple made in the iPhone 4 by fusing the display panel to the digitizer layer, and then fusing both layers directly to the front panel made of Corning's ultra-strong Gorilla Glass. Doing so made the display a more expensive, integrated piece, but also eliminated thickness due to air gaps; at the time, the iPhone 4 was the thinnest smartphone on the market. Since then, Apple has used similar techniques in the Retina MacBook Pro, while other smartphone and tablet makers have also begun using fused displays.
Removing extra layers between the display panel's liquid crystal pixels and the user's eye also improves sharpness, color accuracy, and viewing angle. Light bends and diffracts when passing from one material to another, including air, so reducing the number of layers reduces any unnecessary optical aberrations.
Previous rumors have suggested that Apple's next iPhone model will sport a 4" display, possibly adopting a 16:9 aspect ratio similar to many Android smartphones.