CultofMac is reporting that the iPhone 5 will be lighter and thinner, using the in-cell touch panel display. This type of display differs from current solutions in that it merges the LCD layer and the touchscreen layer. That reduces thickness while also getting rid of the glass substrate layer required to separate and LCD from the touch layer.

 cutofmac reports : 

An in-cell touch panel display differs from current solutions in that it merges the LCD layer and the touchscreen layer. That reduces thickness while also getting rid of the glass substrate layer required to separate and LCD from the touch layer.

Digitimes reports:

The adoption of the in-cell touch panels, if realized, will also have a significant impact on the operations of Apple’s current touch panel suppliers TPK Holdings and Wintek, which are specialized in the production of glass on glass touch solutions currently, said the sources.In response, TPK said that it is developing TOL (touch on lens) single-glass touch solutions, which will be more suitable for the production of high-end customized devices and that the market will accommodate more than one technology.