Sony, which builds the camera modules used by Apple in the iPhone 4S, has announced a smaller next-generation CMOS image sensor that could allow for even thinner iPhone models in the future.

The new complementary metal-oxide-semiconductor (CMOS) image sensor announced by Sony on Monday is a back-illuminated module that allows superior image quality in a more compact size. Sony has promised that the new sensors will allow cameras to continue to evolve.

The new image sensor layers the pixel section containing formations of back-illuminated structure pixels onto chips containing the circuit section for signal processing. Benefits of the new stacked CMOS image sensor touted by Sony are:

Large-scale signal processing circuits required for higher image quality and better functionality are built in

More compact image sensor chip size

Even higher image quality of the pixel section by adopting manufacturing processes specialized for superior image quality

Faster speeds and lower power consumption by adopting the lead processes for the circuit section

The camera components are currently one of the thickest pieces of the iPhone's internal hardware. It was said before the release of the iPhone 4S that the height of the 8-megapixel camera found in the handset presented design challenges for Apple, forcing the company to keep the same form factor as the iPhone 4.

Back in April of last year, Sony CEO Howard Stringer accidentally confirmed that Apple planned to add an 8-megapixel camera to its next-generation iPhone. That eventually proved true when Apple unveiled the iPhone 4S in October with a greatly improved lens sporting more pixels, faster picture taking, and image stabilization when shooting 1080p video.

In addition, Sony's entrance into the iPhone camera supply chain was confirmed by iFixit and Chipworks, who disassembled the iPhone 4S and did an X-ray cross-section of the 8-megapixel camera found in the iPhone 4S. Written on the base layer of the camera they found a die marking that clearly reads Sony's name.