Learnt from Anatomy...

By copying the human eye, scientists have developed what may be the world's smallest autofocus lens for mobile devices.  The majority of mobile phones today include built-in cameras, but these are not generally equipped with autofocus like most regular cameras.  This is because autofocus function requires cameras to move their lenses back and forth until they correctly focus on an object, which can prove a slow and energy-draining process, and energy is a paramount concern for mobile devices.  Instead of focusing cameras by using motors to move lenses, researchers have now hit upon having cameras that focus just like the human eye — by changing the shape of the lens. Human eyes squeeze or relax their flexible lenses to alter their curvature and thus how near or far they are focused.

In order to mimic the human eye, scientists needed a soft lens, as well as materials that could mimic the eye muscles that control the lens. The resulting device was a complex sandwich of four different layers. The end product is just a half-millimeter thin and as little as 3.5 millimeters across.  At the very top is a ceramic film made of lead zirconia titanate, which acts much like the muscle in an eye and responds to electricity. When voltage is not running through it, the film remains flat, and light can pass through. However, when a voltage is passed through the film, it flexes, bending the underlying glass membrane into a lens shape that focuses light-the higher the voltage, the greater the curvature.  Under that is a thin glass membrane that serves as the flexible lens. Beneath this membrane is a synthetic transparent rubber, which acts like a cushion when the lens flexes. At the very bottom is a glass support.

The new lens system also uses less than 1 percent of the energy to autofocus than a conventional motor-driven camera in a mobile device. The sharpness of the resulting images is also comparable with other mobile device cameras.  After creating a working prototype, researchers developed the lens further with the Norwegian optics firm PoLight. The company debut a mobile phone camera with the new lens in February at the Mobile World Congress in Barcelona.