Ultra Slim Optical Zoom System Using Alvarez Freeform Lenses

In this paper, we proposed an ultra slim optical zoom system with Alvarez freeform lenses. A 3X optical zoom system with two pairs of Alvarez lenses was developed. Alvarez lenses are fabricated by precise injection molding and the movable elements are actuated by voice coil motors. A slim camera module was fabricated with a size of 25 mm(width)×25 mm(length)×6 mm(height). The zooming and imaging capabilities of this Alvarez zoom system are demonstrated experimentally. The prototype exhibits a promising future for space-constrained application such as mobile phone camera module, wearable imaging system and endoscopic system.