Low profile optic design for mobile camera using dual freeform reflective lenses

摘要

Aspherical glass or plastic lenses are usually adapted in the camera module of handheld phone. Recently, slimmer cameras are required according to reducing thickness of handheld phone. In this paper, we present an ultra slim camera module using multiple freeform off-axis imaging lenses. New optical concept of multiple lens system introduces the planar optics with freeform shaped aspherical lens surface on the wafer, which can achieve the thickness of 50% compared to the conventional symmetric lens system. In order to achieve the resolution specification, we separate the field of view in camera module. As the result, two inverted images are produced on a same imaging sensor and the acquired inverted images are processed by photo stitching algorithm so as to combine them. Finally, in order to verify the new imaging system, we manufacture the new slim lens through the UV embossing replication process. We found the new imaging system is feasible for VGA resolution and it can be expandable to the high resolution system.