Tunable curvature of visible CMOS image sensors: Innovative packaging approach for new optical functions

Abstract

Flexible device can be viewed as the ultimate extension of 3D packaging, providing new functions and advantages. In this work, we propose a new packaging development on tunable curvature of Complementary Metal Oxide Semiconductor (CMOS) image sensors and propose new optical functions. Based on a mechanical study, Tunable Curved Focal Plane Array (T-CFPA) prototypes have been realized. Our investigations prove that our packaging approach for T-CFPA is compatible with spherical shape curving down to 280 mm radius of curvature for a 20*23 mm CMOS image sensor without performance loss. Flexible sensors offer several optical advantages. In single aperture camera, the T-CFPA technology can compensate the Petzval Field Curvature aberration, and simplify the optical design of wide field systems with about 30% less lenses. Applied on monocentric systems, a Field of View of 15° can be imaged, and more than 50° for a modified system. For multi-aperture optics, T-CFPA system allows a Field of View improved by more than 11°. The mechanical flexibility of the system allows a better light collection and also add the capacity of changing the resolution and the Field of View.