Curved CMOS Image Sensors: Packaging Issues, Applications and Roadmaps

Since few years, there has been an increasing interest and demand in flexible electronics. Standard imaging system consists of an optical module (set of lenses) and an image sensor. For wide field of view applications, and due to the curved shape of lenses and mirrors, the flat image after being propagated through the optical system is not flat but curved, i.e. the off-axis light focuses in a curved manner. This problem is called Petzval Field Curvature Aberration (Petzval FCA). It is generally fixed by additional complex lenses to “flatten” the image plane. We propose another approach with a hemispherical curved sensor technology. It allows eliminating FCA directly at the sensor level and thus makes it possible to drastically simplify, and hence miniaturize, the optical system architecture. First, a brief state of the art on curved detectors will be detailed for different application fields. Bendable capacities of hydrid detectors (included interconnection layer) were fully investigated and tested in the...