Due to the increasing dimension , complexity and cost of the future astronomical surveys , new technologies enabling more compact and simpler systems are required .
The development of curved detectors allows to enhance the performances of the optical system used ( telescope or astronomical instrument ) , while keeping the system more compact .
We describe here a set of five curved CMOS detectors developed within a collaboration between CEA-LETI and CNRS-LAM .
These fully-functional detectors 20 Mpix ( CMOSIS CMV20000 ) have been curved to different radii of curvature and spherical shapes ( both convex and concave ) over a size of 24x32 mm ^ { 2 } .
Before being able to use them for astronomical observations , we assess the impact of the curving process on their performances .
We perform a full electro-optical characterization of the curved detectors , by measuring the gain , the full well capacity , the dynamic-range and the noise properties , such as dark current , readout noise , pixel-relative-non-uniformity .
We repeat the same process for the flat version of the same CMOS sensor , as a reference for comparison .
We find no significant difference among most of the characterization values of the curved and flat samples .
We obtain values of readout noise of 10e ^ { - } for the curved samples compared to the 11e ^ { - } of the flat sample , which provides slightly larger dynamic ranges for the curved detectors .
Additionally we measure consistently smaller values of dark current compared to the flat CMOS sensor .
The curving process for the prototypes shown in this paper does not significantly impact the performances of the detectors .
These results represent the first step towards their astronomical implementation .