Abstract: A vertically stacked image sensor with HDR imaging functionality and a method of operating the same are disclosed. The image sensor comprises, a first substrate, a pixel array organized into a plurality of pixel subarrays, of which each pixel comprises a photoelectric element for integrating a photocharge during each one of a plurality of subframe exposures, a transfer gate and a buffered charge-voltage converter. A first charge accumulation element of the charge-voltage converter is operatively connectable to at least one second charge accumulation element through a gain switch. The image sensor comprises control circuitry configured to trigger a partial or a complete transfer of the and to time-interleave at least two rolling shutter control sequences. Separate readout blocks are provided on the second substrate for each pixel subarray, each comprising in a pipelined architecture an A/D conversion unit, a pixel memory logic and a pixel memory unit.

Abstract: A pixel for a global shutter pixel array includes a sensing layer and a storage layer. The sensing layer has a sensing element adapted to provide charges upon receiving radiation and a floating diffusion region for receiving charges from the sensing element. The storage layer has at least one storage node for receiving charges from the sensing layer's floating diffusion region and storing the charges. The sensing layer and storage layer form a stack of layers, the sensing layer covering at least the storage node of the storage layer, and the stack has a light shield between the sensing layer and the storage node of the storage layer, so the storage node is shielded from impinging radiation. The storage node is between two transfer gates. The storage node and its surrounding gates are provided between the first floating diffusion region and a second floating diffusion region.