An image sensor comprising at least: CMOS-type photodiodes and transistors produced in a semiconductor layer having a thickness of between approximately 1 μm and 1.5 μm, a dielectric layer in which electrical interconnect layers are made, which are electrically connected to one another and/or to the CMOS photodiodes and/or transistors, said dielectric layer being arranged against a first face of the semiconductor layer opposite a second face of the semiconductor layer through which the light received by the sensor from the exterior is intended to enter, light-reflecting means arranged in the dielectric layer, opposite the photodiodes, and capable of reflecting at least a portion of the light received by the sensor towards the photodiodes.