| In this thesis, we have studied and characterized a novel CMOS filterless color image sensor, which uses a new method of light detection. The results of this study allow for more understanding of the sensor's behaviour in real environment, which will be later taken into account for future image sensor design. The targeted applications encompass a wide range of digital cameras.;First of all, we studied a method to generate the proper biasing to the pixels of the sensor. This task was accomplished by the FPGA circuit and some discrete electronic components in order to apply sequentially an electric field to every pixel of the sensor according to the chosen scanning sequence of reading.;Secondly, a monitoring system was implemented. This has been accomplished by interfacing the image sensor with the computer. It allows a monitoring in real time of the captured picture in order to distinguish the right effect of the light detecting concept from the other perturbations effects. In order to do so, we also used the FPGA circuit for reading sensor's pixels and at the same time providing the synchronization signals to the frame grabber located inside the computer. Video signals were converted by transimpedance amplifiers made from discrete components, before being sent to the frame grabber. A testbench including a printed circuit board for all the described biasing and the interface electronics, taking into account the constraints of the test environment, was achieved.;The major contribution of this project was the design of a complete system able of studying and characterizing the prototype sensor. This includes the pixels biasing circuit, scanning and reading circuit, interfacing the sensor with the computer's frame grabber, the mechanical design of an appropriate testbench, as well as the characterization of the sensor. FPGA's programming, interfacing the sensor with the computer's frame grabber including the essentials files C++, Matlab and DCFs have been entirely conceived in this project. Even though they are based on the well known structures of push-pull and the transimpedance amplifier, the biasing circuit has been adapted for this application.;During tests, we had to deal with two major challenges. The first one was the minimisation, and even eliminate if possible the mechanical influence of the magnetic field on the reading circuit and optic components. If not, the magnetic effect of the concept is blurred by mechanical displacement of the sensor board or the optic alignment. The second one was to be able to illuminate only the sensor's area reserved for light detection. Otherwise, given the fact that column select transistors were not entirely isolated from the collections of electrons and holes generated by illumination, result in an additional current flowing in the opposite direction compared to the one coming from the pixels. All the electronic circuits have been first realized and validated on the breadboard first before being transferred on a printed circuit board. The printed circuit board allows to reduce the effect of noise on the output video signals and was designed to take into account the constraints imposed by the testbench.;Through the test results, the entire system proves his capabilities to characterize, validate and to extract accurately key parameters of the prototype image sensor. Test results are conclusive and promising. Charges generated by the electromagnetic radiation are collected by the three electrodes of the well, the sensitivity of the sensor increases with the magnetic field as predicted by the concept, and the sensor responds differently to different wavelengths so acting as a filterless color image sensor. |
