CMOS image sensor cameras are widely used in various applications, across industries such as aerospace and defense, automotive, and consumer electronics. With the emergence of high-resolution cameras, obtaining the best image quality is becoming a must-have requirement. There is a growing need to design and optimize each camera component considering image quality of the full system in the targeted application environment. Accurate modeling of such components can be challenging due to multiscale structures going from nanoscale photonics to macroscale optics. To mitigate the modeling problem, Ansys provides ray and wave optics tools [1] to simulate and optimize the design of the different modules of the camera system (lens imaging system, nanoscale pixel structure, digital processing) in a virtual environment with different illuminations, scenes, and scenarios, and evaluate the quality of the complete camera system. The lens system is designed with the optical design software Ansys Zemax OpticStudio [2]. Then, an optical Reduced Order Model (ROM) of this lens system is exported to Ansys Speos [3], a ray tracing software embedded in a 3D CAD environment that provides fast yet accurate simulation while accounting for environmental conditions, including artificial and natural light sources. In parallel, Ansys Lumerical provides the quantum efficiency of the sensor by combining FDTD [4], a fully vectorial 3D electromagnetic solver, for the light absorption and CHARGE [5], a 3D charge transport solver, for the probability of collection of photogenerated charges. Light exposure from the 3D scene through the lens system onto the sensor is combined with the quantum efficiency of the sensor to generate raw images. Finally, digital processing allows the generation of the final image. The ROM has been validated by comparing it against full lens system simulations. The MTF50 differs by less than 10% between the models, and the ROM offers between 10 and 100 times speed performance while maintaining accuracy.
