Ultimate Wafer-level Lens Integration and Optimization for High-end Active Pixel Sensor Application

This paper presents the design and optimization of both microlenses and metalenses for an active pixel sensor array. To achieve the highest quality microlens configuration, we conducted a design of experiments by varying the array shrink ratio for both the color filter and microlens. Our experiments demonstrated that we could reduce the difference metric of major green channels to just 1.7%. Furthermore, the maximum difference in all Bayer color channels was decreased to 24.8% in wide-angle mode. Additionally, we explored the potential of metalenses as a future imaging technology. Our metalenses have been fabricated in wafer by creating a layer containing a set of irregular titanium dioxide (TiO2) buttes surrounded by SiO2. We have investigated various novel TiO2 metasurfaces with nanostructures of different sizes and patterns. The comparison with microlenses showed that metalenses contributed to enhance sensitivity by 20%. Ultimate microlenses and metalenses will persist as the foremost technologies for enhancing sensitivity.