Alignment and assembly strategies for AWARE-10 gigapixel-scale cameras

Gigapixel cameras using lens arrays can contain hundreds to thousands of precisely positioned optical components and thus require fast, reliable methods for optical assembly and alignment verification. Our first one-gigapixel prototype camera (AWARE-2) and our four-gigapixel camera currently under development (AWARE-10) need active alignment and performance measurement procedures during assembly to ensure high quality images. Here we describe the methods that we have developed to ensure proper positioning of all optical components in the AWARE-10 system and the resulting optomechanical design decisions. AWARE cameras employ a single monocentric objective lens that is shared by an array of smaller "micro-cameras", each composed of a set of smaller scale lenses. In AWARE-10, approximately two thousand pieces of individual optics must be aligned to a high level of accuracy in order to attain the desired optical resolution over four gigapixels. To guarantee proper alignment before final assembly, the objective lens and the micro-optics are checked separately. Using tools including auto-stigmatic microscopy, slanted edge MTF measurements, and flat field measurements, we can confirm the correct alignment of individual components before assembly. Optomechanical designs that incorporate the application of these alignment tools are described.