Lens design approach to optical relays

A process to design a relay lens is presented. The process is to concatenate a collimator lens and an imaging lens. For this study the imager and collimator are required to have an external or remote stop in collimated space to prevent interference upon concatenation. The relay is created by concatenating the collimator and imager at the external or remote stop. This process allows the use of optimized infinite conjugate imagers to develop a relay lens. A collimator lens can be created by reversing the path of an imager. Magnification is achieved by scaling the focal length of the imager while keeping the focal length of the collimator constant. Computer design software is used to develop examples of relays designed using the process. A discussion of the aberration theory governing the integration of the collimator and imager to create a relay is also presented.