A heuristic approach for actuator layout designs in deformable mirror devices based on current value optimization

Deformable mirrors are vital components in fundus imaging modality incorporating adaptive optics systems. The application of precisely controlled electric currents to multiple electrodes located under the mirror surface deform its shape so that optical aberrations caused by a patient’s eye can be nullified. The higher number of actuators used, the more accurately the mirror surface can be transformed to a target shape. However, deformable mirror manufacturability limitations demand that the number of electromagnetic actuators be minimized, so there is a pressing need for an efficient method to determine the layout of a minimum number of actuators that will deliver desired aberration correction performance. In this paper, we present an actuator layout design method based on the degree to which each actuator contributes to mirror shaped adjustment, calculated according to the amount of electric current supplied to individual actuators. This method minimizes the number of actuators while preventing the error between a target mirror shape and the actual deformed mirror shape from exceeding a certain limit. To assess the aberration correction performance for each actuator layout, we also provide a method for optimizing the electric currents supplied to an array of actuators that will correctly adjust the mirror surface to target Zernike modes, corresponding to defocus, astigmatism, coma and trefoil aberrations, given the imposition of upper and lower limits upon the currents supplied to the actuators.