Focal Plane Array Optical Focusing and Alignment

A need for active adjustment of a focal plane array (FPA) exists for space based telescopes at Sandia National Laboratories. Legacy systems relied upon manual alignment of the FPA to the optics train. The alignment was done by checking the image then adjusting the position of the FPA with shims, repeated until the desired alignment and focus were achieved. This approach has several drawbacks, including the cost of labor and clean room time, potential for damage of sensitive equipment, and potential for loss of alignment due to launch, thermal expansion, etc. An active system will allow for quicker and more robust alignment. The system will utilize three actuators that will be able to adjust the FPA in tip (θx), tilt (θy), and despace (z). [Fig. 1] The FPA will be used as the sensor that will detect when proper alignment is achieved. [Fig. 2] To do this an algorithm is needed to process the image to generate numerical vales of alignment and focus that can be compared.