Development of MWIR continuous zoom with large zoom range

Abstract

A thermal imaging zoom system has been developed for the mid wave infrared band with greater than 30X zoom range. The zoom system provides continuous changes in the field of view from the narrow field of view to the wide field of view. Athermalization was also a key feature included in the design. An active thermal compensation approach is being used to cover a broad thermal range. A preloaded rail approach is used to maintain boresight and vibration requirements. The final optical layout and mechanical design resulted in a system suitable for tactical and other harsh environments. The current design is very compact for the extremely large zoom range but, the lens layout also provides adequate space for folding. In this way the zoom system can be easily configured for applications with compact space claims such as small turrets or gimbals. The fundamental optical design has also been found to be capable of accommodating different camera formats (focal plane array size and F number).