Design of New Night Vision Goggle (NVG) Optics

New helmet mounted device concepts have demonstrated the need for fast and more photon efficient optical systems operating in the visible from 400 nm to 700 nm. Current NVGs have been designed for the near IR, from 600 nm to 900 nm. This shift inwaveband requires a change in the glass selection due to the different dispersion characteristics of most glasses at the shorter wavelengths. Because of the greater dispersion in the visible, specifically in towards the blue spectrum, chromatic aberrationbecomes more difficult to control. In addition, packaging to meet a specific helmet layout configuration also becomes a challenge. Packaging can be very simple with no folds, but this configuration results in a large shift in the helmet center of gravityaway from the user causing significant fatigue for the user. Configurations with multiple folds allow the CG closer to be closer to the user at the cost of added complexity.