Night Vision Goggle (NVG) Compatible Light Sources
|Publication Date:||1 August 2017|
This ARP covers three common light sources, incandescent, electroluminescent and light emitting diode that, when NVG filtered, can be used to illuminate NVG compatible aerospace crew stations. It is recognized that many other different light sources can also be used for this purpose. Also see 2.1.1 for other SAE documents that cover particular applications within the crew station environment.
This ARP sets forth recommendations for the design of NVG compatible lighting, utilizing these light sources, that will meet the requirements of MIL-L-85762 Lighting, Aircraft, Interior, Night Vision Imaging System (NVIS) Compatible. This also includes the replacement document MIL-STD-3009: Lighting, Aircraft, Night Vision Imaging System (NVIS) Compatible.
Although this ARP concentrates on lamp light sources for illumination, the information contained within this ARP may be directly applied to incandescent, electroluminescent and light emitting diode information display devices. Regardless of the light source, the focus of this document is the understanding that the radiometric energy that can be amplified by the Night Vision Goggles (NVG's) must be filtered to such an extent that it will not impact the operational use of the NCG's while still allowing sufficient visible (photometric) energy to be viewed by the pilot.
This SAE Aerospace Recommended Practice recommends certain basic considerations which the design engineer should observe when designing NVG compatible lighting. Key design issues include the right type of light source to use, how to match the filter to the light source and what trade offs need to be made in optimizing the design. Each of the various light sources have different spectral distributions from the 380-980NM wavelengths and therefore the filter selection must take that into consideration. For example, most LED light sources are very saturated (with the exception of white LEDs) and require little filtering in the near Infra-Red (IR) wavelengths to allow NVIS compatibility. However, incandescent light sources have the majority of their radiometric energy within the near IR wavelengths (780-930NM) and therefore require significant filtering that will in most situations also impact chromaticity and photometric outputs.