|Category:||Head-Mounted Equipment [HMD/NVG/Glasses]|
|Year of Manufacture:||Unknown|
|Location:||Main Object Store|
This is an early prismatic eyepiece design probably from around the 1980’s. It was steadily refined to provide an ejection-safe Night Vision Goggle integrated within a specially designed helmet and also for the early Helmet Mounted Displays. The use of a prism allows a straight through view from the eye to the outside world but also allows an image from a CRT to be accurately superimposed over the outside world at the same focus such that the pilot sees both images as one. This system was used on the I-NIGHTS HMD for the US Navy. These early prisms were quite heavy, being solid glass, and gave a very forward centre-of-gravity.