The application of holographic optical waveguide technology to the Q-Sight family of helmet-mounted displays

Traditionally head up displays and helmet mounted displays use a conventional arrangement of complex lenses to generate a display for the pilot from an image source such as a Cathode Ray Tube (CRT) or Liquid Crystal Display (LCD). These systems tend to be complex, comprising many components and they also add mass and adversely modify the centre of the gravity of the helmet. This has resulted in the development of the Holographic Optical Waveguide, a revolutionary new optical technology which dramatically reduces size and mass whilst liberating the designer from many of the constraints inherent in conventional optical solutions. This technology is basically a way of moving light without the need for a complex arrangement of conventional lenses. This is made possible by embedding within the substrate a specially designed hologram which has carefully tailored set of optical properties. The image (or light waves) is constrained to follow a path through the substrate. As these waves pass through the substrate the hologram is programmed to allow some energy to escape in a carefully controlled manner reforming the image that was injected into the substrate. At the same time the hologram design modifies the image geometry such that the user views it as a full size conformal image precisely overlaid on his outside world view. Furthermore this image is maintained over a very large exit-pupil giving the user great flexibility in the installation of the display onto a helmet. The image is formed conventionally from a reflective LCD illuminated with a high brightness LED. The Q-SightTM Helmet Mounted Display (HMD) which exploits this concept is part of a modular-family of Helmet Mounted Displays; allowing the addition of capability as required in a flexible, low-cost way. The basic monocular QSightTM architecture offers plug-and-play solutions into any cockpit with either Analog (stroke) or Digital Video Interface (DVI) connections. This offers a significant upgrade opportunity to those users currently struggling with cumbersome legacy CRT using conventional glass optical lenses. Q-SightTM is configured to fit onto any aircrew helmet in service today, the large eye motion box permitting flexible installation onto loose fitting helmets. The Q-SightTM approach results in design solutions which are fully compatible with all in-service Night Vision Googles (NVGs) and does not require any adaptation to the NVG or its mounting bracket. This approach has distinct advantages that at night the user gets unimpaired Night Vision performance with very high quality symbology.