Liquid Crystal Matrix Image Source for Helmet Mounted Displays (HMDs).

摘要

The Liquid Crystal Matrix Image Source for Helmet Mounted Displays program was started in September 1982, with the dual objectives of, first, demonstrating the status of miniature liquid crystal light modulating devices and, second, developing a very high brightness image source for experimentation with helmet mounted display optical concepts. This image source was desired for experiments with helmet mounted display configurations in which an off-helmet image source is coupled to the on-helmet optical system through a coherent fiber optic bundle. The approach taken was to project a high brightness image from a miniature reflective liquid crystal display device which was being developed under Tri-Service sponsorship and refined under company sponsorship. Substantial problems were encountered during the development of the liquid crystal devices, including excessive element and line defects, nonuniform contrast ratio, low contrast ratio, and short life. These problems were only partly resolved when the hardware was delivered on this program. The hardware delivered on this program is comprised of an illuminator Unit containing a high intensity arc lamp light source, an Arc Lamp Power Supply unit, and two identical Display Units. Except for the previously described problems with the development of the liquid crystal devices, the rest of the hardware generally meets the contract objectives. The results of this program demonstrate that a liquid crystal approach can provide an extremely high brightness (>40,000 fL) replacement for the 1-inch CRTs commonly used in Helmet Mounted Displays.