Designing the right visor
Pinhas Gilboa · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1991
In a visor-projected helmet-mounted display (HMD), the volume and helmet shape are constrained by visor curvature and location. An approach is presented which determines optimal visor and optical configurations which lead to minimal helmet envelope size. A model based on a spherical visor and a criterion for an envelope size is defined. Three parameters are left free to be set by the designer: visor curvature, eye relief, and a degree of optical assembly obscuration. The influence of these free parameters on helmet size and shape are examined for an unobscured field of view. An adaptation of the model for nonspherical visors is also discussed.