Abstract: A helmet mounted display system comprising: a transparent visor; and an optical system which directs rays of light from a display produced by a display source onto a spherical region of the visor to provide by reflection at the visor, at a helmet wearer's eye position, a collimated virtual image of the display on a line of sight of a wearer of the helmet through the visor; the region of the visor being of a shape which is rotationally symmetric about a first axis and the optical system being mounted for rotation about the first axis, thereby to allow rotation of the eye position about the axis.

Abstract: There is disclosed two helmet systems, each comprising a helmet (11) and, carried by the helmet (11), an optical arrangement (13). In each system, the optical arrangement (13) both provides a collimated display superimposed on the helmet wearer's view of the forward scene through an eyepiece (15 or 50) of the arrangement (13), and senses the angular position of that eye of the helmet wearer looking through the eyepiece (15 or 50) with respect to the helmet axes. The optical arrangement (13) senses such angular position by sensing the position, within a sensing area of a sensor (37 or 72), of the point focus of infra-red radiation, from an infra-red point source (35 or 71A), reflected by the eye, and producing an electrical output representative of this position. In one helmet system the eyepiece (15) is of the open optics type and in the other the eyepiece (50) is of the solid optics type.

Abstract: A helmet system including a head-up display system wherein the combiner comprises a tuned optical coating (17) carried on the inner surface of a transparent vizor (15) provided on the helmet (13), and light from the display source (27) is directed onto the combiner, for reflection to the helmet wearer's eyes (29), after passing through a body of light refractive material material (25). Light from the display source passes into the body via a cylindrical surface (33), is reflected within the body at a planar surface (35) and exits the body via a convex surface (37). The system provides a high quality collimated display with minimal change of the physical size and aerodynamic performance of the helmet and vizor so as to provide improved fast jet ejection capability.