1385908 Optical simulators REDIFON Ltd 11 Apr 1972 [12 May 1971] 14494/71 Heading G2J A simulator designed to present a collimated display to at least one viewer 1, 2 comprises a concave mirror 7 positioned for viewing, a curved rearprojection screen 6 positioned substantially at the focal surface of the concave mirror and an optical projector 3 positioned to project a visual scene on to the rear-projection screen. The screen 6 is preferably located above the viewers heads, and the mirror 7 located such that the line from the centre of the mirror 7 to the viewers eyes is horizontal. The screen 6 may be a conventional diffusion screen or it may have that surface facing the projector formed as a series of prisms which act to deflect the light from the screen to the mirror, the angle of the prisms (which may be in strip form) varying from the top to the bottom of the screen. The projected scene may be directed by a series of mirrors between the projector and the screen. The projector may be a television camera, or several such. Means may be provided for compensating for image distortion, i.e. anamorphotic systems e.g. lenses, refracting wedges or curved mirrors. One embodiment includes a concave mirror and a flat mirror 14, 16 Fig. 6 with an intermediate projection lens 15 which produces the required distortion of the image from the projector on the back of screen 6. The mirror 7, which is preferably spheroidal may be vacuum-formed from cast acrylic sheet. The mirror finish on the concave side is obtained by vacuum deposition of silicon monoxide or magnesium fluoride over aluminium. The mirror is supported on an epoxy and glass fibre. reinforced backing.
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