A display for providing an image to an eye of an observer along a viewing direction from a display area, the display comprising: an image projector projecting collimated image illumination along a projection direction; and an optical element formed from at least partially transparent material having first and second major surfaces, said optical element including a plurality of partially reflective surfaces (24, 41, 52), said plurality of partially reflective surfaces being internal to said optical element, planar and mutually parallel characterized in that: said plurality of partially reflective surfaces (24, 41, 52) are at least partially overlapping relative to the projection direction and relative to the viewing direction so that reflections of different parts of the projected image from different facets are superimposed to contribute to a single output ray, and said image projector is deployed relative to said optical element with said projection direction incident on one of said major surfaces within the display area and oriented such that each ray of said collimated image illumination enters said optical element and is partially reflected by at least two of said partially reflective surfaces (24, 41, 52) without prior reflection from one of said major surfaces so as to be redirected to exit said first major surface along the viewing direction. an image projector projecting collimated image illumination along a projection direction; and an optical element formed from at least partially transparent material having first and second major surfaces, said optical element including a plurality of partially reflective surfaces (24, 41, 52), said plurality of partially reflective surfaces being internal to said optical element, planar and mutually parallel characterized in that: said plurality of partially reflective surfaces (24, 41, 52) are at least partially overlapping relative to the projection direction and relative to the viewing direction so that reflections of different parts of the projected image from different facets are superimposed to contribute to a single output ray, and said image projector is deployed relative to said optical element with said projection direction incident on one of said major surfaces within the display area and oriented such that each ray of said collimated image illumination enters said optical element and is partially reflected by at least two of said partially reflective surfaces (24, 41, 52) without prior reflection from one of said major surfaces so as to be redirected to exit said first major surface along the viewing direction. said plurality of partially reflective surfaces (24, 41, 52) are at least partially overlapping relative to the projection direction and relative to the viewing direction so that reflections of different parts of the projected image from different facets are superimposed to contribute to a single output ray, and said image projector is deployed relative to said optical element with said projection direction incident on one of said major surfaces within the display area and oriented such that each ray of said collimated image illumination enters said optical element and is partially reflected by at least two of said partially reflective surfaces (24, 41, 52) without prior reflection from one of said major surfaces so as to be redirected to exit said first major surface along the viewing direction.