US Patent 9720234 See-through computer display systems

A head worn display for displaying a displayed image overlaid onto a see-through view of a surrounding environment that includes multiply folded optics, includes a solid prism with at least one optically powered surface and a planar surface that provides a first internal fold of an optical axis of an image light associated with the displayed image, a combiner that provides a second fold the optical axis associated with the image light and wherein a flat plate reflector is bonded to the planar surface of the solid prism to provide a flat reflective surface to the solid prism.