A system projects a user-viewable, computer-generated or -fed image, wherein a head-mounted projector is used to project an image onto a retro-reflective surface, so only the viewer can see the image. The projector is connected to a computer that contains software to create virtual 2-D and or 3-D images for viewing by the user! Further, on projector each is mounted on either side of the user's head, and, by choosing for example a retro angle of less than about 10 degrees, each eye can only see the image of one of the projectors at a give distance up to 3 meters, in this example, from the retro-reflective screen. The retro angle used may be reduced with larger viewing distance desired. These projectors use lasers to avoid the need for focusing, and in some cases there projectors use instead of lasers highly collimated LEO light sources to avoid the need for focusing.