| 主权项 |
1. A computer-based method for designing a free space reflective optical surface for use in a head-mounted display that reflects a virtual image of a display surface for viewing at a preselected spatial location by a user's eye, the method comprising using one or more computers to perform the steps of:
(a) representing, by the one or more computers, the display surface by a plurality of display objects based on optical properties not tied to a particular substrate or plane; (b) representing, by the one or more computers, the free space reflective optical surface, not tied to a particular substrate or plane, by a plurality of surface elements, each surface element being characterized by (i) a spatial location relative to the display surface, a nominal user's eye, and the preselected spatial location of the virtual image, (ii) a normal, and (iii) a radius of curvature; (c) associating, by the one or more computers, each display object with at least one surface element in the direction of which a virtual image of the display object at the preselected spatial location will be displayed to the nominal user's eye, each surface element being associated with a single display object; (d) for each surface element:
(i) defining an initial spatial location of the surface element;(ii) calculating, by the one or more computers, an initial direction of the surface element's normal using the surface element's initial spatial location, the location of the display object with which the surface element is associated, and the location of a center of rotation of the nominal user's eye so that light from the display object that reflects off of the surface element will pass through said center of rotation; and(iii) calculating, by the one or more computers, an initial radius of curvature for the surface element so that the virtual image of the display object is at the preselected spatial location; and(iv) calculating, by the one or more computers, a final spatial location of the surface element, a final direction of the surface element's normal, and a final radius of curvature for the surface element and a set of surrounding surface elements by iteratively adjusting the spatial locations of the surface elements until an error function satisfies a predetermined criterion; and (e) calculating a smoothed free space reflective optical surface based on the final spatial locations, the final directions of the normals, and the final radii of curvature of the plurality of surface elements. |
