A method of producing a desired hologram for a holographic optical element for use in imaging a multi-dimensional array of points, in which two coherent recording beams are utilized to produce an interference pattern which is recorded to form the desired hologram, characterized in that one or both of...http://www.google.de/patents/US4998786?utm_source=gb-gplus-sharePatent US4998786 - Method of producing holograms particularly for holographic helmet displays
