The angular and/or spectral bandwidth of a holographic lens assembly can be widened to accomodate highly diverging and/or wide spectral bandwidth illumination sources, respectively. Each lens in the lens assembly is comprised of a plurality of angularly customized holograms (an angularly ...http://www.google.co.uk/patents/US5680231?utm_source=gb-gplus-sharePatent US5680231 - Holographic lenses with wide angular and spectral bandwidths for use in a color display device 
