Patent ID: 6930811
Filing Date: 2005-08-16
Classification: G03H

Abstract:
1. A holographic printer for directly writing 1-step white-light viewable holograms, comprising: a pulsed laser source arranged to produce a laser beam at a first wavelength, said laser beam being split into an object beam and a reference beam which is mutually coherent with said object beam; a spatial light modulator wherein, in use, said object beam illuminates said spatial light modulator; a lens system for writing a holographic pixel of a hologram on to a photosensitive medium, said lens system being arranged downstream of said spatial light modulator, wherein said lens system has an effective field of view selected from the group consisting of: (i) greater than 70 degrees; (ii) greater than 75 degrees; (iii) greater than 80 degrees; and (iv) at least 85 degrees; means for modifying images sent to said spatial light modulator so as to at least partially correct for inherent optical distortions of said lens system; positioning means for positioning a photosensitive medium at the Fourier plane of said lens system; and automatic spatial coherence varying means for automatically varying the spatial coherence of said object beam so as to control the diameter of said object beam at said Fourier plane.