Patent ID: 6771403
Filing Date: 2004-08-03
Classification: G02B,G03H

Abstract:
A holographic element that is a reflective holographic element formed on a substrate and constituted by a composite hologram having a plurality of patterns of interference fringes composed of interference fringes nonparallel to the substrate, the holographic element forming, out of image light having a predetermined wavelength width emanating from an image display element, a plurality of observation pupils at spatially different locations,wherein the holographic element acts in such a way as to fulfill the following conditional formulae (I) and (II) for an identical incident ray over an entire area in which the image light is incident on the holographic element: &Dgr;&thgr;<2â€ƒâ€ƒ(I) &Dgr;&eegr;>50â€ƒâ€ƒ(II) where&Dgr;&thgr; represents the difference (Â°) in angle of diffraction among the different patterns of interference fringes; and &Dgr;&eegr; represents the difference (%) in diffraction efficiency among the different patterns of interference fringes.