Hologram optical element, method of fabrication thereof, and image display apparatus

A method for fabricating a hologram optical element, comprising:

• a step (a) of forming a volume-phase reflection hologram optical element on a substrate through exposure of a hologram photosensitive material to a first wavefront of a first coherent light beam and a second wavefront of a second coherent light beam,
• wherein
• the first wavefront is produced as a result of light emitted, for a plurality of different exposure wavelengths, from a plurality of point light sources (i) located at an identical position traveling through an optical system including at least one refractive surface,
• the refractive surface included in the optical system that produces the first wavefront is so designed as to correct for chromatic aberration occurring as a result of light directed to a viewer's pupil being refracted at a refractive surface included in an optical system used at time of reconstruction,
• the second wavefront is produced by use of light emitted, for a plurality of different exposure wavelengths, from a plurality of point light sources (ii),
• at least two of the point light sources (ii) used to produce the second wavefront are arranged at different positions, and
• the point light sources (ii) are so arranged that, as a ratio of an exposure wavelength to a use wavelength at time of reconstruction differs between colors corresponding to two point light sources (ii) that are arranged at different positions, so an angle of incidence on the hologram photosensitive material differs between light emitted from those two point light sources (ii).