VISOR-DISPLAY DESIGN BASED ON PLANAR HOLOGRAPHIC OPTICS

A method for designing and recording visor displays based on planar ho lographic optics is presented. This method can deal with the problem o f recording-readout wavelength shift. The display system is composed o f two holographic optical elements that are recorded on the same subst rate. One element collimates the waves from each data point in the dis play into a plane wave that is trapped inside the substrate by total i nternal reflection. The other diffracts the plane waves into the eye o f an observer. Because the chromatic dispersion of the first element c an be corrected by the dispersion of the second, this configuration is relatively insensitive to source wavelength shifts. The method is ill ustrated by the design, recording, and testing of a compact holographi c doublet visor display. The recording was at a wavelength of 458 nm, and readout was at 633 nm. The results indicate that diffraction-limit ed performance and relatively low chromatic dispersion over a wide fie ld of view can be obtained.