VISOR-DISPLAY DESIGN BASED ON PLANAR HOLOGRAPHIC OPTICS

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