Full color virtual retinal display using a holographic optical element

Abstract

A holographic optical element (HOE) made by photopolymer can be used as an image combining element. Use of HOE enables higher transparency and compact configuration with light and thin form factor. However, unlike other conventional optical elements such as partial mirrors or concave lenses, full color implementation involves some issues to consider since HOE has high selectivity that only reacts to predefined wavelength or angle of incidence light. Also, a shrinkage of photopolymer during the curing process causes grating detuning effect that modulates the characteristic of HOE. In this study, we present a methodology for implementing a full color HOE using a wavelength multiplexing. Especially, pre-compensation recording method is presented that can calibrate wavelength mismatch and shrinkage effect. With the proposed methods, simulation results and experimental result are also provided.