Diffractive waveguides of prohibited light leakage based on surface relief gratings for augmented reality display

Two issues that hindering fast developments of diffractive waveguides based on surface relief grating (SRG) for augmented reality (AR) applications: light leakage at out-coupler and low light efficiency. A layer of subwavelength metal wire grid on commonly used protective glass sheet above diffractive waveguide was designed to prohibit the light leakage and reflect them back to AR waveguide for recycling light usage. One-dimensional (1D) SRG based AR waveguide was analyzed under TE-polarized illumination at 532nm wavelength with 30° field-of-view (FOV). It was demonstrated that 80% efficiency improvement and 9% intensity uniformity increasement could be obtained with completely prohibited light leakage by nanostructures glass cover, compared with that on planar protective glass.