2D Light Homogenization

Abstract

An optical reflective device is disclosed that includes a waveguide and a longitudinal light homogenizing structure mounted to a surface of the waveguide. The light homogenizing structure receives input light and generates longitudinally homogenized light by homogenizing the input light along the longitudinal dimension of the waveguide. A cross coupler in the waveguide can receive longitudinally homogenized light from the light homogenizing structure and can generate two-dimensionally homogenized light by redirecting the longitudinally homogenized light along the transverse dimension of the waveguide. The light homogenizing structure may include partially reflective layers, stacked substrate layers having a refractive index mismatch, and / or a combination of partially reflective and fully reflective layers. Cross couplers and / or partially reflective layers can be formed using sets of holograms. Prisms or sloped substrate surfaces can couple the input light into the substrate.

Description

2D Light Homogenization This patent application claims priority to U.S. Provisional Patent Application 62 / 572,779 filed on October 16, 2017 The US Provisional Patent Application is hereby incorporated by reference in its entirety. Background technique [0002] The present invention relates generally to optical reflective devices, including light homogenization in optical reflective devices. [0003] Optical waveguides have physical structures that guide electromagnetic waves in the spectrum (eg, light). In some cases, the optical waveguide can be So it is a fiber or planar waveguide structure. Optical waveguides can use total internal reflection (TIR) ​​to guide light to the output. according to light relative to The incidence angle of the surface normal to the TIR surface, the intensity or power distribution of the light can vary. Therefore, due to the incident angle of the light, the optical waveguide The area may receive more or less energy from the directed light...

AI Technical Summary

Problems solved by technology

However, light propagating through a waveguide can exhibit a spatially inhomogeneous power distribution within the coupled modes

This spatially non-uniform power distribution can also lead to non-uniform intensity distribution at the optical coupling device

Therefore, this non-uniform intensity distribution can enlarge the point spread function associated with the output beam reflected towards the exit pupil, thereby reducing the resolution of the projected image and causing non-uniform brightness of the projected image

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