US Patent 11226261 Optical device testing method and apparatus

At various positions in an eye motion box (EMB) an output image from an optical device can be captured and analyzed for detection and evaluation of image propagation via the optical device. Optical testing along a specific axis can evaluate optical engine transfer function uniformity across facet's active area, detect the existence and degree of “smearing” of a projected image from an optical device, and detect the existence and degree of a “white stripes” (WS) phenomenon related to scattering and diffraction in the wedge-to-LOE interface. A variety of metrics can be derived for quality control and feedback into the production system, and for disposition of the optical devices.