In-Plane Folded Light Guide for Wider Smart Glasses Viewing Angles

The patent introduces an in-plane folding mechanism that redirects image beams along a folded path within the light-guide optical element. Instead of propagating in a straight line, the beams follow a multi-segment path that folds back on itself, effectively reducing the linear distance traveled while maintaining the spatial separation needed for projector placement. This dimensional reconfiguration resolves the contradiction between convenient projector placement and image quality preservation.

The patent merges the aperture expander functionality directly into the light-guide optical element by integrating partially reflecting facets onto the internal surfaces of the light-guide itself. This integration eliminates the need for separate, bulky aperture expander components that would obstruct the view field. The viewing angle expansion is achieved through the folded beam path and internal reflections within the light-guide, maintaining a clear view field while still expanding the aperture.

The light-guide optical element is designed to perform multiple functions simultaneously: it guides image beams from the projector, folds the beam path to reduce propagation distance, integrates aperture expansion through internal facets, and maintains a clear view field. This multi-functionality consolidates what would traditionally require multiple separate components into a single integrated element, improving image quality without proportionally increasing device complexity.