Cascaded Waveguide Beam Expansion for XR Eyebox

The patent replaces the mechanical approach of increasing MEMS mirror size with an optical approach using waveguides. The waveguide system uses total internal reflection and optical path manipulation to expand the beam without requiring larger mechanical components. The beam is guided through multiple reflections within the waveguide structure, achieving beam expansion while keeping the physical footprint compact.

The patent utilizes the third dimension (depth/thickness) by implementing a waveguide structure that manipulates light propagation in multiple spatial dimensions. Instead of expanding the beam in the plane of the MEMS mirror, the waveguide extends the optical path through vertical stacking and lateral propagation, effectively increasing beam size by utilizing dimensional space more efficiently.

The patent introduces waveguides as intermediary optical components between the MEMS mirror and the final output. These waveguides act as mediators that take the small beam from the compact MEMS mirror and progressively expand it through controlled optical paths. The waveguides include input couplers, propagation sections, and output couplers that work together to achieve beam expansion without requiring large mechanical components.

The beam expansion function is segmented into multiple discrete waveguide components rather than requiring a single large optical element. The system divides the beam expansion task across multiple waveguide sections, each contributing to the overall expansion. This segmentation allows the system to achieve large output beam size through a series of smaller, manageable optical stages.