Rod-Equipped Light Guide Assembly for 2D Pupil Expansion

The patent transitions from unidimensional prism arrays to bidimensional pupil expansion by introducing a rod component that expands the pupil in both horizontal and vertical dimensions. The rod with its specific refractive index and curvature works together with the light guide assembly to achieve 2D pupil expansion, thereby increasing the field of view and eye-box without requiring thick light guides or large collimator systems.

The light guide assembly is divided into multiple functional components: the light guide assembly itself with prism arrays, and a separate rod component with specific optical properties. This segmentation allows each component to perform its specialized function - the light guide assembly handles light guidance and partial expansion, while the rod provides additional dimensional expansion, collectively achieving large field of view with a compact structure.

By implementing bidimensional pupil expansion through the rod component, the patent achieves large field of view and eye-box with a thin light guide assembly. The rod's specific refractive index and curvature enable efficient light manipulation in multiple dimensions, eliminating the need for thick light guides or large collimator systems that would increase device weight.

The patent optimizes the rod's refractive index and curvature parameters to achieve efficient bidimensional pupil expansion. By carefully selecting and adjusting these optical parameters, the system achieves large field of view with a compact, lightweight structure rather than requiring massive optical components.

Instead of requiring uniform partially reflective surfaces across the entire rod assembly, the patent applies localized optical treatments to specific regions of the rod and light guide assembly. The prism arrays are positioned and configured to work with specific zones of the rod, allowing for more relaxed manufacturing tolerances while maintaining effective pupil expansion capability.

The patent addresses the ghost image problem by using the rod's refractive index difference and curvature to intentionally guide and control light paths. Rather than trying to eliminate all reflections, the design channels reflected light into beneficial paths that enhance pupil expansion while minimizing ghost image formation through careful optical geometry.

The patent converts potentially harmful reflections into beneficial light paths by using the rod's refractive index and curvature to guide reflected light into controlled trajectories. The optical geometry is designed so that reflections contribute to pupil expansion rather than creating ghost images, effectively turning a harmful effect into a useful function.

By implementing bidimensional pupil expansion with the rod component, the patent separates the main light path from potential ghost image paths in multiple dimensions. The rod's curvature and positioning create distinct optical zones that guide primary light rays to the intended destination while directing reflected rays into separate, controlled paths that minimize ghost image formation.