Surface Relief Grating with Conformal Dielectric Layer for Waveguide Angular Bandwidth

The patent applies local quality by varying the thickness of the dielectric layer at different positions on the grating surface. The dielectric layer thickness is specifically adjusted to compensate for attenuation effects, with thicker regions compensating for areas experiencing greater light loss, thereby maintaining uniform light intensity across the entire field of view while preserving the high angular bandwidth provided by the surface relief grating structure

The patent employs parameter changes by modifying the dielectric layer thickness parameter across the grating surface. This continuous variation in the dielectric layer thickness parameter allows for precise control of light extraction efficiency at different angular and spatial positions, compensating for attenuation and ensuring uniform illumination while maintaining the broadband angular response of the surface relief grating

The patent applies the nested doll principle by embedding the exit grating within the waveguide structure. The grating is positioned inside the waveguide body rather than being exposed on the external surface, allowing it to maintain its light extraction function while being protected from environmental factors such as moisture, dust, and physical damage, thus improving reliability without sacrificing extraction efficiency

The patent uses the waveguide medium as an intermediary between the grating and the external environment. The grating interacts with light through the waveguide material, which acts as a protective barrier against environmental exposure. This intermediary arrangement allows the grating to perform its light extraction function effectively while being shielded from harmful external factors that would otherwise reduce its reliability

The patent manages device complexity by implementing a systematic approach to dielectric layer thickness variation. Rather than arbitrary complexity, the thickness parameter is varied according to a designed profile that specifically compensates for measured or calculated attenuation patterns. This purposeful parameter change achieves light intensity uniformity while maintaining manufacturability and structural clarity

The patent applies local quality by introducing the dielectric layer with spatially varying thickness only where needed on the grating surface. This localized modification targets specific regions requiring attenuation compensation rather than uniformly increasing complexity across the entire device. The selective application of varying thickness maintains overall structural simplicity while achieving the desired optical uniformity