Micro-LED Waveguide Trenches for Directional Light Extraction

The patent introduces waveguide structures and grating couplers that operate in the lateral dimension to extract light that would otherwise be trapped by total internal reflection at the vertical interfaces. The waveguides confine and guide light laterally to extraction regions, adding a dimensional pathway for light extraction that bypasses the limitations of vertical emission in miniaturized LEDs.

The patent modifies the refractive index distribution by introducing dielectric waveguide layers with specific refractive indices between the semiconductor mesa structures. These waveguide layers create refractive index contrasts that enable total internal reflection for light confinement in the waveguide, followed by grating-induced diffraction for extraction, thereby changing the optical parameters to overcome size-related extraction limitations.

The patent introduces dielectric waveguide layers as intermediary structures between the high-refractive-index semiconductor materials and the external environment. These waveguide layers act as optical mediators that confine light through controlled total internal reflection and then enable extraction via grating couplers, thereby facilitating light extraction from materials that would otherwise trap light due to their high refractive indices.

The patent changes the optical parameters by introducing intermediate dielectric layers with refractive indices between those of the semiconductor and air. This creates a stepped refractive index profile that reduces the abrupt index contrast at semiconductor-air interfaces, thereby reducing total internal reflection losses while maintaining the high emission intensity properties of the III-phosphide materials.

The patent uses waveguide structures to redirect light emission from the vertical dimension to the lateral dimension. By confining light in the waveguide and extracting it through lateral grating couplers, the emission pattern is transformed from omnidirectional to a more directional lateral emission, improving coupling efficiency with display optics while maintaining compact device dimensions.

The patent introduces dynamic light management through the waveguide-grating system that actively directs light propagation. The waveguide dynamically confines and guides light based on incident angles, and the grating couplers dynamically extract light at specific angles, creating a dynamic emission pattern that can be optimized for display optics coupling rather than static omnidirectional emission.