Dual-Task Optimization Method for Inverse Design of RGB Micro-LED Light Collimator

Area of Science:

• Optics and Photonics
• Nanotechnology
• Display Technology

Background:

• Miniaturized pixels in near-eye displays cause large light divergence angles.
• Conventional collimators are wavelength-sensitive and struggle with simultaneous red, green, and blue (RGB) light collimation.
• Spatial incoherence of micro-LED emission poses challenges for efficient light coupling.

Purpose of the Study:

• To design an efficient beam collimation solution for near-eye digital displays using micro-LEDs.
• To overcome the limitations of traditional collimation optics for RGB light.
• To improve light coupling efficiency by addressing spatial incoherence.

Main Methods:

• Employed inverse design optimization and finite-difference time-domain (FDTD) simulations.
• Developed a dual-task optimization strategy, modeling collimation as color routing.
• Utilized a multiple-dipole simulation method for evaluating performance with spatially incoherent RGB micro-LED light.

Main Results:

• Designed a collimator composed of nano-sized photonic structures.
• The dual-task optimization successfully integrated color routing and beam collimation.
• Achieved an increase in light coupling efficiency from approximately 30% to 60% within a ±20° divergence angle for RGB light.

Conclusions:

• The designed photonic nano-structure collimator effectively addresses challenges of micro-LED displays.
• The dual-task optimization strategy offers a novel approach for simultaneous RGB light collimation.
• Significant improvement in light coupling efficiency demonstrates the potential for enhanced near-eye display performance.