Highly collimating micro-LED projection source enabled by metasurface

As an important trend in future display technology, Micro-LED has significant advantages in brightness and contrast, as well as better color performance and response speed. Micro-LED and related display technologies have attracted increasing attention from the academic community in recent years. However, Micro-LEDs with Lambertian emission patterns cannot be directly used in projection displays. Therefore, complex relay optics are often required to collimate the emission light, increasing the system complexity. This paper proposes a novel Micro-LED structure that combines with meta surfaces on top of the Micro-LED. This structure can optically control the light field of Micro-LED into a highly collimating one from the originally Lambertian distribution. Compared with the initial Micro-LED structure, this configuration has good light emission characteristics with primary light concentration between 10 degree intervals. The designed structure has the light distribution with the full width at half maximum (FWHM) angle ±5.48°. At the same time, compared with the traditional Micro-LED structure, its center light intensity is increased to 21.98 times the original. This structure optimizes and improves the performance of Micro-LED in the field of projection display.