Collimated LED Array With Mushroom-Cap Encapsulation for Near-Eye Display Projection Engine

As metaverse continues to evolve, near-eye display technologies are increasingly focused on achieving compactness, lightweight, and high brightness design. Self-emitting projection sources have garnered significant attention due to their potential to meet these requirements. However, current projection sources typically exhibit a Lambertian-like divergence angle, leading to challenges in miniaturization and substantial energy loss. In response to these issues and inspired by the shape of "mushroom cap", this paper proposes a collimated light-emitting diode array encapsulated with mushroom-cap optical units for near-eye display projection engine. The study discusses the optimal parameters for the limited diode spacing and validates these parameters through both simulation and experimental results. The mushroom-cap optical units effectively harness the emitting energy, confining the full width at half maximum of Lambertian sources within the ±10° range, while enhancing the central light intensity by 80%. The built experimental prototype demonstrates a significant enhancement in projection quality and visibility. This design holds promise for ultra-small self-emitting projection engines, offering robust support for the high performance and lightweight design of near-eye display devices.