Micro-LED Retinal Projection for Augmented Reality Near-Eye Displays

Retinal projection display enables the direct projection of virtual images onto the retina through the pupil center via a projection engine, showing promise in addressing the vergence-accommodation conflict in augmented reality near-eye displays. However, existing RPD architectures universally employ passive luminous micro-electromechanical systems or spatial light modulators, encountering challenges associated with beam aperture limitations and structural inflexibility. In response to these, this paper presents a novel micro-LED retinal projection display architecture that integrates the active luminous full-color micro-LEDs with a pixel-to-pixel imaging fiber bundle, effectively subverting conventional RPD designs. Additionally, the flexible fiber bundle brings an adaptable design that enables optoelectronic separation capabilities. The design principles and feasibility are thoroughly described and validated through simulations and experiments. A full-color mu RPD prototype is developed, demonstrating sharp imaging across an extensive focal depth range. Remarkably, the mu RPD architecture exhibits a groundbreaking advancement in enabling underwater AR displays without necessitating special waterproof treatments, underscoring its potential versatility and adaptability to challenging environments. This design paves a new way for practical applications of NEDs in complex and demanding conditions, thereby contributing to the evolution of NED systems.