Simplified See-Through Head-Mounted Display Optics with Achromatic Metalens

To address the critical challenges of minimizing optical thickness and correcting chromatic aberrations in optically transparent head-mounted displays (HMDs), we propose a folded hybrid design incorporating freeform prisms and a discrete multi-wavelength achromatic metalens. Our approach integrates advanced optical engineering techniques to achieve optimal performance while maintaining compactness. The system leverages a phase-optimized SiNx/SiO2 metalens combined with ray-tracing-based system optimization, enabling the development of a compact 12 mm thickness OST-HMD featuring an 8 mm exit pupil and a 39° virtual field of view (FOV). Through simulations, we demonstrate that this configuration achieves impressive modulation transfer function (MTF) values exceeding 0.7 at 50 lp/mm for see-through viewing and maintaining MTFs above 0.3 at 30 lp/mm for virtual imaging across wavebands. Simulation results highlight an improvement both in the miniaturization of the HMD while maintaining high resolution and in effective correction of chromatic aberrations, offering a robust solution for lightweight, high-performance AR display systems. This work represents an advancement in optically transparent display technology by providing an optimized design framework that balances compactness with visual fidelity.