Design and demonstration of a compact Split-Lohmann multi-depth near-eye display

Multi-depth near-eye displays provide discrete focal cues to mitigate the vergence–accommodation conflict. Split-Lohmann modulation can generate discrete depth states through phase control, but existing display implementations have mainly been demonstrated in optical systems with relatively large volumes and have not fully addressed compact near-eye integration under volume and length constraints. This paper proposes a compact Split-Lohmann multi-depth near-eye display system that combines a multi-depth display module with a short focal length relay and a birdbath-type eyepiece module for depth modulation and near-eye virtual image formation. The Fourier relay is optimized to reduce focal shift deviation from the ideal Split-Lohmann model, and optical coupling between modules is designed to improve eyepiece input beam characteristics and imaging consistency across depth states. The system covers a dioptric range of 0.2–4 D, provides a 40 ∘ diagonal field of view, and keeps the total system length within 200 mm. Simulation analysis and prototype experiments demonstrate the feasibility of focus-selective multi-depth virtual image generation in a compact near-eye display architecture.