Dual-View and Multi-Content Head-Up Display Using a Single Picture Generation Unit and Two-Layer Volume Holographic Grating

Considering that the driver and passengers need different display content in the vehicle display, we propose a dual-view and multi-content head-up display (HUD). Based on the angle selectivity of volume holographic grating (VHG), the multiplexed VHGs diffract light beams at different angles to achieve dual-view display. Based on the wavelength selectivity of VHG, the multiplexed VHGs diffract light beams of different wavelengths that carry different information to realize multi-content display. The HUD prototype is composed of a miniature laser projector, a diffuser, and a holographic combiner. The holographic combiner with a size of 20 cm × 15 cm includes a red-green multiplexed VHG₁, a red-blue multiplexed VHG₂ and a glass substrate. The field of views (FOVs) and eye-boxs (EBs) of the two viewing zones are 10° × 5° and 8° × 4°, 147 mm × 81 mm and 105 mm × 87 mm, respectively. In addition, compared with the traditional dual-view HUD, the proposed HUD only requires one picture generation unit (PGU), which is beneficial for its application to compact vehicle or aviation displays. Moreover, the driver and passengers can see the red warning information displayed by the system at the same time, which can significantly improve driving safety.