Holographic Retinal Projection With Wide Field of View and Large Eyebox Based on an Electrically Switchable Liquid Crystal Grating

ABSTRACT Holographic retinal projection display has become a focal point of the display field because of its imaging characteristics with constant focus and flexible wavefront modulation advantages. However, due to the restriction between the field of view (FOV) and the eyebox under the limited bandwidth, the holographic retinal projection with wide FOV and large eyebox has not been realized so far. Here, a holographic retinal projection strategy based on an electrically switchable dual‐period liquid crystal grating is proposed, enabling simultaneous expansion of the FOV and eyebox. While designing the electrically switchable liquid crystal grating, an angular‐carrier multiplexing hologram generation method is proposed, so that multiple sub‐images can be encoded into different angles for secondary diffraction by the liquid crystal grating. The proposed method achieves a retinal projection with a 15°FOV and a 25.6 mm horizontal replicated‐viewpoint span, corresponding to approximately a threefold FOV increase and a fourfold horizontal replicated‐viewpoint span increase relative to the conventional holographic RPD reference configuration. The product of these two relative improvements corresponds to a 12× increase in the FOV‐viewpoint‐span performance metric. Such holographic retinal projection with a wide FOV and a large eyebox is expected to promote the development of holographic near‐eye displays.