Holographic multiplane augmented reality head-up display with switchable display modes based on polymer dispersed liquid crystal.

The multiplane augmented reality (AR) head-up display (HUD) is important in improving driving safety and comfort. In this paper, we propose an AR-HUD with switchable display modes based on polymer dispersed liquid crystal (PDLC) and lens holographic optical elements (HOEs), which can provide two display modes: the dual-virtual-image mode and the virtual-real-image mode. The dual-virtual-image mode can produce two virtual images at different depths, which can provide a better sense of reality integration for the driver to improve driving safety and comfort. The virtual-real-image mode can produce one far virtual image and one near real image at different depths, and it provides a larger eye box (EB) for both driver and passengers in the car and a higher image contrast. The two display modes can be switched by an electronically controlled scattering module consisting of a pair of PDLC films. The proposed AR-HUD system is compact and equipped with multiplane display and mode-switching functions, and is expected to be applied in the future.