80° low-twist nematic liquid crystal viewing angle controller for unidirectional privacy protection of automotive co-driver displays.

To address severe large-polar-angle light leakage of conventional 90° twist-nematic (TN) viewing angle controllers (VACs) for automotive co-driver displays (CDDs), we propose an 80° low-twist nematic liquid crystal (LC) VAC. The light leakage suppression mechanism is quantitatively elucidated through analysis of the equivalent included angle of polarizers under oblique incidence, together with the residual birefringence effect of the low-twist LC layer. Numerical and experimental results show that the device maintains high transmittance over a wide viewing angle in shared mode. In privacy mode, it achieves ultra-low transmittance of 0.0012 (simulation) and 0.0133 (experiment) at the 40° target polar angle, with light leakage at 60°-80° suppressed below 0.034, all without compensation films. This VAC effectively suppresses driver visual distraction, while ensuring co-driver display visibility.