Optical design of automotive augmented reality 3D head-up display with light-field rendering

Abstract

Although head-up displays (HUDs) have already been installed in some commercial vehicles, their application to augmented reality (AR) is limited owing to the resulting narrow field of view (FoV) and fixed virtual-image distance. The matching of depth between AR information and real objects across wide FoVs is a key feature of AR HUDs to provide a safe driving experience. Meanwhile, current approaches based on the integration of two-plane virtual images and computer-generated holography suffer from problems such as partial depth control and high computational complexity, respectively, which makes them unsuitable for application in fast-moving vehicles. To bridge this gap, here, we propose a light-field-based 3D display technology with eye-tracking. We begin by matching the HUD optics with the light-field display view formation. First, we design mirrors to deliver high-quality virtual images with an FoV of 10 × 5° for a total eyebox size of 140 × 120 mm and compensate for the curved windshield shape. Next, we define the procedure to translate the driver eye position, obtained via eye-tracking, to the plane of the light-field display views. We further implement a lenticular-lens design and the corresponding sub-pixel-allocation-based rendering, for which we construct a simplified model to substitute for the freeform mirror optics. Finally, we present a prototyped device that affords the desired image quality, 3D image depth up to 100 m, and crosstalk level of <1.5%. Our findings indicate that such 3D HUDs can form the mainstream technology for AR HUDs.