Contact Lens with Moir\'e patterns for High-Precision Eye Tracking

Eye tracking is a key technology for human-computer interaction, particularly crucial in augmented reality (AR) and virtual reality (VR) systems. We propose a novel eye-tracking approach based on incorporating passive eye-tracking modules into contact lenses. These modules comprise two superimposed gratings separated by a narrow gap. The overlapped gratings produce moir\'e pattern, while the spatial separation between them results in parallax effect, namely, pattern transformation upon variations in viewing angle, which enables accurate angular measurements. This method is insensitive to ambient lighting conditions and requires neither scale and color bars nor perspective corrections. Using this approach, we have experimentally measured lens orientation with angular resolution exceeding 0.3{\deg}, which is satisfactory for gaze detection in most AR/VR applications. Furthermore, the proposed technological platform holds a potential for many-fold enhancement in measurement precision.