SBIR Phase I: Subtractive-waveguide based Display for Augmented Reality Smart Glasses using Spatial-temporal Multiplexed Single-CMOS Panels

The broader impact of this Small Business Innovation Research (SBIR) Phase I project is the realization of Augmented Reality (AR) displays for smart glasses that can show digital content in the full dynamic range, including the black color. The conventional optical components currently used in AR smart glasses cause the digital content to appear translucent and, hence, lack realism. The proposed work is on developing a display technology that controls per-pixel transparency in the virtual image plane, virtual objects, and 3D holograms for black color. The blocking of light for black-colored parts in a hologram can show as realistic physical objects over the background reality. Using this approach, each display pixel can be made black, semi-transparent, or transparent at a user’s will, making visibility of digital content possible even in direct sun-lit environments. This SBIR Phase I project proposes a holistic display solution for AR smart glasses that consists of three key elements: a spatially-multiplexed Total Internal Reflection–based subtractive-waveguide combiner; a single photo-reflective spatial light modulator (SLM) that is illuminated by two spatially-multiplexed illuminants; and a temporal multiplexing algorithm whereby the two spatially-multiplexed illuminants can be selectively modulated by the SLM during their dedicated sub-frame times. Since pixel-wise transparency control allows hard-edge occlusion, hence the proposed smart spatiotemporal multiplexed approach enables a single display that achieves pixel-wise hard-edge occlusion using only a single silicon display panel, thereby reducing cost and complexity while increasing see-through efficiency and battery life performance. These technological improvements are industry firsts and together allow for addressing a market need for AR devices for outdoor well-lit scenarios. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.