DigiLens holographic photopolymers for wide angle AR waveguides

Augmented reality is still in its infancy and is projected to grow substantially over the next few years. Grating-based waveguides are now established as the key enabling display technology for merging the physical and digital worlds in implementations as diverse as near eye displays, auto HUDs and large-scale retail displays. Despite significant design effort, delivering wide field-of-view (FoV) color, daylight-compatible brightness and ultra-compact glasses-like form factors at an acceptable price remain major development hurdles for consumer AR displays. The form factor challenge is only partially met using thin waveguides; current picture generation units, comprising the microdisplay beam splitter and projection optics, are increasingly seen as too bulky to satisfy the aesthetic requirements of consumer eyewear, while traditional input, fold and output grating architectures occupy too much waveguide real estate. Brightness and power consumption are compromised by losses of typically 95% incurred in coupling light from a picoprojector into a waveguide. DigiLens is prototyping a compact wide angle, full-color laser-illuminated consumer AR waveguide based on its Integrated Dual Axis (IDA) waveguide architecture which uses Digilens’s proprietary Switchable Bragg Grating (SBG) technology. An IDA waveguide multiplexes beam expansion and extraction gratings using a high index modulation holographic LC-photopolymer material system optimized for wide angle multiplex grating applications. A 50-degree diagonal FoV, full-color, low-cost IDA waveguide lens was demonstrated at the Consumer Electronics Show (CES) in Las Vegas (January 2020). As shown in Figure 1, DigiLens’s current waveguide display range includes helmet (25° diagonal), smart glass (30° diagonal) and head-worn (50° diagonal) color waveguide displays.