SCHOTT AND LUMUS PARTNER ON AR TECH

Time：2020-11-16Department：

GERMAN SPECIALTY GLASS MANUFACTURER SCHOTT HAS ENTERED into a strategic partnership with Israeli augmented reality (AR) display firm Lumus to mass‐produce Lumus' reflective waveguide technology for use in consumer AR displays. Waveguide technology is considered key for making AR glasses that are lightweight and comfortable to wear while still delivering solid optical performance, compared to the “bird bath” technology used in early AR devices like Google Glass, which has limitations in high light loss and a narrow field of view (FOV).

There are three types of waveguide for AR: diffractive, holographic, and reflective. Although each has its tradeoffs in optical performance and unique manufacturing challenges, they all hold promise for making consumer AR displays a mainstream product. “Waveguide is the only technology that allows you [to create] something sleek that looks like a real pair of glasses,” notes Zine Bouhamri, an analyst for Yole Développement. He says the first consumer AR headsets based on waveguide could hit the market in 2023.

Manufacturers already use Schott RealView high‐refractive index optical glass in diffractive and holographic waveguides for AR displays. However, with Schott and Lumus teaming up, this means the glass is also a player in reflective waveguides. Lumus is a leader in reflective waveguide technology with its patented Lightguide Optical Element (LOE), which uses multiple tiny mirrors stacked within a single substrate to reflect a virtual image into the wearer's eye. Formed in 2000, the company has found success in military applications and with industrial customers such as Lenovo's ThinkReality A6 headset.

Although reflective waveguides offer better image quality and optical efficiency than diffractive or holographic alternatives, they are expensive to manufacture—and until now, Bouhamri says, they had a more limited unidimensional pupil expansion scheme. Schott will help Lumus tackle those challenges by manufacturing its new Lumus Maximus LOE product.

Maximus was developed using a higher refractive index glass from the company. The higher the refractive index of the glass used in a waveguide, the wider the FOV, explains Rüdiger Sprengard, Schott's head of AR. “Maximus currently offers a diagonal FOV of 50 degrees,” Sprengard says. “A roadmap to go beyond this is also in place. Additionally, the Maximus design now enables very small projector systems and offers a large eyebox, an essential feature for consumer product designers.”

Schott's considerable manufacturing expertise also helps Lumus overcome the high production costs of reflective waveguides. Lumus will continue to focus on R&D while taking advantage of Schott's international production network with high‐end optical glass melting in Germany; substrate processing lines in China; a component factory in Penang, Malaysia; and dedicated engineering hubs in Germany, Switzerland, China, and Malaysia. “Lumus has a 20‐year track record on developing reflective waveguides and manufacturing these on a small scale,” Sprengard says. “Schott entered the scene to give this technology the perspective of high‐volume manufacturing.” —G.D.