In the upcoming AR display solution, micro LED technology plays a key role, which generates images within the dedicated lens of the AR system and ultimately presents them to the user.
Now, the recently established Laser Display for AR working group, part of the AR Alliance, is undertaking the challenge of changing the status quo. Led by industry veteran Barry Silverstein, former CTO of optics and display at Meta’s Reality Labs, the working group aims to bring together industry and academic partners to collaboratively advance laser display technologies for AR.
While micro-LED offers a viable path to the fashionable smart glasses pursued by Meta, Snap, Xreal, Huawei, and others, the technology may face a ceiling of technological achievement. This is particularly evident in the case of large displays, where power efficiency becomes more critical, as well as in the pursuit of challenges such as holography and steered retinal projection — a favorite topic of Silverstein’s.
The working group held its inaugural meeting at Optica’s Frontiers in Optics + Laser Science (FiO LS) show in Denver last month, in which more than 50 companies expressed interest in the group’s mission. Laser displays for AR are nothing new — Silverstein cites the Microsoft Hololens 2, released in 2019, as an example. Progress since then has been mainly driven by individual component makers rather than system integrators. While pieces of the technology have made tremendous progress, putting those pieces together into full system solutions has been a challenge.
The working group will pick up the pieces from individual component makers and figure out how they fit together.
“You don't need to start at steered retinal projection, even though you think that's going to be the very best, and you don't have all the answers on how to get there,” Silverstein said. “But if you start with simple laser projectors and simple laser systems, you start to build an industry, and the investment grows because there's return from selling products.”
In addition to the firms who attended FiO LS, the working group has already generated significant interest from both industry and academia. Companies including ams OSRAM, TDK, TriLite, Swave Photonics, Brilliance, OQmented, Meta, and Ushio, have joined, as have academic and R&D powerhouses Fraunhofer and the University of Rochester.
Silverstein, for his part, officially joined the University of Rochester last week: He will head up the newly established Center for Extended Reality at the University of Rochester.
Industry on board
Forming a working group of 50 or more participants is a substantial proposition, and something that requires a kind of constant nurturing. Recruitment is one thing. Ensuring all members are comfortable enough to participate openly and freely, is another.
“We are used to working competitively. So, you try to protect everything,” Silverstein said. “But if you are rational about it, you say, ‘Well, what am I trying to protect? I don't have any business yet.’”
The first area of focus for the group is to create demonstrators that validate the technology’s credibility. Collaboration, which has become a strong area of focus for the photonics industry, will be key to the group’s success.
“I may not have to be the one to be showing the demonstration for me to be taking advantage of it,” Silverstein said. “This is an interesting twist for companies, especially if it's a small company.”
Silverstein said that there have been some demonstrations to date. But those likely came with caveats — given the use of waveguides designed for micro-LED.
“And of course, it doesn’t look great,” he said. “It was designed for a micro-LED system, which is a very different source.”
Bad demonstrations can lead to incorrect conclusions — for example that laser displays are unable to produce an image at the same level of a micro-LED system. To avoid the potential for such setbacks, the working group is developing a set of standards to enable interchangeability for quality demonstrations. Much of the initial work, including these demonstrations, will focus on changing perceptions and allowing potential customers to draw new and more accurate conclusions about the viability of laser displays. Paradoxically, the technology could be viewed as both too new, given its perceived lack of infrastructure, and potentially outdated, given its inclusion six years ago in the commercially unsuccessful Hololens 2.
Predictably, attachment to the technology from potential customers, such as Meta, Snap, Huawei, and others, is a major gauge for early success for the working group. If decision-makers at these companies see and feel that there is infrastructure available, and if they see some big names alongside the various startups involved — companies that can scale — Silverstein believes that a level of trust can be built that may turn the tides. Regardless, there is likely space for multiple technologies. After all, glasses come in a wide variety of form factors and often people have multiple pairs for particular uses cases. A similar situation for AR glasses could be expected as well.
Consumer driven
Industry players aren’t the only ones the technology must convince.
“Putting on a pair of glasses with a laser in it might give people some pause,” Silverstein said. The role of the consumer is both ever-present and vital to down-the-road success. While industry insiders may be fully aware that laser-driven systems are safe and effective, popular perception of laser safety lacks a certain level of nuance. The fact that there’s a laser in most modern smartphones pointed directly at the user’s face hasn’t yet entered the realm of common knowledge.
“You need to get ahead of that and explain to people that the lidar in that car is a lot brighter than the laser in the smart glasses,’” Silverstein said.
Beyond proving the viability of the setups that use liquid crystal on silicon and laser beam scanning, the working group’s membership will need to effectively communicate the advantages and improvement potential of laser-based technologies. This quest itself faces barriers, given the technical nature of the competing technologies: lasers and micro-LEDs. For example, micro-LEDs may be more efficient in producing photons, but these are broadband large etendue unpolarized sources. Lasers, owing to their polarization and small etendue, can provide greater efficiency in this controlled angle space.
Advanced applications like holography as well as Silverstein’s Holy Grail (steered retinal projection) will be best accomplished with lasers. Beyond application, privacy is another focus. Polarization and narrow bands will allow smart glasses where only the user can view the content being projected. The technology also provides the opportunity to utilize metasurfaces and diffractive optics to create more compact and efficient solutions. Emerging technologies — such as metasurfaces, as well as PICs — provide ample opportunity for improvement. They may also hold the key to overcoming challenges, such as foveated vision, which must be addressed to produce steered retinal projection.
Silverstein expects that a good division of labor and specific focus will enable the working group to attain specifications and requirements quickly, with product optimization taking perhaps another year, followed by about two years in the product stream.
Within three to four years, depending on how fast and aggressive companies approach these challenges, products utilizing laser-based displays could be on the shelves.
Of course, the work doesn’t end with commercialization and consumer adoption. Current technologies already provide ample opportunity for innovation. Many, however, including metasurfaces and PICs, for example, have yet to reach their potential.
“As far as I'm concerned, AR display is just at an infancy,” Silverstein said.
Source: photonics
