Augmented reality (AR) continues to be a hot topic, as it has been for decades now. As AR aims to change our reality, it is extremely important to have systems that are properly designed to trick our brain, providing a sharp image. As explained in Yole Développement’s report “Displays and optical vision systems for VR, AR and MR“, for which a new update for 2020 is coming soon, consumers want nothing but a sleek design. To ensure that, carefully crafted optical systems need to be manufactured, using waveguiding technologies. But technical and manufacturing challenges are such that today, no technology dominates the market, yet.
Dr. Zine Bouhamri, Display Technology and Market Analyst for Yole, has had the opportunity to talk with Dr. Eli Glikman, Chief Product Officer at Lumus Ltd, one of the major companies involved in optical systems for AR headsets. Read on to find out the vital details of what’s happening in this industry.
Zine Bouhamri (ZB): Could you please introduce Lumus and its activities?
Eli Glikman (EG): Lumus is an early pioneer in the near-eye display market, as well as the current optics leader in the AR market. Our company has made see-through displays since 2000, before the market was called AR. Based on our patented reflective waveguides, our optical engines are unique and straightforward to manufacture. Lumus’ optics have been compared favorably by third parties to many other alternatives, demonstrating advantages in key parameters including image quality, optical resolution, brightness, color and form factor.
ZB: What kinds of products and/or services do you provide?
EG: Lumus designs and manufactures optical engines, the enabling technology for AR glasses. The optical engine is comprised of two sub-components. One is the micro-pod projection module, the other is the reflective waveguide. Lumus designs for several product categories on the AR continuum, from monocular optical engines targeted at military and industrial markets to binocular, high resolution optics for the pro-consumer market, now sold by companies like Lenovo. Today, most of our R&D efforts are directed towards next generation consumer-focused optics.
ZB: Are you targeting specific markets, like consumer, medical, industrial or defense?
EG: Lumus was an early provider of military AR optics through a nearly decade-old partnership with Thales Avionics. Thousands of sorties have been flown using Lumus optics in both the A10 and F16 aircraft platforms. We also provide AR optics for medical applications through partnerships with companies like Augmedics, who make an AR surgical navigation tool for spinal surgeries. Our recent engagement with Lenovo is targeted at the industrial/enterprise markets. However, our main focus is creating the optimal specifications for Tier 1 consumer AR devices.
ZB: AR is a field with a lot of hype and a lot of competing technologies, for example reflective and diffractive approaches. How do you use factors like optical efficiency to differentiate yourselves from your competitors?
EG: Among all potential AR optics solutions, the only solution small enough, light enough, high-performance and scalable enough for AR glasses are waveguides. Within the world of waveguides, there are two main approaches – reflective and diffractive. Reflective waveguides use partially reflective mirrors which are coated, angled and embedded into the waveguide in a manner that makes them invisible to the wearer, and only partially visible to the observer. Alternatively, diffractive waveguides use various methods for creating diffractive gratings, which create the image overlay for the user. Lumus’ reflective waveguides have several advantages over diffractive waveguides including overall architecture, transmittance, ghosts, brightness and color uniformity and ease of manufacturing.
From the overall architecture perspective,with diffractive waveguides, coupling-in disperses wavelengths. This leads many waveguide manufacturers to use multiple waveguides to create their optical engines. In many cases a separate waveguide is used for red, green and blue wavelengths. Some companies have begun using two waveguides by creating blue and red waveguides and splitting the green wavelengths. In fact, at least two companies are using only one waveguide that contains red, blue and green. Their performance and manufacturing prospects remain open questions. In contrast, reflective waveguides like those Lumus makes use a single waveguide in which all wavelengths are multiplexed and co-propagate. This translates to a simpler approach, with many degrees of freedom and an easy path to mass production with more than 90 percent yield.
From the transmittance perspective, the Lumus single reflective waveguide configuration enables unobstructed visibility of the world and the virtual image transposed. The mirror essentially reflects back the image and the transmittance allows for the real-world view to remain unperturbed.
In contrast, diffractive waveguides require the real-world light to pass through the cascaded waveguides, which causes aberrations such as scattering.
With regards to brightness uniformity and color uniformity, in all waveguides, light intensity of the different color wavelengths is reduced as they propagate within the waveguide and outcouple. With reflective technology, we have the ability to adjust the reflectivity of the partial mirrors in our waveguide. These adjustments allow a near-to-perfect compensation when light intensity is reduced. This adjustment results in an image that is uniform in brightness and color, which is pleasing to the eye.
In contrast, diffractive waveguides – and this is true for all diffractive solutions – lose intensity with little, if any, ability to adjust their image resulting in a lack of uniformity across the field of view (FoV) and the eye box, the viewer’s active area. Moreover, the light intensity varies between the different colors, creating both total intensity and brightness non-uniformity and color non-uniformities.
ZB: How hard are these waveguides to manufacture?
EG: Our waveguides are actually relatively simple to manufacture, using standard optic manufacturing equipment for coating, slicing, lapping and polishing. The materials and machines we use have been around for several decades. At volume, reflective waveguides should cost around $10.
ZB: For AR to become mainstream there needs to be a combination of low price, good performance and sleek form factor. Can you deliver on all these aspects?
EG: Until now Lumus has delivered on performance, power consumption, resolution and a meaningful FoV. Our current focus is to create even larger FoV while reducing the bulk and weight of the micro projector. This will allow designers more degrees of freedom to create fashionable near-to-eye display products. The first product of this next generation will start with FoV of 50 degrees in a more natural looking form factor. Beyond this, we have a roadmap for achieving up to 70-degree FoVs.
ZB: What is your business model, manufacturing, engineering services or licensing?
EG: Our main business model is to license our patented optics to world class manufacturers. We will continue to sell direct for the military aviation market.
ZB: Do you have specific partners to help you grow along the way?
EG: Our relationship with Quanta has been an amazing growth experience for both sides – really forcing us to up our game on designing for cost. While our technology is inherently scalable, getting deeper into the manufacturing process has brought Lumus greater sensitivity to the importance of reducing costs even more. Other partnerships in the supply chain that we hope to announce soon are also adding value in further innovation in the production process to further reduce costs.
ZB: What kinds of hurdles are you facing today to move forward with your roadmap?
We are pushing the envelope to deliver the hero product in AR optics, for 1) natural looking form-factor 2) very wide FoV 3) consumer-ready price point and 4) the top-level performance that everyone comes to expect from Lumus. Some breakthroughs in R&D over the last 18 months on our waveguide architecture now enable us to deliver on all of these. One area where we are still negotiating the bottle-necks to reach even higher FoV without compromising form factor is the display source, whether it’s LCoS, LCD, OLED, laser or something else. Moving beyond 60 degree FoV, we need to squeeze in more pixels to keep the image sharp and crisp. As a rule, we always aim for 1-1.5 arc minutes per pixel – beyond that you see the pixels, which hurts the experience. The challenge with off-the-shelf display sources is that as you increase pixel counts there is a correlating increase in size, which translates to a larger projection module. We are pleased that our technology scales to wider FoV without compromising form factor. One temporary hurdle is our dependence on the micro display industry to find display solutions that can catch up to our waveguide potential and to supply us with the optimal component. Having this once we go beyond 60 degrees will help us avoid uncomfortable compromises.
ZB: Thank you very much for having shared your insights. Any future events we may be able to meet you at, and try your products?
EG: You can meet us at the SID Display Week on June 8-11, 2020. By then, we will have something that will reinforce our company slogan: The Future is Looking Up.
Dr. Eli Glikman is Chief Product Officer at Lumus. He has over 25 years of experience in Product Management and R&D leadership. Prior to joining Lumus, Eli was the R&D Manager at Scanmaster (acquired by EVS) and served in various product management positions in leading software companies. Eli holds a Ph.D. in Physics from Tel-Aviv University.
As a Technology & Market Analyst, Displays, Zine Bouhamri, PhD is a member of the Photonics, Sensing & Display division at Yole Développement (Yole).
Zine manages the day to day production of technology & market reports, as well as custom consulting projects. He is also deeply involved in the business development of the Displays unit activities at Yole.
Previously, Zine was in charge of numerous R&D programs at Aledia. During more than three years, he developed strong technical expertise as well as a detailed understanding of the display industry.
Zine is author and co-author of several papers and patents.
Zine Bouhamri holds an Electronics Engineering Degree from the National Polytechnic Institute of Grenoble (France), one from the Politecnico di Torino (Italy), and a Ph.D. in RF & Optoelectronics from Grenoble University (France).
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