For the past few years, augmented reality (AR) headsets have been a dream, with no credible alternative but to use microdisplays, be they OLED-on-Si, microLED or Liquid Crystal on Silicon (LCOS). As Yole Développement analyzed in our Microdisplays – Market, Industry and Technology Trends 2020 report and our Displays and Optics for AR & VR 2020 report, an interesting aspect in all these technologies is the fact that they all require a silicon CMOS backplane to drive the images. Some players are trying to provide an efficient solution that can serve as a driver, while being frontplane agnostic. As the key to technological development also lies in how this is handled, we believe that there could be ‘one wafer to rule them all’. If a player were to be able to provide a solution compatible with any given frontplane technology, it could be a game changer for the industry.
In this context, Compound Photonics recently announced a partnership with GlobablFoundries to manufacture the world’s first monolithic microdisplay for real-time augmented reality. This unlocks the real potential for amplitude liquid crystal on silicon (LCoS), emerging microLED and future phase-based holographic systems.
After an eventful year, Dr. Zine Bouhamri, Team Lead Analyst in Imaging & Displays at Yole Développement sits down again with Edmund Passon, co-CEO at Compound Photonics. Prior to the SPIE AR | VR | MR 2021 event where they will be speakers, they discuss this newly announced partnership with GlobalFoundries. Read on to find out what it means for the future, whether or not augmented reality for consumers can happen, and what steps are being taken in order to meet this dream.
Zine Bouhamri (ZB): Last summer you introduced IntelliPix. Now you are partnering with Global Foundries for mass production for this product. What’s the story behind this partnership?
Edmund Passon (EP): The Compound Photonics (CP) IntelliPix™ microdisplay technology platform will be made on the Global Foundries (GF) 22FDX™ semiconductor platform creating the world’s first real-time Augmented and Mixed Reality (AR/MR) specific monolithic microdisplay. The result will be the industry’s most advanced light modulation agnostic backplane and video pipeline. It has the ability to extend a roadmap of current amplitude Liquid Crystal on Silicon (LCoS) through to emerging microLED technology. This goes all the way to future holographic systems, while providing the required performance for real-time AR/MR systems.
The 22FDX platform delivers cost effective performance for connected and low power embedded applications such as AR/MR and consumer wearables. One of the signature features of CP’s microdisplay is that we offer the smallest pixel pitch and highest optical efficiency available in the industry. While our current pixel size is 3.015µm, 22FDX based on 22nm FD-SOI transistor technology offers ultra-low power capabilities and higher SRAM density. This is critical to enable an integrated IntelliPix backplane and driver pushing the pixels as small as 2.5µm, depending on the feature set.
At the core, IntelliPix’s design revolutionized the drive architecture to manage images intelligently at the pixel level with its proprietary feature called OnDemand Pixels™. IntelliPix directs bandwidth to modulate pixels representing objects that are active, while conserving power in inactive pixel regions, resulting in high image quality and brightness, while significantly lowering the overall display sub-system power. 22FDX was designed for effective back-gate biasing that enables dynamic tradeoffs between power, performance and leakage. This supports the design flexibility and precision that IntelliPix requires to optimize its innovative feature set.
ZB: Is this an exclusive partnership? Who approached whom first? How long did it take to sign a partnership?
EP: CP did an extensive assessment of foundries due to the customization required for our specific optical needs. At the end of the assessment GF was the clear choice. We had originally targeted 28nm, but on finalizing the feature set, and to maintain our pixel size, it became clear that 22FDX was required. We are very happy that GF could pivot with us to 22FDX to fully achieve the design and feature set goals. The partnership was solidified once we had locked the feature set and achieved the design goals, such as pixel size. This took a bit longer than both sides desired but allowed us to push performance to a level that should span multiple generations of AR/MR products.
To customize features for our key customers, 22FDX enables IntelliPix to easily integrate design IP that is customer-specific. Hence, it took some time to complete the actual design process together with our customers before we could fully complete the scope of work with GF.
IntelliPix-based products will further change the microdisplay driving paradigm by integrating its real time video pipeline and software definable drive scheme with either an adjustable constant current iDrive or voltage driven vDrive option into a single chip solution. All these flexible and scalable features unlock many inspirations and possibilities for system architects to push the design limits to a new level for their next-gen AR/MR glasses.
ZB: The first IntelliPix products are expected by 2023. Are they going to be LCOS based or MicroLED based?
EP: The first generation of IntelliPix on 22FDX will be amplitude LCoS based. Once microLED pixels are competitive with LCoS, changing the final drive transistor layout to iDrive allows CP to provide a fully integrated constant current backplane. Given the increased modulation speed afforded by 22nm FDX, combining microLEDs with CP’s IntelliPix will provide performance that leapfrogs any currently available architectures. As soon as microLEDs are commercially viable, IntelliPix will be ready to drive them!
Both CP and GF have invested a significant amount of effort into design and development for this partnership. The intellectual property developed in the process by each party will be leveraged to service other markets and customers, beyond AR/MR applications. These include automotive in terms of AR Heads Up Displays (HUDs) and conceivably LIDAR applications both by applying phase and holographic light modulation.
ZB: You mention you are frontplane agnostic when it comes to microLEDs. What do you think about OLED-on-Si technology compared to the two technologies you promote, microLED and LCOS? Regarding OLED-on-Si, can you be compatible with it? Are you looking for partnerships there too?
EP: At this point, we are monitoring the progress of OLED-on-Si development. We would be happy to apply microOLEDs to our IntelliPix backplane. Current feedback from our customers is that from a brightness and lifetime point of view along with pixel and display size and the associated product size, there are still challenges for OLED-on-Si to be viable and meet the requirements for true AR/MR applications for the consumer market. Given that CP is agnostic with respect to the light modulation layer of the display, if OLED-on-Si becomes competitive we are absolutely open to supporting OLED-on-Si or any other emerging light modulation technologies.
ZB: Do you have a design win with an OEM?
EP: We have multiple wins with global tier-one technology brands. We shifted our microdisplay development focus to AR/MR and HUDs circa 2016 and since then have worked closely with our ecosystem partners and directly with global customers in consumer electronic and mobile space. We are excited that our solutions have gained strong traction in the market today. We continue to work with our customers to develop a technology roadmap for near-term, mid-term and beyond that spans improvements in our IntelliPix real-time video pipeline and walks through the available light modulation technologies as they mature.
ZB: The first microLED products come with monochromatic panels, as we know providing RGB panels is no simple feat. How do you think the consumer market will use this?
EP: We believe that in the consumer space there is a huge potential for multiple market segments based on different hardware, feature sets and use cases. Spatial color displays are meant for premium segments to deliver advanced features. However, some applications, such as infographic displays for sports goggles and smart watches, can be designed with monochrome or even lower resolution RGB displays to meet the required feature sets and price points.
ZB: Last year you were advertising your smallest-to-date 3.015µm pixels. Now you are at 2.5µm. Is this for microLEDs and LCOS or only microLEDs?
EP: We are light module agnostic and IntelliPix can create both LCoS and microLED pixels. That said, the pixel size is a complex problem to solve, based on a lot of parameters. Designers of both LCoS and microLED pixels have an opinion of how big they should be, depending on performance needs. Pixel size versus resolution and the associated physics play into the device étendue required to achieve the needed output luminance to the eye and the diffraction limit starts to kick in below 3μm depending on f-numbers. We also have custom features, depending on the customer, that require more logic under the pixel. That can limit the smallest achievable pixel size. In the end the pixel size is the best compromise in meeting our customers’ needs given the parameters described above, plus many more. The CP team has decades of experience in helping create the best overall performance/power/cost compromise in concert with customer needs.
ZB: If this is available for LCOS, this must mean you have specifically developed LCs working at these sizes? Is this an internal effort or a partnership?
EP: CP had to develop our own proprietary Vertically Aligned Nematic (VAN) LC formulation that is the most desirable, highest contrast, LC mode. Once we achieved the smallest digital pixel it required an extremely thin cell gap and associated drive optimization. This work took around four to five years of R&D effort. We are extremely happy with the results that, together with the custom optical coating designs, our LCoS display can achieve industry-highest duty cycles, as high at 95%, and reflectivity, 40% better than our rivals. This provides efficiency levels far above our competitors, enabling size and weight advantages at the product level.
ZB: What do you think is the sweet spot in terms of pixel size that you could reach on the GF platform?
EP: For the past few years we have kept coming back to 3μm as being optimal. We can get to 2.5μm with 22FDX with the full IntelliPix feature set and maybe a bit smaller given some future optimizations. As mentioned above, other physics problems creep in with respect to maintaining luminance and resolution performance to the eye in moving towards too small a pixel. These physics limitations will likely be more of a limiter than the backplane or silicon pixel size limit in the short to mid-term.
ZB: Tell us a bit more about the SPIE Panel that CP will be moderated for The Development of XR Hardware Standards. What is the background and what do you plan to address in this discussion?
Based on recent AR and Virtual Reality (VR) reports from Yole Development, the high demand for AR and MR is forecast to continue in the next five years. During the pandemic, we have witnessed the adoption rate accelerating as the technologies became more valuable for companies to conduct business and operations. As an industry, we used to devise our developments and products in our own bubbles. And when market demands are accelerating, then comes competition. Yet we realized that the industry does not have a common language in place for us to compare performance of the products. For example, how should we measure field of view? What is the effective luminance? When everyone has different definitions, it is impossible to compare from one product to the other.
In the past few years, there were various standards development initiatives pulled together by different industry groups, yet somehow they were dropped for various reasons. Therefore, we worked with the SPIE team this time to group together a panel consisting of industry professionals and thought leaders to discuss how the stakeholders in the ecosystem can cater to the multiple disciplines involved.
Currently Augmented, Mixed and Virtual Reality Head Mounted Devices (XR HMD) are like the Wild West. We need to find the balance so that it will not be over-regulated or under-regulated. Perhaps some areas belong to standards, and some areas belong to competition. As the technologies and markets are still evolving quickly, we don’t want to stifle the innovation that we all value and likely need to achieve minimum viable performance in the consumer market. We hope the event on March 28 will reignite these efforts and exchange industry perspectives to work on a common language based on the building blocks for the entire AR/MR system. Compound Photonics will moderate the special event of SPIE AR/VR/MR Panel: The Development of XR Hardware Standards, which will be held live online at 4:30pm Pacific Time on March 28, 2021.
Edmund Passon serves as Co-CEO at Compound Photonics (CP Display) with 33 years of experience leading technology, operations, and business. Prior to being named Co-CEO, Ed was Senior Vice President of Product Development overseeing design and engineering activities. Additionally, Ed drives the companywide technical and product roadmaps working with industry leaders to enable world class, compelling display systems for current and emerging applications.
Ed brings a track record of results through an extensive career spanning multiple industries and disciplines including electro-optical-mechanical design, project architecture and business development. Prior to joining Compound Photonics, Ed held senior engineering and business development positions at InFocus, Philips, Omnivision, Ratheon, Honeywell and Oerlikon where he led teams designing systems & products spanning consumer, commercial, military and space applications.
Zine Bouhamri, PhD. is Team Lead Analyst, Imaging & Display within the Photonic & Sensing Division at Yole Développement (Yole).
Zine is managing the expansion of the technical expertise and the market know-how of the company.
In addition, he actively assists and supports the development of dedicated imaging collection of market & technology reports and monitor as well as custom consulting projects.
Prior to Yole, Zine oversaw 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. He is author and co-author of several papers and patents.
Zine Bouhamri holds an Electronics Engineering Degree from the National Polytechnic Institute of Grenoble (FR), one from the Politecnico di Torino (IT), and a Ph.D. in RF & Optoelectronics from Grenoble University (FR).
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