The legacy OLED-on-Silicon player MICROOLED shares its views on augmented reality – An interview by Yole Développement

After analyzing the overall ecosystem for augmented reality (AR) headset hardware in our “Displays and Optics for AR & VR 2020”, we wanted to focus on microdisplay technologies and markets. We know that microdisplays are necessary to drive the momentum for AR headsets, among other applications. That being said, many microdisplay technologies are competing, each having its pros and cons. And with a compound annual growth rate of more than 100% in value expected until 2025 for microdisplay modules for AR headsets, competition is fierce. Incumbent technologies like Liquid Crystal on Silicon (LCOS) and Digital Light Processing (DLP) have the lion’s share, but newer technologies like Organic Light Emitting Diodes (OLED)-on-Silicon and microLEDs are trying to break in, as we analyze in our recent “Microdisplays – Market, Industry and Technology Trends 2020” report.

Zine Bouhamri, Technology and Market Analyst in Displays at Yole Développement, was lucky enough to talk with a legacy player from the OLED-on-Silicon microdisplay industry, the French company MICROOLED. Eric Marcellin-Dibon, CEO and Gunther Haas, CTO, kindly answered Yole’s questions and share their knowledge and insights on the technologies at play for AR headsets.

Yole Développement (YD): You are the co-founders of MICROOLED. What is your background and what is the story behind the creation of the company?

Eric Marcellin-Dibon (EMD): Gunther and I have been working in the display industry since the early 90s, and we have been dealing with almost all technologies in our past experience, from LCD projection to plasma display, but also LCOS and DLP.

The core of our technology at the creation of the company is a specific low voltage technology. Previously it was made for glass substrates, but we decided to adapt it to silicon backplanes, because at that time we believed that the mobile video market was going to boom, and that everybody would watch high-definition movies in glasses connected to an iPod nano. That was back in 2007, and it did not actually develop this way. But anyway, our first products were out in 2009 with a beautiful picture quality and very low power consumption, and we quickly developed the market. One of our first customers was Panasonic with the Lumix GH3. It was the first camera with an OLED microdisplay. When I look back over the ten past years, we succeeded in developing many worldwide innovations with our customers. The Zeiss Cinemizer was the first consumer goggle product with an OLED microdisplay, the night vision device as well. There have been many others, and now the Julbo EVAD-1 AR sunglasses. We think outside the box, and we like partnership because innovation is when you meet partners who are ready to innovate with you.

YD: OLED-on-Silicon is a mature technology but has long been affiliated with specific applications like electronic viewfinders, sports optics and defense. What are the advantages of this technology compared to the other incumbent ones?

Gunther Haas (GH): First of all, one main differentiator of OLED-on-Silicon technology compared to other established microdisplay technologies like LCoS is the excellent contrast and overall picture quality. Especially for near-to-the eye applications, users are very sensitive to this as there is no light from the external environment affecting the display image. We developed an OLED technology with excellent uniformity. The gap between the pixels is so small that it is invisible. In addition, our pixel structure has even smaller sub-elements due to our quad pixel arrangement. Compared to LCOS or LCD microdisplays, the difference in picture quality is very visible in an electronic viewfinder. This is key for digital cameras, but also for defense applications, because it relates to the distance of detection. In addition, for head-up or AR type applications, where the display image is optically laid over the user’s natural view, we can provide extremely high contrast, meaning a black level close to zero, which is mandatory in order not to get parasitic light in the user’s view.

Secondly, our OLED-on-silicon technology has a much better power efficiency compared to our competitors, and to the other technologies mentioned. The display, with its optical system, has a very compact footprint as it does not require external illumination.  All near-to-eye applications are portable and battery operated, so a power-efficient and compact technology really makes the difference. This is especially key for eyewear VR/AR applications.

Last but not least, the wider temperature range and faster response times compared to LCD and LCOS has been one of the main drivers for defense and sport optics applications, where LCOS or LCD are now rarely used.

YD: AR has been promised for many years. Given the need for a microdisplay technology, OLED-on-Silicon products have tried to make a push for this application in wearables and  headsets. What would be the advantages of using OLED-on-Silicon?

GH: In the AR space, initially LCOS-based systems were dominating because they can provide very high brightness, but it was at the cost of a bulky and power-hungry system with low picture quality. As explained before, AR glasses require compact and power-efficient displays with very high contrast. As of today, only OLED microdisplays can deliver this. In the past, the limited brightness of OLED microdisplays has been the main limitation. However, advances in OLED materials as well as new device architectures we developed, have allowed us to overcome this issue. As the first products based on our ActiveLook platform impressively demonstrate, OLED microdisplays can be used in full optical see-through systems, even in brightest sunlight. These first products are based on a monochrome display, but a two-primaries red and green microdisplay is used by another customer in an AR system for outdoor applications. We currently have full color versions of high brightness OLED microdisplays under development and sampling to our customers.

YD: You very recently raised 8M€ to accelerate the deployment of your ActiveLook Smartglass Platform. What is this platform?

EMD: ActiveLook is a compact module for AR sunglasses, which connects to various devices, such as mobile phones and smartwatches. The overall system weighs less than 7g with over 12 hour autonomy, including battery, optics, microdisplay and full electronics.

Our first target was the sport eyewear market, and we wanted to do it differently from all the other techie smartglasses. Everything is built around our core technology, our ultra-efficient high brightness microdisplay, with only 1mW power consumption. We designed the system to be very lightweight and to enable stylish good-looking sport sunglasses that are indistinguishable from regular eyewear, and are designed to project data directly in the lens without obstructing and obscuring your vision. Julbo, the extreme sport sunglass maker, recently introduced the EVAD-1digital sports glasses this year. They did a fantastic job integrating our ActiveLook module. We are very proud of this collaboration. The design is amazing. The glasses are very comfortable, and include photochromic lenses. When you wear them, nobody can guess it includes a real heads-up-display. The Julbo EVAD-1 comes with an ActiveLook sport application, which is available on the Apple App Store, Google Play, and Connect IQ from Garmin.ActiveLook is an open platform. It includes a Software Development Kit, which enables partners to develop their own custom designed applications. We are working with many partners who see a unique opportunity to extend their market access by making their data available directly in the ActiveLook module. Examples include coaching applications and performance monitoring. Thanks to its low weight, long duration autonomy, and form factor, ActiveLook will also be an excellent platform for industrial applications, such as connected safety glasses. We have many projects in the pipeline. This is a very exciting time for us.

YD: Why have you decided to go towards developing more than a display, and producing a complete platform? Was it an internal effort or a pull from your clients and partners?

EMD: We have always been a very customer-focused company. Step by step it became obvious that our customer base and new markets were looking for solutions rather than just a microdisplay. It is especially true for new use cases and augmented reality. The consumer brands are very strong in marketing, product design and retail, but they do not necessarily have a good understanding of the technology. Many have tried to assemble technology parts together but for a poor result. This is where we have a key role to play.

We were convinced that by taking into account the requirements of the customer’s product, from an end-user point of view, we could do things differently, by optimizing the technology all along the chain, from the optics, to the microdisplay and the electronics.

At the beginning, it was fully an internal effort, we had to grow the team, integrating many forms of expertise, including mechanical, system engineering, optics and firmware. Our deep understanding of microdisplays, video and optics technologies helped us to develop a module that meets market demand.  Very quickly customers approached us, and started collaborating on projects together. We provided the expertise and technology they did not have. We have many partners working with us to develop new products and use cases. Julbo’s EVAD-1 sunglasses are the first of these projects. We will extend ActiveLook to many customers and partners but also to other AR applications.

YD: A long-talked but still in prototype early-phase technology has been around for a few years now, namely microLEDs. There is lots of promise but no product yet. Do you see this technology as a threat?

GH: The display industries always went through major technology changes, from cathode ray tubes, to liquid crystal displays, to OLEDs. For sure new technologies will arise. However, some did not succeed or had very limited market access such as field emission displays, plasma and DLP, because their key features only matched niche market requirements.

We have so far seen early prototypes of monochrome microLED based microdisplays with very high brightness. However the samples show many defects and it is not really possible to evaluate picture quality. There are numerous technical hurdles that would have to be overcome for microLEDs before becoming a competitive microdisplay technology even for monochrome displays.

In contrast to OLED-on-Silicon, microLED-on-Silicon is a heterogeneous technology. This means that millions of interconnects at pixel level are required in order to connect the individual pixel circuits to the corresponding microLED element. It is not clear how a reasonable manufacturing yield can be achieved for these interconnects as only very few or sometimes zero defect pixels can be tolerated in a display. Also, the overall manufacturing process is very complex and includes further steps for pixelization and common connection of the LEDs as well as steps like substrate release. Overall, the cost of manufacturing will be very high.

Efficiency of microLEDs drastically decreases with pixel size, and from available data we can see that power consumption will be significantly higher compared to OLED, at equal brightness.

MicroLEDs require pixel-to-pixel homogeneity calibration including full-frame memory, which increases both cost and power consumption.

In addition, for AR and other near-the-eye applications, there is no real advantage. The required brightness for monochrome applications is easily met already by our OLED-based microdisplays. However, I think it is in principle possible to realize such monochrome microdisplays that could be used for projection applications where really high brightness is required and where power efficiency and cost are not essential.

When it comes to color, as of today there is no realistic solution how to make a full color microLED-based microdisplays. Full color direct view microLED displays using color conversion via red and green Quantum Dots has been demonstrated, however with a quite low resolution of 100-200ppi, and with rather low brightness. In microdisplays we typically have resolutions between 2000 and 4000ppi which correspond to pixel sizes down to 6µm, which is impossible to realize with quantum dots.

Many efforts in microLED today target larger size, relatively low-resolution direct view displays, using mass transfer techniques from red, green and blue microLED wafers to large glass substrates. I cannot comment on how successful this might be, however I do not see how microLED technology for very high-resolution display like microdisplays could become a reality.

On the other hand, OLED materials and devices in general are still making significant progress. There is a large critical mass of material and technology developers behind. One example is the recent progress in highly efficient blue emitters.  For microdisplays, we are current making great progress in term of efficiency and light output, as well as for optical system for AR applications which are becoming more efficient as well.   Only few applications like projection or some HUD type applications really require extremely high brightness. Therefore, there will be only a very small space for an expensive and very capital-intensive technology to breakthrough. It is not obvious that even if all the technical and cost related problems could be solved that this technology will reach the market.

Interviewees

Eric Marcellin-Dibon_MicroOLED_circle

CEO and co-founder of MICROOLED, Eric Marcellin-Dibon, has over 25 years of experience in the field of High Technologies and Consumer Electronics and holds several management positions in France, Germany and the UK. 

With a talented engineering team, he developed MICROOLED to the forefront of the technology in the field of very low power, high resolution microdisplays. More recently, he has extended the expertise of the company by creating the most compact integrated solution for augmented reality eyewear, with the ActiveLook® technology.

Gunther Haas_MicroOLED_circle

Gunther Haas is one of the two founders of MICROOLED and its CTO. He has over 25 years of experience mainly in R&D management, business development, and transfer from R&D to production, gained in different companies (Bosch, Thomson, start-ups), from very large to very small size, in Germany and France. He started and lead the Thomson OLED activity from 2001-2006 which laid the initial technical foundation for MICROOLED. He has a M.S. in Physics and a PhD in Electronic Engineering from Karlsruhe Institute of Technology (KIT), Germany.

Interviewer

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).

Related reports

YDR20109-Microdisplays 2020_bd2

Microdisplays – Market, Industry and Technology Trends 2020
Will automotive HUD and AR headsets spawn new microdisplay tech?

Displays and Optics for AR & VR 2020

Source: http://www.yole.fr/

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