We’re pleased to feature Plessey Semiconductors, a UK-based leader in advanced photonics and microLED technology, as part of our series highlighting members of the MicroLED Industry Association.
Based in Plymouth, Plessey operates one of the few fully integrated microLED manufacturing facilities globally, bringing together design, epitaxy, wafer processing and device production on a single site. With over 70 years of engineering heritage and a growing commercial base across AR displays and optical interconnects, the company is focused on enabling the next generation of computing through photonic technologies.
We spoke with Phil Greenhalgh, Chief Technology Officer at Plessey, about the company’s technology, progress, and vision for the industry.
Can you introduce your company and technology?
Plessey is an advanced semiconductor and photonics company focused on designing and manufacturing optical technologies for next-generation near eye displays and computing.
What differentiates us is our end-to-end capability. We bring together materials science, epitaxy, device engineering, pilot production and augmented reality (AR) system engineering within a single site. This gives us great R&D agility as well as giving us direct control over both performance trade-offs and scale.
Today, our core focus remains microLED displays for AR, where the performance requirements are very demanding. In parallel, we are developing optical emitters optimised for short distance high-speed data communication, an area that is becoming increasingly critical as AI infrastructure scales.
Can you say why you joined the MicroLED Association and what you hope to achieve?
Display-compatible MicroLED panels have reached a point where the industry needs to move from isolated breakthroughs to coordinated execution and real commercial deployment.
The industry also needs to adopt consistent measurement methods and conditions, so that customers can assess if microLED devices will suit their AR optical system.
Through the MicroLED Association, we hope to help socialise this and, over time, contribute to establishing agreed performance standards. This would allow MicroLED vendors to present device performance using consistent and comparable data.
At the same time, successful deployment depends on alignment across the value chain, particularly with materials providers, equipment manufacturers, device companies and system integrators. The Association provides a valuable view of how the broader ecosystem is evolving and ensures we remain aligned with where the market is heading.
As one of the few companies operating at the intersection of advanced photonic engineering and high-value semiconductor manufacturing, we see our role as both delivering technology and helping shape the direction of the industry as it matures.
What is your biggest challenge, and success to date in the microLED industry?
The fundamental challenges with microLED display panels are exactly the same as other technologies. I just think that when development is at minimum viable product level, the resultant display will provide a better blend overall.
At the engineering level, the challenges for microLEDs are firstly enabling sufficient efficiencies so that they are daylight usable in conjunction with diffractive waveguides. The second level challenge is maintaining that hard fought for efficiency with a truly monolithic RGB panel. We are succeeding at the first and like everyone else, working on the second.
And then it is delivering that performance in a way that is manufacturable, repeatable and cost-effective at scale.
Overall, we are close and as a result, we are now supplying high‑performance microLED displays to global customers in AR.
At the same time, we are extending this capability beyond displays. The same human and equipment resources that enable class leading microLED display architectures are the same as those required for next generation data communications.
But the semiconductor trade-offs are different for displays and interconnects. Modulation speed is paramount for interconnects but is an insignificant consideration for display applications. Energy efficiency is very important for both application areas and the work we have done in optimising light extraction for display applications translates over directly to highly efficient energy coupling into optical fibres. In both cases we need as many photons as possible to be used doing useful work!
Advantageously, Plessey is just the right size and capability for agile R&D and rapid iteration of ideas and methods.
That transition, from promising technology to something that can be reliably manufactured and deployed across both display and visible light communication applications, is one of the most important steps for the industry, and where we are continuing to push forward.
Can you detail your latest prototype or demonstration?
This is a challenge to detail without quoting tables of performance data and disclosing customer data. From a demonstration perspective we have full featured examples of our standard panels fusion bonded to CMOS backplanes that are plenty bright enough for a typical diffractive waveguide image combiner.. These are nominally 1 micron mesas on a 2.5 micron pitch but we can go smaller or larger if required. At our smallest pixels we are not at 10% WPE but are well above 1% for all three colours. But very significantly those WPE figures are quoted over a range of angles useful to light engine designers not the full and unrepresentative lambertian spread commonly used.
How do you see microLEDs changing the display industry in the next 5–10 years?
MicroLEDs are set to become a foundational technology in most implementations of see-through AR displays. Of course, there are competing technologies and they have their advantages. But I am aligned with the very largest corporate proponents of AR who, almost universally, have chosen microLEDs as the technology of choice for their consumer AR display programmes. The notion of having both the light generating function and the image forming function inherent in a single device is unique to microLEDs.
In the 5 to 10 year timeframe, microLED displays will enable the best AR product balance of attributes; specifically compact light engines that are bright, efficient with high enough pixel density to match a typical eye’s resolution.