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MicroLED chip
New colour MicroLED display technology
MicroLED chip
MicroLED chip with 3 micron pitch pixels (Image courtesy of MICLEDI Microdisplays BV)

Small is beautiful. Small and brightly coloured is very beautiful indeed! Belgium companies QustomDot BV and chip designers MICLEDI Microdisplays BV have teamed up to produce a major advance in mass producing display devices for augmented and virtual reality (AR and VR) applications.

MicroLED displays are emerging as possibly the best devices for AR and VR applications in the metaverse. They are bright, high resolution and have low power consumption. Gallium nitride microLED sources are small and bright but typically emit blue light. Great for a blue display but what about red and green pixels? This is where the QustomDot technology comes in. QustomDot have developed quantum dot materials which absorb blue light and re-emit green or red light.

QustomDot show off their red and green quantum dot solutions

So why are these quantum dots special? Cadmium sulphide (CdS) or selenide materials have been around for some time but cadmium is problematic in the environment and avoided in new materials technologies. QustomDot have a solution (literally). Their indium phosphide (InP) dots have high efficiency and avoid the use of harmful cadmium. By controlling the size of the nano-particles, they are able to change the colour of light the quantum dots emit. InP based dots can be produced not only in solutions but also transferred to surfaces such as those of gallium nitride microLEDs.

Partners MICLEDI, a spin-out from the Belgian microelectronics hub at IMEC, are able to produce the required wafer-scale GaN microLEDs. The significance of the technology is that IMEC  has decades of experience of advanced CMOS fabrication. CMOS technology can produce industry standard 12″ wafers with sub-micro resolution and alignment of transfers. Amazing.

Competing technologies based on less well-established materials currently produce 4″ wafers, with more development work required to scale-up. It remains to be seen which technology will finally win in the AR/VR marketplace.

Find out more about MICLEDI BV.

Find out more about QustomDot BV.

Find out more about Corbeau’s microLED inspection tools.

tooz and JBD
Smart glasses get smarter
Curved waveguide smart glasses (Image courtesy of JBD & tooz technologies GmbH)

What happens when you put two superior optical technologies together? In the case of smart glasses you get bigger, brighter and less blurry.

Kingsman-style smart glasses have been available for more than a year now but they typically have flat glass lenses which are difficult to adjust for the 50% of the adult population who wear prescription glasses. A new joint venture between microLED device manufacturer Jade Bird Display (JBD) and smart glasses developer tooz technologies GmbH (tooz) is set to change that. On January 20th 2022 the companies announced a collaboration to put bright microLED displays into glasses with curved lenses. A first demonstration is taking place at the Photonics West SPIE AR VR MR 2022 exhibition (23rd – 25th January 2022 in San Francisco, USA).

Almost exactly one year ago Corbeau reported an Insight on new micro-LED driven smart glasses from Vuzix, a major breakthrough in terms of connectivity and what we now call the Metaverse. With existing products for industrial and medical applications, Vuzix announced the NGSG (Next Generation Smart Glasses) for the consumer market. NGSG combined tiny high resolution microLED red/green/blue displays with their state-of-the-art waveguide optics for displaying 3D images in front of the wearer’s eyes.

Vuzix AR glasses
Vuzix NGSG smart glasses for Augmented Reality display (Image with courtesy from Vuzix)

In the past year a number of new players have entered the market with their own smart glasses. Xiaomi, a budget smartphone manufacturer from China, has glasses with a monochrome green display based on what looks like a Jade Bird Display 0.1″ device. Lenovo has launched the ThinkReality A3 with high resolution AR display but a rather heavy look. TCL’s Nxtwear G glasses offer high resolution cinema-style projection and get around the prescription lenses issue with a custom frame that looks a bit like Neo and Trinity’s eyeware from the Matrix. But on stalks.

tooz (it seems strange to start a sentence without a capital letter) make much of their new curved waveguide technology. Vuzix developed a waveguide element to their smart glasses which enabled light of different wavelengths to be projected as a image in three dimensions in front of the wearer’s eyes. This was amazingly cool. tooz have gone one better and invented a curved waveguide, which realises a number of improvements to the design and performance of smart glasses. Reading through technical presentations from tooz, Corbeau spotted seven major advantages of curved waveguides compared to planar waveguides:

  • unbreakable plastic rather than brittle glass
  • lighter and more compact than glass
  • use less optical elements due to curved surfaces bending light
  • require just one waveguide layer rather than one for each colour
  • material rejects sunlight and rain interference outdoors
  • curved waveguide reduces display visibility to others
  • curved waveguide claimed to be more efficient than planar ones
Curved waveguide advantages compared to planar waveguide (Image courtesy of tooz)

Where do Jade Bird Display fit into the picture? tooz started developing their smart glasses with OLED light sources rather than microLED. OLEDs typically have some advantages but their big disadvantage is the displays are not as bright as microLED displays. Waveguides have amazing properties but are lossy, they waste much of the light intensity passing through them. The tiny microLED displays from JBD have brightness values of millions of nits (the iPad has a humble several thousand nits). This means they can be used outdoors in full sun, to project usable images over wide angles even though much of the light is lost in the waveguide. JBD also have a rather neat X-cube optic which combines the outputs from tiny individual red, green and blue microLED displays no bigger than a grain of rice.

Exploded view of JBD X-cube microLED and tooz curved waveguide lens (Image courtesy of tooz)

So where does this great technical synergy lead? With the possibility of smart glasses for the whole population, including the 50% who require prescription lenses, a massive potential market is opened up. tooz aren’t just targeting technophiles, they have real-life commercial applications in their sights. Vuzix have a business model that has targetted early adopters in the engineering services sector. tooz are pushing their new products into engineering and medicine. They have a fascinating promo video of a pilot study at the University Hospital of Dresden (see the bottom of this Insight for a link).

University Hospital Dresden pilot study of tooz smart glasses (Image courtesy of tooz)

One more thing. tooz started out as a new venture between optics experts Carl Zeiss and IT giant Deutsche Telekom. They have automated manufacture for volume manufacture of optics and real reach into IoT in the field.

Smart glasses are now real products with commercial benefits. The party is just getting started and we haven’t seen what Apple and Facebook will bring to the party yet. Could the next two years see the death of the smart phone and the birth of the Matrix?

Visit the Photonics West SPIE AR | VR | MR 2022 .

Find more tooz company information .

Find more Jade Bird Display company information .

See the Xiaomi smart glasses video.

View the TCL Nxtwear G glasses.

See the tooz glasses University Hospital Dresden promo video

Red microLED breakthrough for AR displays
Porotech red InGaN 960×540 pixel display (courtesy Poro Technologies Limited)

Autumn is a time of year that the folk at Porotech in Cambridge, UK seem to love. Those deep red autumn colours mark a year of significant growth. This time last year Porotech announced they could fabricate wafer-scale red emitting nano-porous InGaN, suitable for microLEDs.

This autumn Porotech are announcing a ‘world first’ red microLED display based on InGaN. Red microLED display devices based on InGaN are a game-changer for AR (augmented reality) and VR (virtual reality) display devices. Why?

All video display devices are based on composite red, green and blue light signals which the human eye recognises as a millions of different colours. To achieve this pc monitors, televisions and digital projectors use red, green and blue light sources. A variety of different LED choices are available for each of these colours however until recently their light emitting materials had quite different compositions. For large panel displays this is not a huge problem, individual LEDs can be picked and placed together by machine. Tiny display devices used in AR are much more demanding.

For smart glasses, the display device must be less than 10 mm in size and to get anything approaching high definition, it must contain something like 1000×1000 pixels. A simple sum tells us that each of the one million pixels can be no larger than 10 microns! Modern microelectronics fabrication methods can easily make structures 100 times smaller than this but mixing different LED materials is a huge practical challenge. Enter the Porotech solution.

640nm red light emission from nano-porous InGaN (inset shows powered array of red LEDs) (courtesy Poro Technologies Limited)

Porotech was spun out of the University of Cambridge to exploit so-called nano-porous gallium nitride materials. InGaN (indium gallium nitride) is a compound semiconductor whose optoelectronic properties can be tuned not only by changing the precise composition but also by creating nano-scale voids.

The traditional way to produce red light from InGaN was to add aluminium and phosphorous atoms to produce red-emitting AlInGaNP. However making very small volumes of uniform semiconductor material from many elemental components is problematic as well as expensive. CEO and co-founder of Porotech Tongtong Zhu put it like this:

Porotech’s new class of porous GaN semiconductor material is now redefining what is possible – enabling the creation of efficient and bright native-red InGaN micro-LEDs and micro-displays

Tongtong Zhu CEO & co-founder, Porotech

Just how likely is this to happen? Over the summer Porotech have been busy adding three valuable components to the technology. In June a further £3M funding round was secured, led by Speedinvest. In August a key partnership was announced with major Chinese device manufacturer Jade Bird Display. Finally in September Porotech secured the services of former ARM executive Helen Adams as Chief Commercial Officer.

One mobile phone network provider used to claim that “the future’s bright, the future’s Orange”. Today for Porotech it seems “the future is bright, the future is red, green, blue, in fact any colour you want!”

Find out more about Porotech’s technology here.

Discover more about the Jade Bird Display venture here.

Discover our own microLED inspection & defect review products

Vuzix AR glasses
Micro-LED driven AR smart glasses
Vuzix Next Generation Smart Glasses
Vuzix Next Generation Smart Glasses (courtesy Vuzix)

Augmented Reality (AR) glasses are now looking remarkably stylish. Forget bulky Virtual Reality (VR) headsets and piratical Google Glass. Optoelectronics company Vuzix (Rochester, NY) has announced a pair of stereo vision glasses offering a head-up display (HUD) of the smartphone in your pocket. Or car. Or back home, actually.

CES 2021 (Jan 11-14), a consumer electronics show, handed Vuzix three CES2021 Innovation Awards for their Next Generation Smart Glasses (NGSG). Vuzix are saying we can expect the NGSG in the shops (pandemic permitting) summer 2021.

How did this happen?

Paul Travers founded Vuzix in 1997 with a desire not only to combine new technologies in innovative ways but also to provide solutions to customers’ problems. Vuzix has focused its AR product development on solving specific problems for specific customers. The Vuzix business model has therefore been B2B sales of wearable devices that: enable service engineers and technicians to follow instructions in manuals hands-free; allow clinicial experts to get a carer’s eye view of a patient; give advanced understanding to a surgical team awaiting the arrival of paramedic’s casualty.

Vuzix wins three CES 2021 Awards (courtesy Vuzix)

Existing Vuzix products from the BLADE to the M4000 have exploited state-of-the art light sources, optical components and low power high performance microprocessors. Their latest NGSG exploits the latest microLED displays, Internet of Things chips and waveguide optics.

Probably the most significant new technology is the introduction of microLED light sources which offer high brightness, high spatial resolution displays with very low power consumption. Matching the colour detectors in the human eye, red green and blue microLED displays are combined in the glasses to project colour images to a focal plane in front of the wearer. MicroLED packages are indeed awesome things. Vuzix source their microLED components from Jade Bird Display (Shanghai, China). Incredibly, a monochrome display panel with 6000 DPI GaN diodes is smaller than a grain of rice! Jade Bird Display (JBD) claim their components are the worlds smallest VGA resolution displays. More information on Jade Bird Display components can be seen below.

Jade Bird Display microLED technologies

So just how far can this technology go? how slim can the glasses’ frames be made and how big can the projected 3D images become?

Arguably the limit of the technology is set by the dimensions of the microLEDs themselves. JBD use GaN diodes in their displays that are tiny, just 4 microns in diameter. Microelectronic fabrication techniques can certainly make smaller devices. CMOS technology for example can produce structures on silicon wafers that are tens of nanometers in diameter. When a diode junction has to operate simply as a switch, subtle changes in material properties that result from their small size are not critical. The same isn’t true for the external optical properties of an LED. As the diameter of an LED gets smaller, its properties are increasingly determined by its edges rather than its bulk. Edge effects change the emission wavelength of the light and reduce the efficiency of the microLED device.

To really drive AR smart glasses and other display products forwards requires both increasing the resolution of microLED components and reducing their cost. This is challenging and requires improved test and inspection tools that can quickly detect defects on whole semiconductor wafers and analyse individual defects less than the size of a single pixel.

We will have to wait until later this year before we can get our hands on the latest AR glasses technology but microLED test and inspection instrumentation is available from Corbeau Innovation now, click below for product information.

Finding rare earth elements by hyperspectral imaging
Rare earth elements (15 lanthanides plus Scandium and Yttrium)

Imagine a world without smart phones, the latest medical imaging or great bass response from your earphones? Nope, nor can I. Worryingly, the continued availability of these essential 21st century pieces of tech is far from certain because they each rely on so-called Rare Earth Elements (REEs). REEs are not particularly rare but they are rarely found in the earth at sufficiently high concentrations to make it commercially viable to mine them.

The vast majority (>90%) of the world’s supply of REEs comes from China; the USA and Australia producing most of the remainder. With the fast growing demand for REEs and the equally fast growing economic Cold War between China and the West, supply is looking precarious.

Historical REE production 1958 – 2008 (courtesy US Geological Survey)

In 2016 a detailed report was published by the European Union EURARE project. European geological survey groups from Finland to Greece reported rare earth elements were widely present across Europe but there were just a few potentially viable REE mines. The figure below shows the EURARE distribution of ‘belts’ of REE geology. The next step would be to send a geologist with her rock hammer out into the field and then drill cores to find exactly where viable concentrations of rare earth minerals could be mined. But how to examine these areas of hundreds of square miles of land?

Belts of potential European REE geology (image courtesy of Elsevier Ore Geology Reviews)

Researchers from the Helmholtz Institute in Freiberg in Germany believe they have found the answer. Rene Booysen and her colleagues reported this month that Unmanned Aerial Vehicles (UAVs) can be used to deploy hyperspectral imaging cameras to accurately locate REE deposits on the earth’s surface. Lanthanide minerals absorb light in very characteristic ways. Rather than absorbing broadly yellow light like a sapphire for example, the lanthanide REEs have very narrow absorption bands. Narrow bands are loved by spectroscopists because they can be much more easily picked out against backgrounds. Providentially, REEs tend to be found together and one lanthanide in particular, neodymium Nd (see the blog title image), absorbs light very strongly indeed in its narrow absorption bands.

Reflectance spectra from the surveyed area in Siilinjaervi Finland, showing narrow absorption peaks due largely to REE neodymium. Survey points contain increasing amounts of neodymium. (courtesy Nature Scientific Reports)

The Helmholtz Institute group cleverly exploited this fact by mounting a hyperspectral imaging camera on a drone and then rapidly covering 10,000 m2 areas of interest in Namibia and Finland. In addition to the hyperspectral camera on a copter drone, a small UAV plane was used for 3D imaging so that geometric corrections could be made to the images taken by the drone.

UAV plane (A) used to correct HSI images and copter drone (B) with HSI imaging camera (courtesy Nature Scientific Reports)

Areas in Finland and Namibia were pre-selected from geological regions rich in so-called carbonatites, rocks on the surface known to contain REE minerals.

Geological maps of Namibia (A) and Finland (B) showing locations of carbonatite rocks where REEs can often be found (courtesy Nature Scientific Reports)

Impressively, comparison of the HSI neodymium images with elemental analysis of rock samples from the survey sites in Namibia and Finland showed good agreement with concentrations of neodymium and other rare earth elements.

Further extensive surveying and mining in Europe will be required to establish what mineable reserves of essential REEs Europe holds. The team from Helmholtz Institute in Germany have nevertheless validated hyperspectral imaging as a major step towards securing the economic future of many key modern technologies.

Read the full Nature Scientific Report here.

The European EURARE report was published by Elsevier here.

More information on rare earth minerals and geology can be found at the American Geosciences Institute.

Returning to the fold
galaxy fold testing
Samsung returns to the fold

September is a time for returnings and one of the most intriguing promises to be the return of the folding phone. At the beginning of the year tech commentators were sad to be returning their Samsung Galaxy Folds with, well, folds in them. It turned out that the super AMOLED displays were not as robust as they needed to be and repeated bending backwards and forwards produced nasty wear marks in the screen. Since the pre-launch of the Galaxy Fold in February 2019, Huawei’s Mate X with 5G mobile and further folding devices from Xiaomi, Sony and Motorola have all been trailed.

Inside or outside? Samsung decided to fold the screen inside, giving it protection but requiring a cleverly designed hinge to allow the screen to lie flat. Royole, who produced the very first folding screen phone, the FlexPai, chose to fold the screen on the outside of the phone. A changable outer display instantly shows phone information without having to open the device but makes it vulnerable to scratching. Motorola have followed Samsung with their retro Razr clam-shell design while Huawei and Xiaomi have opted for outside displays. Sony’s phone-become-tablet doesn’t fold at all but slides and therefore has a gappy blank line down the centre of the tablet display.

All the big players have access to the same technology but have come up with different products. Which new product will win? With technical issues out of the way, Corbeau reckons this will come down to function rather than innovation. All the folding phones (with perhaps the exception of the Xiaomi) will cost the best part of $2,000. Customers will therefore be cash-rich and space-poor mobile workers.

The Galaxy Fold could meet the needs of business women and men who want to carry a tablet but only have space in their suit pockets and handbags for a phone. These train, plane and automobile warriors will not be checking their social media a hundred times a day and therefore concerned about the lifetime of the fold. Huawei’s Mate X on the other hand offers faster 5G streaming and neat camera technology. For customers, think Instagram influencers and other social media workers whose down-time is work-time and work-time is me-time.

And for Joe and Jo public? well if a 16:9 video format can be provided by the Razr at a less aspirational price, Motorola might well have a hit on their hands.

Take a look at the Samsung Galaxy Fold here and the Huawei Mate X here. Motorola teasers from CNET can be seen here. Royole’s FlexPai and other AMOLED technologies are on their website.

Samsung Galaxy Fold
Samsung Galaxy Fold

It makes calls. It takes photos. It browses the internet. It opens like a book? Wow.

Smartphone giant Samsung this week announced what it believes will become a new category of smartphone. According to DJ Koh, President and CEO of IT & Mobile Communications Division, Samsung Electronics,

Today, Samsung is writing the next chapter in mobile innovation history by changing what’s possible in a smartphone. Galaxy Fold introduces a completely new category that unlocks new capabilities never seen before with our Infinity Flex Display.” Koh continued, “We created Galaxy Fold for those that want to experience what a premium foldable device can do, beyond the limitations of a traditional smartphone.”

In an interview with BBC technology correspondent Rory Cellan-Jones, Samsung spokesman Mark Notton said that Samsung has a need to “continuously, relentlessly innovate“.

Corbeau reckons there are fascinating aspects to these statements, worth unboxing for closer inspection (well we can’t get our hands on the device until March!).

If Mr Koh is right that the Fold is the next chapter in mobile innovation history then Samsung didn’t really write it. Samsung more kind of edited it. Just one month before the Fold, the FlexPai foldable smartphone was launched by Shenzhen-based Royole Corporation. While the Fold is a bit on the thick side for a phone, the FlexPai looks more like a bookie’s wallet on race day. With similar pricing (around £1200 for the FlexPai and £1300 for the Galaxy Fold), Royole will find it difficult to compete. Actually this is probably not the huge problem for Royole that it appears. The venture-backed Chinese corporation has IP, fabrication facilities and a line of milestone AMOLED products dating back to 2014. Their innovation model is to transfer a core technology to different products in different market sectors.

Samsung on the other hand has been a major player in the smartphone market for some years, finally getting a nose in front of Apple at the end of 2018. According to IDC a global market intelligence company, Samsung presently has 20% of the market in terms of unit sales, with Apple and Huawei around 15% and Xiaomi and OPPO each taking around 8% of handset sales. The drive for continuous and relentless innovation at Samsung has produced incremental improvements in their flagship Galaxy S to keep them out in front but with the smartphone market finally saturating and rivals like Xiaomi snapping at their heels, they need to innovate an entirely new premium product.

Is the Samsung Galaxy Fold the answer? Time will tell. Users can certainly understand the value of being able to carry a single device that functions both as a phone and a tablet.

The first flexible screen smartphone from Royole Corporation may find it difficult to compete against the stylish Fold but Royole are an organisation to keep a beady-eye on.

Further information on the Samsung Galaxy Fold can be found on the company website. Further information on the FlexPai smartphone from Royole Corporation can be found on their product information page. A detailed review of new tech revealed last month at CES 2019 can be found at TechRadar.