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52 EE|Times EUROPE

ST Sees AR Glasses Replacing Smartphones

depth camera with a very large field of view, and
ST said its MEMS micromirror enables continu-
ous laser scanning across the entire field of view.
In the meantime, to advance the adoption
of piezoelectric MEMS, ST has established the
Lab-in-Fab R&D line in collaboration with
Singapore’s A*Star Institute of Microelectron-
ics and Japanese vacuum-device manufacturer
ULVAC. “For AR, we have defined that piezo-
electric is the best compromise in terms of
dimension, power consumption, and per-
formance,” said Angelici. “Now we have a
fast-prototyping line in Singapore for piezo
actuation, so there will be a seamless transfer
from prototype to production.”
ST is also collaborating with OQmented, a
2019 spinoff from Germany’s Fraunhofer Insti-
tute for Silicon Technology, on the development
of MEMS mirror-based LBS solutions. OQmented
claims its Lissajous scan pattern and vacuum
encapsulation Bubble MEMS technology improve
resolution, energy consumption, and chip size
while ensuring long-term reliability for the her-
With LBS, he claimed, it is possible to achieve up to a 100° field of metically sealed micromirrors. Angelici commented, “It’s really cutting,
view, but there is always a tradeoff: “The more I open, the more power by a factor of 10, the power consumption of a MEMS mirror if you put it
it consumes.” under vacuum.” OQmented joined the LaSAR Alliance in May.
ST and Quanta Computer are developing the optical, electronic, and
photonics design to enable volume manufacturing of AR smart glasses INITIATING AND PLANNING
in line with the LaSAR Alliance. “They [Quanta] have put a lot of effort ST has set up what it calls a one-stop shop for LBS. Dubbed MEMS
into R&D, and they will have a full pair of glasses based on our laser- ScanAR, it comprises MEMS mirrors, MEMS mirror drivers, laser diode
beam scanning technology, embedding the application processor, the drivers, mirror control loops, and relay optics.
connectivity, the sensors, the glasses, and the lenses,” said Angelici. To accelerate the integration cycle, ST developed Star0, a first
reference design for AR smart glasses based on the MEMS ScanAR
OPTIMIZING MEMS MICROMIRRORS components, Dispelix’s lens, and Osram’s three-color RGB module. It
ST has extensive experience in MEMS design, development, and then developed a second generation, Star1, that reflects insights gained
manufacturing, with competencies in electrostatic, electromagnetic, from the LaSAR Alliance, Angelici said. Based on thin-film piezoelec-
and piezoelectric technologies. The group started investing in MEMS tric technology, Star1 features a 65° field of view, 1,280 × 720-pixel
micromirrors in 2009 and boosted its activities by acquiring bTendo, resolution, and 50% lower power consumption at a similar size to Star0
an Israeli startup specializing in LBS solutions, in 2012. Since then, it (0.7 cc). ST is currently sampling Star1 to key partners and expects to
has sealed partnerships with Intel, MicroVision, LeddarTech, and North have it “assembled in engineering samples for customers” in the third
(now Google). quarter of this year, said Angelici.
MEMS micromirrors are used in LBS systems to project visible Star0 has power consumption of 1,220 mW for a full white display
images or infrared patterns. They work by deflecting laser beams emit- and of 742 mW for a 10% white spot. In contrast, Star1 has power con-
ted from laser diodes to project images onto the required field of view. sumption of 781 mW for a full white display and of 312 mW in a 10%
The beam deflection is generally performed using a combination of two white spot, said Angelici.
mirrors rotating on perpendicular axes. ST has defined a piezoelectric process roadmap and expects to
Detractors note that LBS is not a mature technology, but Angelici is improve the actuation efficiency by 50% within the next couple of
convinced of its “high value” and outlined its brightness and years. For a design of the same performance, it anticipates a 50% power
power-efficiency advantages. “We have a flying spot, meaning we are consumption reduction and 30% die size reduction; for a design of the
not illuminating the full frame but [instead are] illuminating pixel by same size and power consumption, it anticipates 1,080p resolution or a
pixel where the content is needed,” he said. “If I am projecting the time 90° field of view.
on my screen, I have 95% of the screen black and 5% white, and I am “Without changing anything — just by working on the material and
illuminating only this path. We don’t need to buffer the full frame; process, which is enabled by this big investment in Singapore — we can
we can just buffer the line where the pixel is going to land.” provide scalability to this technology,” said Angelici.
By working with application developers, ST can visualize where the Asked when the 50% actuation efficiency target will be achieved,
content will be projected and where the white spots should be. It can Angelici said that “2023–2024 is when we expect the augmented reality
then design components that are faster in resuming operation from market for all wearables to start flying, and it will be available by then.”
power-down and “switch off the lasers to consume zero” when the pixel Of course, his group is not just developing components. “Our voca-
is not painted, Angelici said. tion is billions of units,” said Angelici, specifying that the group can
Over the past few months, ST has confirmed its commitment to LBS mass-produce its MEMS mirrors at its 8-inch fabs in Milan and
through strategic initiatives and partnerships. Singapore. “We are also using two new fabs for drivers, so we are ready IMAGE: SHUTTERSTOCK
Besides the LaSAR Alliance to develop AR eyewear applications, ST to go with volumes when augmented reality takes off.” ■
and Intel have worked on a MEMS micromirror for integration in Intel’s
RealSense LiDAR depth camera L515. RealSense is a 10-meter–distance Anne-Françoise Pelé is editor-in-chief of EE Times Europe.

SEPTEMBER 2021 | www.eetimes.eu