echanical movements may be claiming the lion’s share of innovation, advances are being made in quartz calibres, too. One of the most promising comes out of Besançon, France, where, after twenty years of R&D, deep tech company SilMach has developed a micromotor that is the world’s smallest and has the longest autonomy.
This revolutionary system is designed to replace the Lavet step motor that has equipped electronic watches since the 1960s*. Comprising four parts around a monolithic silicon core, its advantages are its extremely small size (the smallest in its category by a substantial margin), resistance to magnetic fields, lubricant-free operation, as well as enhanced robustness and durability.
Very low energy consumption translates into a movement with a battery life that a conventional system cannot hope to match. The watch’s hands are driven clockwise and anticlockwise with extreme precision, enabling a retrograde motion with smooth accelerations and decelerations. Because of its tiny size, SilMach’s micromotor can be surface-mounted on the circuit board of a hybrid smartwatch (one that displays information using hands) like any standard electronic component. This paves the way for the production of cutting-edge electronic watch movements in France. Currently, Lavet motors are assembled by hand in countries where labour costs are low, mainly in Asia.
From Tokyo to Besançon
Pierre-François Louvigné, Co-CEO and CSO, told us how the project took shape. SilMach (short for Silicium Machinery) was set up by Patrice Minotti, former director of the CNRS (France’s national research organisation) micromechanics lab in Besançon, in 2003, when silicon was emerging as one of the materials of the future. A five-strong team left Besançon for Japan where, over the next two years, they established a joint laboratory with Tokyo University, a specialist in silicon and cleanroom technologies. Twenty years later, the competencies acquired would produce this high-potential micromotor.
“Patrice Minotti and his team left Tokyo convinced that silicon technology could replace the Lavet motor,” says Pierre-François Louvigné. “The Japanese lab team were working on silicon applications, but none of these were in micromechanics or watchmaking. Patrice Minotti set up SilMach to explore these possibilities.”
- SilMach’s silicon heart is the world’s smallest micromotor with the longest autonomy.
After an initial patent, it took several more years to mature the technology and make it technically operational as well as economically viable. Meanwhile, the development in the United States of application-specific integrated circuits, around a square millimetre in size, accelerated research by enabling SilMach to miniaturise its future micromotor’s commands.
“We’re doing something quite specific by combining silicon components such as actuators and micro-toothed gears with traditional watch parts,” notes Pierre-François Louvigné. The watch industry was SilMach’s target market from the very beginning, although there are multiple potential applications in fields such as healthcare, medtech, implants and micro-machines. The final stage in the project was to develop specific assembly techniques. “We identified the machines that we could adapt to this mix of silicon and micromechanics, and succeeded in onboarding one of the leaders in the manipulation of silicon chips for microelectronics.”
- This revolutionary micromotor is designed to replace the Lavet step motor that has equipped analogue electronic watches since the 1960s.
The end of an era?
SilMach’s micromotor is designed to replace only the Lavet motor in an electronic watch movement: time division is still by a quartz oscillator. “Today’s quartz watches and smartwatches are assembled entirely from microelectronics, except for the Lavet motor,” Pierre-François Louvigné continues. “It was the one incoherency.” Using a B2B model, the company supplies the micromotor and can also offer consultancy services on industrialisation, assembly line and technology transfer. It also plans to produce its own ready-to-use movement.
SilMach operates a micromotor assembly plant in Besançon, which is also a showcase for future projects. Following on from a single-hand motor, production has started on two-hand motors. “Like any new technology, there are barriers to adopting our micromotor in place of something as familiar and established as the Lavet motor. We need to make a strong case for our technology and even then, there will always be obstacles. Customers need guarantees, which is why we are bringing out our own watch.”
- This new motor drives the watch’s hands clockwise and anticlockwise, enabling a retrograde motion of both hands with smooth accelerations and decelerations.
The watch in question - The TimeChanger - is the first in the world to be powered by a silicon heart. A showcase for the technology, it was funded by a Kickstarter campaign that ran from October 11th to November 11th. For each mode and function, the possibility to accelerate the movement’s frequency creates the illusion of perpetually moving hands.
- Twenty years after it was set up, SilMach is launching The TimeChanger: the first concept watch powered by a silicon heart, developed and assembled in Besançon, the capital of the French watch industry.
At the press of the pushers, TheTimeChanger offers a “secret entrance” to advanced operating modes: a synchronized double balance wheel animation of the hands, a manual calibration mode for the hands plus a time-jump mode, where hours become minutes and minutes become seconds (lots of fun to be had there!).
The silicon microrotor advances in 30-micron steps every 10 milliseconds, creating the impression of completely fluid movement of the hands that appears almost continuous to the naked eye (up to 100 Hz). TheTimeChanger is accurate to +/-0.5 seconds a day. Its autonomy – more than ten years – is exceptional for a standard battery watch.
Timex as a key partner
“We hope this watch will answer any questions our potential customers may have and, most of all, that it will convince them to adopt this technology, in view of its advantages and multiple possibilities,” says Pierre-François Louvigné. SilMach is making the watch, priced at €1,850, with its strategic partner, Timex Group, whose Milan-based creative director, Giorgio Galli, is behind the design. “We need a major industrial partner if we are to make a global impact. The fact that [Timex’s] micromechanics hub is next door to us, in Besançon, is an additional advantage.” Also in Besançon, TiMach (a Timex/SilMach joint venture) will market the micromotors worldwide. French smartwatch brand Withings is one of the first potential customers, as is Fossil, for whom developments in this segment are of particular interest.
French smartwatch brand Withings is one of the first potential customers, as is Fossil, for whom developments in this segment are of particular interest.
“Our micromotors are especially well adapted to smartwatches because they can be personalised and because they can be mounted anywhere on a circuit board, which opens up a whole range of design possibilities,” says Pierre-François Louvigné. “On top of their compact size, magnetic resistance and low energy consumption, this flexibility is a huge competitive advantage over Asian-made calibres which are cheaper but highly standardised with limited configurations.”
On the subject of price: how much will a “silicon heart” micromotor cost? “In the long term, probably no more than a few dollars, because that’s how the market works. MEMS [micro-electromechanical systems] are extremely volume-dependent, which is why we need to focus on automated production. But to begin with, we’re counting on customers who believe in this technology.”
Currently, SilMach’s fifty-square-metre cleanroom is equipped to produce up to 300,000 micromotors a year on its fully automated pilot line: a figure that could ultimately run to millions and even tens of millions, knowing that an estimated one billion electronic watches are made yearly. Will France become a leader in volume production? Watch this space.
*The step motor in quartz movements is another French innovation, invented in 1936 by Marius Lavet. It was industrialised for watch production much later, by Seiko, in the 1970s. Proof of the time required for a new technology to find applications and, importantly, become economically viable (remember that SilMach was set up 20 years ago).