8 minutes

Innovative Escapements: From Silicon to Microsystems Technology

By Tim Breining

For quite a long time, silicon escapement components were reserved for concept watches with limited runs. Your average watch customer had no choice but to opt for more classically designed models. Over the past 20 years, however, silicon hairsprings have made their way into more and more affordable collections. Their introduction to the Tissot lineup made one thing abundantly clear: Silicon escapements have arrived on the mass market. 

It’s no coincidence that the Swatch Group now equips its entry-level brands with this supposedly exclusive technology. The patent for silicon hairsprings, which guaranteed a certain degree of exclusivity for the research group composed of the Swiss Center for Electronics and Microtechnology (CSEM), Rolex, Patek Philippe, and the Swatch Group, is 20 years old and soon to expire. 

Many competitors have been waiting in the wings, ready to pounce when the moment is right. It is pretty much a given that silicon components are set to become the new industry standard, not only because of their attractive properties, but also due to their efficient manufacturing processes.  

This begs the question, what’s the next big thing if silicon becomes standard? It would be presumptuous of me to make too strong an assertion at this stage, but I do believe whatever comes next will move away from the conventional escapement system we know today with its balance wheel, hairspring, pallet fork, and escape wheel. I think we will be seeing completely new escapements that draw on the vast possibilities offered by silicon and microsystems technology. Similar to when silicon was first introduced, the microsystems technology trend started in the high-end sector and has since broken the $5,000 barrier. So, let’s take a closer look at some of the dynamic developments in this area over the past few years. 


Flexure Mechanisms: The building blocks of the future? 

While the escapement revolution has yet to come, the concepts that could pave the way for it are not necessarily new. Depending on where you read, you’ll come across terms like “compliant mechanism” or “flexure.” The latter seems to be catching on a bit more in the literature and on the market, so we’ll stick with that for consistency purposes. 

Flexure refers to a single component that relies on material geometry and flexibility to transfer force or generate a defined degree of movement. In a sense, the material’s elasticity alone achieves what formerly required the assembly of a series of springs, guides, and bearings. While this may sound quite complicated on paper, it is easily explained with a few practical examples. A classic example is the nail clipper, which is usually made up of punched metal parts that perform the clipping movement due to the material’s flexibility as opposed to a separate spring or axis. Another example are food bag clips (those without springs, of course): They close tightly and open flat due to the material elasticity of the extremely thin connecting piece between the two halves. 

But why are these components suddenly interesting for the watch world when they’ve been used for ages in everyday life? In short, due to manufacturing processes made possible by microsystems technology, which enable the production of large quantities of components with near perfect geometry in a single step on the computer. Given the unique demands of precision watchmaking, conventional mass production of tiny components with hinges measuring just a few thousandths of a millimeter would not feasible. In any case, such delicate structures wouldn’t survive standard manufacturing processes like turning and milling.  

However, the first affordable, series-produced watches have proven that these new concepts not only minimize the overall number of parts required, but also reduce finishing and adjustment efforts. Moreover, the chronometric performance and power reserves of these timepieces have the potential to outdo conventional timepieces that rely on the classic configuration of hairspring, pallet fork, and escape wheel, including those that use silicon components.   

The Forgotten Pioneer: Parmigiani Fleurier 

CSEM is anything but an amateur when it comes to silicon and microsystems technology. The institute doesn’t just partner with large research groups, but also previously paired up with the small, refined brand Parmigiani Fleurier. In 2016, they introduced the Genequand escapement, aptly named after its inventor Pierre Genequand. 

This escapement combines two well-established concepts into a single, groundbreaking design. The first is the grasshopper escapement, a friction-optimized concept designed by legendary watchmaker John Harrison. The second is the flexure mechanism, to which we have already gotten a brief introduction. 

Genequand took Harrison’s grasshopper escapement and replaced the friction-bearing axis with wafer-thin leaf springs integrated into a single oscillating mass. The “pallet fork” is also integrated into the mass and likewise relies on flexible leaf springs instead of bearings subject to friction. In theory, the only friction remaining is the internal material friction and the air resistance acting against the oscillating mass between transmissions. 

The inherently low-friction transmission, which was the driving force behind the design of the grasshopper escapement, has been further optimized by the use of silicon components. At SIHH 2016, Parmigiani unveiled the concept watch dubbed “Senfine,” which boasted an unbelievable power reserve of 70 days and a frequency of 16 Hz. 

While SIHH is now a relic of the past, it still lives on as Watches & Wonders. The whereabouts of Mr. Genequand and Parmigiani’s mind-blowing escapement, on the other hand, remain unknown. There are some anecdotal whispers about the challenges of industrial-scale production and miniaturization, but I have yet to hear a definitive explanation. 

Even if the Senfine concept wasn’t feasible economically or in terms of production technology at the time, the step was nothing less than revolutionary. The best evidence of this, of course, is the range of increasingly affordable, comparable concepts from competitors that are slowly but surely finding their way on to the market.  

Zenith Defy Lab: Small Series Innovation 

2017 proved to be an extremely important year for Zenith. That was the year they presented their new Defy collection. The press mainly focused on the Defy 21, which could easily be considered the collection’s signature piece with its two escapements and 50 Hz frequency. The Defy 21 models were flanked by watches featuring the classic El Primero caliber as well as the Defy Lab. 

Zenith Defy El Primero 21
Zenith Defy El Primero 21

Alongside the permanent collection, a groundbreaking development from Guy Sémon’s R&D department was also unveiled. This is the same team that has been behind a number of technical marvels within LVMH’s watch division. 

The Defy Lab shares the same aesthetic as the rest of the Defy collection. In fact, from a few meters away, you could easily mistake it for the skeletonized version of the Defy 21. However, a completely unique caliber is beating inside its ultralight Aeronith case (a composite foam material comprised of aluminum and plastic). 

A closer look at the Defy Lab’s movement reveals a highly complex oscillating mass with extremely thin elements, giving it away as a flexure mechanism. Here, the similarity to a classic escapement ends with the escape wheel. Approximately 30 components have been replaced by the single “Zenith Oscillator.” The watch runs at an impressive frequency of 15 Hz and boasts a power reserve of 60 hours. Even more impressive is the Defy Lab’s chronometric performance: According to Zenith, the watch deviates by just 0.3 seconds per day.  

But LVMH didn’t manage all this on their own. The oscillator was made in tandem with the company Flexous, a spin-off from the Delft University of Technology. As its name suggests, the firm specializes in flexure research. If you browse the Flexous homepage, you’ll quickly come across some of the advantages of using these mechanisms in watches: longer running times, fewer components, thinner movements, and the elimination of lubricants. 

The technology from the Defy Lab was finally made available to the public in 2019 as part of the Defy Inventor. These models are still available at some authorized dealers, and at the time of writing, there was even one listed on Chrono24. The model has been more or less abandoned on Zenith’s website, however, and much more focus has been placed on other Defy and El Primero models in the years since.  

Zenith Defy Inventor, released in 2019
Zenith Defy Inventor, released in 2019

It’s hard to judge as an outsider whether the lack of attention is due to the effort involved, whether it’s proven to be uneconomical, or if there is simply not enough interest. It wouldn’t be the first time that an ingenious creation from Guy Sémon’s team has been packed away in a drawer. I’m thinking of the carbon-nanotube balance spring, which was positioned to offer real innovation in the mid-range Autavia Isograph. Unfortunately, it was very short-lived. After a major product recall, references to the carbon balance spring disappeared and the movement was replaced by another featuring a conventional hairspring. It was reported that the production of the balance spring was simply proving too difficult for such a popular model. 

This brief digression perfectly illustrates the tension brands face with this type of innovation. No one can say whether the ambitious technologies powering the Defy Lab and Inventor will have a future at Zenith or elsewhere in LVMH.   

Frederique Constant Slimline Monolithic: A breakthrough in series production? 

Frederique Constant is the brand behind what can probably be described as the best contender for a watch with a groundbreaking escapement concept that has reached the mass market. The Slimline Monolithic was also developed in partnership with Flexous, the same company responsible for the Zenith Oscillator, which explains why the escapement concepts are quite similar. 

The Frederique Constant Slimline Monolithic
The Frederique Constant Slimline Monolithic

That being said, unlike the Zenith Defy Lab, the oscillator in the Slimline Monolithic doesn’t take up the watch’s full case diameter. It is, however, all the more striking thanks to a well-placed cutout on the otherwise conservatively designed dial. As expected, the compact oscillator runs much faster than either the Zenith or Parmigiani versions at 40 Hz.  

If you implemented such an outrageous frequency in a classic watch, the power reserve would be reduced to hours or even minutes. But that is far from the case with the Slimline Monolithic: It has a power reserve of 80 hours, which even outperforms the Zenith. Fine adjustment is made possible via two masses.  

This is a far cry from the months-long power reserve that Parmigiani once promised. The chronometric performance is also pretty mediocre at -4/+6 seconds per day. But nevertheless, there is no doubt that this technology has potential. There are a number of hurdles that stand between concepts for limited production models and mass production, which is why the achievements of Frederique Constant and Flexous deserve all the more recognition. 

The models in this collection are officially limited, but with production numbers hitting the three-digit range, it definitely counts as series production. Frederique Constant hasn’t yet said whether this watch will enter their permanent collection or not. They are likely waiting to see what the response is to the first limited releases. 

Unfortunately, I don’t have a crystal ball, but if you look at how harshly silicon in watchmaking was initially critiqued and then consider how ubiquitous it is today, I’d wager a guess that flexure escapements have a bright future ahead of them. Classic anchor escapements aren’t going anywhere anytime soon, but the innovative niche will only grow from here. The only question that remains is, who dares to take the next leap? 

What do you think about this article?

About the Author

Tim Breining

My interest in watches first emerged in 2014 while I was studying engineering in Karlsruhe, Germany. My initial curiosity quickly evolved into a full-blown passion. Since …

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