The Rise of Silicon

Exploration into the use of silicon in watchmaking began in the Swiss watch industry sometime in the late ’90s, with the most significant efforts being undertaken by the Centre Suisse d’Electronique et de Microtechnique (CSEM). The research done at this institute was underwritten by a consortium that included Rolex, Patek Philippe and the Swatch Group — companies that had seen the potential of silicon to solve some of the problems that watch movements had not been able to address for centuries.

The advantages of silicon were already well-known. First, it was extremely light — a third of the mass of steel — which means that the amount of energy required to move a silicon component is much less, thus allowing a movement to run longer. Secondly, it is harder than steel and extremely smooth, allowing interacting components that could function without the need for lubrication and with insignificant surface wear over the lifetime of the component. Thirdly, it could be fashioned very precisely through a process known as Deep Reactive Ion Etching (DRIE), allowing components to be made with absolute precision, with no need for further intervention after they had been made. Fourthly, due to it being highly elastic in micro-dimensions but not durably deformable, it was also extremely shock resistant and could always rebound back to its original shape. Lastly and perhaps significantly as well, it was also anti-magnetic, negating the effects of an old and common enemy of watch movements for a long time.

In fact, the only downside to silicon was how it could be affected by extreme temperature variation. To this end, the efforts of the research focused on a solution to the problem, with the result being the creation of a proprietary silicon dioxide known as Silinvar (coming from the terms ‘Silicon’ and ‘Invariability’). Obtained through the oxidation of silicon components in a vacuum, the result is the molecular modification of the surface of the pure silicon, creating a material that is virtually unaffected by temperatures ranging from −10°C to +60°C.

The Advanced Research Project

Having realized the vast potential of what had been learnt, Patek Philippe started its Advanced Research project with the aim of bringing technically useful advances that would improve long term dependability and timekeeping precision.

The first four watches that were to come over the years from 2005 showed Patek Philippe bringing in more silicon components into the regulation mechanism with each new generation. The first, in 2005, was the 100-piece limited edition Patek Philippe Annual Calendar “Advanced Research” (ref. 5250), which came with an escape wheel made of Silinvar. The use of this silicon component was a momentous first step for Patek Philippe — immediately, dramatic improvements to the regulation system could be realized. But the journey was only beginning.

The second watch, in 2006, was the 300-piece limited edition Patek Philippe Annual Calendar “Advanced Research” (ref. 5350), which added the Spiromax balance wheel made of Silinvar to the assortment, thus bringing additional benefits through a new shape that differed from the conventional Breguet overcoil. With its new geometry and its thicker boss at the outer end, it was not only able to mathematically match the isochronistic performance of the Breguet overcoil, but it also came with a flatter profile, saving space within the movement. Notable for these unique characteristics, it has thus far been the only innovation deployed to other Patek Philippe calibers outside the Advanced Research project, such as the calibers 240, 215, 28-520 and 324.

The third watch from 2008 was the 300-piece limited edition Patek Philippe Annual Calendar “Advanced Research” (ref. 5450), which added a silicon lever to the mix and, together with a silicon balance spring and silicon escape wheel, came to be known as the Pulsomax escapement. In this watch, which had basically all the regulation components — except the balance wheel — made of silicon, the energy transmission gain improved by 15 percent, making it possible to have longer service intervals.

Finally, in 2011, the last piece of an all-silicon regulation system would appear, but this time, the watch it was fitted in, perhaps to reflect the pinnacle of the achievement, was a perpetual calendar instead of an annual calendar as before. The 300-piece limited edition Patek Philippe Perpetual Calendar “Advanced Research” (ref. 5550) not only came with all the innovations seen previously, but also added something drastically new. The original Gyromax balance, first invented and patented by Patek Philippe in 1951, had, in its main innovative idea, the ability to be easily rate-adjustable via weights on the periphery of the balance. With the 2011 version of the “Advanced Research” watch, Patek Philippe had taken the basic premise behind this idea and brought forth a new upgraded version of it into the GyromaxSi balance. In silicon and with a brand new shape, all the precision adjustment advantages of the original had been preserved.

When comparing the original Gyromax with the GyromaxSi, you can’t miss out the radical departures to the original design. Instead of being circular as one would expect of a typical balance wheel, the new version came shaped like a butterfly, with four asymmetric poising weights (masselots) and pure gold infills acting as the effective mass. Thanks to its radical shape and with a smaller rotational footprint, the aerodynamics of the GyromaxSi balance were able to allow a 15 percent gain in efficiency. Added to the Pulsomax escapement and in conjunction with the Spiromax balance, this new totally silicon regulation system became collectively known as the Oscillomax ensemble.

The next chapter to be added to the Advanced Research epic brought the world the Ref. 5650 Aquanaut Travel Time Patek Philippe “Advanced Research” in white gold, in a limited edition of 500 watches. With it Patek Philippe introduced two new innovations. The first came with an optimized and updated Spiromax® balance spring that boasted improved isochronism of the balance in the vertical positions, thanks to an inner boss (thicker part at the inner end). This progress accounted for several patents, allowing an accuracy rate of -1 to +2 seconds per day in comparison with a Patek Philippe Tourbillon watch. Since then, the optimized Spiromax® balance spring has been integrated in most Patek Philippe movements, especially in calibers 240, 215, 28-520 and 324.

The second innovation focuses on the Travel Time complication’s timezone corrector mechanism, which they had now managed to execute a integrated monobloc piece forged completely out of steel. The classical method of advancing indications — such as a timezone display, or a calendar, or a moonphase, or seriously just whatever — usually involves lots of blade springs, chunky levers, articulated slot joints, advancing wheels or levers, pawl-and ratchet mechanisms (unidirectional) or star-wheel-and-sautoir mechanisms (bidirectional).

Patek Philippe’s Advanced Research came up with a beautiful steel frame, with crisscrossing steel filaments flaring out into high-mass extremities, that condenses a bunch of components into a single efficient beast that is simultaneously robust and elastic. It has reduced a set of 37 parts to a system of 12. Fewer components mean less friction, less oil floating around the movement and less space needed.

Advanced Research Takes on the Minute Repeater

Today, Patek Philippe is announcing the sixth chapter of the Advanced Research program, which at long last has taken on the highest echelons of the maison’s watchmaking: minute repeaters. The Ref. 5750 Patek Philippe “Advanced Research” Minute Repeater boasts a superb 40mm platinum case, inspired by the Ref. 5178 minute repeater with cathedral gongs and, according to Patek Philippe, is able to “amplify the volume of the time strike in a purely mechanical manner while preserving the excellent acoustic quality.”

The Advanced Research department considered several approaches and eventually agreed that they would start with the mini-rotor Caliber R 27, the movement with which Patek Philippe ushered the comeback of the minute repeater in 1989, and add to it a module that would answer the brief at hand. All this while preserving the original design of the Caliber R 27.

The idea behind the module was that it would serve as a mechanical loudspeaker. But where the typical loudspeaker amplifies by means of a flexible membrane, Advanced Research’s new solution is based on a 0.2mm oscillating wafer made of synthetic sapphire that while rigid and free moving is able to provide optimised sound propagation within the confines of a wristwatch, thanks to angular motion. It is a solution for which Patek Philippe has registered three new patents. Okay, but how’s it all work?

The Fortissimo “ff” Amplifier Module

In order to understand how the module that the Advanced Research department has devised over the Caliber R 27, we must first learn it’s components. We start with a steel sound lever that is attached to the middle of the oscillating wafer on one end and the other end, resembling a tuning fork, is a flexible 0.08mm thick that is used to secure the sound level to the gong assembly.

Therefore, when the hammers strike the gongs, sound is directed to the sound lever which in a first phase is meant to amplify the audio as it channels it to the oscillating wafer where it is further amplified. It is the earlier mentioned angular motion that is allowed of the oscillating wafer that enables it to excite the layers of air above and beneath the sapphire glass, thus, resulting in a discernibly louder sound.

The Platinum Challenge

Point in the list of three innovations presented within the 5750 requires us to understand that when a classic minute repeater movement chimes out, its oscillations reverberate and propagate through all sides of the case that contains it. Meaning to say that the loudness of a minute repeater is significantly reliant on how well the case material is able propagate the sound from the movement to outside of the case. In this regard, titanium is understood to be one of the best and rose gold thereafter when considering traditional precious materials, with platinum being the worst, with its higher material density.

Patek Philippe has circumnavigated the challenge posed by platinum by implementing “an insulation rim made of a high-tech composite material” that uncouples the Fortissimo “ff” module from the rest of the movement. The audio generated by the chiming mechanism, once routed through the sound lever and then to the oscillating wafer, is thereafter allowed to ring out from the case through four narrow openings in a titanium ring, at 12, 3, 6, and 9 o’clock, placed between the caseback and the caseband. Effectively, the Advanced Research’s development has negated the need to consider case material when concerned with the loudness of a chiming timepiece.

The last of the patents has to go with the hammers of the minute repeater hammers, which on the 5750’s movement are forged in platinum and is said to improve, “the quality of the strike in line with the directives of the Patek Philippe Seal and produces a softer strike as well without reducing its sonority.”

There is yet another patent of Patek Philippe’s contained within the 5750 that has to do with the R 27. Which that the gongs on the movement are helical in shape and attached at the same plane on the point of assembly which ensures the balanced amplification of both the hour and minute strikes.

Chiming in the New Year

The seemingly physics defying Ref. 5750 Patek Philippe “Advanced Research” Minute Repeater’s 40mm case, while similar in design and diameter to that of the Ref. 5178 minute repeater with cathedral gongs, is thicker by 0.57mm, measuring at a height of 11.1mm. Its dial consists a five-part construction that starts with white gold, black nickel-plated snailed base with spiraling lines. On top of this is an openworked motif inspired by the spoked wheels of vintage automobiles. A similar rotating disc is used for the small seconds counter, which has a point on its outer edge serving as the seconds hand.

Turning the watch over we’re not only treated to this new generation of the R 27 movement, but as well the Fortissimo “ff” module. Point to note is that while the original R 27 has a white gold mini-rotor, the 5750’s variation has been given a platinum one for a thinner mini-rotor with the same material density. This way, the thickness of the fortissimo module can at least be partially offset into the movement’s thickness, rather than adding to it.

Late in 2020, when Patek Phillipe launched the Ref. 6301P Grande Sonnerie, Revolution and The Rake’s founder, Wei Koh wrote in his concluding lines saying, I love that Patek [Philippe] made the case [of the 6301] in platinum because this is the hardest material to craft a great-sounding striking watch in. Because of platinum’s density, it is notorious for being a poor amplifier of sound. Journe overcame this by making his 700,000-euro 42mm Sonnerie, in steel, but to me, that has always seemed to be a bit of a copout. But this is not the path Patek [Philippe] decided to take. Instead, they decided to demonstrate that not only could they make the world’s best-sounding Grande Sonnerie, but that they could design it to be a masterpiece of stealth elegance and craft the case from the most challenging material possible — and still have it set a benchmark in terms of tonal quality that exceeds all others. I just love the sheer badassness of this statement from Patek Philippe to the rest of the watch world.”

It’s late in 2021 now, and seems like someone held that beer a year too long. Because a year on from the launch of the Ref. 6301P Grande Sonnerie Patek Philippe has manged to negate how case material density affects the sonic qualities of their highest creations.

Technical Specifications

Ref: 5750P-001 Patek Philippe “Advanced Research” Minute Repeater
Movement: Self-winding Caliber R 27 PS with off-center laser-textured platinum minirotor; minute repeater with classic gongs and platinum hammers; 43-hour to 48-hour max. power reserve
Functions: Hours, minutes and small seconds; minute repeater
Case: 40mm diameter; 11.1mm height; platinum; humidity- and dust-protected only (not water-resistant)
Dial: White gold, snailed black nickel-plated base, openworked spoke-type decor, hand-guilloched edging, circular satin- brushed chapter ring, applied blackened white gold “kite-type” hour markers; 18K gold dial plate; white gold dauphine hands topped with black transfer-print
Strap: Alligator leather with square scales, hand-stitched, shiny orange; fold-over clasp
Price: CHF 590,000
Availability: Limited edition of 15 pieces
More information: patek.com