The transponder’s wiring and its transmitter antenna needed to be completely redesigned, combining technical inventiveness with a subtle and elegant integration within the overall design.
Developers had in fact to take account of a major technical constraint: a mechanical watch acts like a Faraday’s cage, protecting the movements from the influences of electrical fields that may adversely affect the rating precision. Therefore, in order to endow the timepiece with the proverbial reliability of Jaeger-LeCoultre movements and to enable the transponder to operate despite the neighbouring metal oscillating weight, an innovative antenna had to be created.
The solution lay in placing the antenna as far as possible from the watch mechanism and the case, and lengthy research resulted in using the sapphire crystal as a medium. Measuring exactly 128mm in length so as to guarantee an optimal range, the antenna is metallised on the inside of the sapphire crystal in a shape following the curve of the inner bezel ring and the hour-markers between 4 and 6 o'clock, and is connected at these strategic points to the two locking control contact rectangles (OPEN and CLOSE).
Contrary to the chronograph vertical-trigger mechanism based on pivoting the entire case and bezel, activating and deactivating the locking system does not involve any displacement of any part of the watch, occurring instead merely by making contact with the OPEN and CLOSE zones. This connection is facilitated by capacitive technology, which reacts to touches on a given surface.