Design and optimization of silicon bridges in a tourbillon watch

Tourbillon was invented to cancel the gravity effect on the timekeeping accuracy of a mechanical watch. However, the complicated structure generates new errors. In the last decade, micro-electro-mechanical system (MEMS) technology appeared in Swiss watch industry and showed advantages in design flexibility and fabrication precision. In this paper, a new application, silicon bridges, is introduced in a tourbillon watch. A mathematical model of the forces and torques in the mechanism is developed in both horizontal and vertical positions. Using the model, the silicon bridges are designed and optimized based on a specific movement. The result shows that the properties of the mechanism improve due to the material and design. Prototypes were made by Deep Reactive Ion Etching (DRIE) method.