A magnetic, micro-spring-suspended system for the safe electrical interconnection of neural implants

This paper reports on the development and validation of a magnetically operated connector system based on spring-suspended contact pads. This novel electrical interface designed for neural implants addresses the problem of excessive forces possibly exerted when plugging and unplugging electrical connectors during experiments with freely behaving animals. The novel interface relies on magnets of different orientations which inherently guarantee the correct positioning of the connector parts without the need of alignment pins. Connector test structures with 32 channels, exhibiting a connection yield of up to 100 %, were successfully fabricated using MEMS technologies. Disconnection forces are reduced to values down to 100 mN and are thus considerably reduced compared to state-of-the-art devices. The improved connector performance helps increasing animal safety during in-vivo experiments. Analytical modeling and numerical simulation results regarding the response of the integrated spring-suspended contact pads are in good respectively reasonable agreement with experimental data. A lateral alignment accuracy better than 50 μm, achieved solely by the specific magnet implementation, is demonstrated.