Magnetic bistable micro relay

Magnetic bistable micro relay

Electrothermal polymeric bidirectional micro actuator

Intellectual Property and Innovation Management

Deniz Bayramoglu, +49 6151 16-57215

Robert Heitzmann, +49 6151 16-57228

Status quo

Despite their low cost, polymeric micro actuators are commercially not available. This is due to the fact that many questions such as their long-term stability have not yet been clearly answered.

Present technological solutions consist of a polymeric actuator which heats up unilaterally. This gradually leads to plastic deformation and causes power loss and breakdown.

Our technology: micro relay with a higher long-term stability

The micro relay consists of a magnetostatic bistable electrical contact system and two electrothermal polymeric actuators which lead to a considerable increase in its long-term stability due to its bilateral actuation. Commercially competing products have not been found on the market at the moment.


  • No plastic deformation through asymmetrical heating
  • Micro actuator is compensated by the surrounding temperature
  • Ceramic substrate houses the technology such that a passive glass or ceramic cover is not required.


  • Cheap and robust production
  • Very compact design (reduction factor > 2.5 compared to present-day design)
  • High long-term stability with more than two million switching cycles
  • Low resistance, high voltage and current control capacity and large transmission frequency range
  • Galvanic separation between control and load circuit
  • High dielectric strength in load and control circuit
  • Energy efficiency through magnetic bistability
  • Completely housed micro-relay matrix

Operating principle

The contact is maintained with the help of a static magnetic field in one of the two stable end stops. Through this, an electrical route between the signal input and the signal output (A or B) is produced.

A switch-over is then initiated with the help of two polymeric electrothermal micro drives which are coupled with the contact system by a hysteresis-bounded mechanical coupling.