Office of Technology Transfer – University of Michigan

Compliant Displacement-Multiplying Apparatus for Microelectromechanical Systems

Technology #1770

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Researchers
Sridhar Kota
Managed By
Joohee Kim
Licensing Specialist, Physical Sciences & Engineering 734-764-8202
Patent Protection
US Patent Pending

Background

The limitation of many currently available actuators, and in particular smart material actuators, is their small stroke and power. In the formation of microelectromechanical (MEM) devices, a motive forcer or actuator is required. The previous used electrostatic comb actuators have generally consumed a large portion of the die on which the MEM device is formed. Further, the die size is constrained by available steppers used for the photolighographic processes. As a result, the size and complexity of MEM devices is presently constrained by the size of the actuator used. As such, there is a need in a MEM device for a mechanism that multiplies the range of displacement from a short-stroke actuator and provides an increased range of displacement that is sufficient for actuating a particular MEM device.

Technology

Researchers at the University of Michigan have developed a pivotless compliant structure for receiving an input displacement from a motor source and generating a multiplied displacement for provision to a load. This device can be used on a variety of scale sizes including MEM structures. The compliant structure, based on a combination of interconnected flexible beams and cross beams formed of one or more layers of polysilicon or silicon nitride, can provide a geometric advantage to stroke displacement provided by a short-stroke actuator. The compliant structure has less play than conventional displacement-multiplying devices based upon lever arms and pivoting joints, and is expected to be more reliable than such devices. An output displacement range can be greater than a multiplication factor of 5-60 than the first linear displacement range when that first range is 5 microns or less. An output displacement range can also be less than the first linear displacement range by about 1/5 to 1/60.

Applications and Advantages

Applications

  • MEMS actuators

Advantages

  • Energy efficient, easy to manufacture, long lasting, and highly reliable
  • Enables use of compact short-stroke electrostatic or thermal actuators to generate a suitable range of displacement in driving MEM devices