Normally closed microgrippers using a highly stressed diamond-like carbon and Ni bimorph structure

A normally closed microgripper with a radius of curvature of 18-50 mum using a diamond-like carbon (DLC) and stress free electroplated Ni bimorph structure has been demonstrated. The large curvature in the fingers of the microgrippers is due to the high compressive stress of the DLC layer. The radius of curvature of the figures can be adjusted by the thickness ratio, and the closure of the devices can also be adjusted by varying the finger length. This device works much more efficiently than other bimorph structures due to the large difference in thermal expansion coefficients between the DLC and the Ni layers. Preliminary electrical tests have shown these microgrippers can be opened by 60degrees-90degrees at an applied power of <20 mW. (C) 2004 American Institute of Physics.