1999CS

沈建宏 (ChienHong Sheng)

Investigation of A Thermally Actuated Valveless Micropump

熱動式無閥微泵的研究

In this paper, a micro pump is providing by the thermal membrane actuator and diffuser/nozzle elements are used as flow rectifying.

The structure of the membrane actuator is like a sandwich; the top and bottom layers are the bimorph structure and the middle one is the micro heater. The bimroph structure is including SiNx and aluminum layers. Micro heater here is used for local temperature regulation. According to the bimorph effect, the membrane will oscillate by varying temperature. The numerical finite element program ANSYS 5.3 is used to simulate the behavior of the membrane actuators. The size of the fabricated membrane actuator is 780 μｍ in square. The vibration stroke is 25μｍ when input power is 1 W.

Referring to the previous design, the diffuser/nozzle elements including rounded inlet and reentrant outlet. By means of this design on shapes of the flow channels, a larger volume flow can de predicted to reach in a pumping cycle. Here, we interest in fabricating thick chamber structure (i.e. 100μｍ) and a " LIGA-like " process is used to fabricate metallic chamber. Such method is an UV lithography-based LIGA process. This method combine thick film photoresist and micro electroplating to form a metallic chamber structure or act as a mode insert. Then a hot embossing system is applied for hot embossing of planar chamber structures in thermoplastic materials. The most thick metallic chamber structures is 300μｍ in thickness and the side wall of the diffuser/nozzle elements is quite sharp.

Finally, the membrane actuator and chamber structure are glued together to form the prototype of micro pump.