2012 年 6 巻 7 号 p. 1180-1189
A valveless micro pump, utilizing a multi-layer thin film NdFeB/Ta permanent magnet (TFPM), is presented. The micro pump consists of a diaphragm actuator, comprising a TFPM, 6µm in thickness and 3 mm in diameter, which is bonded to a membrane made of polydimethylsiloxane (PDMS) of about 80µm in thickness, together with a pump chamber and a pair of diffuser elements. TFPM is sputtered on a 50µm thick Nb sheet. The diffuser elements are used to generate a one-way fluid flow. The chamber is made of acryl plates. UV negative film resist is used to bond the different layers. Compared to sinusoidal driving signal with same amplitude, a square driving signal can generate a higher flow rate. Applying a square wave voltage, ±7.5V in amplitude, the pump flow rate attains 130µL/min at a frequency of 15Hz. The flow rate is highly dependent on frequency and driving signal type. Diaphragm displacement, pump frequency is measured and analyzed.
