Magnetic Polymer Based Micropumps for Microfluidic Sample Delivery System

In this paper we present the development of electromagnetic (EM) microfluidic pumps incorporating the magnetic polymer composite for the transport of microfluidic bio-sample. The pump system includes the electromagnetic field generator, a flexible actuator membrane made of polymer material with embedded magnetic particles and valve-less microfluidic channel and chamber. The micropump is fabricated using a MEMS process with additional bonding process. Various types of the magnetic membrane as well as electromagnetic coils were fabricated and characterized to find optimum pump performance. As the results, it is found that the fabricated pump systems were able to deliver fluidic sample within a large flow-rate range from 6 ml/min down to several nl/min which can be adjusted by setting the input electrical current parameters, such as intensity, frequency and type of the current signal.

Design and Fabrication of a Kirigami-Inspired Electrothermal MEMS Scanner with Large Displacement

Large-displacement microelectromechanical system (MEMS) scanners are in high demand for a wide variety of optical applications. Kirigami, a traditional Japanese art of paper cutting and folding, is a promising engineering method for creating out-of-plane structures. This paper explores the feasibility and potential of a kirigami-inspired electrothermal MEMS scanner, which achieves large vertical displacement by out-of-plane film actuation. The proposed scanner is composed of film materials suitable for electrothermal self-reconfigurable folding and unfolding, and microscale film cuttings are strategically placed to generate large displacement. The freestanding electrothermal kirigami film with a 2 mm diameter and high fill factor is completely fabricated by careful stress control in the MEMS process. A 200 μm vertical displacement with 131 mW and a 20 Hz responsive frequency is experimentally demonstrated as a unique function of electrothermal kirigami film. The proposed design, fabrication process, and experimental test validate the proposed scanner’s feasibility and potential for large-displacement scanning with a high fill factor.

Active Thermoelectric Vacuum Sensor Based on Frequency Modulation

This paper introduces a thermoelectric-type sensor with a built-in heater as an alternative approach to the measurement of vacuum pressure based on frequency modulation. The proposed sensor is fabricated using the TSMC (Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan) 0.35 μm complementary metal-oxide-semiconductor-microelectro-mechanical systems (CMOS–MEMS) process with thermocouples positioned central-symmetrically. The proposed frequency modulation technique involves locking the sensor output signal at a given frequency using a phase-lock-loop (PLL) amplifier to increase the signal-to-noise ratio (SNR) and thereby enhance the sensitivity of vacuum measurements. An improved first harmonic signal detection based on asymmetrical applied heating gives a precise measurement. Following calibration, the output voltage is in good agreement with the calibration values, resulting in an error of 0.25% under pressures between 0.1–10 Torr.