Bonnie Tingting Chia

Development of a Flexible Temperature Sensor Array System

A flexible temperature sensor array and a scanning system are developed in this paper. A 16×16 temperature sensor array in a 25×20 mm2 area is fabricated on a flexible copper-PI substrate using MEMS fabrication technology. Platinum is employed as the temperature sensing material, which is often so called the resistance temperature detector (RTD). Copper patterns on both sides of the flexible substrate serve as the row and column interconnects for scanning circuitry. In each element of the temperature sensor array, the resistance of platinum, which is patterned by lift-off process, can be measured by the scanning system.

Development of a 2×2 optical switch using bi-stable solenoid-based actuators

This paper presents the development of a 2×2 optical switch which consists of a MEMS-based silicon micro-mirror structure and two bi-stable solenoid-based actuators. The silicon micro-mirror structure is realized by using a proposed simple single-step anisotropic silicon etching process. Bi-stable solenoid-based actuators are designed and developed. The proposed device, which adapts the split-cross bar (SCB) design as the optical-path configuration, has many advantages such as low power consumption, easy fiber alignment, simple manufacturing process, and simple actuation scheme. The measured insertion loss of the device is about −0.9 ∼ −1.1 dB. The long-term reliability test shows that the deviations of the insertion losses are less than 0.03 dB after 10,000 switching cycles. Also, the measured cross-talk is about −60 dB, and the measured switching time is less than 10 ms.

A novel thermo-pneumatic peristaltic micropump with low temperature elevation

In this work, the development of a novel thermo-pneumatic peristaltic micropump, which consists of two separate zones for air-heating and fluid-squeezing, is presented. The device is realized by using micromachining techniques, and operated with simple actuation sequences. With a 5V applied voltage and 40% heating duty ratio, maximum temperature elevation measured on the pumping diaphragm above the fluid-squeezing zone is 2.9K, while a maximum value of 68.8K is measured above the air-heating zone. Since significant reduction of temperature elevation on the working fluid is achieved, the device is suitable for the applications such as DNA chips or protein chips. Furthermore, applying higher voltage generates larger flow rate accompanied with relatively small increase of temperature elevation.

A DNA-extraction and polymerase-chain-reaction microchip using magnetic beads and thermo-pneumatic valves

In this work, we develop a miniaturized system for DNA extraction and polymerase chain reaction (PCR). DNA is extracted from whole blood sample by using silica coated magnetic beads. Electromagnetic actuation is employed to manipulate the magnetic beads for transporting DNA molecules in fluidic channels. Thermo-pneumatic valves with low temperature elevation are integrated into the microfluidic chip for isolating/releasing fluidic samples and reagents. The size of the system is 72mm×54mm×11mm. The device fully operates with a 12V DC voltage and automatically performs DNA extraction and amplification processes after samples and reagents are loaded.

A 2

In this paper, a 2 × 2 split cross-bar optical switch which employs a hybrid actuation configuration is presented. The main advantages of this proposed switch include low actuation voltage, low power consumption, and easy fiber alignment. This optical switch consists of a micromachined micro-mirror structure and a mini-actuator module. The micro-mirror structure, which comprises two movable vertical mirrors with cantilevers, two fixed vertical mirrors, and light-path trenches, is realized by using a simple KOH silicon etching process. The mini-actuator module, which includes two commercially-available electromagnetic bistable actuators attached with L-shaped arms, is used to actuate micro-mirrors. The measured insertion losses of the proposed switch is between -1- -1.2 dB, the cross-talk is about -60 dB, and the switching time is less than 13 ms. The long-term reliability test of the SCB switch is performed by continuously actuating the device for 10 000 cycles at 1 Hz, and the deviation of the measured insertion loss is less than 0.05 dB.

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This paper presents the design, fabrication and measurement results of a flexible temperature sensor array based on MEMS technology. The temperature sensor array is composed of 256 (16times16) sensors inside a 28times20 mm2 area. Using a polyimide (PI) thin film (35 mum) with a copper layer (40 mum) on one side as the starting material, a double-sided fabrication process is applied to create the sensing elements as well as the interconnects for scanning circuitry. As the resistance of platinum changes with temperature, the corresponding temperature can be obtained by measuring the resistance of each element in the temperature sensing array.

2 Split Cross-Bar Optical Switch Using a Hybrid Actuation Configuration

In this paper, the development of a portable polymerase chain reaction (PCR) device is presented. The fully integrated self-contained system consists of four major parts: a disposable chamber chip with micro-channels and pumping membranes, a heater chip with micro-heaters and temperature sensors, a linear array of electromagnetic actuators, and a control/sensing circuit. The system can be fully operated with a 5V DC voltage, and does not require any external air compressor or bulky power supply. The size of the whole system is 67 mm × 66 mm × 25 mm, and is smaller than a PDA cell-phone. The miniaturized PCR system not only has the advantage of smaller size, less consumption of DNA solution, but also can effectively reduce the PCR process time into one-third of the time required by typical commercial PCR system.