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A capacitive tactile sensor comprising two capacitors was developed to enhance detection by more than doubling the spatial resolution. This arrangement reduced the number of required capacitors from four to two and reconfigured the capacitor shape from square to rectangular, resulting in a symmetric spatial resolution in the x- and y-directions. The theoretical evaluations, simulation predictions, device fabrication, and data analysis conducted in this study yielded identical results. In addition, angle detection errors resulting from fabrication and material uncertainties were comprehensively examined for the first time. The evaluations performed regarding the capacitor configuration further indicated that the sensitivity of shear force detection in this study was optimized with the requirement of a symmetric design. [ABSTRACT FROM AUTHOR]

The design, fabrication, and experimental test of an awl-shaped serpentine microspring (ASSM) for providing in-plane motion and low spring constant-to-layout area are investigated. The ASSM can provide low stiffness for in-plane motion under a restricted layout area. The spring constants of ASSMs for in-plane motion are theoretically analyzed by using Castigliano’s theorem, and validated through simulation using COMSOL Multiphysics. These ASSMs are successfully fabricated on a silicon-on-insulator wafer. The parameter K/A (spring constant-to-layout area) is used as the performance index. Smaller K/A induces larger deformation under the same layout area. It shows that K/A of ASSM is smaller than the classic one with the same dimensions (total length and number of turns). Geometric sizes having effect on K/A are discussed. The spring constants for in-plane and out-of-plane motion are compared and discussed. The taper angle and beam width-to-thickness ratio (w/h) are two key factors. As w/h being >1, the spring constant of in-plane motion (ky ) is always larger than that of out-of-plane motion (kz ). If w/h is <1, the spring constant kz would be larger than ky if the taper angle are larger than its critical angle ϕr. [ABSTRACT FROM AUTHOR]

With the rapid development and technical support by microelectromechanical systems, a lab-on-a-chip or micrototal analysis system has been widely developed for medical tests due to its low cost, simple, disposable, and less contamination. Comparing to the continuous microfluidics system, a digital microfluidics system has the advantages of being without micropump and easily driven using the alternative change of hydrophilic and hydrophobic properties. A feedback control system is proposed for driving digital microfluidics by using capacitive catenary as a sensor. In the proposed system, the moving droplet can be real-time positioned and controlled to overcome the imperfection of fabricated devices and the environmental disturbance. Furthermore, with the compensation of adjusting the amount of applied voltage online, the droplets can run smoothly toward the desired position in the chip through the feedback control. As a result, the proposed system is capable of moving droplets with higher speed, compared to most of the existing system, and improves the reliability of handling microfluidics. The chip for microfluidics operation has been successfully fabricated. With the self-designed circuit and LabVIEW interface, the experiments for operating microdroplets in an open channel are conducted to verify the performances of proposed devices. [ABSTRACT FROM AUTHOR]

We present the new mold fabrications for nanoimprint lithography for the application of ordered array of rod or pore patterning. The concave and convex types of the mold are achieved. For this technology, the master is required preparation before the mold fabrication. The master is utilized by step and repeated to achieve the structures over a large area on the mold. The master, mold, and imprint results demonstrate that the new approaches of mold fabrication could be a feasible scheme with low cost and high throughput. [ABSTRACT FROM AUTHOR]

In this paper, a high resolution Vernier-type displacement sensing mechanism is proposed by utilizing Vernier-type suspended gate field-effect transistors (SGFETs), The field-effect transistor benefits from its linear output signal and simple structure, and the concept of Vernier gate is used to enhance the resolution. The displacement of the comb-drive actuator is sensed via the output drain current of SGFET. Design and analysis for Vernier-type suspended gate were presented and some characteristics of the Vernier-type SGFETs were also discussed in simulation results. [ABSTRACT FROM AUTHOR]

The vertical comb electrodes capacitive sensor (VCECS) has been widely used in inertia sensors, resonant sensors, and pressure sensors, etc. In this paper, we present an improved microspring, called a W-form spring, that provides a large stiffness ratio in an out-of-plane direction while retaining a long sensing range for a VCECS. The stiffness ratio, defined as the ratio of the stiffness in the lateral direction to the out-of-plane direction, is an important parameter for determining the stability of the VCECS. To realize the properties of the W-form spring, such as the spring constant and stiffness ratio, theoretical analysis and numerical simulations are performed. In addition, VCECSs with W-form and other springs have been fabricated using microelectromechanical systems (MEMS) micromachining technology. The spring constants of the sensor have been calculated from simulations and measured results. The characteristics among different suspension springs are compared. According to the numerical simulations and experiment results, the working range and stability of the device are both improved for the VCECS by using the W-form suspension spring. [ABSTRACT FROM AUTHOR]

We report a novel prototype of a two-dimensional micromachined accelerometer based on thermocapillary heat transfer. The only moving element in this accelerometer is a thermal bubble generated by vaporizing the working liquid in the microchamber. The accelerometer consists of two key components, a heating resistor for creating symmetrical temperature profiles and two pairs of temperature detectors placed symmetrically and orthogonally to each other. The prototype devices demonstrate that a sensitivity of 1.5°C/g for an operating power of 60 mW can be realized. The frequency response of the accelerometer containing deionized water is 200 Hz, and the corresponding noise equivalent acceleration is ∼1 mg/Hz1/2. [ABSTRACT FROM AUTHOR]