Analysis of microsprings for calculating the force produced by microactuators

We present models of two types of microsprings namely box-spring and zig-zag spring that can be used to measure the force generated by microactuators. The spring constant for both springs is calculated by FEM using ANSYS software. In these models, the effects of short beams that act as connectors in the spring structures are considered and analyzed by changing their width. Also, from the results, we find that the box spring appears more balanced than the zig-zag spring when the force is applied in the single central direction. A series of SDAs with box spring have been fabricated and forces ofthose SDAs have been calculated

MEMS VOA with polymeric thermal microactuators

A MEMS VOA with polymeric microactuators using microoptics is presented. Its insertion loss < 0.5 dB, dynamic range > 50 dB, power and time for 20 dB, < 40 mW and 40 ms resp

A fabrication process for electrostatic microactuators with integrated gear linkages

A surface micromachining process is presented which has been used to fabricate electrostatic microactuators. These microactuators are interconnected with each other and linked to other movable microstructures by integrated gear linkages. The gear linkages consist of rotational and linear gear structures, and the electrostatic microactuators include curved electrode actuators, comb-drive actuators, and axial-gap wobble motors. The micromechanical structures are constructed from polysilicon. Silicon dioxide was used as a sacrificial layer, and silicon nitride was used for electrical insulation. A cyclohexane freeze drying technique was used to prevent problems with stiction. The actuators, loaded with various mechanisms, were successfully driven by electrostatic actuation. The work is a first step toward mechanical power transmission in micromechanical system

Micromachined capacitive displacement sensor for long-range nano-positioning

Integrated long-range position sensing with high accuracy will be of paramount importance for high-potential applications in a.o. future probe-based datastorage and microscopy applications [1], provided that nm position accuracy can be obtained over a range of tens of micrometers or more. This work presents the design, fabrication and measurements for an integrated incremental capacitive long-range position sensor for nano-positioning of microactuators. For compactness, economical viability and optimal performance, the aim has been to fully integrate sensor and actuator through micromachining technology, without additional micro-assembly. Two related concepts are presented and evaluated through analysis, 2D-Finite-Element Simulations and experimental assessment. The sensors consist of two periodic geometries (period ≈ 8-16μm) on resp. a slider, movable in x-direction, and sense-structures, movable in y-direction, at both sides of the slider, Fig. 1. In ICMM the displacement of the slider is measured by measuring the periodic change in capacitance ΔCs(x) with a charge-amplifier and synchronous detection technique [2]. Using sense-actuators, the gap-distance between sense-structures and slider is made smaller than is possible with standard available photo-lithography (< 2 μm), thus increasing the capacitance and the S-N Ratio

Piezoresistor-Embedded Multifunctional Magnetic Microactuators for Implantable Self-Clearing Catheter

Indwelling catheters are used widely in medicine to treat various chronic medical conditions. However, chronic implantation of catheters often leads to a premature failure due to biofilm accumulation. Previously we reported on the development of a self-clearing catheter by integrating polymer-based microscale magnetic actuators. The microactuator provides an active anti-biofouling mechanism to disrupt and remove adsorbed biofilm on demand using an externally applied stimulus. During an in vivo evaluation of self-clearing catheter, we realized that it is important to periodically monitor the performance of implanted microactuators. Here we integrate gold-based piezoresistive strain-gauge on our magnetic microactuators to directly monitor the device deflection with good sensitivity (0.035%/Deg) and linear range (±30°). With the integrated strain-gauge, we demonstrate the multi-functional capabilities of our magnetic microactuators that enable device alignment, flow-rate measurement, and obstruction detection and removal towards the development of chronically implantable self-clearing smart catheter

High-Performance Shuffle Motor Fabricated by Vertical Trench Isolation Technology

Shuffle motors are electrostatic stepper micromotors that employ a built-in mechanical leverage to produce large output forces as well as high resolution displacements. These motors can generally move only over predefined paths that served as driving electrodes. Here, we present the design, modeling and experimental characterization of a novel shuffle motor that moves over an unpatterned, electrically grounded surface. By combining the novel design with an innovative micromachining method based on vertical trench isolation, we have greatly simplified the fabrication of the shuffle motors and significantly improved their overall performance characteristics and reliability. Depending on the propulsion voltage, our motor with external dimensions of 290 μm × 410 mm displays two distinct operational modes with adjustable step sizes varying respectively from 0.6 to 7 nm and from 49 to 62 nm. The prototype was driven up to a cycling frequency of 80 kHz, showing nearly linear dependence of its velocity with frequency and a maximum velocity of 3.6 mm/s. For driving voltages of 55 V, the device had a maximum travel range of ±70 μm and exhibited an output force of 1.7 mN, resulting in the highest force and power densities reported so far for an electrostatic micromotor. After five days of operation, it had traveled a cumulative distance of more than 1.5 km in 34 billion steps without noticeable deterioration in performance.\u

Electrostatic microactuators with integrated gear linkages for mechanical power transmission

In this paper a surface micromachining process is presented which has been used to fabricate electrostatic microactuators that are interconnected with each other and linked to other movable microstructures by integrated gear linkages. The gear linkages consist of rotational and linear gear structures and the electrostatic microactuators include curved electrode actuators, comb drive actuators and axial gap wobble motors. The micromechanical structures are constructed from polysilicon. Silicon dioxide has been used as a sacrificial layer and silicon nitride was used for electrical insulation. A cyclohexane freeze drying technique is used to prevent problems with stiction. The actuators, loaded with various mechanisms, have been driven successfully by electrostatic actuation. The work is a first step towards mechanical power transmission in micromechanical system

Fabrication of an active nanostencil with integrated microshutters

An active nanostencil, consisting of a thin (200 nm) silicon nitride membrane with attached polysilicon microactuators that can be used to dynamically open and/or close holes in the silicon nitride membrane, is presented. This nanostencil can be used as a shadow mask in an evaporation setup. Main features of the nanostencil are the absence of sacrificial oxide in the final product, strengthening of the membrane by a polysilicon hexagonal structure that is attached directly to the membrane and the use of low-doped regions in the polysilicon to separate the stator and rotor electrically