Subnanometer Translation of Microelectromechanical Systems Measured by Discrete Fourier Analysis of CCD Images

Abstract—In-plane linear displacements of microelectromechanical systems are measured with subnanometer accuracy by observing the periodic micropatterns with a charge-coupled device camera attached to an optical microscope. The translation of the microstructure is retrieved from the video by phase-shift computation using discrete Fourier transform analysis. This approach is validated through measurements on silicon devices featuring steep-sided periodic microstructures. The results are consistent with the electrical readout of a bulk micromachined capacitive sensor, demonstrating the suitability of this technique for both calibration and sensing. Using a vibration isolation table, a standard deviation of σ = 0.13 nm could be achieved, enabling a measurement resolution of 0.5 nm (4σ) and a subpixel resolution better than 1/100 pixel. [2010-0170

Learning from Crickets: Artificial Hair-Sensor Array Developments

We have successfully developed biomimetic flowsensitive hair-sensor arrays taking inspiration from mechanosensory hairs of crickets. Our current generation of sensors achieves sub mm/s threshold air-flow sensitivity for single hairs operating in a bandwidth of a few hundred Hz and is the result of a few iterations in which the natural system (i.e. crickets filiform hair based mechano-sensors) have shown ample guidance to optimization. Important clues with respect to mechanical design, aerodynamics, viscous coupling effects and canopy based signal processing have been used during the course of our research. It is only by consideration of all these effects that we now may start thinking of systems performing a “flow-camera” function as found in nature in a variety of species

Lifelike MEMS en wat krekels ons influisteren

Door de eeuwen heen heeft de mens zich laten inspireren door de natuur om hem heen. Bijvoorbeeld de eerste pogingen om te vliegen waren gebaseerd op het maken van vleugels zoals je die ziet bij vogels, maar dan gemaakt op de menselijke schaal. De figuren van Leonardo da Vinci met “aangebonden” vleugels zullen menigeen bekend zijn. In de lucht komen m.b.v. “flappende vleugels” bleek geen eenvoudige opgave, zelfs niet als deze verbonden waren aan een rotatie mechaniek gelijkend op de “trapinrichting” van een fiets, en is eigenlijk nooit een succes geworden. Het zou nog tot de tweede helft van de 20ste eeuw duren voordat individuele vluchten zonder hulpmiddelen een feit werden (en\ud daarbij gaat het eigenlijk nauwelijks om “actief vliegen”). Ondertussen hebben bijna twee eeuwen van snelle ontwikkelingen op zeer uiteenlopende gebieden (materiaalkunde, aerodynamica, meettechniek, elektronica, ruimtevaart [GPS], mechanisch ontwerpen, motor- en rakettechnologie, regeltechniek, logistiek, etc.) het idee van individueel vliegen gemarginaliseerd. De vogel is (uit beeld) gevlogen. Maar als inspiratie heeft zij haar invloed gehad

A new method for the calculation of propagation constants and field profiles of guided modes of nonlinear channel waveguides based on the effective index method

In this paper, an extension of the effective index method (EIM) to waveguiding structures containing ideal or saturable third-order nonlinear materials is presented. By applying separation of variables to the dominant field component, the complete problem is subdivided into two scalar problems in the lateral and transverse direction, as in the case of the normal EIM. Making use of the strong transverse confinement, as observed in most real waveguide structures, the nonlinear index changes of the various transverse sections can be lumped into nonlinear effective indexes of the equivalent layered planar structures. By using these nonlinear effective indexes in self-consistent field calculations in the transverse direction, a complete approximate solution is obtained. In this way, the amount of computational effort required for the calculation of the effective indexes and field profiles of the waveguides can be reduced significantl

Tunable sensor response by voltage-control in biomimetic hair flow sensors

We present an overview of improvements in detection limit and responsivity of our biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC-bias voltage to our capacitive flow sensors improves the responsively by up to 80% for flow signals at frequencies below the sensor’s resonance. Application of frequency matched AC-bias voltages allows for tunable filtering and selective gain up to 20 dB. Furthermore, the quality and fidelity of low frequency flow measurements can be improved using a non frequency-matched AC-bias voltage, resulting in a flow detection limit down to 5 mm/s at low (30 Hz) frequencies. The merits and applicability of the three methods are discussed

Simple measuring method for electro-optic coefficients in poled polymer waveguides

A simple measuring technique for the linear electro-optic coefficients in electro-optic waveguides is described. The method is based on the direct evaluation of synchronous angle measurements obtained by prism coupling. No waveguide or electrode patterning is required. A model has been developed in order to simulate the relation between change in synchronous angle and applied electric field across the electro-optic waveguide. The measured values of the electro-optic coefficients in poled polymer waveguides are reported

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