Microelectromechanical systems

Abstract— This paper presents an adaptive control scheme for suppressing jitter in laser beams. The variable-order adaptive controller is based on an adaptive lattice filter that implicitly identifies the disturbance statistics from real-time sensor data. The multi-channel adaptive ...

Scanned displays have potential for achieving high brightness and see-through configurations in many display applications. A MEMS- based solution based on these tradeoffs for SVGA level performance is presented, with test data illustrating optical, mechanical, and electrical performance. Comparison of this scanner against video requirements and other scanners previously reported are illustrated. The feasibility of MEMS-based scanners for Retinal Scanning Displays and other applications is discussed, with extension to higher video performance standards.

The development of a capacitive microphone with an integrated detection circuit is described. The condenser microphone is made by micromachining of polyimide on silicon. Therefore, the structure can be realized by postprocessing on substrates containing integrated circuits (IC's), independently of the IC process, integrated microphones with excellent performances have been realized on a CMOS substrate containing dc-dc voltage converters and preamplifiers. The measured sensitivity of the integrated condenser microphone was 10 mV/Pa, and the equivalent noise level (ENL) was 27 dB(A) re. 20 μPa for a power supply voltage of 1.9 V, which was measured with no bias voltage applied to the microphone. Furthermore, a back chamber of infinite volume was used in all reported measurements and simulations

A fiber Brag grating sensor interrogator has been developed which is capable of gathering vectors of information from individual fiber Bragg gratings by capturing the full optical spectrum 3 kHz. Using a field programmable gate array with high speed digital-to-analog converters and analog-to-digital components, plus a kilohertz rate MEMS optical filter, the optical spectrum can be scanned at rates in excess of 10 million nanometers per second, allowing sensor sampling rates of many kilohertz while maintaining the necessary resolution to understand sensor changes. The autonomous system design performs all necessary detection and processing of multiple sensors and allows spectral measurements to be exported as fast as Ethernet, USB, or RS232 devices can receive it through a memory mapped interface. The high speed - full spectrum - fiber Bragg grating sensor interrogator enables advanced interrogation of dynamic strain and temperature gradients along the length of a sensor, as well as the use of each sensor for multiple stimuli, such as in temperature compensation. Two examples are described, showing interrogation of rapid laser heating in an optical fiber, as well as complex strain effects in a beam that had an engineered defect.

Continuous-facesheet and segmented Boston Micromachines Corporations' (BMC) Micro-Electrical Mechanical Systems (MEMS) Deformable Mirrors (DM) have been tested for their response to high-power visible-wavelength laser light. The deformable mirrors, coated with either protected silver or bare aluminum, were subjected to a maximum of 2 Watt laser-light at a wavelength of 532 nanometers. The laser light was incident on a ~ 3.5×3.5 cm area for time periods from minutes to 7 continuous hours. Spot heating from the laser-light is measured to induce a local bulge in the surface of each DM. For the aluminum-coated continuous facesheet DM, the induced spot heating changes the surface figure by 16 nm rms. The silver-coated continuous-facesheet and segmented (spatial light modulator) DMs experience a 6 and 8 nm surface rms change in surface quality with the laser at 2 Watts. For spatial frequencies less than the actuator spacing (300 mm), the laser induced surface bulge is shown to be rem...

Feasibility of chemically synthesized MnO2 nanowire catalyst embedded silicon MEMS H2O2 monopropellant microthruster has been demonstrated. Due to exothermic reaction process, sustenance of thrust generation does not require any heating of propellant thus minimizing electrical power requirement. The thruster device integrates inlet nozzle, micro channel, MnO2 nanowire embedded reaction chamber, in-plane exit nozzle and a microheater in the silicon layer. Nozzle configuration and catalyst bed was designed using simple analytical equations to achieve complete decomposition of H2O2 and maximum thrust force by controlling the propellant flow. Simulation of hydrogen peroxide decomposition process was carried out to evaluate the thermo-chemical characteristics. The MnO2 nanowire has been obtained using a low cost synthesis process and characterized using FESEM, EDS, TEM and XRD studies. Thruster fabrication using micromachining process and its testing have been briefly described. The devi...

We demonstrate and discuss the performance of fully integrated and flexible micro thermoelectric generators (μTEGs). The devices are fabricated with a low-cost microfabrication process based on electrochemical deposition of a thermoelectric material into a polymer mold. Overall system optimization is demonstrated by means of NiCu and p- and n-type Bi2Te 3-based μTEGs. Influences of design, material, fabrication, and per- formance

The paper demonstrates the advanced simulation methodology based on differentiation of the discretized finite element (FE) equations to parametric simulation of micro-electro-mechanical-systems (MEMS). The idea of the approach is to compute not only the governing system matrices but also high order derivatives (HOD) with regard to design parameters by means of automatic differentiation (AD). As result, Taylor vectors of the model response can be expanded in the vicinity of the initial position with regard to dimensional and physical parameters. The objective of this presentation is to demonstrate the viability of HOD methods to parametric simulation of MEMS in the static, modal, frequency response domains on the basis of the structural analysis and macromodeling.

While micromachined accelerometers are widely available and used in various applications, some biomedical applications require extremely small dimensions (<mm) or mass (<mg) that cannot be fulfilled with commercially available accelerometers. In this work, we present a fully packaged piezoresistive accelerometer that has the smallest dimension (0.034mm3) ever published. We achieve miniaturization by using a film encapsulation technique with a thick