scholarly journals A large displacement, high frequency, underwater microelectromechanical systems actuator

2015 ◽  
Vol 117 (1) ◽  
pp. 014503 ◽  
Author(s):  
David J. Hoelzle ◽  
Clara K. Chan ◽  
Michael B. Scott ◽  
Melinda A. Lake ◽  
Amy C. Rowat
Keyword(s):  
High Frequency ◽  
Microelectromechanical Systems ◽  
Large Displacement

scholarly journals Publisher's Note: “A large displacement, high frequency, underwater microelectromechanical systems actuator” [J. Appl. Phys. 117, 014503 (2015)]

2015 ◽  
Vol 118 (21) ◽  
pp. 219902
Author(s):  
David J. Hoelzle ◽  
Clara K. Chan ◽  
Michael B. Scott ◽  
Melinda A. Lake ◽  
Amy C. Rowat
Keyword(s):  
High Frequency ◽  
Microelectromechanical Systems ◽  
Large Displacement

Optically addressed microelectromechanical systems driven with high-frequency modulated light

2007 ◽  
Vol 46 (8) ◽  
pp. 1194
Author(s):  
Jed Khoury ◽  
Charles L. Woods ◽  
Bahareh Haji-saeed ◽  
Sandip K. Sengupta ◽  
William D. Goodhue ◽  
...  
Keyword(s):  
High Frequency ◽  
Microelectromechanical Systems ◽  
Modulated Light

Metrics for Evaluation and Design of Large-Displacement Linear-Motion Compliant Mechanisms

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Allen B. Mackay ◽  
David G. Smith ◽  
Spencer P. Magleby ◽  
Brian D. Jensen ◽  
Larry L. Howell
Keyword(s):  
Performance Characteristic ◽  
Microelectromechanical Systems ◽  
Compliant Mechanisms ◽  
Large Displacement ◽  
Torsional Stiffness ◽  
Axial Stiffness ◽  
Linear Motion ◽  
Transverse Stiffness ◽  
Actuation Force ◽  
Performance Tradeoff

This work introduces metrics for large-displacement linear-motion compliant mechanisms (LLCMs) that evaluate the performance tradeoff between displacement and off-axis stiffness. These metrics are nondimensionalized, consisting of relevant characteristics used to describe displacement, off-axis stiffness, actuation force, and size. Displacement is normalized by the footprint of the device, transverse stiffness by a new performance characteristic called virtual axial stiffness, and torsional stiffness by the characteristic torque. These metrics account for the variation of both axial and off-axis stiffness over the range of displacement. The metrics are demonstrated for several microelectromechanical systems (MEMS) that are sensitive to size because of high cost and off-axis stiffness because of function. The use of metrics in design is demonstrated in the design of an LLCM; the resulting design shows increased values for both the travel and transverse-stiffness metrics.

Convective Heat Transfer Enhancement With Micro Pin-Fin Surfaces Cooled by a Piezoelectrically-Driven Translational Agitator

2012 ◽  
Author(s):  
Taiho Yeom ◽  
Terrence W. Simon ◽  
Tao Zhang ◽  
Mark T. North ◽  
Tianhong Cui
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Channel Flow ◽  
Convective Heat ◽  
High Frequency ◽  
Single Channel ◽  
Heated Surface ◽  
Large Displacement ◽  
Air Cooling ◽  
Pin Fin

Air cooling of electronic equipment continues to hold many advantages over liquid cooling in terms of simplicity, reliability, cost, etc. Many active and passive air cooling techniques have been developed to meet the thermal challenges of modern, high-power electronics. Active cooling includes such features as piezoelectric flapping fans and synthetic jets that could directly break down and thin the thermal boundary layers on heated surfaces. A microchannel bank of fins, micro pin-fin surfaces, etc. are passive methods for increasing heat transfer area. In the current study, both active and passive methods, piezoelectric translational agitators and micro pin fin arrays, are employed to dramatically enhance convective heat transfer rates. A piezoelectric stack actuator coupled with an oval loop shell displacement amplifier was utilized to generate high-frequency and large-displacement translational agitation over the micro pin fin surface. Two different micro pin-fin surfaces were fabricated using copper and the LIGA process. Heat transfer experiments were performed in a single channel that houses a one-sided, heated surface with attached micro pin fins. The piezoelectric translational agitator oscillates at a high frequency of 596 Hz with a large displacement of up to 1.8 mm. The heat transfer coefficients on the micro pin-fin surface cooled by the agitator and various channel through-flows were compared with those of plain surfaces under the same channel flow rates. A maximum improvement of 222% in the heat transfer rate was achieved when the agitator was operated, the micro pin-fin surface was in place and the channel flow velocity was 11.6 m/sec, compared to that of a non-agitated plain surface case with the same flow rate.

Performance of MEMS Vibratory Gyroscope under Harsh Environments

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000633-000654 ◽  
Author(s):  
Chandradip Patel ◽  
Patrick McCluskey
Keyword(s):  
Temperature Effect ◽  
High Frequency ◽  
Microelectromechanical Systems ◽  
Rate Of Change ◽  
Harsh Environments ◽  
Harsh Environment ◽  
Thermal Cycles ◽  
Mems Gyroscope ◽  
Vibratory Gyroscope ◽  
Mems Gyroscopes

Microelectromechanical systems (MEMS) gyroscope is a sensor that measures the rate of change in an angular position of an object. MEMS vibratory gyroscopes are increasingly used in applications ranging from consumer electronics to aerospace and are now one of the most common MEMS products after accelerometers.With advances in fabrication technologies, the low-cost MEMS gyroscope has opened up a wide variety of applications with environmental conditions ranging from medium to harsh. Despite their widespread use, the performance of MEMS gyroscopes in harsh environments is still under question. While some studies have been conducted to understand the effects of high mechanical shock, high frequency vibration and high frequency acoustic environment on the MEMS gyroscopes,the effects of sustained exposure to temperature combined withother harsh environment stresseshave not been well researched.Thus, it is necessary to quantify MEMS vibratory gyroscope performance under such conditions.This research reviews current harsh environment studies anddemonstrates the effects of an elevated temperature and sustained exposure to temperature combined humidity on the MEMS vibratory gyroscope. In order to quantify such effects, several tests have been performed. A short-term temperature effect on MEMS gyroscope was examined through temperature characterization test forfive thermal cycles at wider temperature ranges. A long-term temperature effect on the MEMS gyroscope was inspected through 500 thermal cycles; while, combined effects of temperature and humidity was studied through temperature humidity bias(THB) test and highly accelerated stress test (HAST).

Fabrication of Low Stress PECVD-SiNx Film in High Frequency Mode

2013 ◽  
Vol 562-565 ◽  
pp. 22-27
Author(s):  
Zheng Guo Shang ◽  
Dong Ling Li ◽  
Zhi Yu Wen
Keyword(s):  
Residual Stress ◽  
High Frequency ◽  
Microelectromechanical Systems ◽  
Bulk Acoustic Wave ◽  
High Deposition Rate ◽  
Resonator Structure ◽  
Bulk Acoustic Wave Resonator ◽  
Wave Resonator ◽  
Film Bulk ◽  
Chamber Temperature

A new fabrication method to produce low residual stress PECVD SiNx layers at high frequency (13.56 MHz) was developed. High frequency up to 60W is employed in this new method to fabricate low stress SiNx. By adjusting the composition of reactant gases, process vacuum and the chamber temperature, the residual stress can be lower to-0.28 MPa, and high deposition rate up to 240 nm/min can be achieved. In addition, this paper investigated the influence of other important parameters on the results, such as pressure, power and gases flow rates. Moreover, by using the optimal process, the refractive index is ranged from 1.98 to 2.20, and the uniformity of run to run wafers is about ±3% for 4 inch wafers. Finally, a typical FBAR (film bulk acoustic wave resonator) structure using these low stress PECVD SiNx layers as solid layer and mask indicated that these layers are compatible in IC technology and suitable for using in fabricating MEMS(microelectromechanical systems) devices.

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