Metal-based Optical MEMS Scanning Devices Using Lead-Free Piezoelectric Sheets Prepared by Aerosol Deposition

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000246-000250
Author(s):  
Jae-Hyuk Park ◽  
Jun Akedo
Keyword(s):  
Resonant Frequency ◽  
Thick Film ◽  
Bulk Material ◽  
Ambient Air ◽  
Aerosol Deposition ◽  
Lead Free ◽  
Mems Devices ◽  
Optical Mems ◽  
Scanning Angle ◽  
Optical Scanning

We demonstrate metal-based lamb-wave resonant optical MEMS scanning devices actuated by aerosol deposition (AD) piezoelectric film and report their temperature properties and durability. Metal-based structure was introduced to reduce the production cost and to improve the optical scanning performance, simultaneously. The optical scanning devices with large mirror size as well as high scanning angle were fabricated. A high optical scanning angle (more than 60 °) and a high resonant frequency (more than 25 kHz) were achieved in ambient air without vacuum packaging. The resonant frequency and the scanning angle do not have any changes during life test of approximately 50,000 hours. In this report, BaTiO3 (BTO) thick film as a lead free piezoelectric material was prepared by AD process for a piezoelectric exaltation source of scanning devices. Piezoelectric d31 of BTO-AD film was approximately −138 pm/V. The performance of optical scanner driven by AD-BTO thick film was comparable with that of BTO bulk material and AD-PZT thick film. From these results, AD-BTO film might be used to practical applications on the MEMS devices.

scholarly journals SARS-CoV-2-Laden Respiratory Aerosol Deposition in the Lung Alveolar-Interstitial Region Is a Potential Risk Factor for Severe Disease: A Modeling Study

2021 ◽  
Vol 11 (5) ◽  
pp. 431
Author(s):  
Sabine Hofer ◽  
Norbert Hofstätter ◽  
Albert Duschl ◽  
Martin Himly
Keyword(s):  
Risk Factor ◽  
Particle Deposition ◽  
Early Stage ◽  
Severe Disease ◽  
Ambient Air ◽  
Aerosol Deposition ◽  
Pulmonary Involvement ◽  
Mild Disease ◽  
Disease Initiation

COVID-19, predominantly a mild disease, is associated with more severe clinical manifestation upon pulmonary involvement. Virion-laden aerosols and droplets target different anatomical sites for deposition. Compared to droplets, aerosols more readily advance into the peripheral lung. We performed in silico modeling to confirm the secondary pulmonary lobules as the primary site of disease initiation. By taking different anatomical aerosol origins into consideration and reflecting aerosols from exhalation maneuvers breathing and vocalization, the physicochemical properties of generated respiratory aerosol particles were defined upon conversion to droplet nuclei by evaporation at ambient air. To provide detailed, spatially-resolved information on particle deposition in the thoracic region of the lung, a top-down refinement approach was employed. Our study presents evidence for hot spots of aerosol deposition in lung generations beyond the terminal bronchiole, with a maximum in the secondary pulmonary lobules and a high preference to the lower lobes of both lungs. In vivo, initial chest CT anomalies, the ground glass opacities, resulting from partial alveolar filling and interstitial thickening in the secondary pulmonary lobules, are likewise localized in these lung generations, with the highest frequency in both lower lobes and in the early stage of disease. Hence, our results suggest a disease initiation right there upon inhalation of virion-laden respiratory aerosols, linking the aerosol transmission route to pathogenesis associated with higher disease burden and identifying aerosol transmission as a new independent risk factor for developing a pulmonary phase with a severe outcome.

scholarly journals Piezoelectric Thick Film Deposition via Powder/Granule Spray in Vacuum: A Review

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 59
Author(s):  
Deepak Rajaram Patil ◽  
Venkateswarlu Annapureddy ◽  
J. Kaarthik ◽  
Atul Thakre ◽  
Jun Akedo ◽  
...  
Keyword(s):  
Thick Film ◽  
Thick Films ◽  
Cost Effective ◽  
Aerosol Deposition ◽  
Ceramic Coatings ◽  
Film Deposition ◽  
Energy Harvesters ◽  
Ceramic Films ◽  
Dense Ceramic ◽  
Processing Techniques

Conventional thin-film processing techniques remain inadequate for obtaining superior dense ceramic thick films. The incompatibility of ceramic films prepared via other methods, such as screen printing, spin coating, and sputtering, is a major obstacle in the fabrication of thick film-based ceramic electronic components. The granule spray in vacuum (GSV) processes and aerosol deposition (AD) are important coating approaches for forming dense ceramic thick films featuring nanoscale crystallite structures at room temperature, which offer excellent material properties and facilitate cost-effective production. AD ceramic coatings require the acceleration of solid-state submicron ceramic particles via gas streams with a velocity of a few hundred meters per second, which are then wedged onto a substrate. This process is economical and particularly useful for the fabrication of piezoelectric thick film-based microactuators, energy harvesters, sensors, and optoelectronic devices. More recently, the GSV technique was improved to achieve more uniform and homogeneous film deposition after AD. This review article presents a detailed overview of the AD and GSV processes for piezoelectric thick films in terms of recent scientific and technological applications.

Large electrocaloric effect in lead-free Ba(ZrxTi1-x)O3 thick film ceramics

2018 ◽  
Vol 742 ◽  
pp. 165-171 ◽  
Author(s):  
Xiao-Dong Jian ◽  
Biao Lu ◽  
Dan-Dan Li ◽  
Ying-Bang Yao ◽  
Tao Tao ◽  
...  
Keyword(s):  
Thick Film ◽  
Lead Free ◽  
Electrocaloric Effect

A Microcontroller Approach to Measuring Transmissibility of MEMS Devices

2015 ◽  
Vol 2015 (DPC) ◽  
pp. 001564-001593
Author(s):  
Chong Li ◽  
Yixuan Wu ◽  
Haoyue Yang ◽  
Luke L. Jenkins ◽  
Robert N. Dean ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Quality Factor ◽  
Real Time ◽  
High Speed ◽  
Mechanical Quality Factor ◽  
Quantization Noise ◽  
Mems Devices ◽  
Input And Output ◽  
Mechanical Quality ◽  
Mems Device

The transmissibility reveals two very useful characteristics of a micro-electro-mechanical systems (MEMS) device, the resonant frequency and the mechanical quality factor. Real time knowledge on these two important factors can enhance application performance or avoid potential problems from environmental disturbances due to fabrication tolerances and the resulting operational differences in otherwise identical devices. Expensive laboratory equipment is typically used to measure the transmissibility. However, these test systems are not readily adaptable to field use. Therefore, it is important to be able to measure the transmissibility using a real time technique with a simplified test setup. This study proposes a technique that can compute the transmissibility in real time using a low cost microcontroller. This technique utilizes two laser vibrometers to detect the input and output motions of the proof mass in a MEMS device, which are fed to high speed 500 KHz analog to digital converters (ADC) in the microcontroller. A filtering step is performed to decrease noise. After the sampling and pre-filtering, a Fast Fourier Transform (FFT) is performed to convert the time-domain signals to frequency domain signals. The amplitude of the output signal at each frequency is divided by the amplitude of the corresponding input signal at each frequency to obtain the transmissibility. To overcome the difficulties resulting from measurement and quantization noise, a recursive calculating algorithm and a de-quantization filter are introduced. The recursive calculating process guarantees that the system updates the results continually, which results in a transmissibility plot covering the entire bandwidth. The de-quantization filter considers the validity of the data and performs the transmissibility division step accordingly. A cantilevered structure was chosen as the device-under-test to verify and evaluate this technique. The cantilevered device was attached to an electromechanical shaker system for vibratory stimulation. Two laser vibrometers were used to detect the input and output motion and this data was fed into a microcontroller. The microcontroller was STM32F407, which is 32-bit and 168 MHz controller. The tests demonstrated that this technique can measure the transmissibility and therefore the resonant frequency and mechanical quality factor accurately compared to a professional signal analyzer.

Evaluation of Glass Frits for Development of Lead-Free Thick Film Resistor

2010 ◽  
Vol 2010 (1) ◽  
pp. 000752-000759
Author(s):  
Xudong Chen ◽  
W. Kinzy Jones
Keyword(s):  
Electrical Properties ◽  
Temperature Coefficient ◽  
Thick Film ◽  
Glass Frit ◽  
Lead Free ◽  
Temperature Coefficient Of Resistance ◽  
Film Resistor ◽  
Thick Film Resistor ◽  
Glass Compositions ◽  
Free Glass

Glass frit is a major component of thick film resistor (TFR) for the production of hybrid circuits. More than thirty commercial lead-free glass frits with different compositions have been evaluated for developing a lead-free thick film resistor that is compatible with typical industry thick film processing and has comparable electrical properties as the lead bearing counterpart. Two glass compositions were selected out of 33 candidates for preparation of RuO2 based TFR inks, which were screen printed on alumina substrates and fired at 850°C. The preliminary results of these resistors showed that the sheet resistance spanned from 400 ohms per square (Ω/□) to 0.4 mega-ohms per square (MΩ/□) with 5–15% RuO2 and the hot temperature coefficient of resistance (HTCR) fell in a range of ±350ppm/°C.

Performance Assessment of a Low Temperature Polymer Conductor for Lead-Free Soldering Processes

2014 ◽  
Vol 2014 (1) ◽  
pp. 000251-000257
Author(s):  
Steven Grabey ◽  
Samson Shahbazi ◽  
Sarah Groman ◽  
Catherine Munoz
Keyword(s):  
Low Temperature ◽  
Thick Film ◽  
Elevated Temperatures ◽  
Printed Electronics ◽  
High Reliability ◽  
Sem Analysis ◽  
Lead Free ◽  
Sac305 Solder ◽  
Soldering Process ◽  
Lead Free Solders

An increased interest in low temperature polymer thick film products has become apparent due to the rise of the printed electronics market. The specifications for these products are becoming more demanding with expectations that the low temperature products should perform at a level that is typically reserved for their high temperature counterparts; including solderability with lead free solders, high reliability and strong adhesion. Traditionally, it has only been possible to use leaded solders for soldering to polymer based thick film conductors. Over the last 15 years environmental concerns and legislation have pushed the industry towards a lead free approach. The shift to lead free solders, while beneficial, provides new challenges during processing. The high temperatures required for a lead-free soldering process yield a naturally harsher environment for polymer thick film pastes. In the past these conditions have proven too harsh for the pastes to survive. The polymer thick film discussed in this document aims to address some of these concerns for a highly reliable and easy to process polymer thick film paste. Due to the poor leaching characteristics of polymer thick films, at elevated temperatures, the predecessors of this paste typically soldered at low temperatures with leaded solders. The goal of this paper is to present a low temperature paste that is compatible with a variety of substrates and readily accepts lead-free solder. This paper will discuss a newly formulated low temperature curing (150°C – 200°C) RoHS and REACH compliant paste that shows excellent solderability with SAC305 solder. The paste was evaluated using a dip soldering method at 235°C–250°C on a variety of substrates. The data presented includes solder acceptance, adhesion data, thermal analysis and SEM analysis.

scholarly journals Fabrication of Mems Devices by Powder-Filling into DXRL-Formed Molds

1998 ◽  
Vol 546 ◽  
Author(s):  
Terry J. Garino ◽  
Todd Christenson ◽  
Eugene Venturini
Keyword(s):  
High Temperature ◽  
Bulk Material ◽  
The Other ◽  
Ceramic Mold ◽  
Magnetic Powder ◽  
Mems Devices ◽  
X Ray ◽  
Energy Product ◽  
Zn Ferrite ◽  
Micro Actuators

AbstractWe have developed a variety of processes for fabricating components for micro devices based on deep x-ray lithography (DXRL). Although the techniques are applicable to many materials, we have demonstrated them using hard (Nd 2Fe14B) and soft (Ni-Zn ferrite) magnetic materials because of the importance of these materials in magnetic micro-actuators and other devices and because of the difficulty fabricating them by other means. The simplest technique involves pressing a mixture of magnetic powder and a binder into a DXRL-formed mold. In the second technique, powder is pressed into the mold and then sintered to densify. The other two processes involve pressing at high temperature either powder or a dense bulk material into a ceramic mold that was previously made using a DXRL mold. These techniques allow arbitrary 2-dimensional shapes to be made 10 to 1000 μm thick with in-plane dimensions as small as 50μm and dimensional tolerances in the micron range. Bonded isotropic Nd2Fe14B micro-magnets made by these processes had an energy product of 7 MGOe.

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