Download or read book Design and Fabrication of an Optical Pressure Micro Sensor for Skin Mechanics Studies written by Siddarth Kumar and published by . This book was released on 2006 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) The entire device is fabricated bottom up on a silicon wafer using soft lithography techniques and the textured pattern is imprinted onto the PDMS using photolithography techniques. This flexible pressure sensor is designed to be used on the fingerpad skin to determine the pressure distribution due to incident loads. The sensor is placed between the OCT head and the finger pad to be imaged. The OCT head (along with the indenter) acts as the mechanical stimulus and is used to indent the finger pad. As a result of this stimulus, the human skin along with the pressure sensor gets deformed and both these deformations are picked up by the OCT image. The deflection between the two bands of patterns is used to estimate the stress at the pressure sensor and skin interface through the development of a continuum mechanics model which is also developed and introduced in this thesis. The manufactured device is tested and calibrated for use with the fingerpad.

Download or read book Integration of Electronic and Optical Techniques in the Design and Fabrication of Pressure Sensors written by Ivan Padron and published by . This book was released on 2010 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the introduction of micro-electro-mechanical systems fabrication methods, piezoresistive pressure sensors have become the more popular pressure transducers. They dominate pressure sensor commercialization due to their high performance, stability and repeatability. However, increasing demand for harsh environment sensing devices has made sensors based on Fabry-Perot interferometry the more promising optical pressure sensors due to their high degree of sensitivity, small size, high temperature performance, versatility, and improved immunity to environmental noise and interference. The work presented in this dissertation comprises the design, fabrication, and testing of sensors that fuse these two pressure sensing technologies into one integrated unit. A key innovation is introduction of a silicon diaphragm with a center rigid body (or boss), denoted as an embossed diaphragm, that acts as the sensing element for both the electronic and optical parts of the sensor. Physical principles of piezoresistivity and Fabry-Perot interferometry were applied in designing an integrated sensor and in determining analytic models for the respective electronic and optical outputs. Several test pressure sensors were produced and their performance was evaluated by collecting response and noise data. Diaphragm deflection under applied pressure was detected electronically using the principle of piezoresistivity and optically using Fabry-Perot interferometry. The electronic part of the sensor contained four p-type silicon piezoresistors that were set into the diaphragm. They were connected in a Wheatstone bridge configuration for detecting strain-dependent changes in resistance induced by diaphragm deflection. In the optical part of the sensor, an optical cavity was formed between the embossed surface of the diaphragm and the end face of a single mode optical fiber. An infrared laser operating at 1.55 was used for optical excitation. Deflection of the diaphragm, which causes the length of the optical cavity to change, was detected by Fabry-Perot interference in the reflected light. Data collected on several sensors fabricated for this dissertation were shown to validate the theoretical models. In particular, the principle of operation of a Fabry-Perot interferometer as a mechanism for pressure sensing was demonstrated. The physical characteristics and behavior of the embossed diaphragm facilitated the integration of the electronic and optical approaches because the embossed diaphragm remained flat under diaphragm deflection. Consequently, it made the electronic sensor respond more linearly to applied pressure. Further, it eliminated a fundamental deficiency of previous applications of Fabry-Perot methods, which suffered from non-parallelism between the two cavity surfaces (diaphragm and fiber), owing to diaphragm curvature after pressure was applied. It also permitted the sensor to be less sensitive to lateral misalignment during the fabrication process and considerably reduced back pressure, which otherwise reduced the sensitivity of the sensor. As an integrated sensor, it offered two independent outputs in one sensor and therefore the capability for measurements of: (a) static and dynamic pressures simultaneously, and (b) two different physical quantities such as temperature and pressure.

Download or read book MEMS Pressure Sensors Fabrication and Process Optimization written by Parvej Ahmad Alvi and published by Lulu.com. This book was released on 2014-07-14 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: MEMS Pressure Sensors: Fabrication and Process Optimization - describs the step by step fabrication process sequence along with flow chart for fabrication of micro pressure sensors taking into account various aspects of fabrication and designing of the pressure sensors as well as fabrication process optimization. A complete experimental detail before and after each step of fabrication of the sensor has also been discussed. This leads to the uniqueness of the book. MEMS Pressure Sensors: Fabrication and Process Optimization will greatly benefit undergraduate and postgraduate students of MEMS and NEMS courses. Process engineers and technologists in the microelectronics industry including MEMS-based sensors manufacturers.

Download or read book The Design Fabrication and Development of Micromechanical Integrated Optical Pressure Sensors for Aerospace written by Alexander Jantzen and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Design Fabrication and Development of Micromechanical Integrated Optical Pressure Sensors for Aerospace written by Alex Jantzen and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Design and Fabrication of Micromachined Capacitive Micro Sensors for Pressure Measurement and Tactile Imaging written by Gegi George and published by . This book was released on 1994 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flexible pressure and temperature sensors towards e skin material mechanism structure and fabrication written by Shengrui Tian and published by OAE Publishing Inc.. This book was released on 2023-08-07 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electronic skin (E-skin) has gained significant attention due to its potential applications in the Internet of Things (IoT), artificial intelligence (AI), and flexible multi-sensing systems. Mimicking human skin, e-skin sensing devices can be employed in various scenarios. Among the most important sensing elements for tactile e-skin sensors are pressure and temperature sensors, which have increasingly garnered research interest over the past few decades. However, the design and fabrication of advanced pressure and temperature sensors can be challenging owing to complications such as signal interference, complex mechanism integration, and structural design issues. This review provides an overview of flexible pressure and temperature sensors used in e-skin, covering four main perspectives: material selection, mechanism integration, structural design, and manufacturing methods. The materials of different elements in the entire sensing system are comprehensively discussed, along with single and compound mechanisms of pressure and temperature sensing. Pressure and temperature sensors are divided into two types based on their electric output signals, which are exemplified in detail. The manufacturing methods used to fabricate these sensors, including printing methods, are outlined. Lastly, a summary of the future challenges faced by flexible pressure and temperature sensors used in e-skin is presented.

Download or read book Opto mechanical Analysis of a Harsh Environment MEMS Fabry Perot Pressure Sensor written by Eric J. Brace and published by . This book was released on 2019 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this thesis is to develop an optically interrogated pressure sensor that is capable of measuring the applied fluid pressure in harsh environments. In its completed state, this sensor is intended be used in plastic injection moulding manufacturing in order to identify the current state of the plastic melt and optimize the process. An extrinsic fiber-optic Fabry-Perot pressure sensor, based on micro-electromechanical system (MEMS) is developed. A series of experiments are designed and carried out to validate the sensor's applicability for high temperature and pressure environments. Preliminary results are gathered using an existing silicon membrane in order to verify the concept, which was fabricated using anisotropic etching. Silicon on insulator (SOI) multiuser fabrication process is used to produce three designs of silicon membranes through Deep reactive-ion etching (DRIE). These devices are packaged with a stainless steel housing using epoxy to support the die and verify alignment between the fiber and reflective membrane. Once assembled, the Fabry-Perot cavity is formed between the membrane and fiber surface. Experimental results are collected using the proof of concept device for temperature ranges of 20 - 100 ʻC and gauge pressures from 0 - 1000 PSI, and for the SOI devices at room temperature and gauge pressures from 0 to 3000 PSI. Analysis of this data shows operating pressure ranges of 150 to 2300 PSI, maximum nonlinearity of less than 2.6% and sensitivities between 0.36 and 1.4 nm/PSI. The experimental deflection results are compared against finite element and analytical models to verify the expected response. This is adjusted for temperature effects using predictions of material property temperature-dependence and thermal expansion. In order to examine the impact of fabrication methodology, a fixed-fixed support analytical model is compared to experimental data of the four membrane designs. It is found that the anisotropic etched membrane shows poor agreement with this analytical model, showing 570% greater sensitivity than predicted using the model. Finite element modeling of the system shows significant deformation in the membrane support structure, resulting in this greater sensitivity. A simply supported analytical model is also compared to the data, showing 100% greater sensitivity. This model is adjusted using a least squares procedure to fit the experimental data through modification of the support-defined leading coefficient. A high temperature trial shows reduced sensitivity to pressure, corroborating the predicted finite element behavior. Silicon on insulator DRIE membranes show similar error, on the order of 100%, when compared to the fixed-fixed analytical model. This model is adjusted in a similar manner to fit the experimental data. The findings of this thesis suggest that unaccounted-for deflection is present in the membrane supports of DRIE and anisotropic etched MEMS devices, which significantly impacts sensor response to pressure. This results in higher sensitivity than analytically predicted occurring in the experimental trials of the as-fabricated devices. Future work should be focused on expanding the predictive power of MEMS membranes, stabilization of the optical signal and integration of temperature sensing to expand the capabilities of the device while correcting for real-time thermal aberration.

Download or read book Design and Fabrication of a Fiber Optic Pressure Sensor written by Jianzhong Hao and published by . This book was released on 2001 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanocrystalline Piezoresistive Polysilicon Film Obtained by Aluminum Induced Crystallizaiton for Pressure Sensing Applications written by Suraj Kumar Patil and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of our research was to integrate various sensors on to a single flexible substrate for multi-sensory information gathering. Additional capabilities could be incorporated towards the realization of 'smart skin' for simultaneous and real time sensing of various mechanical, biological and chemical stimuli. Recent research venues are dictated by the trend of shifting from conventional silicon (Si) substrates to lower weight, low profile, structurally robust and lower cost flexible substrates. These flexible substrates easily conform to non-planar objects, could be batch fabricated at lower cost and enable multilayer construction. This would eventually evolve into seamless assimilation of sensors for various stimuli onto a single flexible substrate for plethora of applications in consumer electronics, robotics, medical prosthetics, surgical instrumentation, structural health monitoring and industrial diagnostics to name a few. Pressure sensors currently find numerous applications in the field of automobiles (airbag deployment, tire pressure monitoring systems (TPMS), fuel systems etc.), smart cell phones (microphones, touch screens etc.) and various biomedical devices. The pressure sensor selection criterion is strictly based on the requirements of specific pressure range and resolution. It is also dependent on the environment (temperature, medium etc.) the sensor would be deployed in. Some commonly used pressure sensor designs include absolute, gauge and differential/tactile types. All of the above sensors could either employ piezoresistive, piezoelectric, capacitive or optical readout methodologies for sensing applied pressure. Piezoresistor-based, differential pressure sensor designs are most commonly used because of their (i) versatility, (ii) relatively simple construction, (iii) linear responsivity with applied pressure, (iv) long-term stability, and (v) maturity of the technology. There has been a growing interest in the development of various sensors that often require deployment of planar micro to nano-scale sized sensors on flexible substrates such as polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and stainless steel (SS). Current work describes the use of piezoresistive-based differential pressure sensors on a flexible polyimide substrate. Our design uses a suspended diaphragm with piezoresistive sensing based on a Wheatstone bridge circuitry. The measurement resolution can be effectively controlled by the diaphragm geometry and size, whereas the diaphragm thickness and the micromachined gap under the diaphragm determine the range. The surface micromachining used here would also facilitate stacking of different sensors (viz. infrared, pressure, chemical, biological) on a single flexible substrate, conforming to the underlying object. For our current application, the aim was to measure low pressure changes ranging from few tens of a pascal (Pa) to few tens of kPa. Fabrication processes on a wide variety of flexible substrates are dictated by their lower glass transition temperatures (Tg). This critical restriction more often requires low temperature film deposition and device fabrication techniques in order to use them as substrates. Polysilicon being CMOS compatible is used both as a mechanical and an electrical material in many sensor designs, as it makes the integration of the sensor with read-out circuitry readily feasible. Since polysilicon also exhibits a relatively high piezoresistive gauge factor, it is also preferred over its metal counterparts. However, conventional polysilicon deposition techniques typically require high temperatures, which are incompatible with polyimide substrates. The work presented here is a low temperature method for obtaining polysilicon piezoresistive thin films using aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) film. A very important step involving the curing of polyimide PI-2611 was successfully developed to withstand AIC annealing temperatures in excess of 500 °C for couple of hours. This facilitated the use of multilayer PI-2611 as our substrate and sacrificial material. We have obtained nanocrystalline polysilicon films with average grain sizes of 45-55 nm at temperatures ranging from 400 °C to 500 °C with annealing time of 60 min utes, and an average grain size of 50 nm at 500 °C for a shorter annealing time of 30 minutes. An additional advantage of this process is that the polysilicon films are simultaneously doped p-type, thereby eliminating any additional doping step. By varying the aluminum (Al) and a-Si layer thicknesses, annealing temperature and duration, the growth of polysilicon grains ranging from few tens of nanometers to tens of microns in diameter can be effectively obtained. Additionally, exploring the piezoresistive properties of the above mentioned low temperature nanocrystalline polysilicon thin films deposited on polyimide substrate for pressure sensing applications was another vital aspect of this research. In order to achieve this firstly, arrays of MEMS based pressure sensors were successfully fabricated on polyimide substrate. Secondly, an atomic force microscope (AFM) in contact mode with a modified probe-tip was used to apply differential pressures. Low pressures (lesser than atmospheric pressure) were successfully applied onto the sensors using AFM. Thirdly, higher pressures (greater than 4 times the atmospheric pressure) were applied onto the sensors by using a load-cell coupled with a nano-positioner. The design of the pressure sensor characterization set-ups and subsequent experimental procedures are described in this work. Finally, experimental characterization of fabricated MEMS pressure sensors on polyimide substrate employing polysilicon resistors obtained by AIC were performed to measure their pressure sensitivity responses.

Download or read book Fabrication Design of Micro Pressure Sensor with Built in Automated Calibration written by Yeong Yau Loh and published by . This book was released on 2006 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Case Studies in Micromechatronics written by Stephanus Büttgenbach and published by Springer Nature. This book was released on 2020-05-15 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book “Case Studies in Micromechatronics – From Systems to Process” offers prominent sample applications of micromechatronic systems and the enabling fabrication technologies. The chosen examples represent five main fields of application: consumer electronics (pressure sensor), mobility and navigation (acceleration sensor), handling technology and automation (micro gripper), laboratory diagnostics (point of care system), and biomedical technology (smart skin). These five sample systems are made from different materials requiring a large variety of modern fabrication methods and design rules, which are explained in detail. As a result, an inverted introduction “from prominent applications to base technologies” is provided. Examples of applications are selected to offer a broad overview of the development environment of micromechatronic systems including established as well as cutting-edge microfabrication technologies.

Download or read book Design Fabrication and Testing of Micro optical Sensors Containing Multiple Aspheres written by and published by . This book was released on 1995 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The micro-sensor field is presently proliferating with designs and approaches. The authors have developed a micro-spectrometer for sensing application containing five precision surfaces, including two off-axis aspheres. The entire monolith is less than six cubic centimeters in volume. This particular design contains a bandwidth of about 1 micrometer which is centered at 980 nm. Once an appropriate starting substrate was produced, the entire system was diamond turned to maintain the required surface figure, inter-surface spacing, and surface tilts. Only three diamond turned fixtures were needed to produce the monolith. The results proved to be more than adequate for many sensing applications. Slightly altered designs could easily be produced containing different bandwidths and resolutions as needed by the customer. Due to the spectrum of interest and the fabrication method, PMMA was the material chosen for this sensor. Other designs configurations incorporating BK7 and sapphire are presently being studied.

Download or read book Design and Fabrication of a MEMS Passive Pressure Sensor written by Penglai Li and published by . This book was released on 2006 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micro-ElectroMechanical Systems is an inter-disciplinary technology field that has seen considerable growth over the years. It utilizes conventional semiconductor fabrication process flow as well as novel micro-fabrication techniques to create highly integrated ElectroMechanical systems such as sensors, actuators, switches, pumps and other devices with a wide range of industrial applications. By providing the capability of creating System-On-A-Chip, MEMS technology offers the prospect of highly sophisticated and integrated systems that are very low cost. The purpose of this project is to design, fabricate, and test a MEMS based, passive pressure sensor as a proof of concept targeted at possible remote sensing applications. For the targeted applications, purely passive sensor is a better alternative to sensors involving active circuitry, since it removes much of the design complexities from the sensor, and no battery is needed. Information such as technology selection, analysis of the sensor's response to pressure, and detailed fabrication process flow will be presented. Results from laboratory testing will also be presented.

Download or read book Optical Microsystems for Static and Dynamic Tactile Sensing written by Roozbeh Ahmadi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Fabrication of a Miniature Pressure Sensor Head Using Direct Bonded Ultra thin Silicon Wafers written by Chad Eugene Statler and published by . This book was released on 1996 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Microfabricated Surface Plasmon Sensor written by Raffi Garabedian and published by . This book was released on 1993 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: