Modern Sensors Handbook

Chapter 1. Pressure Sensors 1 André MIGEON and Anne-Elisabeth LENEL 1.1. Introduction 1 1.2. Pressure 2 1.2.1. Pressure as a physical quantity 2 1.2.2. Absolute, relative and differential sensors 3 1.2.3. Fluid physical properties 5 1.3. Pressure ranges 6 1.3.1. Vacuum and ultra-vacuum 6 1.3.2. Middle range pressure 8 1.3.3. High pressure 10 1.4. Main physical principles 10 1.4.1. The sensing device 11 1.4.2. Sensors with elastic element 13 1.4.3. Vacuum sensors 41 1.5. Calibration: pressure standards 43 1.5.1. Low pressure standard 43 1.5.2. High pressure standard 43 1.6. Choosing a pressure sensor 45 1.7. References 45 1.8. Other pressure sensor manufacturers 46 1.9. Bibliography 46 Chapter 2. Optical Sensors 49 Stanislav AO and Jan FISCHER 2.1. Optical waveguides and fibers 49 2.2. Light sources and detectors 51 2.2.1. Light sources 51 2.2.2. Light detectors 54 2.3. Sensors of position and movement 62 2.3.1. Position sensors using the principle of triangulation 62 2.3.2. Incremental sensors of position or displacement 63 2.3.3. Photoelectric switches 66 2.4. Optical sensors of dimensions 71 2.4.1. Dimensional gauge with scanned beam 71 2.5. Optical sensors of pressure and force 73 2.5.1. Pressure sensor using the optical resonator 73 2.6. Optical fiber sensors 74 2.6.1. Introduction and classification of sensors with optical fibers 74 2.6.2. Optical fiber sensors with amplitude modulation 75 2.6.3. Sensor with wavelength modulation 77 2.6.4. Optical sensors with phase modulation 78 2.6.5. Perspective of optical fiber sensors 78 2.7. Optical chemical sensors 78 2.7.1. Introduction 78 2.7.2. Chemical sensors based on the absorbency measurement 79 2.7.3. Turbidity sensors 80 2.8. Bibliography 81 2.8.1. Books 81 2.8.2. Physical background – websites 82 Chapter 3. Flow Sensors 83 R. MEYLAERS, F. PEETERS, M. PEETERMANS and L. INDESTEEGE 3.1. Introduction 83 3.1.1. Volume flow and mass flow 83 3.1.2. Influences on the flow 85 3.1.3. Bernoulli equation 86 3.2. Flow measurements based on the principle of difference in pressure 88 3.2.1. The Pitot and Prandtl tube 89 3.2.2. The orifice plate 93 3.2.3. The flow nozzle 98 3.2.4. The Venturi tube 99 3.2.5. The Dall tube 99 3.2.6. General guidelines for a correct reading 100 3.3. Flow measurements based on variable passage 101 3.3.1. The float flow meter (rotameter) 101 3.3.2. Target flow meter 103 3.4. Turbine flow meter 104 3.4.1. Principle 104 3.4.2. Practical installation 106 3.4.3. Characteristics 107 3.5. The mechanical flow meter (positive displacement) 108 3.5.1. Principle 108 3.5.2. Characteristics 110 3.6. Magnetic flow meter 110 3.6.1. Principle 110 3.6.2. Construction of the measuring instrument 112 3.6.3. Practical installation 113 3.6.4. Characteristics 115 3.7. The vortex flow meter 116 3.7.1. Principle 116 3.7.2. Construction of the vortex flow meter 117 3.7.3. Practical installation 120 3.7.4. Characteristics 121 3.8. Ultrasonic flow meter 122 3.8.1. Principle 122 3.8.2. Practical installation 125 3.8.3. Characteristics 125 3.9. Coriolis mass flow meters 126 3.9.1. Principle 126 3.9.2. Applications 128 3.9.3. Practical installation 129 3.9.4. Characteristics 129 3.10. Flow measurements for solid substances 129 3.10.1. Flow measurement of solids by means of an impact plate 130 3.10.2. Flow measurement of solids based on the weighing method 132 3.10.3. Capacitive flow measurement of solid substances 133 3.10.4. Detection of solid substances using microwaves 134 3.11. Flow measurement for open channels with weirs 135 3.12. Choice and comparison of flow measurements 137 3.13. Bibliography 137 3.14. Website references 137 Chapter 4. Intelligent Sensors and Sensor Networks 141 Jirí NOVAK 4.1. Introduction 141 4.2. Intelligent sensors 142 4.2.1. Sensors and transducers 143 4.2.2. Signal conditioning (SC) 144 4.2.3. A/D conversion 146 4.2.4. Data processing 147 4.2.5. Human-machine interface 148 4.2.6. Communication interface 148 4.2.7. Industrial examples 149 4.3. Sensor networks and interfaces 151 4.3.1. Centralized and distributed industrial systems 152 4.3.2. Hierarchical structure of distributed communication 154 4.3.3. Data communication basics 155 4.3.4. Simple sensor interfaces 166 4.3.5. Sensor networks 171 4.3.6. Wireless sensor networks 190 Chapter 5. Accelerometers and Inclinometers 193 André MIGEON and Anne-Elisabeth LENEL 5.1. Introduction 193 5.2. Acceleration 194 5.2.1. Physical quantity 194 5.2.2. Application to velocity and position measurements 198 5.2.3. Application to position measurements 199 5.2.4. The inclinometers 200 5.3. Application ranges 201 5.3.1. Static and low-frequency acceleration. 201 5.3.2. Vibrations 202 5.3.3. Shocks 203 5.3.4. Inclination 204 5.4. Main models of accelerometers 205 5.4.1. Piezoelectric accelerometers 206 5.4.2. Piezoresistive accelerometers 213 5.4.3. Accelerometers with resonators 219 5.4.4. Capacitive accelerometers 221 5.4.5. Potentiometric accelerometers 224 5.4.6. Optical detection accelerometers 226 5.4.7. Magnetic detection accelerometers 227 5.4.8. Servo accelerometers with controlled displacement 229 5.5. The signal processing associated with accelerometers 231 5.6. Manufacturing process 232 5.6.1. The monolithic processes 232 5.6.2. Hybrid process 234 5.6.3. Packaging 234 5.7. The calibrations 235 5.7.1. Inclinometers and accelerometers with range lower than 1 g 235 5.7.2. Acceleration range higher than 1 g 235 5.8. Examples of accelerometers and inclinometers 236 5.9. List of manufacturers of accelerometers 242 5.10. References 243 5.11. Bibliography 244 Chapter 6. Chemical Sensors and Biosensors 245 Gillian McMAHON 6.1. Introduction 245 6.2. What is involved in developing a sensor? 249 6.2.1. Molecular recognition 250 6.2.2. Immobilization of host molecules 252 6.2.3. Transduction of signal 253 6.3. Electrochemical sensors 253 6.3.1. Amperometric and voltammetric sensors 254 6.3.2. Potentiometric sensors 258 6.3.3. Resistance, conductance and impedance sensors 263 6.4. Optical sensors 265 6.4.1. Methods of detection 265 6.4.2. Reagent-mediated sensors 268 6.5. Acoustic (mass) sensors 269 6.5.1. Quartz crystal microbalance sensors 270 6.5.2. Sensor arrays 272 6.6. Biosensors 274 6.6.1. Affinity biosensors 275 6.6.2. Catalytic biosensors 285 6.7. Future trends 290 6.7.1. Microanalytical instruments as sensors 291 6.7.2. Autonomous sensing devices 298 6.7.3. Sub-micron dimensioned sensors 298 6.8. Conclusions 301 6.9. References 302 Chapter 7. Level, Position and Distance 305 Stanislav DADO and G. HARTUNG 7.1. Introduction 305 7.1.1. Classification of LPD sensors 305 7.2. Resistive LPD sensors 306 7.2.1. Potentiometer 306 7.2.2. Angular position measurement 307 7.2.3. Draw wire sensors 308 7.2.4. Inclination detectors 308 7.2.5. Application of potentiometers 309 7.3. Inductive LPD sensors 309 7.3.1. Linear variable differential transformers 310 7.3.2. Inductosyns 311 7.3.3. Resolvers 312 7.3.4. Selsyn 313 7.3.5. Inductive sensors of angular velocity 313 7.3.6. Eddy current distance sensors 314 7.4. Magnetic LPD sensors 315 7.4.1. Magnetic field sensors 315 7.4.2. Reed switches 316 7.4.3. Hall sensors 316 7.4.4. Semiconductor magnetoresistors 317 7.4.5. Wiegand wire 318 7.4.6. Magnetostrictive sensor 318 7.5. Capacitive LPD sensors 319 7.5.1. Introduction 319 7.5.2. Signal conditioning circuits for capacitive sensors 320 7.5.3. Using capacitive sensors 321 7.6. Optical LPD sensors 323 7.6.1. Introduction 323 7.6.2. Photo-electric switches (PES) 323 7.6.3. LPD sensors based on triangulation 327 7.6.4. Optical encoders 328 7.6.5. Interferometry 330 7.6.6. Optical LPD sensors based on travel time (time-of-fly) measurement 331 7.6.7. Image-based measurement-machine vision, videometry 332 7.7. Ultrasonic sensors 333 7.7.1. Introduction 333 7.7.2. Travel time principle 334 7.7.3. Doppler effect 334 7.8. Microwave distance sensors (radar) 335 7.8.1. Introduction 335 7.8.2. Microwave sensors based on FMCW 336 7.8.3. Properties of microwave sensors 337 7.9 Level measurement 337 7.9.1. Introduction 337 7.9.2. Detection limits 338 7.9.3. Continuous level measurement 339 7.10. Conclusions and trends 343 7.11. References 343 7.12. Online references 344 Chapter 8. Temperature Sensors 347 F. PEETERS, M. PEETERMANS and L. INDESTEEGE 8.1. Introduction 347 8.2. Thermal measuring techniques 348 8.2.1. Heat and temperature 348 8.2.2. Static and dynamic readings 348 8.2.3. Time constant and response time 349 8.2.4. Thermal units 349 8.2.5. Thermal equilibrium 350 8.2.6. Temperature measuring options 354 8.2.7. Quality of a measurement 355 8.3. Physical or direct temperature measurement 355 8.3.1. Glass thermometer 355 8.3.2. Liquid filled expansion thermometers 356 8.3.3. Gas filled expansion thermometer or pressure thermometer detector 358 8.3.4. Vapor-pressure systems 359 8.3.5. Bimetallic thermometer 361 8.4. Thermoelectric measurements (thermocouples) 363 8.4.1. Measuring principle: thermoelectricity 363 8.4.2. Thermoelectric laws 364 8.4.3. Practical temperature measurement with thermocouples 367 8.4.4. Technological realizations of thermocouples 371 8.4.5. Applications 374 8.4.6. Parallel and series connections of thermocouples 375 8.5. Resistance temperature detectors (RTDs) 377 8.5.1. Principle 377 8.5.2. Used materials and construction 379 8.5.3. Applications 380 8.6. Thermistors 382 8.6.1. Principle 382 8.6.2. Thermistor technology 383 8.6.3. Application 384 8.7. Monolithic temperature sensors (IC sensor) 384 8.8. Pyrometers 385 8.8.1. Introduction 385 8.8.2. Basic principles of pyrometry 386 8.8.3. Measurement possibilities for pyrometers 387 8.8.4. Implementation and construction of pyrometers 389 8.9. References 391 8.10 Bibliography 391 Chapter 9. Solid State Gyroscopes and Navigation 395 André MIGEON and Anne-Elisabeth LENEL 9.1. Introduction 395 9.2. The angular rate 396 9.2.1. Definition of rate gyro 399 9.2.2. Use of rate sensors 401 9.3. Different ranges of rate gyro 401 9.3.1. Control of trajectory 402 9.3.2. Piloting and stabilization 402 9.3.3. Guidance 402 9.3.4. Navigation 402 9.4. Main models of rate gyro 404 9.4.1. Rotary gyrometers 404 9.4.2. Vibrating gyrometers 404 9.4.3. Optical gyrometers 420 9.4.4. Other original principles 426 9.5. Calibration of rate sensors 426 9.6. General features of the gyrometers 427 9.7. The main manufacturers 429 9.8. References 430 9.9. Bibliography 431 Chapter 10. Magnetic Sensors 433 S. RIPKA and Pavel RIPKA 10.1. Introduction 433 10.2. Hall sensors 434 10.2.1. The Hall effect 435 10.2.2. New types of Hall sensors 437 10.3. AMR sensors 439 10.3.1. Operating principles of the AMR effect 439 10.3.2. Measuring configuration of the AMR 443 10.3.3. Flipping 444 10.3.4. Magnetic feedback 446 10.4. GMR sensors 447 10.4.1. Physical mechanism 450 10.4.2. Spin valves 450 10.4.3. Sandwiches and multilayers 453 10.4.4. SDT sensors 454 10.4.5. Linear GMR sensors 454 10.4.6. Rotational GMR sensors 456 10.5. Induction and fluxgate sensors 457 10.5.1. Induction coil sensors 458 10.5.2. Fluxgate sensors 459 10.6. Other magnetic field sensors 463 10.6.1. Resonance sensors 463 10.7. Magnetic position sensors 465 10.7.1. Sensors using permanent magnets 465 10.7.2. Eddy current sensors 466 10.7.3. Linear and rotational transformers 467 10.7.4. Magnetostrictive position sensors 469 10.7.5. Proximity switches 469 10.8. Contactless current sensors 471 10.8.1. Hall current sensors 472 10.8.2. Magnetoresistive current sensors 472 10.8.3. AC and DC transformers 472 10.8.4. Current clamps 472 10.9. References 473 Chapter 11. New Technologies and Materials 477 A. TIPEK, P. RIPKA and E. HULICIUS, with contributions from A. HOSPODKOVÁ and P. NEU?IL 11.1. Introduction: MEMS 477 11.2. Materials 480 11.2.1. Passive materials 480 11.2.2. Active materials 481 11.2.3. Silicon 481 11.2.4. Other semiconductors 483 11.2.5. Plastics 484 11.2.6. Metals 486 11.2.7. Ceramics 486 11.2.8. Glass 486 11.3. Silicon planar IC technology 487 11.3.1. The substrate: crystal growth 488 11.3.2. Diffusion and ion implantation 488 11.3.3. Oxidation 489 11.3.4. Lithography and etching 489 11.3.5. Deposition of materials 490 11.3.6. Metallization and wire bonding 490 11.3.7. Passivation and encapsulation 491 11.4. Deposition technologies 491 11.4.1. Introduction 491 11.4.2. Chemical reactions 492 11.4.3. Physical reactions 495 11.4.4. Epitaxial techniques for semiconductor device preparation 498 11.5. Etching processes 500 11.5.1. Wet etching/micromachining 501 11.5.2. Dry etching/micromachining 502 11.6. 3-D microfabrication techniques 503 11.6.1. LIGA 504 11.6.2. Laser assisted etching (LAE) 504 11.6.3. Photo-forming and stereo lithography 505 11.6.4. Microelectrodischarging (MEDM and WEDG) 506 11.6.5. Microdrip fabrication 507 11.6.6. Manufacturing using scanning probe microscopes and electron microscopes 508 11.6.7. Handling of micro particles with laser tweezers 508 11.6.8. Atomic manipulation 509 11.7. References 510 List of Authors 513 Index 515