Handbook of Modern Sensors (eBook)

Jacob Fraden holds a Ph.D. in medical electronics and is Chief Technology Officer of Kaz, Inc., a company that produces a large variety of medical, consumer electrical and electronic products. He holds over 50 patents in the areas of sensing, medical instrumentation, security and others.

Handbook of Modern Sensors 3
Preface 5
Contents 7
Chapter 1: Data Acquisition 17
1.1 Sensors, Signals, and Systems 17
1.2 Sensor Classification 23
1.3 Units of MeasurementsUnits of Measurements 27
References 28
Chapter 2: Sensor Characteristics 29
2.1 Transfer Function 29
2.1.1 Mathematical Model 30
2.1.2 Functional Approximations 31
2.1.3 Polynomial Approximations 32
2.1.4 Sensitivity 33
2.1.5 Linear Piecewise Approximation 34
2.1.6 Spline Interpolation 35
2.1.7 Multidimensional Transfer Functions 35
2.2 Calibration 36
2.2.1 Computation of Transfer Function Parameters 38
2.2.2 Linear Regression 41
2.3 Computation of Stimulus 42
2.3.1 Computation from Linear Piecewise Approximation 42
2.3.2 Iterative Computation of Stimulus (Newton Method) 44
2.4 Span (Full-Scale Full Scale Input) 46
2.5 Full-Scale Output 47
2.6 Accuracy 47
2.7 Calibration Error 50
2.8 Hysteresis 51
2.9 Nonlinearity 52
2.10 Saturation 53
2.11 Repeatability 54
2.12 Dead Band 54
2.13 Resolution 54
2.14 Special Properties 55
2.15 Output Impedance 56
2.16 Output Format 56
2.17 Excitation 57
2.18 Dynamic Characteristics 57
2.19 Environmental Factors 61
2.20 Reliability 63
2.21 Application Characteristics 65
2.22 Uncertainty 66
References 68
Chapter 3: Physical Principles of Sensing 69
3.1 Electric ChargeElectric charges, Fields, and Potentials 70
3.2 Capacitance 76
3.2.1 Capacitor 78
3.2.2 Dielectric Constant 79
3.3 Magnetism 83
3.3.1 Faraday Law 85
3.3.2 Solenoid 87
3.3.3 Toroid 88
3.3.4 Permanent Magnets 88
3.4 InductionInduction 89
3.5 ResistanceResistance 93
3.5.1 Specific Resistivity 95
3.5.2 Temperature Sensitivity 96
3.5.3 Strain Sensitivity 100
3.5.4 Moisture Sensitivity 101
3.6 Piezoelectric Effect 102
3.6.1 Ceramic Piezoelectric Materials 105
3.6.2 Polymer Piezoelectric Films 109
3.7 PyroelectricPyroelectric Effect 112
3.8 Hall EffectHall Effect 119
3.9 Thermoelectric PeltierEffects 122
3.9.1 Seebeck Effect 122
3.9.2 Peltier Effect 127
3.10 Sound Waves 129
3.11 Temperature and Thermal Properties of Materials 132
3.11.1 Temperature Scales 133
3.11.2 Thermal Expansion 134
3.11.3 Heat Capacity 136
3.12 Heat Transfer 137
3.12.1 Thermal Conduction 138
3.12.2 Thermal Convection 141
3.12.3 Thermal Radiation 142
3.12.3.1 Emissivity 145
3.12.3.2 Cavity Effect 149
3.13 Light 151
3.13.1 Light Polarization 152
3.13.2 Light Scattering 153
3.14 Dynamic Models of Sensor Elements 154
3.14.1 Mechanical Elements 155
3.14.2 Thermal Elements 157
3.14.3 Electrical Elements 158
3.14.4 Analogies 159
References 160
Chapter 4: Optical Components of Sensors 162
4.1 Radiometry 164
4.2 PhotometryPhotometry 169
4.3 Windows 172
4.4 Mirrors 173
4.5 Lenses 176
4.6 Fresnel Lenses 178
4.7 Fiber Optics Fiber optics and Waveguides 180
4.8 ConcentratorsConcentrators 184
4.9 Coatings for Thermal Absorption 185
4.10 Nano-optics 187
References 187
Chapter 5: Interface Electronic Circuits 188
5.1 Input Characteristics of Interface Circuits 188
5.2 Amplifiers 193
5.2.1 Operational Amplifiers 193
5.2.2 Voltage Follower 196
5.2.3 Instrumentation AmplifierAmplifiers:instrumentational 197
5.2.4 Charge Amplifiers 198
5.3 Light-to-Voltage Converters 201
5.4 Excitation Circuits 203
5.4.1 Current Generators 203
5.4.2 Voltage References 207
5.4.3 Oscillators 207
5.4.4 Drivers 209
5.4.5 Optical Drivers 211
5.5 Analog-to-Digital Converters 211
5.5.1 Basic Concepts 211
5.5.2 V/F Converters 213
5.5.3 Dual-Slope Converters 218
5.5.4 Successive Approximation Converter 218
5.5.5 Resolution Extension 220
5.6 Direct Digitization 222
5.7 Capacitance-to-Voltage Converters 223
5.8 Integrated Interfaces 225
5.9 Ratiometric Circuits 226
5.10 Differential Circuits 229
5.11 Bridge Circuits 230
5.11.1 General Concept 230
5.11.2 Disbalanced Bridge 231
5.11.3 Null-Balanced Bridge 233
5.11.4 Bridge Amplifiers 233
5.12 Data Transmission 235
5.12.1 Two-Wire Transmission 235
5.12.2 Four-Wire Sensing 236
5.12.3 Six-Wire Sensing 237
5.13 Noise in Sensors and Circuits 238
5.13.1 Inherent Noise 238
5.13.2 Transmitted Noise 242
5.13.3 Electric Shielding 246
5.13.4 Bypass Capacitors 249
5.13.5 Magnetic Shielding 250
5.13.6 Mechanical Noise 252
5.13.7 Ground Planes 252
5.13.8 Ground LoopsGround loops and Ground Isolation 253
5.13.9 Seebeck Noise 255
5.14 Calibration 257
5.15 Batteries for Low-Power Sensors 258
5.15.1 Primary Cells 259
5.15.1.1 Leclanche (Carbon-Zinc) Batteries 259
5.15.1.2 Alkaline Manganese Batteries 260
5.15.1.3 Primary Lithium Batteries 260
5.15.2 Secondary Cells 260
References 261
Chapter 6: Occupancy and Motion Detectors 262
6.1 Ultrasonic Detectors 264
6.2 Microwave Motion Detectors 264
6.3 Capacitive Occupancy Detectors 269
6.4 Triboelectric Detectors 273
6.5 Optoelectronic Motion Detectors 275
6.5.1 Sensor Structures 276
6.5.1.1 Multiple Detecting Elements 277
6.5.1.2 Complex Sensor Shape 277
6.5.1.3 Image Distortion 278
6.5.1.4 Facet Focusing Element 278
6.5.2 Visible and Near IR Light Motion Detectors 279
6.5.3 Far-Infrared Motion Detectors 282
6.5.3.1 Passive Infrared Motion Detectors 282
6.5.3.2 PIR Sensor Efficiency Analysis 285
6.6 Optical Presence Sensors 289
6.7 Pressure-Gradient Sensors 291
References 293
Chapter 7: Position, Displacement, and Level 294
7.1 Potentiometric Sensors 295
7.2 Capacitive Sensors Capacitive sensors 299
7.3 Inductive and Magnetic Sensors 303
7.3.1 LVDT and RVDT 303
7.3.2 Eddy Current Sensors 305
7.3.3 Transverse Inductive Sensor 307
7.3.4 Hall Effect Sensors 308
7.3.5 Magnetoresistive Sensors 312
7.3.6 Magnetostrictive Detector Magnetostrictive detector 315
7.4 Optical Sensors Optical Sensors 317
7.4.1 Optical Bridge 317
7.4.2 Proximity Detectorproximity detector with Polarized Light 318
7.4.3 Fiber-Optic Sensors Fiber-optic sensors 319
7.4.4 Fabry-Perot Sensors 321
7.4.5 Grating Sensors Grating sensors 323
7.4.6 Linear Optical Sensors 325
7.5 Ultrasonic Sensors Ultrasonic sensors 329
7.6 Radar Sensors 331
7.6.1 Micropower Impulse Radar 331
7.6.2 Ground Penetrating Radars 333
7.7 Thickness and Level Sensors 335
7.7.1 Ablation Sensors 335
7.7.2 Thin Film Sensors 337
7.7.3 Liquid Level Sensors 338
7.8 Pointing Devices 339
7.8.1 Optical Pointing Devices 339
7.8.2 Magnetic Pickup 340
7.8.3 Inertial and Gyroscopic Mice 340
References 340
Chapter 8: Velocity and Acceleration 342
8.1 Accelerometer Characteristics 344
8.2 Capacitive Accelerometers 347
8.3 Piezoresistive Accelerometers 349
8.4 Piezoelectric Accelerometers 350
8.5 Thermal Accelerometers 351
8.5.1 Heated Plate Accelerometer 351
8.5.2 Heated Gas Accelerometer 352
8.6 Gyroscopes Gyroscopes 354
8.6.1 Rotor Gyroscope 355
8.6.2 Monolithic Silicon Gyroscopes 356
8.6.3 Optical (Laser) Gyroscopes 359
8.7 Piezoelectric Cables 361
8.8 Gravitational Sensors Gravitational Sensors 363
References 366
Chapter 9: Force, Strain, and Tactile Sensors 368
9.1 Strain Gauges 370
9.2 Tactile Sensors 372
9.2.1 Switch Sensors 373
9.2.2 Piezoelectric Sensors 374
9.2.3 Piezoresistive Sensors 377
9.2.4 MEMS Sensors 379
9.2.5 Capacitive Touch Sensors 380
9.2.6 Acoustic Touch Sensors 384
9.2.7 Optical Sensors 384
9.3 Piezoelectric Force Sensors 385
References 387
Chapter 10: Pressure Sensors 389
10.1 Concepts of Pressure 389
10.2 Units of Pressure 391
10.3 Mercury Pressure Sensor 392
10.4 Bellows, Membranes, and Thin plates 393
10.5 Piezoresistive Sensors 395
10.6 Capacitive Sensors 401
10.7 VRP Sensors 402
10.8 Optoelectronic Pressure Sensors 404
10.9 Indirect Pressure Sensor 405
10.10 Vacuum Sensors 407
10.10.1 Pirani Gauge 407
10.10.2 Ionization Gauges 409
10.10.3 Gas Drag Gauge 410
10.10.4 Membrane Vacuum Sensors 410
References 411
Chapter 11: Flow Sensors 412
11.1 Basics of Flow DynamicsFlow Dynamics 412
11.2 Pressure Gradient Technique 415
11.3 Thermal Transport Sensors 417
11.3.1 Hot-Wire Anemometers 418
11.3.2 Three-Part Thermoanemometer 422
11.3.3 Two-Part Thermoanemometer 424
11.3.4 Microflow Thermal Transport Sensors 427
11.4 Ultrasonic Sensors 429
11.5 Electromagnetic Sensors 431
11.6 Breeze Sensor 433
11.7 Coriolis Mass Flow Sensors 435
11.8 Drag Force Sensors 436
11.9 Dust and Smoke Detectors 437
11.9.1 Ionization Detector 437
11.9.2 Optical Detector 439
References 441
Chapter 12: Acoustic Sensors 443
12.1 Resistive Microphones 444
12.2 Condenser Microphones 444
12.3 Fiber-Optic Fiber-opticMicrophone 446
12.4 Piezoelectric Microphones 447
12.5 Electret Microphones 449
12.6 Dynamic Microphones 451
12.7 Solid-State Acoustic Detectors 452
References 455
Chapter 13: Humidity and Moisture Sensors 456
13.1 Concept of Humidity 456
13.2 Capacitive Sensors 459
13.3 Electrical Conductivity Sensors 463
13.4 Thermal Conductivity Sensor 466
13.5 Optical Hygrometer 467
13.6 Oscillating Hygrometer 469
References 470
Chapter 14: Light Detectors 471
14.1 Introduction 471
14.2 Photodiodes 475
14.3 Phototransistor 481
14.4 Photoresistors 482
14.5 Cooled Detectors 485
14.6 Image Sensors 488
14.6.1 CCD Sensor 489
14.6.2 CMOS-Imaging Sensors 490
14.7 Thermal Detectors 491
14.7.1 Golay Cells 492
14.7.2 Thermopile Sensors 493
14.7.3 Pyroelectric Sensors 497
14.7.4 Bolometers 501
14.7.5 Active Far-Infrared Sensors 504
14.8 Optical Design 507
14.9 Gas Flame Detectors 508
References 510
Chapter 15: Radiation Detectors 512
15.1 Scintillating Detectors Scintillating detectors 513
15.2 Ionization Detectors Ionization detectors 516
15.2.1 Ionization Chambers 517
15.2.2 Proportional Chambers 518
15.2.3 Geiger-Müller CountersGeiger-Mueller Counters 519
15.2.4 Semiconductor Detectors 521
15.3 Cloud and Bubble Chambers 525
References 527
Chapter 16: Temperature Sensors 528
16.1 Coupling with Object 528
16.2 Temperature Reference Points 535
16.3 Thermoresistive Sensors 537
16.3.1 Resistance Temperature Detectors 537
16.3.2 Silicon Resistive PTC Sensors 538
16.3.3 Thermistors 541
16.3.3.1 NTC Thermistors 541
16.3.3.2 Simple Model 542
16.3.3.3 Fraden Model 544
16.3.3.4 Steinhart-Hart Model 546
16.3.3.5 Fabrication of Ceramic NTC Thermistors 548
16.3.3.6 Germanium and Silicon NTC Thermistors 550
16.3.3.7 Printed Thermistors 550
16.3.3.8 Self-Heating Effect in NTC Thermistors 551
16.3.3.9 PTC Thermistors 554
16.4 Thermoelectric Contact Sensors 558
16.4.1 Thermoelectric Laws 559
16.4.2 Thermocouple Circuits 561
16.4.3 Thermocouple Assemblies 563
16.5 Semiconductor pn-Junction Sensors 565
16.6 Optical Temperature Sensors 569
16.6.1 Fluoroptic Sensors 570
16.6.2 Interferometric Sensors 571
16.6.3 Thermochromic Solution Sensor 572
16.7 Acoustic Temperature Sensor 573
16.8 Piezoelectric Temperature Sensors 574
References 575
Chapter 17: Chemical Sensors1 577
17.1 Overview 578
17.2 History 578
17.3 Chemical Sensor Characteristics 579
17.4 Classes of Chemical Sensors 580
17.4.1 Electrical and Electrochemical Transducers 580
17.4.1.1 Metal-Oxide Semicondutor Devices 582
17.4.1.2 Electrochemical Sensors 583
17.4.1.3 Potentiometric Sensors 585
17.4.1.4 Conductometric Sensors 586
17.4.1.5 Amperometric Sensors 587
17.4.2 Elastomer Chemiresistors 589
17.4.2.1 Chemicapacitive Sensors 590
17.4.2.2 ChemFET 592
17.4.3 Photoionization Detector 593
17.4.4 Physical Transducers 594
17.4.4.1 Acoustic Wave Devices 595
17.4.4.2 Microcantilever 598
17.4.4.3 Ion Mobility Spectrometry 599
17.4.4.4 Thermal Sensors 601
17.4.4.5 Pellister Catalytic Sensors 602
17.4.5 Optical Transducers 603
17.4.5.1 Infrared Detection 603
17.4.5.2 Fiber Optic Transducers 604
17.5 Biochemical Sensors 605
17.5.1 EnzymeSensors 605
17.6 Multisensor Arrays 606
17.7 Electronic Noses and Tongues 607
17.8 Specific Difficulties 610
References 611
Chapter 18: Sensor Materials and Technologies 615
18.1 Materials 615
18.1.1 Silicon as Sensing Material 615
18.1.2 Plastics 619
18.1.3 Metals 623
18.1.4 Ceramics 625
18.1.5 Glasses 625
18.1.6 Optical Glasses 626
18.1.6.1 Visible and Near Infrared Ranges 626
18.1.6.2 Mid- and Far-Infrared Ranges 627
18.1.7 Nanomaterials 628
18.2 Surface Processing 629
18.2.1 Deposition of Thin and Thick Films 629
18.2.2 Spin Casting 629
18.2.3 Vacuum Deposition 630
18.2.4 Sputtering 631
18.2.5 Chemical Vapor Deposition 632
18.2.6 Electroplating 633
18.3 Microtechnology 634
18.3.1 Photolithography 635
18.3.2 Silicon Micromachining 636
18.3.2.1 Basic Techniques 636
18.3.2.2 Thin Films 636
18.3.2.3 Wet Etching 637
18.3.2.4 Concentration-Dependent Etching 639
18.3.2.5 Dry Etching 640
18.3.2.6 Lift Off 641
18.3.2.7 Wafer Bonding 641
18.3.2.8 LIGA 642
References 643
Appendix 644
Index 660