The Kynix Blog - Sensor

Warm hints: The word in this article is about 2500 and  reading time is about 12 minutes. The fiber optic sensor consists of the light source, incident fiber, exit fiber, light modulator, light detector, and demodulator. The basic principle is that the light of the light source is sent to the modulation area through the incident optical fiber, and the light interacts with the measured parameters in the modulation area to change the optical property of the light into the modulated signal light which is then sent through the outgoing fiber optical detector, demodulator and get the measured parameters. In recent years, sensors have evolved in the direction of sensitivity, precision, adaptability, compactness, and intelligence.  Optical fiber has many excellent properties, such as anti-electromagnetic interference and atomic radiation performance, soft and lightweight mechanical properties. Insulation, non-responsive electrical properties. Water, heat, and corrosion resistance of chemical properties, can reach people's eyes and ears in unattainable places (such as high-temperature areas), or in areas harmful to humans (such as nuclear radiation area), but also can transcend human physiological boundaries and receive sensory organs Unexpected outside information.   Catalogs I. Basic Structure and Principle of Fiber Optic SensorII. Application of Light Sensor in Petrochemical Industry2.1 The application of fiber optic sensor in the   petrochemical system2.2 The application of fiber optic sensor in oil   loggingIII. Application of Fiber Optic Sensors in Power Systems3.1 Applications in the high voltage cable temperature   and strain measurement3.2 Application in Electric Power Sensors3.3 Application of optical fiber cable monitoringIV. Fiber Optic Sensors in Medical Applications4.1 Pressure measurement4.2 Blood flow velocity measurement4.3 PH measurementV. Fiber Optic Sensor FeaturesFAQ  I. Basic Structure and Principle of Fiber Optic Sensor The fiber optic sensor consists of the light source, incident fiber, exit fiber, light modulator, light detector, and demodulator. The basic principle is that the light of the light source is sent to the modulation area via the incident fiber, and the light interacts with the measured parameters in the modulation area to make the optical properties (such as intensity, wavelength, frequency, phase, and normality) of the light occur Changes into a modulated signal light, and then sent through the optical fiber into the optical detector, demodulator to obtain the measured parameters. Fiber optic sensors can be divided into two categories by sensing principle: one is the light transmission (non-functional type) sensor, the other is the sensor type (functional) sensor. In the fiber optic sensor, the optical fiber only as a light transmission medium, the measured signal is detected by other sensitive components, this exit fiber, and the incident optical fiber is not continuous. Between the two Modulators are spectrally sensitive or other types of sensitive elements. In the sensing type fiber optic sensor, the optical fiber has both the sensitivity to the signal to be measured and the transmission of the optical signal. And the "sense" and "pass" of the signal are combined so that the optical fiber in such a sensor is continuous. Due to the different roles played by the optical fibers in these two sensors, the requirements for the optical fibers are also different. Optical fiber in the light-transmitting sensor only plays the role of light transmission. The use of communication fiber even ordinary multi-mode fiber can meet the requirements, and sensitive components can be a very flexible selection of high-quality materials. So the sensitivity of these sensors needs more optical coupling devices, the structure is more complex. The structure of sensing type fiber optic sensor is relatively simple with fewer coupling devices, but higher requirements on the optical fiber. It often needs to be sensitive to signal measurement, with good transmission characteristics. So far, most people adopt the former, but with the improvement of optical fiber manufacturing technology, sensor-type fiber optic sensors will also be widely used. According to the principle of light being modulated in optical fiber, fiber optic sensors can be divided into intensity modulation, phase modulation, polarization modulation, frequency modulation, wavelength modulation, and so on. Up to now, optical sensors have been able to measure more than 70 physical quantities. Fiber Optic Sensors have unique advantages over traditional sensors. (1) High sensitivity. Since light is a very short wavelength electromagnetic wave, its optical length is obtained by the phase of light. Taking an optical fiber interferometer as an example, due to the small diameter of the fiber used, its optical length is subject to slight mechanical external force or temperature change, causing a large phase change. Suppose that with a 10-meter optical fiber, a change of 1 ° C causes a phase change of 1000ard. If the minimum phase change that can be detected is 0.01ard, the minimum change in temperature that can be measured is 10 ° C, showing a high sensitivity. (2) Anti-electromagnetic interference, electrical insulation, corrosion resistance, intrinsically safe. Since fiber optic sensors transmit information using light waves, optical fibers are an electrically insulating, corrosion-resistant transmission medium and safe, which makes it easy and effective to use All kinds of large electromechanical, petrochemical, mine and other strong electromagnetic interference and flammable and explosive and other harsh environments. (3) Fast measurement. Light travels fastest and can transmit two-dimensional information, so it can be used for high-speed measurements. The analysis of radar and other signals requires an extremely high detection rate. The application of electronics is difficult to achieve. Using high-speed spectral analysis of light diffraction can be solved. (4) Large information capacity. The signal under test is a light wave carrier, and the light has a very high frequency. The contained frequency band is very wide. The same optical fiber can transmit multiple signals. (5) Suitable for harsh environments. Optical fiber is a dielectric, high voltage, corrosion-resistant, anti-electromagnetic interference that can be used for other sensors that do not adapt to the harsh environment. In addition, fiber-optic sensors are also characterized by their lightweight, small size, flexibility, wide measurement range, good reusability, and low cost. The application of fiber optic sensors is precise because fiber optic sensors have so many advantages, making it a very wide range of applications, involving petrochemicals, power, medicine, civil engineering, and many other fields. Video 1 Introduction of fiber optic sensorsII. Application of Light Sensor in Petrochemical Industry 2.1 The application of fiber optic sensor in the petrochemical systemIn the petrochemical system, due to the underground environment with high temperature, high pressure, chemical corrosion and electromagnetic interference, and other characteristics, the conventional sensor is difficult to play a role in the well. However, the fiber itself is no charge, small and light, easy to bend, anti-electromagnetic interference, and anti-radiation performance. Particularly it is suitable for flammable and explosive, strict restrictions and strong electromagnetic interference, and other harsh environments. Fiber optic sensors in the measurement of the good parameters play an irreplaceable role. It will become the oil and gas exploration and oil logging and other logging A field of broad market prospects of new technologies.  Fiber optic sensor application in oil and gas exploration. Because of its high-temperature capability, multi-communications, distributed sensing capabilities, and the fact that it requires only a small space to meet its use conditions, fiber optic sensors make it particularly unique in exploration drilling. The application of fiber optic sensors can be made into the downhole spectrometer, distributed temperature sensor, and optical fiber pressure sensor, and other products suitable for this special job requirement. (1) The downhole spectrometer fluid analyzer shown in Figure 1 can be used to understand the crude oil composition during the initial development process. It consists of two sensors: one is the absorption spectroscopy fiber and the other is the fluorescence and gas detector. Downhole fluid is introduced into the tubing by formation probes and the optical sensor is used to analyze the fluid within the tubing. Fluid analysis spectrometers provide in-situ downhole fluid analysis and improve formation fluid evaluation. (2) Distributed temperature sensors. Optical fiber distributed temperature sensors are the most popular fiber optic sensors for downhole applications. The application example is to monitor the steam injection heavy oil recovery system. Steam is injected into the heavy oil reservoir to reduce the viscosity of the oil, allowing heavy oil to be mined out. Downhole steam temperature can be as high as 250 ℃. Figure 1 Fluid analyzer structure(3) The fiber-optic pressure sensor is currently under development. Its main focus is on ultra-high temperature and downhole pressure monitoring tasks. Other commercial products based on fiber optic sensors are currently available. For example, fiber optic probes for multiphase flow measurements and distributed dynamic strain measurements. Its high reliability, high efficiency, and low power consumption are key factors in the success of optical fiber products in oil field applications. 2.2 The application of fiber optic sensor in oil loggingOil logging is one of the most basic and key aspects of the petroleum industry. The parameters such as pressure, temperature, and flow rate are important physical quantities in oil and gas wells. These advanced technologies are used for long-term Real-time monitoring, timely access to the information of oil and gas wells, the oil industry has a very important significance. Fiber optic sensors are insensitive to electromagnetic interference and withstand extreme conditions, including high temperatures and pressures, as well as strong shock and vibration, to measure borehole and well site environmental parameters with high accuracy, and have distributed measurement capabilities for fiber optic sensors. The spatial distribution gives the profile information. Moreover, the fiber optic sensor cross-sectional area is small, short in shape, in the wellbore occupies a very small space. Traditional electronic sensors do not have such features in the harsh underground environment. Fiber optic sensors can do downhole flow measurement, temperature measurement, pressure measurement, water (gas) measurement, density measurement, acoustic measurement. (1) Flow measurement. Because the intensity, phase, frequency, wavelength, and other characteristics of light in the optical fiber transmission process will be subject to flow modulation. A certain light detection method can convert the modulation into electrical signals, you can find the fluid flow, which is the fiber flow the working principle of the meter. (2) Temperature and pressure measurement. The distributed optical fiber measurement system (DTS) utilizes the Raman effect of the optical fiber to enable real-time monitoring of the temperature field where the fiber is located. The EFPI type (non-intrinsic FP interference) and FBG fiber optic sensors are wavelength-coded sensors. With high sensitivity, it also can simultaneously measure pressure, temperature, stress, and other parameters of the characteristics. The optical fiber thermal color temperature sensor is a reflective temperature sensor composed of a white light source and a multi-mode optical fiber.  The optical fiber radiation temperature sensor utilizes black body radiation energy. Its non-contact, measurable instantaneous temperature, fast response, and no need for heat balance time are available. In high-temperature measurement, the semiconductor absorption-type optical fiber temperature sensor utilizes the characteristic that the absorption edge wavelength of its semiconductor material shifts to a longer wavelength as the temperature increases, and an appropriate semiconductor light-emitting diode is selected so that its spectral range falls exactly on the absorption edge region. , So the light intensity through the semiconductor decreases with increasing temperature. (3)Water (Gas) Rate and transmission power of U-shaped fiber used for density measurement vary with the refractive index of the external medium. The lightwave serves as an information carrier and has nothing to do with the resistivity, flow pattern, and water quality of the mixed fluid. The fiber holding rate is based on this principle. The density sensor essentially solves the problem of the application of high water content without resolution and radioactive substances in the existing holding ratios. For the multi-phase fluids, the refractive indices of oil, water, and gas are all different, so the refractive index of the mixed fluid will follow. Change the ratio of oil, water, gas changes. Therefore, this refractive index modulation type fiber optic sensor can not only measure the fluid holding rate, fluid density can be measured at the same time, for its accuracy is higher. (4) Sonic measurement. Seismic waves propagate in different media and the waveforms of the received seismic waves will be different. According to different seismic waveforms, the sedimentary sequence and sedimentary structure can be identified to locate the reservoir, determine the gutter, detect the damage and fracture of the casing, and perforation, detect layers and determine the fluid flow, and so on. VSP seismic logging means that the geophone is placed in a well and the seismic signal is received by the geophone in the well by means of a micro-vibration generated by ground-derived seismic waves or fluid flow in the well.  The permanent downhole optical fiber three-component seismic survey has high sensitivity and directionality can produce high-precision spatial images. It can not only provide near-borehole images but also can provide strata images around the wellbore. And the measurement range can reach thousands of kilometers. It withstands harsh environmental conditions and has no moving parts and downhole electronics that can withstand strong shocks and vibrations and Can be installed in an extremely small space for complex completion string.  III. Application of Fiber Optic Sensors in Power Systems Because of the complicated structure and wide distribution of power system networks, various hidden dangers exist on the high-voltage power line and power communication network. Therefore, it is very important for distributed monitoring of various lines and networks in the system.  3.1 Applications in the high voltage cable temperature and strain measurementAt present, foreign countries (mainly Britain, Japan, etc.) have developed the distributed optical fiber temperature sensor products by utilizing the laser Raman spectroscopy effect. And domestically, we are actively carrying out research work in this area. The domestic begin to introduce the distributed optical fiber temperature sensing technology into the power system cable temperature measurement. In connection with the snow disasters suffered in southern China last year, we can consider that if we can lay sensor fiber optic cables in parallel on high-voltage cables and measure the temperature, pressure, and other parameters of power system cables and towers in real-time, we can make timely measurements, so as to minimize economic losses.  Fiber optic sensors in the power system will have a wide range of applications. Ideally, the fiber should be placed as close as possible to the cable core to more accurately measure the actual cable temperature. For direct-buried power cables, although the surface-mount fiber can not accurately reflect the change of cable load, it is more sensitive to the change of thermal resistivity of soil in the buried cable and can reduce the installation cost of optical fiber. 3.2 Application in electric power sensorsElectric power is the basic power reflecting the energy conversion and transmission in the power system. Electric power measurement is an important part of power metering. With the rapid development of the power industry, traditional electromagnetic measurement methods have increasingly exposed their inherent limitations, such as electrical insulation, electromagnetic interference, and magnetic saturation.  Therefore, people have been working hard to find new methods for measuring electrical power. It can be said that the advent of fiber optic sensors has brought people the gospel to solve this problem. The main characteristics of fiber-optic power sensors are: Since electric power sensing involves both voltage and current at the same time, it is usually necessary to consider both electro-optic and magneto-optic effects. At the same time, two kinds of sensing media or one multifunctional media are used as sensitive elements. The structure of the fiber electric power sensor head is relatively complicated; the optical sensor signal of the fiber electric power sensor sometimes includes voltage and current signals at the same time, so the signal detection and processing methods thereof will also be more complicated. 3.3  Application of optical fiber cable monitoringIn Power Systems The power system has a wide variety of optical cables. In addition, China has a vast area and the environment varies widely. Therefore, the environment of optical cables is also very complex. Temperature and stress are the main environmental factors that affect the performance of optical cables. Therefore, while monitoring the breakpoint of the optical fiber, the temperature and stress conditions of the optical cable are also monitored. It can be seen that the optical fiber cable has far-reaching fault warning and maintenance.  By measuring the frequency shift and intensity of the Brillouin scattered light along the length of the optical fiber, the temperature and strain information of the optical fiber can be obtained, and the sensing distance is relatively long, so it has far-reaching engineering research value. Based on Brillouin Optical Time Domain Reflectance (BOTDR) distributed optical fiber sensing system, using coherent detection technology, the system principle shown in Figure 2.  Figure 2 based on BOTDR sensing system principleThe BOTDR fiber sensing system measures the self-distribution of scattering signals of an optical fiber and its signal strength is very weak, but the coherent detection technology can be used to improve the signal-noise ratio of the system. This solution can be a single light source, single-ended work, the system is simple and easy to implement, and can simultaneously detect fiber breakpoints, loss, temperature, and strain.  IV. Fiber Optic Sensors in Medical Applications In medical fiber, sensors are mainly light-transmitting. With its small size, insulation, non-radio frequency, and microwave interference, high measurement accuracy and good affinity with living organisms, and other advantages. This article will mainly introduce the application of transmission optical fiber in pressure measurement, blood flow velocity measurement, and pH measurement. In addition, it can also be applied to the measurement of temperature and medical image transmission. 4.1 Pressure measurementCurrent clinically applied pressure sensors are mainly used to measure intravascular blood pressure, intracranial pressure, intracardiac pressure, bladder, and urethral pressure. The pressure sensor used to measure blood pressure is schematically shown in Figure3. The pressure-sensitive part is a water-repellent film on the sidewall of the tip of the probe catheter connected to the membrane by a cantilever micromirror and an optical fiber opposite the reflector for transmitting incident light to the reflector while The reflected light is also transmitted.  When there is pressure on the film, the film is deformed and can drive the cantilever to change the angle of the mirror. The light beam coming from the fiber is shone on the mirror and then reflected at the end of the fiber. Since the direction of the reflected light changes with the angle of the mirror, the intensity of the reflected light received by the optical fiber also varies. This change passes through the optical fiber to the other end of the photodetector into an electrical signal, so that by changing the voltage to know the size of the probe at the pressure.Figure 3 Optical fiber pressure gauge probe 4.2 Blood flow velocity measurement Doppler-type optical fiber speed sensor measurement of subcutaneous tissue flow velocity shown in Figure 4, this device uses the optical fiber end reflection phenomenon, the measurement system is simple in structure.Figure 4 optical fiber pressure gauge probeLaser light with a frequency of f passes through the lens and the fiber is sent to the epidermal tissue. For immobile tissue, such as the vessel wall, the reflected light does not produce a frequency shift; and for the red blood cells in the cortex capillary flow rate, the reflected light to produce a frequency shift, the frequency change △ f. The frequency shift of the reflected light The intensity is proportional to the concentration of erythrocytes and the change in frequency can be proportional to the velocity of erythrocytes. Emitted light collected by the optical fiber, the first on the light detector for mixing, and then into the signal processing instrument, which get the red blood cell velocity and concentration. 4.3 PH measurementA schematic diagram of the pH fiber optic sensor used to determine tissue and blood values is shown in Figure 4. Its working principle is the use of emission light, the intensity of transmitted light with the wavelength distribution of the spectrum to be measured. The sensor inserts two optical fibers into an ion-permeable cellulose capsule containing reagent, which penetrates the reagent when the needle is inserted into the tissue or blood vessel, causing the reagent to absorb light of a certain wavelength. Measured such changes, you can get the blood or tissue pH.Figure 5 Determination of pH fiber spectrometerV. Fiber Optic Sensor Features 1.High sensitivity. 2.The geometry has a wide range of adaptability, can be made into any shape of the fiber optic sensor. 3.You can create sensors sensing a variety of different physical information (sound, magnetic, temperature, rotation, etc.) of the device. 4.Can be used for high voltage, electrical noise, high temperature, corrosion, or other harsh environments. 5.But also with the inherent compatibility of optical telemetry technology. The advantages of fiber-optic sensors are that optical fiber sensors use light as a carrier for sensitive information, and use optical fibers as a medium for transmitting sensitive information. Compared with conventional sensors. They have the characteristics of optical fiber and optical measurement and have a series of unique advantages. Good electrical insulation, anti-electromagnetic interference, non-invasive, high sensitivity, easy to achieve long-distance monitoring of the signal under test, corrosion resistance, explosion-proof, flexible optical path, easy to connect with the computer. Sensors are developed in the direction of sensitivity, precision, adaptability, compactness, and intelligence. They can serve as human eyes and ears where people cannot reach(such as high-temperature areas, are as harmful to humans, or nuclear radiation areas). But it is also beyond the physical boundaries of human beings, outsiders can not feel the sensory information. FAQ 1. How does a fiber optic sensor work?Fiber optic sensors work based on the principle that light from a laser or any superluminescent source is transmitted via an optical fiber, experiences changes in its parameters either in the optical fiber or fiber Bragg gratings and reaches a detector which measures these changes. 2. What are fiber optic sensors used for?Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the quantity to be measured modulates the intensity, phase, polarization, wavelength or transit time of light in the fiber. 3.How are fiber optic sensors classified?Based on the operating principle or modulation and demodulation process, a optical fiber sensor can be classified as intensity, a phase, a frequency, or a polarization sensor. All these parameters may be subject to change due to external perturbations. ... These sensors are widely used as chemical sensors. 4. What is active and passive optical fiber sensor?Active fibre optic. -In optical fiber communication, because the signal usually decades during long distance transformation, you need to add an amplifier to boost the signal. Passive fibre optic. - Simply receive light data from the environment, it is commonly used for illumination (Fiber optical lighting. 5. What are the characteristics of optical fiber sensors?Optical fiber sensors have unique advantages, such as high sensitivity, immunity to electromagnetic interference, small size, light weight, robustness, flexibility, and the ability to provide multiplexed or distributed sensing. 6. Which is a use of fiber optics?They are widely used in lighting, both in the interior and exterior of vehicles. Because of its ability to conserve space and provide superior lighting, fiber optics is used in more vehicles every day. Also, fiber optic cables can transmit signals between different parts of the vehicle at very fast speed. 7. Why optical fiber is used for communication?Optical fiber is used by telecommunications companies to transmit telephone signals, Internet communication and cable television signals. ... Due to lower attenuation and interference, optical fiber has advantages over copper wire in long-distance, high-bandwidth applications. 8. Is fiber optic WIFI?Like any Internet service, fiber optic Internet download speeds depend on your connection. Not all fiber services are created equal, much like broadband. ... You can download more, faster, with fiber. Fiber Internet is more reliable than copper and less 'patchy' than Wifi. 9. Is fiber optic analog or digital?Digital signals can be transmitted long distances without degradation as the signal is less sensitive to noise. Fiber optic datalinks can be either analog or digital in nature, although most are digital. Both have some common critical parameters and some major differences. 10. How much data can a fiber optic cable transmit?A new fiber-optic system can carry 800 gigabits of data per second, a big step up from top speeds of 100 or 200 gigabits in today's data centers. You May Also Like:GPS and inertial sensors for driverless applicationsA New Technology for Advancing Opticals,Sensors Even Resistant SupercapacitorsSensors are Always In a State of Rapid Progress

SummaryResearchers at TU Wien have succeeded in developing a method for the controlled manufacture of porous silicon carbide. Silicon carbide has significant advantages over silicon; it has greater chemical resistance and can therefore be used for biological applications, for example, without any additional coating required.Extremely fine porous structures with tiny holes – resembling a kind of sponge at nano level – can be generated in semiconductors. This opens up new possibilities for the realization of tiny sensors or unusual optical and electronic components. There have already been experiments in this area with porous structures made from silicon.To demonstrate the potential of this new technology, a special mirror that selectively reflects different colors of light has been integrated into a SiC wafer by creating thin layers with a thickness of approximately 70nm each and with different degrees of porosity. “There is a whole range of exciting technical possibilities available to us when making a porous structure with countless nano holes from a solid piece of a semiconductor material,” says Markus Leitgeb from the Institute of Sensor and Actuator Systems at TU Wien. Leitgeb developed the new material processing technology as part of his dissertation with Professor Ulrich Schmid in cooperation with CTR Carinthian Tech Research AG and sponsored by the Competence Centers for Excellent Technologies (COMET) program.“The porous structure influences the manner in which light waves are affected by the material. If we can control the porosity, this means we also have control over the optical refractive index of the material.” This can be very useful in sensor technology – for example, the refractive index of tiny quantities of liquid can be measured using a porous semiconductor sensor, thus allowing a reliable distinction between different liquids. Another attractive option from a technical and application-oriented perspective is to first make certain areas of the SiC wafer porous in a highly localized manner, before depositing a new SiC layer over these porous areas, and then causing the latter to collapse in a controlled manner – this technique produces microstructures and nanostructures which can also play a key role in sensor technology.  However, in all these techniques it is crucial that the appropriate starting material is selected. “Until now, silicon has been used for this purpose, a material with which we already have a lot of experience”, says Professor Schmid. Silicon also has significant drawbacks, however; under harsh environmental conditions, for example in extreme heat or in alkaline solutions, structures made of silicon are attacked and rapidly destroyed. Therefore, sensors made of silicon are often not suitable for biological or electrochemical applications. For this reason, at TU Wien, attempts have been made to achieve something similar with the semiconductor silicon carbide, which is biocompatible and considerably more robust from a chemical perspective. Some special tricks were required, however, in order to produce porous structures from silicon carbide. THE COLOR-SELECTIVE MIRRORFirst, the surface is cleaned, and then partially covered with a thin layer of platinum. The silicon carbide is then immersed in an etching solution and exposed to UV light, in order to initiate the oxidation processes. This causes a thin porous layer – initially 1μm thick – to form in these areas that are not coated with platinum. An electrical charge is then also applied in order to be able to precisely set the porosity and the thickness of the subsequent layers. Here, the first porous layer promotes the formation of the first pores when the electrical charge is applied.“The porous structure spreads from the surface further and further into the interior of the material”, explains Markus Leitgeb. “By adjusting the electrical charge during this process, we can control what porosity we want to have at a given depth.” In this way, it was possible to produce a complex layered structure of silicon carbide layers with higher and lower levels of porosity, which is finally separated from the bulk material by applying a high voltage pulse. The thickness of the individual layers can be selected such that the layered structure reflects certain light wavelengths particularly well or allows certain light wavelengths to pass through, resulting in an integrated, color-selective mirror. “We have thus demonstrated that our new method can be used to reliably control the porosity of silicon carbide on a microscopic scale”, says Ulrich Schmid. “This technology promises many potential applications, from anti-reflective coatings, optical or electronic components and special biosensors, through to resistant supercapacitors.” 

SummaryRihito Kuroda, a researcher at Tohoku University in Japan who develops UV imagers in his lab said“There's important information hidden in the UV,”. However, this information has been difficult to capture; silicon doesn't absorb ultraviolet wavelengths very well, and other semiconductors that play well with ultraviolet light make slow imagers with low frame rates. But that’s about to change. This week at the International Electron Devices Meeting in San Francisco, two research groups presented ultrathin, flexible UV sensor designs they hope will help make these devices more widespread.  UV images reveal spots that presage rot on mushrooms, dark lines along flower petals that guide insects to nectar, and clouds of acetone in water. And with their relatively short wavelengths, UV sensors could be well suited to more precise navigation for flying swarms of tiny drones. The research aimed at making UV sensors from specially formulated paperA group from King Abdullah University of Science and Technology in Saudi Arabia presented their research aimed at making UV sensors from specially formulated paper. Electrical engineering student Chun-Ho Lin explained that it’s difficult to make flexible UV sensors because they heat up under the high-energy rays. Typical flexible substrates, like plastic and paper, can’t wick away that heat quickly enough. He and other electrical engineers in Jr-Hau He’s lab made thermally conductive, UV-sensitive paper by combining boron nitride nanosheets with cellulose fibers. Flexible sensors made from this formulation can take the heat, withstanding temperatures up to 200 degrees Celsius. What’s more, they are blind to wavelengths above the deep UV band.Other researchers are sticking with silicon, but using graphene to help it along. Yang Xu, an electrical engineer at Zhejiang University in China, says there are good reasons to work with silicon, even though in its native state it is a strong reflector of UV rays. Silicon photodetectors can work quickly, enabling higher frame rates, and they can draw on a vast manufacturing infrastructure. Xu says his philosophy is, “Why not help silicon do better?” With that in mind, his team is pairing the semiconductor with graphene, which absorbs UV light like a champ. To make flexible silicon-graphene UV photodetectors, the Zhejiang University group uses etching and rubber stamps to transfer ultrathin silicon microstructures to a flexible plastic substrate, then coats the silicon with graphene and adds electrodes. This photodetector is blind to visible light, because the silicon layer is just 20 nanometers thick and cannot absorb it. This ultrathin device is flexible and performs as well as state-of-the-art UV photo detectors, says Xu. His lab is currently working on shrinking the size of the photodetectors to improve their resolution. 

SummaryIf you have follow the informations of sensor,you will know that sensors are always in a state of rapid progress.Now I will state a few things to prove it in the following.Sensor,also called Transducer, is a kind of detection device,it can receive the measured information and then output them according to a certain rule or other needed form to meet the transport, handling,storage,recording,displaying and controlling of imformation,etc. Know more about it,you can read the article : Most Comprehensive Sicence Popularizing of Sensor (detection device) Researchers created quantum control technique for quantum sensorsAs we all known,there is a common problem that designers are harder to deal with quantum sensing devices. How,University of Sydney researchers have sloved this trouble associated with this super-sensitive tech. They have created quantum control techniques in collaboration with Johns Hopkins Applied Physics Laboratory and Dartmouth College. This development will allow next-gen ultra-sensitive sensors to identify small signals and reject unwanted background noise.By applying the right quantum controls to a qubit-based sensor,the team adjust its response in a way  that guarantees the best possible exclusion of the background clutter—that is, the other voices in the room. In order to obtain and analyze signals, measurement protocols are set in place. Over the years, these protocols have lagged behind the advancement of electronic devices. The disparity has led to a phenomenon known as “spectral leakage,” which occurs when quantum sensors return unclear results.What's more, the new control protocols have reduced spectral leakage by several orders of magnitude by using improved sensor hardware. All the approach is relevant to nearly any quantum sensing application and can also be applied to quantum computing as it provides a way help identify sources of hardware error.‘quantum control techniques' is a major advance in how to operate quantum sensors.  New sensors uses for effective control of enviroment pollutionEnviromental pollution issue are always paid great attention by human being as the development of all the world. A team from the Faculty of Physics of Lomonosov Moscow State University has suggested using porous silicon nanowire arrays in highly sensitive gas sensors which may be used both for effective control of environment pollution levels and for the monitoring of air composition in closed spaces,from classrooms to space stations.According to researchers, these devices will be able to detect the presence of toxic and non-toxic gas molecules in the air at room temperature.Each sensor consists of an array of 10 micron long organized silicon nanowires with diameters ranging from 100 to 200 nm. Each nanowire has porous crystalline structure. The size of silicon crystals and pores between them in individual nanowire, varies from three to five nanometers.ey can be obtained by means of a cheap method of metal-assisted chemical etching. It is based on selective chemical etching, i.e. partial removal of surface layer from a bulk crystalline silicon with the use of metal nanoparticles as a catalyst. Moreover, the procedure is quick—at least 100 elements can be produced in a lab within just one hour.Such porous nanowires have huge specific surface area due to which their physical and chemical properties are extremely sensitive to molecular environment. It was also found out that the obtained samples exhibited an effective photoluminescence in the red spectrum region at room temperature. What's important,this gas sensors based on porous nanowires both work at home temperatures and also are reusable, because the all observed effects were completely reversible. Military sensor systems collect accurate informationCollecting accurate user and environmental information such as enemy's location,survive shock, vibration, moisture plays an important role in military system. Deployment complaints about the platform aside, Lockheed Martin’s Electro-Optical Targeting System (EOTS) for the F-35 Lightning II is a high-performance, lightweight, multi-function sensing solution for precision air-to-air and air-to-surface targeting (Figure 4). Integrated into the aircraft fuselage with a rugged sapphire viewport, the device talks to the aircraft via a fiber-optic interface.Presented as the first sensor to combine forward-looking and infrared search along with track functionality, EOTS enables situational awareness and precision delivery of laser and GPS-guided weapons. Advanced EOTS, the next iteration, will incorporate enhancements and upgrades like short-wave infrared, high-definition television, and an infrared marker.Today’s military sensors must operate well on their own, and function as part of a combined-arms approach with an interlaced network of sensing, to detect threats of any nature from any direction. One such way to address this is with a battlefield awareness solution like 3D Advanced Warning System (3DAWS) from BAE Systems, which can provide universal threat detection to an aircrew with a layered countermeasure defense.The modular and expandable system can integrate with fixed- and rotary-wing aircraft and countermeasure systems, with the flexibility to work with existing radar or laser warning systems. The core of the 3DAWS suite is the passively-cued, semi-active radio frequency 3D Tracker element, which serves as an adjunct to current and future passive threat detection systems. 

Summary Energy-efficient sensor nodes are crucial to the development of the industrial internet of things (IIoT).Engineering team are trying to optimise energy efficient IIoT sensor nodes.In many cases, these devices will have to perform for years on a single battery charge. That calls for an implementation that is as energy efficient as possible. Achieving this demands a holistic approach to energy optimisation, one that reaches from the system level down to process and circuit-design choices.     Problem met Engineering team are trying to optimise the energy comsumption of an IIOT sensor node is that many of the design decisions interact with each other. And there are often hidden complexities of designs that lead to energy consumption being much higher than expected. For example, conventional wisdom points to the power consumption of an RF transmitter being a major influence on total energy. But, even though the receiver element may consume far less instantaneous power, system-level decisions that call for the device to listen for intermittent updates from a server can lead to it being left active for long periods of time – tens of seconds per hour versus tens of milliseconds for the transmitter. Because of the long operational life of a typical IoT sensor node, the energy used even when subsystems are sleeping can be responsible for a heavy drain on the battery.   Integration Despite the complex interaction between application design and implementation, there are some high-level choices that are likely to lead toward an optimal solution. One of these is the use of integration. Although it is entirely possible to use 2D-IC and 3D-IC multi chip packaging to assemble a compact IIoT sensor node from off-the-shelf components, integration into a single custom integrated circuit (IC) provides not just significant benefits in terms of cost and size but reductions in power consumption. In order to communicate with off-chip memories and analogue and RF on traditional PCB-based implementations, Input/Output (I/O) drivers with significant current draw are often required. A single system-on-chip (SoC) makes it possible to remove such power-hungry circuits.     The duty cycle and lifetime energy consumption The other fundamental consideration for designing energy-efficient IIoT sensor nodes is an understanding of the duty cycle and its impact on lifetime energy consumption. Simply minimising the power consumption of individual elements is not enough to guarantee that a remote or  inaccessible sensor can operate on a single battery charge for a decade or more. In such a situation, every microjoule the node requires from its battery is important. But that does not mean the system powered by a typical battery can consume no more than a few microwatts at any point in its life. Such a system would not be able to take measurements and communicate them wirelessly in any practical way. The use of duty-cycle planning makes it possible for the system to perform tasks that take significant amounts of power for short periods, trading those bursts against savings that can be made while much of the system is quiescent. For example, the RF subsystem of a wireless sensor node need only be powered when it is active. This is likely to be one of the most power-hungry parts of the overall design because of the need to supply enough transmitter power to ensure packets of data can be delivered reliably. However, the power consumed by the transmitter portion of the RF subsystem is relatively easy to control. Once a packet has been delivered the transmitter can be shut down. But there can still be significant power drawn by subsystems such as the RF receiver that continue to remain active once the transmitter has finished sending.   The RF receiver often needs to remain active because of timing uncertainty and this type of uncertainty has a major influence on overall energy consumption. Whereas the transmitter has predictable requirements – it need only be activated when data is ready to send – the receiver needs to be active for much longer. It needs to wait for acknowledgments from nodes to which it is sending data, and also needs to activate periodically to be able to listen for unsolicited messages. As a result, the overall energy consumption of the RF receiver will often exceed that of the transmitter over the lifetime of the sensor, even though its instantaneous power demand is lower. An efficient design will exploit power-saving techniques such as putting much of the circuitry into a low-activity state until an RF signal is detected. Another optimisation is to reduce the amount of time per minute the receiver is active at the cost of the sensor node’s responsiveness to external commands.     Although they might appear to be essential to all operations, the microprocessor core and its memory subsystem need careful duty-cycle management because they can demand very high levels of power. The problem for many designs is that software running on the processor is often responsible for core tasks such as fetching data from sensors and passing messages to the RF subsystem. This appears to mandate that the processor be fully active whenever sensor inputs need processing.   However, in many cases, the work performed by the software is very simple. It is quickly checking data values to see if they have passed a limit that might signal a problem, or for increased activity that needs closer inspection. Activating the processor to handle all the data is wasteful and can easily be offloaded to custom hardware or a programmable state machine. These circuits consume far less power and can run independently of the processor, so that and the memory array can be powered down.   Current leakage Even when most of the device is powered down, the power drawn during lengthy periods of sleep can be surprising. Energy lost through current leakage in subsystems that need to remain powered can incur a heavy overhead when analysed over the lifetime of the system because the time the system spends sleeping can be orders of magnitude longer than that during which the system is active. The problem of leakage calls for design techniques that limit leakage in subsystems such as real-time clocks and interrupt controllers to the nanoamp level. It might seem reasonable to disable interrupts for external events and only keep the real-time clock running in some applications. However, in that design the system needs to wake at regular intervals to check inputs that may incur unwanted energy consumption if there is no overall change to record. If the long-term energy usage of an interrupt controller is low enough, keeping that active to respond to events as they happen may make more sense.   When the processor and memory subsystem are powered down, a key decision is how to manage temporary data. One option is to use specialised retention register and memory cells, at the cost of some leakage power. Another is to put important data, such as calibration values, into non-volatile memory (NVM). This allows values to be restored quickly on restart but allows the leakage-prone SRAM arrays and registers to be powered down fully until then. But NVM choices are not always straightforward.   Processes that are optimised for low leakage and that support high-density NVM options may not have the performance required to support efficient RF modules on-chip. The energy needed for I/O drivers that transfer data to an off-chip RF transceiver may outweigh the power savings and security advantages obtained from implementing NVM on-chip. Careful analysis of the application’s requirements will indicate which choice is better for the custom SoC solution.   For the portions of the design that will be active for much of the device’s lifetime, careful attention to detail is required. Seemingly small details such as choosing to multiplex inputs into an analogue-to-digital converter (ADC) will help determine the architecture of choice for those circuits. A sigma-delta ADC may initially appear to offer a good trade-off between accuracy, energy efficiency and silicon area. But it is not suited to multiplexing. Often a successive approximation (SAR) architecture offers superior performance for industrial sensor signals. Advances in SAR design have pushed the energy per bit per conversion down into the range of tens of femtojoules.   Front-end analogue circuits are just as important as the ADC. Amplifiers and buffers that isolate and condition signals before conversion can consume high levels of power and they will be active for long periods of time. Analysis of the specific requirements for bandwidth and accuracy often allow for optimizations that reduce the energy of front-end circuitry and ADCs.   To tie all the subsystems together into a working custom SoC demands the use of power-aware design methodologies to ensure subsystems and circuits are activated properly when required, and can be powered down without disrupting the operation of other parts of the custom IC that need to stay running. Standards such as the Unified Power Format (UPF) have been designed to support such power-aware methodologies, but their application requires experience and attention to detail at different levels of abstraction.   Take an example For example, there may be a logical connection between two subsystems that demands they be active at the same time. But physical restrictions may call for them to form part of a larger power island – an area of the mixed-signal ASIC with a common set of power and ground rails – that includes other subsystems that are not required during that time. Design verification needs to ensure that the entire island is powered up correctly. If not, the final SoC will fail. Such physical design considerations may call for changes to the power-control architecture if the consumption of the whole island is higher than the budget allows. It may call for subsystems to be assigned to different power islands, for example.   Verification also needs to pay attention to on-chip noise, which may point to further optimization of the power-island strategy. For example, a low-noise LDO may be used to power sensitive mixed-signal sections that operate autonomously. Once measurements have been taken or RF communications have been completed, a higher-efficiency DC/DC converter may then be reactivated to analyse incoming data and make decisions.   Although the core requirements of energy efficiency in IIoT sensor nodes are readily understood, as can be seen, the implementation choices are complex and often subtle. Many factors affect the optimum solution for a given IIoT sensor node application, although a custom SoC will frequently be the best target in terms of energy and overall cost. Therefore, the ability to call on the expertise of design teams with extensive experience in custom mixed-signal IC implementation is key to success.  

SummaryA digital temperature sensor IC which offers accurate measurements in the temperature range -20 to 10°C has been introduced by ams. The performance of the AS6200C makes it easier for designers of refrigerators and data loggers in cold-chain storage equipment to meet demanding targets for system-level accuracy. The AS6200C’s measurements are accurate to ±0.2°C between -20°C and 10°C, the temperature range over which storage equipment for perishable goods operates.  AS6200C Sensor ICAS6200C sensor's accuracy is guaranteed over the device's supply voltage range of 1.8~3.6V. In temperature control and temperature logging applications, the total error budget is made up of multiple components. By minimising the error at the point of measurement, the designer gains extra headroom for other error and noise sources, such as the heat generated by board-mounted com-ponents. The use of the highly accurate AS6200C gives the designer more flexibility to modify other elements of the system design while keeping total error below a specified maximum level. The AS6200C integrates a sensor front end, 12-bit analogue-to-digital converter and digital logic in a small WL-CSP package. It provides a digital output over an I2C interface to any host microcontrol-ler. The device performs on-board digital signal processing, which means that it needs no user calibration, and its linearised output requires no compensation by an external microcontroller. The AS6200C is intended for use in equipment for storing and transporting food, pharmaceuticals, flowers and other perishable goods, as well as in domestic and commercial refrigerators. It is well suited to data loggers that comply with the EN12830:1999 class 1 standard.The new device extends the ams family of small, accurate digital temperature sensor ICs, joining the AS6200 sensor, which achieves peak accuracy between 0 and 65°C. “The AS6200C offers the market a unique combination of small size - its footprint is only 1.5mm2 - very high accuracy over the cold-chain monitoring and storage temperature range, and a convenient digital output requiring no calibration or linearisation. It provides a new example of the value of the low noise, high sensitivity, high linearity semiconductor technology underlying the outstanding performance of ams' sensor solution products,” said Nikolai Haslebner, Marketing Manager at ams.