Gas conductive sensor technology and application
光电传感器(中英文对照版)
Photoelectric sensorKey word: photoelectric effect photoelectric element photoelectric sensor classification sensor application characteristics .Abstract: in the rapid development of science and technology in the modern society, mankind has into the rapidly changing information era, people in daily life, the production process, rely mainly on the detection of information technology by acquiring, screening and transmission, to achieve the brake control, automatic adjustment, at present our country has put detection techniques listed in one of the priority to the development of science and technology. Because of microelectronics technology, photoelectric semiconductor technology, optical fiber technology and grating technical development makes the application of the photoelectric sensor is growing. The sensor has simple structure, non-contact, high reliability, high precision, measurable parameters and quick response and more simple structure, form etc, and flexible in automatic detection technology, it has been widely applied in photoelectric effect as the theoretical basis, the device by photoelectric material composition. Text:First, theoretical foundation - photoelectric effectPhotoelectric effect generally have the photoelectric effect, optical effect, light born volts effect.The light shines in photoelectric material, according to the electronic absorption material surface energy, if absorbed energy large enough electronic electronic will overcome bound from material surface and enter the outside space, which changes photoelectron materials, this kind of phenomenon become the conductivity of the photoelectric effectAccording to Einstein's photoelectron effect, photon is moving particles, each photon energy for hv (v for light frequency, h for Planck's constant, h = 6.63 * 10-34 J/HZ), thus different frequency of photons have different energy, light, the higher the frequency, the photon energy is bigger. Assuming all the energy photons to photons, electronic energy will increase, increased energy part of the fetter, positive ions used to overcome another part of converted into electronic energy. According to the law of conservation of energy:Type, m for electronic quality, v for electronic escaping the velocity, A microelectronics the work done.From the type that will make the optoelectronic cathode surface escape the necessary conditions are h > A. Due to the different materials have different escaping, so reactive to each kind of cathode materials, incident light has a certain frequency is restricted, when the frequency of incident light under this frequency limit, no matter how the light intensity, won't produce photoelectron launch, this frequency limit A -h m 212νν=called "red limit". The corresponding wavelength for type, c for the speed of light, A reactive for escaping.When is the sun, its electronic energy, absorb the resistivity reduce conductive phenomenon called optical effects. It belongs to the photoelectric effect within. When light is, if in semiconductor electronic energy big with semiconductor of forbidden band width, the electronic energy from the valence band jump into the conduction band, form, and at the same time, the valence band electronic left the corresponding cavities. Electronics, cavitation remained in semiconductor, and participate in electric conductive outside formed under the current role.In addition to metal outer, most insulators and semiconductor have photoelectric effect, particularly remarkable, semiconductor optical effect according to the optoelectronics manufacturing incident light inherent frequency, when light resistance in light, its conductivity increases, resistance drops. The light intensity is strong, its value, if the smaller, its resistance to stop light back to the original value. Semiconductor produced by light illuminate the phenomenon is called light emf, born volts effect on the effect of photoelectric devices have made si-based ones, photoelectric diode, control thyristor and optical couplers, etc.Second, optoelectronic components and characteristicsAccording to the outside optoelectronics manufacturing optoelectronic devices have photoelectron, inflatable phototubes and photoelectric times once tube.1. Phototubes phototubes are various and typical products are vacuum phototubes and inflatable phototubes, light its appearance and structure as shown in figure 1 shows, made of cylindrical metal half cathodic K and is located in the wires cathodic axis of anode in A package of smoke into the vacuum, when incident light within glass shell in the cathode, illuminate A single photon took all of its energy transfer to the cathode materials A free electrons, so as to make the freedom electronic energy increase h. When electrons gain energy more than escape of cathode materials, it reactive A metal surface constraints can overcome escape, form electron emission. This kind of electronic called optoelectronics, optoelectronic escaping the metal surface for after initial kinetic energyPhototubes normal work, anode potential than the cathode, shown in figure 2. In one shot more than "red light frequency is premise, escape from the optoelectronic cathode surface by positive potential attracted the anode in photoelectric tube forming space, called the current stream. Then if light intensity increases, the number of photons bombarded the cathode multiplied, unit of time to launch photoelectron number are also increasing, photo-current greatens. In figure 2 shows circuit, current and resistance is the voltage drop across the only a function of light intensity relations, so as to achieve a photoelectric conversion. When the LTT optoelectronic cathode K, electronic escape from the cathode surface, and was the photoelectric anode is an electric current, power plants absorb deoxidization device in the load resistance - I, the voltagePhototubes photoelectric characteristics fig.03 shows, from the graph in flux knowable, not too big, photoelectric basic characteristics is a straight line.2. Photoelectric times had the sensitivity of vacuum tube due to low, so with people developed has magnified the photomultiplier tubes photo-current ability. Figure 4 is photomultiplier tube structure schematic drawing.图4光电倍增结构示意图From the graph can see photomultiplier tubes also have A cathode K and an anode A, and phototubes different is in its between anode and cathode set up several secondary emission electrodes, D1, D2 and D3... They called the first multiply electrode, the second multiply electrode,... Usually, double electrode for 10 ~ 15 levels. Photomultiplier tubes work between adjacent electrode, keeping a certain minimum, including the cathode potential potentials, each multiply electrode potential filtering increases, the anode potential supreme. When the incident light irradiation, cathodic K escape from the optoelectronic cathode multiplied by first accelerated, by high speed electrode D1 bombarded caused secondary electron emission, D1, an incident can generate multiple secondary electron photonics, D1 emit of secondary electron wasD1, D2 asked electric field acceleration, converged on D2 and again produce secondary electron emission... So gradually produce secondary electron emission, make electronic increased rapidly, these electronic finally arrived at the anode, form a larger anode current. If a n level, multiply electrodes at all levels for sigma, the multiplication of rate is the multiplication of photomultiplier tubes can be considered sigma n rate, therefore, photomultiplier tube has high sensitivity. In the output current is less than 1mA circumstances, it in a very wide photoelectric properties within the scope of the linear relationship with good. Photomultiplier tubes this characteristic, make it more for light measurement.3 and photoconductive resistance photoconductive resistance within the working principle is based on the photoelectric effect. In semiconductor photosensitive material ends of mount electrode lead, it contains transparent window sealed in the tube and shell element photoconductive resistance. Photoconductive resistance properties and parameters are:1) dark resistance photoconductive resistance at room temperature, total dark conditions stable resistance called dark resistance, at the current flow resistance is called dark current.2) light resistance photoconductive resistance at room temperature and certain lighting conditions stable resistance measured, right now is called light resistance of current flow resistance is called light current.4, volt-ampere characteristics of both ends photoconductive resistance added voltage and current flows through photoconductive resistance of the relationship between called volt-ampere characteristics shown, as shown in figure 5. From the graph, the approximate linear volt-ampere characteristics that use should be limited, but when the voltage ends photoconductive resistance, lest than shown dotted lines of power consumption area5, photoelectric characteristics photoconductive resistance between the poles, light when voltage fixed the relationship between with bright current photoelectric characteristics. Called Photoconductive resistance photoelectric characteristics is nonlinear, this is one of the major drawback of photoconductive resistance.6, spectral characteristics is not the same incident wavelength, the sensitivity of photoconductive resistance is different also. Incidence wavelength and photodetector the relationship between relative sensitivity called spectral characteristics. When used according to the wavelength range by metering, choose different material photoconductive resistance.7, response time by photoconductive resistance after photo-current need light, over a period of time (time) rise to reach its steady value. Similarly, in stop lightphoto-current also need, over a period of time (down time) to restore the its dark current, this is photoconductive resistance delay characteristics. Photoconductive resistance rise response time and falling response time about 10-1 ~ 10-3s, namely the frequency response is 10Hz ~ 1000Hz, visible photoconductive resistance cannot be used in demand quick response occasion, this is one of the main photoconductive resistance shortcomings.8 and temperature characteristic photoconductive resistance by temperature affects greatly, temperature rise, dark current increase, reduced sensitivity, which is another photoconductive resistance shortcomings.9, frequency characteristic frequency characteristics refers to an external voltage and incident light, strong must be photo-current I and incident light modulation frequency, the relationship between the f, photoelectric diode is the frequency characteristic of the photoelectric triode frequency characteristics, this is because of the photoelectrictriode shot "yankees there capacitance and carrier base-combed need time's sake. By using the principle of the photoelectric efficiency of optoelectronics manufacturing frequency characteristics of the worst, this is due to capture charge carriers and release charge need a certain time's sake.Three, photoelectric sensorsPhotoelectric sensor is through the light intensity changes into electrical signal changes to achieve control, its basic structure, it first figure 6 by measuring the change of change of converting the light signal, and then using photoelectric element further will light signals into electrical signal by photoelectric sensor general. Illuminant, optical path and optoelectronics. Three components of photoelectric detection method has high precision, fast response, non-contact wait for an advantage, but measurable parameters of simple structure, sensors, form flexible, therefore, photoelectric sensor in the test and control is widely used.By photoelectric sensor generally is composed of three parts, they are divided into: transmitter and receiver and detection circuit shown, as shown in figure 7, transmitter aimed at the target launch beam, the launch of the beam from semiconductor illuminant, general light emitting diode (LED), laser diode and infrared emission diode. Beam uninterrupted launch, or change the pulse width. Receivers have photoelectric diode, photoelectric triode, composed si-based ones. In front of the receiver, equipped with optical components such as lens and aperture, etc. In its back is detection circuit, it can filter out effective signal and the application of the signal. In addition, the structural components in photoelectric switch and launch plate and optical fiber, triangle reflex plate is solid structure launch device. It consists of small triangle cone of reflective materials, can make a beam accurately reflected back from plate, with practical significance. It can be in with the scope of optical axis 0 to 25, make beams change launch Angle from a root almost after launch line, passes reflection or from the rotating polygon.some basic returns.图7Photoelectric sensor is a kind of depend on is analyte and optoelectronics and light source, to achieve the relationship between the measured purpose, so the light source photoelectric sensor plays a very important role, photoelectric sensor power if a constant source, power is very important for design, the stability of the stability of power directly affect the accuracy of measurement, commonly used illuminant have the following kinds:1, leds is a change electric energy into light energy semiconductor devices. It has small volume, low power consumption, long life, fast response, the advantages of high mechanical strength, and can match and integrated circuits. Therefore, widely used in computer, instruments and automatic control equipment.2, silk light bulb that is one of the most commonly used illuminant, it has rich infrared light. If chosen optoelectronics, constitutes of infrared sensor sensitive colour filter can be added to the visible tungsten lamps, but only filter with its infrared does illuminant, such, which can effectively prevent other light interference.3, compared with ordinary light laser laser with energy concentration, directional good, frequency pure, coherence as well as good, is very ideal light sources.The light source, optical path and photoelectric device composition photoelectric sensor used in photoelectric detection, still must be equipped with appropriate measurement circuit. The photoelectric effect to the measurement circuit of photoelectric element of widerange caused changes needed to convert the voltage or current. Different photoelectric element, the measurement circuit required is not identical also. Several semiconductor introduces below optoelectronic devices commonly used measurement circuit.Semiconductor photoconductive resistance can through large current, be in so usually, need not equipped with amplifier. In the output power of demand is bigger, can use figure 8 shows circuit.Figure 9 (a) with temperature compensation given the photosensitive diode bridge type measuring circuit. When the incident light intensity slow change, the reverse resistance photosensitive diode is the slow change, the change of the temperature will cause the bridge output voltage, must compensate. Drift Picture a photosensitive diode as the test components, another into Windows, in neighboring bridge, the change of the temperature in the arms of the influence of two photosensitive diode, therefore, can eliminate the same output with temperature bridge road drift.Light activated triode incident light in work under low illumination, or hope to getbigger output power, also can match with amplifying circuit, as shown in figure 9 shows.Because even in the glare photosensitive batteries, maximum output voltage also only 0.6 V, still cannot make the next level 1 transistor have larger current output, so must add positive bias, as shown in figure 9 (a) below. In order to reduce the transistor circuit impedance variations, base si-based ones to reduce as much as possible without light, when the reverse bias inherit in parallel a resistor si-based ones at both ends. Or like figure 9 (b) as shown by the positive ge diode produces pressure drop and test the voltage produced when exposed to light, make silicon tube e stack, b the voltage between actuators than 0.7 V, and conduction work. This kind of circumstance also can use silicon light batteries, as shown in figure 10 (c) below. Semiconductor photoelectric element of photoelectric circuit can also use integrated operational amplifier. Silicon photosensitive diode can be obtained by integratingop-amp larger output amplitude, as shown in figure 11 (a) below. When light is produced, the optical output voltage in order to guarantee photosensitive diode isreverse biased, in its positive to add a load voltage. Figure 11. (b) give the photocell transform circuit, because the photoelectric si-based ones short-circuit current and illumination of a linear relationship between, so will it up in the op-amp is,inverse-phase input, using these two potential difference between the characteristicsof close to zero, can get better effect. In the picture shows conditions, the output voltageThe photoelectric element by flux the role of different made from the principle of optical measurement and control system is varied, press the photoelectric element (optical measurement and control system) output nature, namely, can be divided into second analog photoelectric sensor and pulse (switch) photoelectric sensor. Analog photoelectric sensors will be converted into continuous variation of the measure, it is measured optical with a single value relations between analog photoelectric sensor. According to be measured (objects) method detection of target can be divided into transmission (absorption) type, diffuse type, shading type (beam resistance gears) three categories. So-called transmission style means the object to be tested in optical path in constant light source, the light energy through things, part of being measured by absorption, transmitted light onto photoelectric element, such as measured liquid, gas transparency and photoelectric BiSeJi etc; speed.gratifying The so-called diffuse style means the constant light by the light onto the analyte from the object to be tested, and projected onto surfaces reflect on after optoelectronic devices, such as photoelectric colorimetric thermometer and light gauge etc; The so-called shading style means the when illuminant issued by the flux of light analyte covered by a part Jing optoelectronics, make projection on the flux change, change the object to be tested and extent of the position with the light path, such as vibration measurement, the size measurement; And in pulse photoelectric sensor in the sensors, photoelectric element acceptable optical signal is intermittent change, therefore photoelectric element in switch work of the state, the current output it is usually only two steady state of the signal, the pulse form used for photoelectric counting and photoelectric speed measurement and so on.And infrared photoelectric sensor classification and working way generally have thefollowing kinds:1, groove photoelectric sensor put a light emitter and a receiver in a slot face-to-face outfit are on opposite sides of the photoelectric groove. Lighter emits infrared light or visible light, and in unimpeded cases light receptors can receive light. But when tested objects from slot zhongtong obsolete, light occluded, photoelectric switches and action. Output a switch control signal, cut off or connect load current, thus completing a control movement. Groove switch is the overall of detection distance because general structure limits only a few centimeters.2, DuiShe type optoelectronic sensor if you put lighter and receive light is separated, can make the detection distance increase. By a lighter and an inbox light sensor into a photoelectric switch is called DuiShe separate photoelectric switches, referred to DuiShe photoelectric switch. Its detection distance can reach a few meters and even a dozen meters. When using light-emitting device and receive light device are installed in test object through the path of the sides, test object by blocking light path, accept light implement action output a switch control signals.3, reflex plate.it photoelectric switch light-emitting device type and receive light device into the same device inside, in its front pack a reflex plate.the using the reflection principle of complete photoelectric control function is called reflex plate.it reflex (or reflector reflex) photoelectric switch. Under normal circumstances, lighter the light reflected by reflex plate.it is received by accept light; Once the light path be test object to block, accept light, the light is not receive photoelectric switch is action, output a switch control signals.4, diffusion reflective photoelectric switches its detection head with a lighter and also an inbox light ware, but no reflex plate.it ahead. Normally lighter for the light collect light is not found. When test object by blocking the light, and the light reflected light, receive part implement received light signals, output a switch signals.Four, I'm the idea of photoelectric sensorWith the development of science and technology people on measuring accuracy had the higher request, this has prompted the pace with The Times photoelectric sensor have updated, improve the main means photoelectric sensor performance is the application of new materials, new technology manufacturing performance is more superior photoelectric element. For example, today the prototype of the photoelectric sensor is a small metal cylindrical equipment, with a calibration lens, transmitter into receiver focused light, the receiver out of cable to the device got a vacuum tube amplifiers in metal cylinder on the incandescent light bulb inside a small as the light source a strong incandescent lamp sensor. Due to the sensor various defects existing in the fields, gradually faded. To appear, because of it of fiber of excellent performance, then appeared with sensors supporting the use of optical passive components, another fiber without any interference of electromagnetic signal, and can make the sensor of the electronic components and other electrical disturbance in isolation. Have a piece of plastic optical fiber core or glass light core, light outside a metallic core skins and bread this layer metal cortical density lower than light core, so low, the beam refraction in the two materials according to the border (incident Anglewithin a certain range, reflected), is all. Based on optical principle, all beams can be made by optical fiber to transmission. Two incident beam Angle in an Angle (along the fiber length direction within) by multiple reflections from the other end after injection, another incident angles than accept the incident light in metal skin, loss. This accept Angle within the biggest incident Angle than two times, this is because fiber slightly larger from air into density larger fiber materials hitting may have a slight refraction. In light of the optical fiber transmission from inside the influence of fiber bending (whether more than bending radius minimal bending radius). Most optical fiber is flexible, easy to install in the narrow space. Photoelectric sensor is a kind of non-contact measurement small electronic measurement equipment, rely on detect its receives the light intensity change, to achieve measurement purposes, andit's also a vulnerable to external disturbance and lose the measurement accuracy of the device. When be being designed so besides the choice optoelectronic components, still must set GSCC signal and temperature compensating measures used to weaken or eliminate the impact of these factors.Photoelectric sensor must pass a light modulation, like radio waves of light modulation of sends and receives, the radio to a station, can ignore other radio signal sensors without modulation long-focal-length only through the use of mechanical shielded, scenes that receiver transmitter only can receive the emission of light, can make its energy becomes very high. In contrast, through modulation transceivers can ignore ambient light, only to own light or with the same modulation frequencies of light without modulation response. The sensor used to test the infrared rays or around the radiation, if just baked red bottle, in this application situation if use other sensor, may be incorrect actions.Photoelectric sensor due to non-contact, high reliability, etc, and to change in measurement, damage the object to be testedSo since its invention in fields since play a significant role, at present it has been widely used in measuring mechanical quantity, thermal quantity, weight, intelligent vehicle system into etc. Now it in power system automatically grid device plays a very important role, because generator input power grid operation often USES accurate with law, must meet: three-phase line sequence is consistent, frequency, phase agree unanimously, voltage amplitude equal, one of the conditions in system design has been satisfied, after three conditions must also meet to grid, of course, artificially grid is more difficult, photoelectric grid is easier.The development of times, science and technology in the update, photoelectric sensor types are increasing and application domain more and more widely, such as a recent kind of infrared already in intelligent vehicle electrical sensors in to the application, one of which had based on infrared sensor is the core of intelligent vehicle, reflective type infrared sensor using reflex infrared sensor design path detection module and speed monitoring module; Another method based on infrared sensor using the car tracing is to collect infrared sensor data.Photoelectric sensor has cannot be replaced by other sensors superiority, so it development foreground is very good, the application will also become more widespread.光电传感器关键字：光电效应 光电元件 光电特性 传感器分类 传感器应用 摘要：在科学技术高速发展的现代社会中，人类已经入瞬息万变的信息时代，人们在日常生活，生产过程中，主要依靠检测技术对信息经获取、筛选和传输，来实现制动控制，自动调节，目前我国已将检测技术列入优先发展的科学技术之一。
传感器的工作原理
传感器的工作原理Working Principles of Sensors。
Sensors are electronic devices that are designed to detect and respond to changes in the environment. They are widely used in various industries and applications, such as automotive, aerospace, medical, and consumer electronics. The working principles of sensors vary depending on their types and functions. In this article, we will discuss the most common working principles of sensors.1. Resistive Sensors。
Resistive sensors are based on the principle of changing resistance in response to changes in the environment. They consist of a sensing element and a signal conditioning circuit. The sensing element is made of a material that changes its resistance when exposed to a specific stimulus, such as temperature, pressure, or humidity. The signal conditioning circuit amplifies andconverts the resistance change into a measurable output signal, such as voltage or current.The most common types of resistive sensors are thermistors, strain gauges, and humidity sensors. Thermistors are used to measure temperature, strain gauges are used to measure strain and force, and humidity sensors are used to measure humidity.2. Capacitive Sensors。
GAS SENSOR
专利名称：GAS SENSOR发明人：FUJIOKA TORU,KAWAMURA HIDEO,KAWAI TOMOJI申请号：JP18636185申请日：19850823公开号：JPS6246247A公开日：19870228专利内容由知识产权出版社提供摘要：PURPOSE:To provide the titled gas sensor suitable for the selective detection of gas to be inspected, requiring no maintenance and easy to handle, by setting the electrical change of a semiconductive photocatalyst material generating by gas to be inspected at the time of the irradiation of light to a gas detecting signal. CONSTITUTION:A gas sensor 1 has a three-layered structure wherein a Pt-layer 3 is mounted to the upper surface of a TiO2-layer and a Ti-layer 4 is mounted to the under surface of said TiO3 layer 2. As lead wires, Au-wires 5, 5' are respectively adhered to the layers 3, 4 one at a time by conductive pastes 6, 6'. Further, the layers 2, 4 are connected so as to obtain ohmic contact. When a shot key barrier is formed, the separation of carriers generated in the layer 2, that is, an electron and a positive hole is rapidly performed and, therefore, the reaction of gas to be inspected and the carriers is promoted while it can be prevented that the electron and the positive hole generated at once are rebonded in the layer 2 and distincted. Therefore, efficient redox reaction is performed between the molecule of the gas to be inspected transmitted through the porous Pt-layer to be contacted with the layer 2 and the positive hole successively appearing to the surface.申请人：MATSUSHITA ELECTRIC WORKS LTD 更多信息请下载全文后查看。
Gas Sensing Materials and Devices
Gas Sensing Materials and DevicesGas sensing materials and devices play a crucial role in various fields such as environmental monitoring, chemical analysis, safety and security, medical diagnosis, and industrial applications. They are designed to detect and measure the concentration of gases such as carbon dioxide, carbon monoxide, methane, ammonia, and many others. The development of gas sensing materials and devices has greatly contributed to the advancement of these fields and has led to a better understanding of gas interactions and their effects on the environment and human health.Overview of Gas Sensing MaterialsGas sensing materials can be classified into two categories: organic and inorganic materials. Organic materials include polymers, carbon-based materials, and organic molecules. Inorganic materials, on the other hand, include metal oxides, conducting polymers, and semiconductors.Metal oxide gas sensors are the most widely used type of gas sensor due to their high sensitivity, low cost, and ease of fabrication. They are composed of a metal oxide thin film deposited onto a substrate and are capable of detecting a wide range of gases. The metal oxide thin film interacts with the target gas, causing a change in resistance, which is then measured and used to calculate the gas concentration.Semiconductor gas sensors are another type of inorganic gas sensor commonly used in the industry. They are based on the principle of changes in electrical conductivity when exposed to the target gas. The semiconductor material interacts with the gas through the adsorption and desorption of gas molecules, which causes changes in the concentration of free charge carriers. These changes in charge carriers are then measured and used to calculate the gas concentration.Polymer gas sensors are a type of organic gas sensor that operates based on the principle of swelling of the polymer film when exposed to gas. The swelling of the polymer leads to changes in its optical, mechanical, or electrical properties, which can bemeasured and used to determine the gas concentration. Polymer gas sensors are more sensitive to gas concentrations than metal oxide or semiconductor sensors, but they are also more expensive to produce.Gas Sensing DevicesGas sensing devices are designed to incorporate gas sensors into a device that is capable of measuring gas concentrations in real-time. The devices can be classified into three categories: handheld, portable, and fixed devices.Handheld devices are compact and easy to use, making them ideal for use in small spaces. They are commonly used in air quality monitoring, combustible gas detection, and personal safety applications.Portable devices are larger and more durable than handheld devices, but they are still relatively lightweight and easy to use. They are commonly used in industrial settings where gas detection is necessary for safety and compliance purposes.Fixed devices are the largest and most complex type of gas sensing device. They are permanently installed in buildings and other facilities and are used to detect gas leaks and ensure the safety of the occupants. Fixed devices can be connected to building automation systems to provide real-time gas monitoring and control.Applications of Gas sensing materials and devices have a wide range of applications in various fields. Some of the most common applications include:Environmental monitoring: Gas sensing devices are used to monitor air quality and identify pollutants in the environment. They are commonly used in urban areas to measure levels of carbon dioxide, carbon monoxide, and nitrogen oxides.Industrial applications: Gas sensing devices are used in industrial settings to detect gas leaks and ensure the safety of workers. They are commonly used in the petrochemical, manufacturing, and mining industries.Medical diagnosis: Gas sensing devices are used in medical diagnosis to detect gases that are produced by the body during certain diseases. For example, acetone is producedby the body when a person has diabetes, and gas sensors can be used to measure the concentration of acetone in a patient's breath.ConclusionIn conclusion, gas sensing materials and devices are essential tools for the detection and measurement of gases in various fields. The development of gas sensing materials and devices has greatly contributed to the advancement of these fields and has led to a better understanding of gas interactions and their effects on the environment and human health. With continued research and development, gas sensing materials and devices will continue to improve, allowing for greater precision and accuracy in gas detection and measurement.。
Gas sensor
专利名称：Gas sensor发明人：Joel Abdullah,Alexei Tikhonski,Ronald I.Dass,James Novak申请号：US12543260申请日：20090818公开号：US08117894B2公开日：20120221专利内容由知识产权出版社提供专利附图：摘要：A sensor system issues measurement commands at a predetermined regular rate. If a measurement indicates that a gas of interest is present, then the sensor system is signaled to wake-up thereby pulsing a heater for the sensor element that improves theaccuracy of measurements. Measurements of humidity, temperature and gas concentration are made. If the gas of interest is detected then the data is used to indicate a compensated gas measurement. The gas level is classified as to its hazard and an adaptive detection algorithm is used to set an activity mode. If the gas of interest is not detected, the adaptive detection algorithm is used to set a sleep mode that saves power. Measurement rates are kept constant while heater power is controlled to reduce power consumption. Measurement rates are changed to increase concentration sensitivity.申请人：Joel Abdullah,Alexei Tikhonski,Ronald I. Dass,James Novak地址：Austin TX US,Cedar Park TX US,Austin TX US,Austin TX US国籍：US,US,US,US代理机构：Matheson Keys Garsson & Kordzik PLLC代理人：Kelly Kordzik更多信息请下载全文后查看。
生物反馈治疗仪说明书
MYOTRAC INFINITIDual SEMGThe Manufacturer: Thought Technology Ltd.2180 Belgrave AvenueMontreal, Quebec, CanadaH4A 2L8Product Name: MyoTrac Infiniti System Product #: T9800Device Name: MyoTrac Infiniti Encoder Device #: SA9800•Type BF Equipment •Internally powered equipment•Continuous operation•Read Instruction Manual•The pins of the connectors identified with the ESD warning symbol should not be touched unless ESB precautionary procedures are used.CAUTION•US Federal Law restricts this device to sale by, or on order of, a physician or any otherpractitioner licensed by the law of the state in which he or she practices to use or order theuse of this device.WARNING•Do not operate Active Sensors within 10 feet of an operating cellular phone, similar radio transmitting device, other powerful radio interference producing sources such as arcwelders, radio thermal treatment equipment, x-ray machines, or any other equipment thatproduces electrical sparks. Portable and mobile RF communication equipment can affectthis equipment.•With the MyoTrac Infiniti Encoder SA9800 use only with supplied power supply. GlobTek Part Number WR92B2500LF9P-Y-MED (WR95/WR93/WR97) or GS889•The PC used with MyoTrac Infiniti must be placed outside the patient/client environment(more than 3 meters or 10 feet) or the PC must comply with EN60601-1 (system safety).•After use, the Batteries or the Battery pack must be disposed of in accordance with local, state and federal regulations and laws.•After use, the Disposable Electrodes may be a biohazard. Handle, and when applicable, dispose of these materials in accordance with accepted medical practice and any applicablelocal, state and federal laws and regulations.•Reusable electrodes present a potential risk of cross-infection especially when used onabraded skin, unless they are restricted to a single patient or sterilized between patients. Ifsterilizing electrodes, employ only gas sterilization.•Radiated radio frequency electromagnetic fields can cause performance degradation in the MyoScan-Pro EMG sensor. In the worst case, an RF field strength of 22mV/M can causean increase of 1μV in the signal reading from a MyoScan-Pro sensor. Be sure to keep inmind that a very relaxed muscle should provide an EMG reading of approximately 1-3μV.•This device is capable of generating current densities exceeding 2mA r.m.s./cm² this may require special attention of the operator.•Avoid accidental contact between connected but unused applied parts and other conductive parts including those connected to protective earth.•Explosion Hazard; Do not use in the presence of a flammable anesthetic mixture with air, or with Oxygen or Nitrous Oxide.•Not to be immersed in water.•Take care in arranging patient and sensor cables to avoid risk of patient entanglement or strangulation.•The operator is responsible for ensuring the safety of any devices controlled or triggered by Infiniti equipment or software, or by any software or hardware receiving data from Infinitiequipment. Infiniti equipment must not be configured or connected in such a way thatfailure in its data acquisition, processing or control functions can trigger patient feedbackstimulus that poses an unacceptable level of risk.•Use of any equipment in a biofeedback or stimulation context should be immediatelyterminated upon any sign of treatment-related distress or discomfort.•Not to be connected to a patient undergoing MRI, Electro surgery or defibrillation.•Not for use with patients with undiagnosed pain conditions.•Only use the unit for which it was prescribed.•Do not immerse the unit in water or any other liquid substance.•Do not use if you have symptoms of bladder infection.•Do not use with diminished mental capacity or physical competence limiting the use of the device.•Caution should be used for patients with suspected or diagnosed heart problems.•Caution should be used for patients with suspected or diagnosed epilepsy.•Electrode placement and stimulation settings should be based on the guidance of theprescribing practitioner.•If damage is evident of the unit or accessories, discontinue use and contact your supplierfor further information on repair.•The system should not be used adjacent to or stacked with other equipment, if usedadjacent or stacked the unit should be observed to verify normal operation in theconfiguration in which it will be used.•Use of accessories, transducers or cables other than those specified by ThoughtTechnology ltd may result in increased emissions or decreased immunity of the equipmentto electromagnetic energy.ATTENTION•Sensors and equipment damaged by static electricity are not covered under warranty. Toprevent static discharge from damaging the sensor and/or encoders, use anti-static mats orsprays in your working area. A humidifier may also be used to prevent static environmentsby conditioning hot, dry air. It is recommended that all staff involved with the unit receive anexplanation of the ESD symbol and the precautions described above as a minimum.•Do not apply any electrode gel or equivalent directly on the sensor snaps. Always useelectrodes as a medium between the sensor and the client.•Not for diagnostic purposes, not defibrillator proof, not for critical patient monitoring.•To prevent voiding warranty by breaking connector pins, carefully align white guiding dot onsensor plug with slot on sensor input.•Make sure to remove electrodes from sensor snaps immediately after use.•Do not plug third party sensors directly into instrument inputs. Plug only ThoughtTechnology Active Sensor cable connectors into instrument inputs. All electrodes and thirdparty sensors must be connected to active sensors, either directly or through an adapter.•Remove batteries when the device is not being used for an extended period of time. Pleasedispose of battery following local regulations.INTENDED PURPOSE•Biofeedback, Relaxation & Muscle Re-Education purposes•Relaxation of muscle spasms•Prevention or retardation of disuse atrophy•Increasing local blood circulation•Muscle re-education•Maintaining or increasing range of motionNOTE•No preventative inspections required; maintenance must be performed by qualified personnel.Factory re-calibration can be requested.•The supplier will make available, upon request, circuit diagrams, component parts lists anddescription or other information required for the repair of product by qualified personnel.•The operator must be familiar with typical characteristics of signals acquired by thisequipment, and be able to detect anomalies in the acquired signal that could interfere withtreatment effectiveness. Depending on the importance of signal integrity, it may be advisableto continuously monitor the raw signals, in time and/or frequency domain, while the device isbeing used for biofeedback or other purposes. If anomalies are observed on acquired signals,and if you suspect a problem with electromagnetic interference, contact Thought Technologyfor a technical note on identification and remediation.•This product conforms to standards EN60601-1, EN60601-2-10 and EN60601-2-40; someencoder labeling may indicate superceded standards.MAINTENANCE AND CALIBRATION•Wipe encoder with a clean cloth•Factory testing and calibration ensure equipment accuracy and frequency response. Contact Thought Technology for factory re-calibration if necessary.STORAGE•Store in its original case at up to 90% humidity / 30C°TRANSPORTATION•Transport in its original caseManual # SA9814 Rev 4Guidance and manufacturer’s declaration – electromagnetic immunity The MyoTrac Infiniti is intended for use in the electromagnetic environment specified below. The customer or the user of the MyoTrac Infiniti should assure that it is used in such an environment, and that precautions regarding that environment are heeded.Immunity test IEC 60601test level Compliance level Electromagnetic environment –guidanceElectrostatic discharge (ESD) IEC 61000-4-2 ±6 kV contact±8 kV air±6 kV contact±8 kV airFloors should be wood, concrete orceramic tile. If floors are covered withsynthetic material, the relative humidityshould be at least 30 %.Electrical fast transient/burst IEC 61000-4-4 ±2 kV for powersupply lines±1 kV for input/outputlines±2 kV for powersupply lines±1 kV for input/outputlinesMains power quality should be that of atypical commercial or hospitalenvironment.SurgeIEC 61000-4-5 ±1 kV differentialmode±2 kV common mode±1 kV differentialmode±2 kV common modeMains power quality should be that of atypical commercial or hospitalenvironment.Voltage dips, short interruptions and voltage variations on power supply input linesIEC 61000-4-11 <5 % U T(>95 % dip in U T)for 0,5 cycle40 % U T(60 % dip in U T)for 5 cycles70 % U T(30 % dip in U T)for 25 cycles<5 % U T(>95 % dip in U T)for 5 sec<5 % U T(>95 % dip in U T)for 0,5 cycle40 % U T(60 % dip in U T)for 5 cycles70 % U T(30 % dip in U T)for 25 cycles<5 % U T(>95 % dip in U T)for 5 secMains power quality should be that of atypical commercial or hospitalenvironment. If the user of theMyoTrac Infiniti requirescontinued operation during powermains interruptions, it is recommendedthat the MyoTrac Infiniti bepowered from an uninterruptible powersupply or a battery.Power frequency (50/60 Hz) magnetic field IEC 61000-4-8 3 A/m 3 A/m Power frequency magnetic fieldsshould be at levels characteristic of atypical location in a typical commercialor hospital environment.NOTE U T is the a.c. mains voltage prior to application of the test level.NOTE 1 At 80 MHz and 800 MHz, the higher frequency range applies.NOTE 2 These guidelines may not apply in all situations. Electromagnetic propagation is affected by absorption Field strengths from fixed transmitters, such as base stations for radio (cellular/cordless) telephones and land mobile radios, amateur radio, AM and FM radio broadcast and TV broadcast cannot be predicted theoretically with accuracy. To assess the electromagnetic environment due to fixed RF transmitters, an electromagnetic site survey should be considered. If the measured field strength in the location in which the MyoTrac Infiniti is used exceeds the applicable RF compliance level above, the MyoTrac Infiniti should be observed to verify normal operation. If abnormal performance is observed, additional measures may be necessary, such as reorienting or relocating the MyoTrac Infiniti.Over the frequency range 150 kHz to 80 MHz, field strengths should be less than [V1] V/m.Guidance and manufacturer’s declaration – electromagnetic emissionsThe MyoTrac Infiniti is intended for use in the electromagnetic environment specified below. The customer or the user of the MyoTrac Infiniti should assure that it is used in such an environment.Emissions test Compliance Electromagnetic environment – guidanceRF emissions CISPR 11 Group 1 The MyoTrac Infiniti uses RF energy only for its internal function.Therefore, its RF emissions are very low and are not likely tocause any interference in nearby electronic equipment.RF emissionsCISPR 11Class BHarmonic emissionsIEC 61000-3-2Not applicableVoltage fluctuations/ flicker emissions IEC 61000-3-3 Not applicableThe MyoTrac Infiniti is suitable for use in all establishments,including domestic establishments and those directly connected tothe public low-voltage power supply network that suppliesbuildings used for domestic purposes.Table of ContentsAbout This Guide (9)Chapter 1 (10)Introduction to your MYOTRAC INFINITI™ Dual SEMG Encoder (10)System Requirements (11)MyoTrac Infiniti Components (12)Connection to the Client (15)Connection to the PC (19)Screen Elements (20)Thought Support (20)Settings Menu (21)Chapter 2 (25)SEMG sessions on your MYOTRAC INFINITI™ Dual SEMG Encoder (25)Open SEMG Sessions (25)Script SEMG Sessions (27)Chapter 3 (28)Data Management on your MYOTRAC INFINITI™ Dual SEMG Encoder (28)MyoTrac Infiniti Review (29)Chapter 4 (30)Display Options on your MYOTRAC INFINITI™ Dual SEMG Encoder (30)Displays (30)Chapter 5 (34)Flow on your MYOTRAC INFINITI™ Dual SEMG Encoder (34)Chapter 6 (35)Reference (35)Technical Support and Order Placing (36)Technical Support (36)Product Numbers & Accessories (37)Placing Orders (38)Specifications (39)MyoTrac Infiniti Hardware Copyright Notice (44)About This Guide Welcome to the MYOTRAC INFINITI™ encoder. This guide is designed to help you get up and running quickly with your new encoder. It will describe the operation of the encoder, and how it interfaces to the host personal computer (PC).It walks you through:•Physical Operation of the encoder.• EMG sessions.• Data management.• Display options.After you have become familiar with the key concepts of your new encoder, you can use the rest of this guide as a reference for less common tasks, and also as a source of information if you have problems operating it.Chapter 1 Introduction to your MYOTRAC INFINITI™ Dual SEMG EncoderThis chapter explains the physical interface with the MyoTrac Infiniti Encoder, how to use it for the first time, and how to transfer data to the host PC.Getting to know your MyoTrac Infiniti Dual SEMG EncoderWhat is a MyoTrac Infiniti Dual SEMG Encoder?The MyoTrac Infiniti is the cutting edge in handheld, dual channel Surface Electromyography(SEMG). With it you will be able to deliver targeted and customized treatment directly to the client’s clinically relevant areas.A simple first approach has been adopted in the design of the MyoTrac Infiniti to make it as easyand fast as possible to get the clinical results desired from this powerful device.Customizing the MyoTrac Infiniti to your clinical needs couldn’t be easier; all users input is directed through a series of intuitive and guided screens using touch screen technology.The partnership of the MyoTrac Infiniti with the BioGraph Infiniti PC software enhances yet further the power and flexibility of the MyoTrac Infiniti. This link enables you to transfer session data to the PC for further viewing, analysis and reporting, in real time or post session.System RequirementsTo install the BioGraph Infiniti software, your computer system must meet or exceed the following requirements.•IBM PC compatible(Intel/Pentium/Celeron family or AMDK6/Athlon/Duron family, CPU P4 speed 3GHz or higher), Desktop or Laptop withtwo monitor capability•Windows 2000/XP Professional or Home edition.•50 - 60 gigabytes hard disk space for video recording and processing. (Thesoftware needs 2.5 gigabytes to installand run on available hard drive space) •Memory, 512 MB of RAM or more•CD ROM or DVD drive•SVGA graphic card (1024 x 768) or higher resolution adapter & monitor•32 bit Sound Blaster compatible sound card & speakers• 1 to 4 USB ports, depending on thedesired number of MyoTrac Infinitiencoders•Mouse or compatible pointing device •MS Word 97 or higher (for printingpurposes)•Compact Flash Reader (For use with compact flash card only)•Webcam 30 frames per second (for video purposes only)NOTE: When using certain more complex screens, you must adhere to the Recommended Computer Requirements.••IBM PC compatible(Intel/Pentium/Celeron family or AMDK6/Athlon/Duron family, CPU P3speed 1.8 GHz), Desktop or Laptop •Windows 2000/XP Professional or Home edition.•10 - 20 gigabytes hard disk space •(The software needs 2.5 gigabytes to install and run on available hard drivespace)•Memory, 256 MB of RAM or more •CD ROM or DVD drive•SVGA graphic card (1024 x 768) or higher resolution adapter & monitor •16 Bit Sound Blaster compatible sound card & speakers• 1 to 4 USB ports, depending on the desired number of MyoTrac Infinitiencoders•Mouse or compatible pointing device •Word 97 or higher (for printingpurposes)NOTE: For most recent computer requirements contact Thought Technology Ltd for MAR473Update informationPeriodically updates may become available for the BioGraph Infiniti software and for the MyoTrac Infiniti Hardware. Please contact your local distributor or visit our website for further information on how to obtain updates.MyoTrac Infiniti Components•Compact Flash for increased memory capacity and one method for transfer of data to the PC.•USB for real time transfer of data to the PC.•Touch screen enables graphically guided navigation through the software.•Rugged Ergonomic Case, easy to hold or attach to the subject and will withstand the rigors of daily use.•Battery Charging jack for wall connection enables fast built-in battery charging.•Headphone Jack for stereo sound feedback (or use the built-in speaker).•Push button On/Off switch to prevent accidental switching.• 2 Channels of Surface EMG.PowerThere are three basic methods to power the MyoTrac Infiniti unit: Inserting batteries into the battery compartment of the unit, plugging it into the wall using the supplied AC adapter, or plugging it into a powered up computer using a USB cable.The MyoTrac Infiniti is available with battery charging capabilities. It will work with four standard Alkaline AAA batteries available in all consumer electrical stores. It is also possible to run the unit on removable, externally rechargeable batteries. A rechargeable battery pack is supplied with the MyoTrac Infiniti and can be charged while still inside the unit.Note: When changing batteries it is recommended to plug the unit into external power, either USB or wall transformer so that data is not lost. Failure to supply external power will result in data and script loss.The battery compartment cover slides open by pushing up using the notch provided. Place four AAA batteries in the slots, observing the polarity as illustrated. Please note that a diagram of the correct battery polarity is embossed on the inside surface of the compartment.Alternatively it is possible to use a rechargeable battery pack (Thought Technology Part Number MI1028). This battery pack is plugged into the connector in the battery compartment marked BATT. The pack then fits into the normal battery area. Note: only use battery packs from Thought Technology or authorized representative, as use of other battery packs will damage the device.A wall mounted AC power adapter, supplied with the MyoTrac Infiniti, is used to connect the unit toan electrical outlet. This can be used in conjunction with the batteries or without.The unit can also be powered from the computer via the USB cable. The cable is connected to the unit on one side and on the other side to the USB port of the computer. This can be used inconjunction with the batteries or without.Charging the BatteriesNote: exact power supply subject to change without notice.Internal ChargerIf your MyoTrac Infiniti was supplied with a wall mounted AC adapter it is possible to charge the battery pack while it is inserted in the device.Note: Only use Thought Technology Ltd supplied wall mounted chargers with this device. Failure to do so could result in potential injury. Use only GlobTek Part Number WR9אB2500LCP-Y-MED where א= 2 for North America, א=3 for Europe, א=5 for United Kingdom and א=7 for Australia with the exception of Japan where the part number is GS 889.To start the charging plug in either the wall mounted AC adaptor or the USB cable. A full charging cycle from fully empty to fully charged will take approximately 2hrs for AC adaptor and 5.5hrs for the USB cable. The unit can be used while plugged in to either power source. The charging cycle does not need to be completed in full; it can be stopped at anytime by removing the connector.When the unit is turned off while plugged into an external power source, the screen displays a battery symbol. Charging action is shown with an animation of the battery filling up. When the battery is fully charged, the symbol shows a full battery.If the unit is plugged into an external power source while it is turned off, it will start charging within one minute.The state of the battery charging is available by going to the power menu in the settings menu of the device. It indicates the current mode of power and whether the unit is currently charging the batteries.Note: The rechargeable batteries must be fully charged prior to initial use. In order for the batteries to reach full capacity it may be necessary to charge them several times (~2-8) after initial use.MemoryRecorded data can be saved using three methods - choose the one which most closely matches your usage needs. To select saving method, select the Settings menu from the main menu, and tap on the Save icon.•Internal Memory – Limited size, only the statistical summaries are recorded. Specifically, the statistics for 13 open sessions or 9 training sessions (work/rest) or 6 assessment sessions(work/rest + fast-flick + endurance) can be recorded. Data can be lost if the batteries areremoved from the unit for longer than a few minutes.•Compact Flash Card – Most flexible method of data saving: save all the raw data for review on the encoder or for download to the PC. Available in most electronics stores in a range ofmemory sizes. Since all EMG data is recorded, the amount of data that is saved to thecompact flash card depends on the size of the card:hours64MB 1.75128MB 3.5 hours256MB 7 hours512MB 14 hourshours1GB 27.5hours2GB 55.5The encoder is delivered with a protective insert in the compact flash slot. To remove it, push the button next to the slot once to eject the card. The CF card can then be inserted; you willnotice that the CF card can only be inserted one way into the encoder to protect from incorrect insertion. When inserted properly it will be flush with the encoder rear. Follow the procedure above to remove this card when no longer required, and re-insert the protective insert. CFcards require a CF card reader to transfer data to the PC. The CF cards and reader can bepurchased from most computer stores. Before its first use in the encoder, a CF card requires PC formatting using the file manager, then format the card using the BioGraph Infiniti MainApplication. Formatting and transferring CF data to the PC is covered in depth in theBioGraph Infiniti software manual.•Real Time PC Transfer – Connect to the PC via the USB and save and display the data on the PC in real time. See the following section “Connection to the PC”.Attention: Do not remove the CF card without first stopping recording. If the CF card is removed during recording, you will lose all the data for the current session.TappingLike using a mouse on a computer screen the MyoTrac Infiniti allows you to use your finger or a stylus to tap the buttons directly on the screen. The first time you start your handheld unit, or if the power has been disconnected for a while, you will be guided through a set of welcome screens including calibration, time and date setting. The calibration aligns the internal circuitry of theencoder with its touch sensitive screen so that when you tap a button on the screen, the handheld unit can detect exactly which button is being pressed. It is recommended to use a stylus when calibrating the device as it will provide a more accurate calibration than using a finger.Note:Always use a finger or stylus for tapping the screen. Never use a pen, pencil or othermarking or sharp object on the screen.Damage resulting from misuse of the screen is notcovered by the warranty.The software is designed so that once the screen has been calibrated it is possible to use all the buttons with a finger. In many cases the touch sensitive area is greater than the graphicalconstraints of the button allowing for easier operation using a finger. As necessary wipe screen with a dry cloth to clean. Screen protectors are available from good stationary suppliers and are a good way to extending the life of your screen.Connection to the ClientDepending on the type of session you are going to record there are different ways to connect the two channels to the client. Either plug the extender cable into the device directly and connect to the client with EMG electrodes, or plug them into the pre-amplifier and the pre-amplifier into the MyoTrac Infiniti.Attention: When you insert the extender cable (lead wire) into the electrode connector, MAKE SURE THAT NO BARE METAL OF THE PINS IS EXPOSED.Before applying electrodes, be sure the skin surface is cleaned and dried. Make sure theelectrodes are placed firmly to the skin and make good contact between the skin and electrodes.Please consult the clinical guide for information on electrode selection for different placements. The illustration below shows the division of the body into six areas of treatment.Arms and ShouldersHead and NeckAbdominalsBack and ButtocksLegs and HipsWhen connecting a sensor or extender cables, be sure to properly line up the guiding dot on the top of the plug with the notch in the encoder's input socket. Forcing the plug into the jack in any other position may damage your equipment.Using the MyoTrac Infiniti with AC Power Adapter or Connected to a PCThe MyoTrac Infiniti is designed for safe operation on ungrounded AC power sources. However, if you are using the MyoTrac Infiniti while it is connected to an ungrounded AC power source, for best results you may need to follow some simple guidelines for skin preparation and electrode placement. These measures will help to avoid falsely elevated EMG readings while the muscle is at rest.If you notice elevated resting EMG levels not related to the patient’s condition, and if this occurs only when the unit is connected to AC power (directly via the supplied AC adapter or indirectly via a USB connection to the PC), and if it is necessary to run the MyoTrac Infiniti on ungrounded power(i.e. no 3rd ground pin on the AC wall socket or on the PC power supply), try the followingtechniques to improve the readings.First, if you are using a PC with only 2 prongs on the wall plug and you have a grounded outlet (3 pin wall sockets with a working ground), plug the ac adapter into the MyoTrac-Infiniti and into the grounded outlet to provide a ground for the system.If you have no opportunity to ground either the PC or the AC adapter, use the following electrode placement tips:•If the EMG site is located on an extremity or limb, be sure to place the REF (black colored) electrode more proximally (on or closer to the trunk of the body) than the sense electrodes(yellow and blue), and at least ten centimeters away from either sense electrode.•Prepare the skin under all three electrodes, using a product designed for skin preparation prior to electrode application (mild abrasives such as NuPrep are effective).•If you are using Ag/AgCl (silver/silver chloride) electrodes, put some conductive electrode paste or cream on them before applying them to the skin, or try using gel-type rather than dry Ag/AgCl electrodes.Resting EMG readings will not be affected by connection to AC power, in the following cases:•Running the MyoTrac Infiniti stand-alone, with no AC power adapter and no connection to the PC (only on its rechargeable batteries).。
Electronic Skin电子皮肤
ARTICLES
PUBLISHED ONLINE: 12 SEPTEMBER 2010 | DOI: 10.1038/NMAT2834
Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers
The development of an electronic skin is critical to the realization of artificial intelligence that comes into direct contact with humans, and to biomedical applications such as prosthetic skin. To mimic the tactile sensing properties of natural skin, large arrays of pixel pressure sensors on a flexible and stretchable substrate are required. We demonstrate flexible, capacitive pressure sensors with unprecedented sensitivity and very short response times that can be inexpensively fabricated over large areas by microstructuring of thin films of the biocompatible elastomer polydimethylsiloxane. The pressure sensitivity of the microstructured films far surpassed that exhibited by unstructured elastomeric films of similar thickness, and is tunable by using different microstructures. The microstructured films were integrated into organic field-effect transistors as the dielectric layer, forming a new type of active sensor device with similarly excellent sensitivity and response times.
GAS SENSOR
专利名称：GAS SENSOR发明人：NISHIZAWA HAJIME,SHIBATA KAZUYOSHI 申请号：JP22897986申请日：19860927公开号：JPS6382355A公开日：19880413专利内容由知识产权出版社提供摘要：PURPOSE:To achieve a higher measuring accuracy, by limiting a diffusion path route of gas which diffuses through a porous solid electrolyte body as diffusion controlled means composing an electrochemical cell to obtain a sharp characteristic curve stably. CONSTITUTION:A diffusion route of gas which diffuses through a porous solid electrolyte body 2 is limited with an airtight solid electrolytic layer 8 so that the introduction of the gas into an internal space 5 is only allowed through an opening 14 of the airtight solid electrolytic layer 8. With such an arrangement, a gas to be measured in an external space where it exists enters an internal space 5 through the opening 14 under a specified diffusion resistance, diffuses horizontally therein 5 and then, reaches a first electrode 10. Thus, the gas introduced is mixed effectively in the internal space 5 to make uniform the concentration of gas which is brought into contact with the first electrode 10 thereby stabilizing a polarization characteristic curve in a sharp form with respect to an electrochemical pump cell comprising the solid electrolytic members 2 and 8 and the electrodes 10 and 12.申请人：NGK INSULATORS LTD更多信息请下载全文后查看。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
Gas conductive sensor technology and applicationYou Ke , Chang Min HuiBeijing Union University, Beijing, Chinayouke@ ,xxtminhui@Abstract—In this paper, a kind of general gas-conductive sensor is proposed. Gas-conductive sensor Based on ZigBee technology ,the model employs star topology and STOP mode. The efficiency of the new model is reducing the power consumption of each sensor node and meanwhile lengthening its life-span. Furthermore, the security and reliability of the system are greatly improved because of the Cyclic Redundancy Check and the encryption algorithm’s application.Index Terms—Gas-Conductive; Sensor; Pressure;I.P REFACEGas sensor is a device that may perceive a certain gas and its concentration in the ambient. The sensor convert the information in relation with gas type and concentration into electrical signals, by analyzing the electrical signals, we may acquire the information relevantto the existence nature of the tested gas in the environment, so as to perform detection, monitoring and alarming. Through interface circuits, the sensors may constitute automatic detection, control and alarm system with computer, so as to create a highly functional environmental monitoring system. This sensor architecture features advantages such as high measurement accuracy, less sample and prompt response, and enjoys extensive applications.II.W ORK PRINCIPLE OF GAS SENSORThe work principles of gas sensors may include semiconductor type, contact burning type, chemical reaction type, light interference type, thermal conduction type, IR ray adsorption type, etc. This article will focus on the work principles of popular semi-conductor gas sensor and solid electrolyte gas sensor.Semi-conductor gas sensor is comprised of detector, heating coil and blast protection screen, in this type of gas sensor, sensitizers such as Pt and Pd are added into metal oxides such as SnO2, Fe2O2 and ZnO2. Refer to Figure 1 for constitution of SnO2 series gas sensor. The selectivityof gas sensor is determined by the dosage of sensitizer, for example, for ZnO2series sensor, if Pt is added, then the sensor will be more sensitive to propane and isobutene; if Pd is added, the sensor will be more sensitive to CO andH2.SnO2 is a material with poor sintering tendency and high thermal stability. This type of sensor may only host reversible oxidation reactions on the surface of semi-conductor, while the chemical structure inside the semi-conductor will remain unchanged, to this end, high stability may be achieved even after long term use. SnO2is widely used in most cases of application. The work principle is as follows: when SnO2 is being heated, the oxygen in the air may bore off electrons from the donor level of SnO2 crystal particles, while negative electrons are attached on the surface of crystal, resulting in an increase of surface potential and subsequent blocking of the movement of conduction electrons. Hence, the gas sensor may present a constant resistance in the air. At this time, reducing gas form oxidation reaction with the oxygen adsorbed on the surface of semi-conductor, isolation effect of gas molecules results in the change of surface potential, consequently the resistance of sensor may change. For reducing gas, resistance reduces; for oxidizing gas, resistance increases. In this way, gas concentration may be detected by measuring the change of resistance.Construction of electrochemical solid electrolyte CO sensor is shown in Figure 2. It uses solid electrolyte to overcome strong acid electrolyte solution leakage and the necessity of frequent addition of electrolyte solution. The replacement of electrolyte solution by solid electrolyte is being studied. Solid electrolyte sensor uses inorganic salts such as Zr02, Y2O3, KAg4I5, K2CO3 and LaF3 as solid electrolyte, the solid electrolyte and electrodes. The pure solid electrolyte may conduct ion, but it can’t conduct electron, at the same time pure solid electrolyte features very low conductivity. To this end, high temperature ambience is usually required, this may be realized by installing internal heater. The solid electrolyte ZrO2 is mainly used for oxygen sensor, and can also be used for detection of CO. Due to the very low conductivity of inorganic salt solid electrolyte in low temperature and the electrolyte operates by potential difference and being insensitive to slight temperature change, and vulnerable to interference of other gas. Hence, CO detection in complicated sites is not recommended.III.A PPLICATION TECHNOLOGY OF GAS SENSORA.How to improve performance of gas sensorGas sensor’s life is limited and it is vulnerable to the influence of coexisted gas so it requires timely calibration. To this end, measure should be taken to improve the performance of sensor.1)Improve the sensitivity of gas sensorThere are allowable concentration regulations for various gas issued by environmental and health authorities. In recent years, highly toxic gas has been in more frequentISBN 978-952-5726-00-8 (Print), 978-952-5726-01-5 (CD-ROM) Proceedings of the 2009 International Symposium on Web Information Systems and Applications (WISA’09)Nanchang,P.R. China, May 22-24, 2009,pp.541-543Figure 1. Constitution of Sn02 Series Gas Sensorus. So it is expected that the sensitivity of gas sensor may be increase so it may detect a gas concentration lower than 10%.2) Reduce the influence of coexisted gasGas emission of ordinary plants may include the tested gas and many coexisted gases. So it is expected that the gas sensor in operation may not subject to the influence of coexisted gas.3) Longer sensor lifeLife of existing gas sensors varies from 6 months to 3 years as per the type of tested gas, electrolyte solution and shape. It is expected that the minimal life of sensor may be extended to at least one year. 4) Calibration-freeGas sensor needs to be calibrated by using calibration gas, the calibration frequency may vary from 6 months to 1 year per different types of gas. For water soluble gases such as HCL and HF, calibration is rather difficult to handle. So it is expected to use the gas sensors that doesn’t require calibration.5) Extend the scope of operation environmentTake certain measures on preset potential, electrolyte material and electrode material may help to improve the sensitivity to gas, and reduce the influence of co-existed gas. Currently electrode is primarily made of Pt, Au and Pd, by using new electrode materials may improve the selectivity of coexisted gas and improve the sensitivity of the detected gas.In addition, chemicals may also be used to remove the co-existed gas, in other cases, the electrical property difference of sensors may also be used to reduce the influence of coexisted gas.The gas emission from semi-conductor plants contains many types of gases. In order to detect as many types of gases as possible, the gas sensor being sensitive to multiple types of gas may be used.In order to prolong the service life of sensors, efforts should be taken on sensor construction and materials so as to prevent the evaporation of electrolyte solution in high temperature, materials with high temperature resistance should also be developed.B. Gas sensor output voltage acquiring methodSemi-conductor gas sensor adopts heater to warm up the detection element, at this time, the heating temperature of the heater has profound influence on the gas sensor’s property. To this end, the voltage stability is vitally important. In addition, the consumption power of the gas sensor should not exceed the rating, otherwise the detection element might be damaged.The gas sensor’s output voltage acquiring pattern is shown in Figure3.On that Figure, Figure (a) is a resistorR S in series with gas sensor, the voltage reduction at R S is then the output voltage of the sensor. If harmful gas is detected, resistance of the detection element may decrease. At this time, the voltage on both sides of R S may increase, consequently, the output voltage may change. R S is determined by the resistance of the detection element corresponding to a certain gas concentration. For ordinary applications, when the sensor output voltage is 2～3V, the processing of subsequent circuit may be very convenient. In Figure (b), the sensor output is connected with the same phase input of comparator A 1. When the gas concentration exceed the preset value, A 1 will give high level, so a simple gas detection circuit is constituted.Furthermore, semi-conductor gas sensor’s resistance in gas is in relation with temperature and temperature, to this end, in different temperatures, the same gas concentration will bring about different resistance, so compensation is required. Figure (c) is a simple temperature compensation circuit. Connect negative temperature coefficient thermal resistor R T is connected with reverse phase input end(reference voltage end), when temperature decreases, R T value increases, so the reference temperature decreases; when temperature increases, reference voltage also increase, so the temperature deviation is compensated. Material constant of thermal resistor is determined according to the temperature dependence of gas sensor, ordinarily, the selected material constant is 3700~4000 thermal resistor, that may provide temperature compensation to many semi-conductor gas sensor. However, when using thermal resistors, effective compensation can not be achieved in both high and low temperatures, at this time, when gas is detected, low temperature compensation should beconsidered as a priority.IV. E XAMPLE OF GAS SENSOR APPLICATION Figure 4 is a linear circuit of gas sensor. When detecting CH 4 concentration, perform indirect heating on CH 4 gas sensor by current I H =167mA, the CH 4 concentration equivalent resistant R S will tend to reduce non-linearly along with the increase of gas concentration. The typical example is that when CH 4 concentration=l000ppm, R S =14.0K Ω; when CH 4 concentration =l0000ppm 时，R S =4.2 K Ω. If the current through R S remain constant(I=0.5mA), then voltage V T =IRS will indicate CH 4concentration.Figure 2. Construction of Electrochemical Solid Electrolyte CO Sensor(a)Output voltage (b)Simple gas (c)Simple temperatureacquiring pattern test circuit compensation circuitFigure 3. Gas sensor output voltage acquiring patternWhen V T passes linear circuit AD538 and amplifier A 3, output voltage V OUT is obtained. V OUT is linear to CH 4 concentration. In the Figure, REF-03 provides reference voltage and generate constant current I=0.5mA. A 1 plays isolation role, A 3 plays buffering role.When adjusting the sensor, place the sensor in a room whose volume is already known, then feed in the room CH 4 gas to the pre-determined concentration (1000ppm), and use fan to mix. Adjust resistor R 1, set the output U O to l.0V, then increase CH 4 concentration to 10000ppm, adjust resistor R 6, set the output U O to 10.0V. Repeat adjustment till satisfaction is achieved.Figure 5 shows a gas monitoring circuit using AF30L as sensor. AF30L/38L is a type of semi-conductor gas sensor whose detection element resistance may change per the oxidation/reduction reaction on its surface, the sensor is applicable to detection of smoke and odor, etc. The heating coil voltage is AC or DC 5V±0.2V, theconsumption power 300mW, service temperature -10℃～+55. In the ℃Figure, 7805 provides AF30L with +5V stable voltage, its heating may influence the property of AF30L, so AF30L should be installed at a location far away from 7805. A 2 and other elements constitute relay circuit to prevent the possible misoperation cased by the instable sensor resistance at start-up. When the circuit isstarted, capacitor C 3 subject to a 0 voltage, A 3 output low level, VT 1 is cut off, even though VT 3 is connected due to sensor misoperation, relay K will not operate; after a certain relay time(determined by R 5 and C 3 value), C 3 is fully recharged, A 2 output high level, VT 1 is in connection status. A 1 is a comparator, RP 2 adjust the preset voltage. When the detected gas is clean, the resistance between electrode A and B of AF30L is high, the in-phase input side voltage of A 1 is lower than that of the anti-phase (preset value), A 1 output low level,VT 1 cuts off, relay K doesn’t operate. When the detected gas concentration surpasses the pre-set value, the resistance between electrode A and B, the in-phase input side voltage of A 1 is higher than that of the anti-phase input side, A1 outputs high level, VT 1 is connected, relay K is activated and start up the blower fan, so the function of monitoring is achieved.Figure 6 shows a smoke monitoring circuit using AF38L. the output of gas sensor AF38L passes through A 1 voltage follower and reaches the in-phase input side of differential amplifier A 2, A 2 output is amplification of voltage differential between the in-phase input and anti-phase output. A 3 is in-phase amplifier, gain factor of A 3 may be adjusted through RP 3, in another word to adjustthe in-phase input side voltage of A 4～A 8 comparator. In this way, the number of illumination among LED 2～LED 6 may be determined to indicated the level of air pollution so as to control smoking.V.C ONCLUSIONThis article introduces work principle and voltage acquiring pattern of a type of gas sensor. Compared with traditional sensors, this sensor enjoys advantages such as higher measurement accuracy, less sampling and prompt response and is expected to be used widely. By directly using or slightly modifying the gas sensor application examples, the gas sensor may be used in environment monitoring and control circuit, in order to constitute a high quality monitoring systemFigure 4. Linear circuit of gas sensorFigure 5. Gas monitoring circuit using AF30LFigure 6. Smoke monitoring circuit using AF38L。