Analysis of Pressure Sensor Technology
2016-12-06 16:34:20 Source:Shenzhen YLZ technology co., LTD Author:Admin Visit:631
A variety of mechanical sensors, such as resistance strain gauge pressure sensor, semiconductor strain gauge pressure sensor, piezoresistive pressure sensor, inductive pressure sensor, capacitive pressure sensor, resonant pressure sensor and capacitive acceleration sensor. But the most widely used is the piezoresistive pressure sensor, which has a very low price and high accuracy and good linearity.
In understanding the piezoresistive pressure sensor, we first know what the resistance strain gauge such components. Resistance strain gauge is a device to be tested on the strain changes into a kind of electrical signal sensitive devices. It is a piezoresistive strain sensor is one of the main components. Resistance strain gauge is the most widely used metal strain gauges and semiconductor strain gauges two. Metal resistance strain gauge and wire-like strain gauge and metal foil strain gauge two. Usually the strain gauges through a special adhesive close adhesion in the production of mechanical strain on the substrate, when the stress of the substrate stress changes, the resistance strain gauges are also deformed together, so that the resistance of the strain gauges change, The voltage on the resistor changes. This strain gauge in the force generated when the resistance change is usually smaller, the strain gauge composed of strain bridge, and through the subsequent instrumentation amplifier to amplify, and then transferred to the processing circuit (usually A / D conversion and CPU ) Display or actuator.
Internal structure of metal resistance strain gauges
It consists of the base material, metal strain wire or strain foil, insulation protection chip and lead wire and other components. According to different purposes, the resistance of the resistance strain gauge can be designed by the designer, but the range of resistance should be noted: the resistance is too small, the required drive current is too large, while the strain gauges of the fever caused their own temperature is too high , The use of different environments, so that the resistance of the strain gauges change too much, the output zero drift significantly, zero-crossing circuit is too complex. While the resistance is too large, the impedance is too high, resistance to external electromagnetic interference is poor, are generally dozens of Europe to tens of thousands of Europe.
The working principle of resistance strain gauge
Metal strain gauge works is adsorbed on the substrate material strain resistance with the mechanical deformation of the phenomenon of resistance change, commonly known as the resistance strain effect.
We wire strain gauges, for example, when the metal wire by external force, its length and cross-sectional area will change, the resistance will change. If the wire is stretched by external force, its length increases, while the cross-sectional area decreases, the resistance will increase. When the wire is compressed by external forces, the length decreases and the cross-section increases and the resistance decreases. As long as the change in the resistance measured (usually measuring the voltage across the resistor), you can get strain strain wire strain.
Ceramic pressure sensor
Corrosion-resistant ceramic pressure sensor without liquid transfer, the pressure directly on the front surface of the ceramic diaphragm, the diaphragm has a small deformation, thick film resistor printed on the back of ceramic diaphragm, connected into a Wheatstone bridge Bridge), the piezoresistive effect of the varistor, the bridge produces a high linearity proportional to the pressure, and the excitation voltage is also proportional to the voltage signal, the standard signal according to the pressure range of different calibration for the 2.0 / 3.0 / 3.3 MV / V, etc., and strain sensors can be compatible. By laser calibration, the sensor has a high temperature stability and time stability, the sensor comes with temperature compensation 0 ~ 70 ℃, and the vast majority of media and direct contact.
Ceramics is a recognized high elasticity, corrosion resistance, wear resistance, impact and vibration of the material. Ceramic thermal stability and its thick film resistance can make it the operating temperature range up to -40 ~ 135 ℃, but also has the measurement of high precision and high stability. Electrical insulation greater than 2kV, the output signal strength, long-term stability. High-performance, low-cost ceramic sensor will be the development direction of pressure sensors in Europe and the United States have many types of sensors to replace the trend in China, more and more users to replace the use of ceramic sensors diffusion silicon pressure sensor.
Diffused silicon pressure sensor
The pressure of the measured medium directly on the sensor diaphragm (stainless steel or ceramic), the diaphragm pressure is proportional to the micro-displacement, so that the sensor resistance changes, with the electronic circuit to detect this change and convert A standard measurement signal corresponding to this pressure is output.
Sapphire pressure sensor
Using the principle of strain-type resistance, the use of silicon - sapphire as a semiconductor sensor, with unparalleled metering characteristics.
Sapphire is composed of single crystal insulator elements, does not occur hysteresis, fatigue and creep phenomenon; sapphire is stronger than silicon, higher hardness, not afraid of deformation; sapphire has a very good elasticity and insulation properties, therefore, the use of silicon - sapphire Semiconductor-sensitive components, the temperature change is not sensitive, even in high temperature conditions, also has a good working characteristics; sapphire radiation resistance is extremely strong; In addition, the silicon - sapphire semiconductor sensor, no pn drift, therefore, fundamentally Simplifies the manufacturing process, improve the repeatability, to ensure a high yield.
Pressure sensors and transducers made of silicon-sapphire semiconductor sensitive components are designed to operate under the most severe operating conditions, with high reliability, good accuracy, low temperature error and high cost performance.
Gauge pressure transmitter and transmitter by the dual diaphragm composition: titanium alloy diaphragm and titanium diaphragm. A sapphire wafer printed with a heteroepitaxial strain sensitive bridge circuit was soldered to a titanium alloy measuring diaphragm. The measured pressure is transmitted to the receiver diaphragm (the diaphragm is firmly connected with the measuring diaphragm by means of a pull rod). Under the action of pressure, the titanium alloy receives the diaphragm to produce the deformation. After the distortion is sensed by the silicon-sapphire sensor, the output of the bridge will change. The amplitude of the change is proportional to the measured pressure.
The sensor circuit can guarantee the power supply of the strain bridge circuit and convert the unbalanced signal of the strain bridge into a unified electrical signal output (4 ~ 20mA or 0 ~ 5V). In the absolute pressure sensors and transmitters, the sapphire wafer and ceramic base glass solder joint together, played the role of the elastic element, the measured pressure is converted to strain gauge deformation, so as to achieve the purpose of pressure measurement.
Piezoelectric pressure sensor
Piezoelectric materials used in piezoelectric sensors include quartz, sodium potassium tartrate and dihydrogen phosphate. Among them quartz (silica) is a natural crystal, piezoelectric effect is found in this crystal, within a certain temperature range, the piezoelectric properties have been there, but the temperature exceeds this range, the piezoelectric properties completely Disappeared (the high temperature is the so-called "Curie point"). As it changes with the stress of the electric field is small (that is, piezoelectric coefficient is relatively low), so the quartz is gradually replaced by other piezoelectric crystals. Potassium sodium tartrate has a large piezoelectric sensitivity and piezoelectric coefficient, but it can only be used at room temperature and low humidity environment can be applied. Dihydrogen phosphate is an artificial crystal, can withstand high temperatures and very high humidity, it has been widely used.
Piezoelectric effect is now also used in polycrystalline, such as the current piezoelectric ceramics, including barium titanate piezoelectric ceramics, PZT, niobate-based piezoelectric ceramics, lead niobium magnesium lead-acid piezoelectric ceramics and so on.
Piezoelectric effect is the main working principle of piezoelectric sensors, piezoelectric sensors can not be used for static measurement, because the external force after the charge, only in the loop with an infinite input impedance was saved. This is not the case, so this determines that the piezoelectric sensor can only measure the dynamic stress.
Piezoelectric sensors are mainly used in the measurement of acceleration, pressure and force. Piezoelectric acceleration sensor is a commonly used accelerometer. It has a simple structure, small size, light weight, long life and excellent features. Piezoelectric acceleration sensors have been widely used in the vibration and shock measurement of aircrafts, automobiles, ships, bridges and buildings, especially in the aerospace and aerospace fields. Piezoelectric sensors can also be used to measure the combustion pressure inside the engine and the measurement of vacuum. It can also be used in the military industry, for example, to measure the instantaneous change in chamber pressure and the shock wave pressure of the muzzle in the bore. It can be used to measure large pressure, can also be used to measure the small pressure.
Piezoelectric sensors are also widely used in biomedical measurement, such as ventricular catheter microphone is made of piezoelectric sensors, because the measurement of dynamic pressure is so common, so the application of piezoelectric sensors is very extensive.
In understanding the piezoresistive pressure sensor, we first know what the resistance strain gauge such components. Resistance strain gauge is a device to be tested on the strain changes into a kind of electrical signal sensitive devices. It is a piezoresistive strain sensor is one of the main components. Resistance strain gauge is the most widely used metal strain gauges and semiconductor strain gauges two. Metal resistance strain gauge and wire-like strain gauge and metal foil strain gauge two. Usually the strain gauges through a special adhesive close adhesion in the production of mechanical strain on the substrate, when the stress of the substrate stress changes, the resistance strain gauges are also deformed together, so that the resistance of the strain gauges change, The voltage on the resistor changes. This strain gauge in the force generated when the resistance change is usually smaller, the strain gauge composed of strain bridge, and through the subsequent instrumentation amplifier to amplify, and then transferred to the processing circuit (usually A / D conversion and CPU ) Display or actuator.
Internal structure of metal resistance strain gauges
It consists of the base material, metal strain wire or strain foil, insulation protection chip and lead wire and other components. According to different purposes, the resistance of the resistance strain gauge can be designed by the designer, but the range of resistance should be noted: the resistance is too small, the required drive current is too large, while the strain gauges of the fever caused their own temperature is too high , The use of different environments, so that the resistance of the strain gauges change too much, the output zero drift significantly, zero-crossing circuit is too complex. While the resistance is too large, the impedance is too high, resistance to external electromagnetic interference is poor, are generally dozens of Europe to tens of thousands of Europe.
The working principle of resistance strain gauge
Metal strain gauge works is adsorbed on the substrate material strain resistance with the mechanical deformation of the phenomenon of resistance change, commonly known as the resistance strain effect.
We wire strain gauges, for example, when the metal wire by external force, its length and cross-sectional area will change, the resistance will change. If the wire is stretched by external force, its length increases, while the cross-sectional area decreases, the resistance will increase. When the wire is compressed by external forces, the length decreases and the cross-section increases and the resistance decreases. As long as the change in the resistance measured (usually measuring the voltage across the resistor), you can get strain strain wire strain.
Ceramic pressure sensor
Corrosion-resistant ceramic pressure sensor without liquid transfer, the pressure directly on the front surface of the ceramic diaphragm, the diaphragm has a small deformation, thick film resistor printed on the back of ceramic diaphragm, connected into a Wheatstone bridge Bridge), the piezoresistive effect of the varistor, the bridge produces a high linearity proportional to the pressure, and the excitation voltage is also proportional to the voltage signal, the standard signal according to the pressure range of different calibration for the 2.0 / 3.0 / 3.3 MV / V, etc., and strain sensors can be compatible. By laser calibration, the sensor has a high temperature stability and time stability, the sensor comes with temperature compensation 0 ~ 70 ℃, and the vast majority of media and direct contact.
Ceramics is a recognized high elasticity, corrosion resistance, wear resistance, impact and vibration of the material. Ceramic thermal stability and its thick film resistance can make it the operating temperature range up to -40 ~ 135 ℃, but also has the measurement of high precision and high stability. Electrical insulation greater than 2kV, the output signal strength, long-term stability. High-performance, low-cost ceramic sensor will be the development direction of pressure sensors in Europe and the United States have many types of sensors to replace the trend in China, more and more users to replace the use of ceramic sensors diffusion silicon pressure sensor.
Diffused silicon pressure sensor
The pressure of the measured medium directly on the sensor diaphragm (stainless steel or ceramic), the diaphragm pressure is proportional to the micro-displacement, so that the sensor resistance changes, with the electronic circuit to detect this change and convert A standard measurement signal corresponding to this pressure is output.
Sapphire pressure sensor
Using the principle of strain-type resistance, the use of silicon - sapphire as a semiconductor sensor, with unparalleled metering characteristics.
Sapphire is composed of single crystal insulator elements, does not occur hysteresis, fatigue and creep phenomenon; sapphire is stronger than silicon, higher hardness, not afraid of deformation; sapphire has a very good elasticity and insulation properties, therefore, the use of silicon - sapphire Semiconductor-sensitive components, the temperature change is not sensitive, even in high temperature conditions, also has a good working characteristics; sapphire radiation resistance is extremely strong; In addition, the silicon - sapphire semiconductor sensor, no pn drift, therefore, fundamentally Simplifies the manufacturing process, improve the repeatability, to ensure a high yield.
Pressure sensors and transducers made of silicon-sapphire semiconductor sensitive components are designed to operate under the most severe operating conditions, with high reliability, good accuracy, low temperature error and high cost performance.
Gauge pressure transmitter and transmitter by the dual diaphragm composition: titanium alloy diaphragm and titanium diaphragm. A sapphire wafer printed with a heteroepitaxial strain sensitive bridge circuit was soldered to a titanium alloy measuring diaphragm. The measured pressure is transmitted to the receiver diaphragm (the diaphragm is firmly connected with the measuring diaphragm by means of a pull rod). Under the action of pressure, the titanium alloy receives the diaphragm to produce the deformation. After the distortion is sensed by the silicon-sapphire sensor, the output of the bridge will change. The amplitude of the change is proportional to the measured pressure.
The sensor circuit can guarantee the power supply of the strain bridge circuit and convert the unbalanced signal of the strain bridge into a unified electrical signal output (4 ~ 20mA or 0 ~ 5V). In the absolute pressure sensors and transmitters, the sapphire wafer and ceramic base glass solder joint together, played the role of the elastic element, the measured pressure is converted to strain gauge deformation, so as to achieve the purpose of pressure measurement.
Piezoelectric pressure sensor
Piezoelectric materials used in piezoelectric sensors include quartz, sodium potassium tartrate and dihydrogen phosphate. Among them quartz (silica) is a natural crystal, piezoelectric effect is found in this crystal, within a certain temperature range, the piezoelectric properties have been there, but the temperature exceeds this range, the piezoelectric properties completely Disappeared (the high temperature is the so-called "Curie point"). As it changes with the stress of the electric field is small (that is, piezoelectric coefficient is relatively low), so the quartz is gradually replaced by other piezoelectric crystals. Potassium sodium tartrate has a large piezoelectric sensitivity and piezoelectric coefficient, but it can only be used at room temperature and low humidity environment can be applied. Dihydrogen phosphate is an artificial crystal, can withstand high temperatures and very high humidity, it has been widely used.
Piezoelectric effect is now also used in polycrystalline, such as the current piezoelectric ceramics, including barium titanate piezoelectric ceramics, PZT, niobate-based piezoelectric ceramics, lead niobium magnesium lead-acid piezoelectric ceramics and so on.
Piezoelectric effect is the main working principle of piezoelectric sensors, piezoelectric sensors can not be used for static measurement, because the external force after the charge, only in the loop with an infinite input impedance was saved. This is not the case, so this determines that the piezoelectric sensor can only measure the dynamic stress.
Piezoelectric sensors are mainly used in the measurement of acceleration, pressure and force. Piezoelectric acceleration sensor is a commonly used accelerometer. It has a simple structure, small size, light weight, long life and excellent features. Piezoelectric acceleration sensors have been widely used in the vibration and shock measurement of aircrafts, automobiles, ships, bridges and buildings, especially in the aerospace and aerospace fields. Piezoelectric sensors can also be used to measure the combustion pressure inside the engine and the measurement of vacuum. It can also be used in the military industry, for example, to measure the instantaneous change in chamber pressure and the shock wave pressure of the muzzle in the bore. It can be used to measure large pressure, can also be used to measure the small pressure.
Piezoelectric sensors are also widely used in biomedical measurement, such as ventricular catheter microphone is made of piezoelectric sensors, because the measurement of dynamic pressure is so common, so the application of piezoelectric sensors is very extensive.
