In the past 10 years, technologies such as smartphones, smart watches, , drones, etc. have quickly entered our lives. In the next 10 years, various wearable devices, Internet of Things devices, robots, autonomous driving, etc. will be integrated into our lives.
Among them, as one of the technical cornerstones of these technologies, sensor technology not only promotes the development of technology, but also redefines the demand for future sensor technologies: more micro, more integrated, smarter, and lower power consumption...
In the future, which technologies will promote sensors to continue to develop? This article summarizes 8 key technologies for sensor development, which may be inspiring.
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. Sensing technology that adopts new principles and new effects
sensor is the crystallization of many high-tech and the result of the intersection of knowledge of many disciplines. Based on various physical, chemical, and biological effects and laws, we have developed sensitive components such as force-sensitive, thermal-sensitive, photo-sensitive, magnetic-sensitive and gas-sensitive, and has formed more than 26,000 sensor types worldwide today.
Therefore, it is necessary to develop sensitive components and sensing components with new principles and new effects, and to develop new sensors. is an important way to develop high-performance, multi-functional, low-cost and miniaturized sensors.
Take the inertial sensor as an example. The inertial sensor is a sensor that uses the inertial principle of and measurement technology to detect and measure acceleration, tilt, impact, vibration, rotation and multi-degree of freedom (DOF) motion. Inertial system composed of accelerometer and gyroscope can realize real-time monitoring of carrier position and motion information.
Different types of gyroscopes are driven by different physical principles, such as mechanical dry type, liquid float, semi-liquid float, air float angular rate gyro, flexible angular rate gyro, MEMS silicon, quartz angular rate gyro (including hemispherical resonant angular rate gyro), etc. mainly uses Coriolis effect (Coriolis) effect refers to a phenomenon in which an object moving in a rotating coordinate system deflects (Coriolis force is proportional to the input angular rate).
, but in optical fiber angular rate gyro, laser angular rate gyro and other sensor technologies. mainly uses another principle: the Sagnac principle, also known as the Sagnac effect (phase difference is proportional to the input angular rate) .
htt ml0 These new principles and new effects play a key role in promoting the development of sensing technology and developing more sensor applications.
At the same time, interdisciplinary new technology also plays an important role in the development of sensing technology. For example, the development of integrated circuit technology for sensors. In MEMS sensor , high-performance application-specific integrated circuit (ASIC) can integrate thousands of transistor circuits into a chip, reducing the impact of environmental factors and parasitic parameters on sensor performance, greatly improving Accuracy of MEMS sensor.
▲MEMS acoustic sensor structure diagram (from Goertek Micro Prospectus)
quantum sensor is one of the important application scenarios of quantum technology. Previously, the National Science and Technology Commission (NSTC) issued the national strategy for quantum sensors "Putting quantum sensors into practice" (for details, please refer to "The Strategy of the Powerful Technological Power on the Earth Releases Quantum Sensors, Writing 4 Words: National Interests!".)
Using the related effects in quantum mechanics , quantum sensitive devices can be designed and developed, such as resonance tunnel diode , quantum well laser and quantum interference components, etc., with high speed (1000 times faster than electronic sensitive devices) and low consumption (1000 less than electronic sensitive devices' energy consumption ), high efficiency, high integration, economic and reliable advantages.
and the development of nanoelectronics will also cause a new technological revolution in the field of sensing technology . Sensors made using nanotechnology have reduced size, improved accuracy, and greatly improved performance. Nanosensors stand on the atomic scale, thus greatly enriching the theory of sensors, promoting the production level of sensors, and broadening the application fields of sensors.
, sensor miniaturization and chipization technology
sensor miniaturization and chipization technology, mainly including MEMS process and the new generation of solid-state sensor microstructure manufacturing process , among which MEMS process has been widely used in sensors.
micro electromechanical system (MEMS) is a micro system or device integrating micro mechanisms, micro sensors, micro actuators, control circuits, signal processing, communication, interfaces, power supply, etc. It is a technology for designing, processing, manufacturing, measuring and controlling micro/nanomaterials.
MEMS Material includes functional material (usually semiconductor material with silicon as the main body), structural materials (such as piezoelectric materials, supermagnetic materials, photosensitive materials, etc.) and intelligent material (mainly shape memory alloys).
MEMS process key technologies include: deep reactive ion etching, LIGA technology, molecular assembly technology, body micromachining, surface micromachining, laser micromachining and micropackaging technology , etc.
Among them, the silicon micromachining process is MEMS Mainstream technology, it is a precision three-dimensional processing technology, and is the core technology for the development of sensors, microactuators, microactuators, and micromechanical systems. It has been successfully used to manufacture various microsensors and multifunctional sensitive element arrays, such as microsilicon capacitance sensors, microsilicon mass flow sensors, dynamic sensors for aerospace, microsensors, automotive-specific pressure and acceleration sensors, environmentally friendly microchemical sensors, etc.
deep reactive ion etching (DRIE) is one of the important processes of MEMS structure processing . It is mainly used for etching of polysilicon , silicon nitride , silicon dioxide thin films and metal films. It is a microelectronic dry corrosion process.
LIGA technology, namely photolithography, electroforming and injection molding , is a method of forming deep three-dimensional microstructures through electroforming molding and plastic casting.
▲MEMS gyroscope structure
Currently, in order to adapt to the development of MEMS technology, many new MEMS packaging technologies and processes have been developed, such as anode bonding, silicon melt bonding, eutectic bonding, etc. MEMS packages are usually divided into the following levels: die-level packaging, device-level packaging, silicon wafer-level packaging, single-chip packaging and system-level packaging.
Single-chip package (SCP) belongs to the category of device-level package , which refers to making a protective layer on a chip to shield easily damaged components and circuits to avoid adverse effects from the environment, and making a path to the active sensor /brake to achieve electrical contact with the outside to meet the device's technical requirements for electrical, mechanical, thermal and chemical aspects.
Multi-chip components (MCM) is a major breakthrough in electronic packaging technology and belongs to system-level packaging . MCM assembles two or more IC/MEMS chips or CSP on a circuit board to form a functional circuit board, namely multi-chip components, providing signal interconnection, I/O management, thermal control, mechanical support and environmental protection for each chip (component) in the component. MCM has the ability to support multiple chips on the same substrate without changing the manufacturing process of MEMS and circuits.
, integrated technology for sensor array and multi-sensing parameter composite
This type of integrated technology includes integrated process and multi-variable composite sensor microstructure integrated manufacturing process, multi-variable composite sensor for industrial control, etc., such as pressure, static pressure, temperature, four-variable sensors, air pressure, wind power, temperature, and humidity, micro-silicon composite strain pressure sensor , array sensor.
Integration refers to the integrated of multiple sensing functions with data processing, storage, bidirectional communication, etc., which can fully or partly realize signal detection, transformation processing, logic judgment, function calculation, two-way communication, as well as internal self-test, self-calibration, self-compensation, self-diagnosis and other functions. It has the characteristics of low-cost, high-precision information collection, data storage and communication, programming automation and diversified functions.
sensor integrated has two types: One is to build multiple sensing modules on a chip through micromachining technology, and forms a linear sensor (such as CCD image sensor ) ; One is to make sensitive components with different functions on the same silicon wafer , and is to make integrated multifunction sensors, with high integration and small size, making it easy to achieve compensation and correction.
micromachining technology and precision packaging technology have a significant impact on the integration of sensors.
Multi-sensor information fusion integrates sensor application technology, data processing technology, computer software and hardware technology and industrial control technology.
It uses computer technology to analyze, eliminate the possible redundancy and contradictions between multi-sensor information, complement each other, reduce its indecision, and obtain the consistency explanation and description of the object being tested. has the advantages of fault tolerance, complementarity, real-time, and economical.
4, sensor digitalization and intelligent technology
Intelligent technology and intelligent sensor signal wired or wireless detection, transformation processing, logic judgment, function calculation, two-way communication, self-diagnosis and other intelligent technologies; intelligent multivariable sensors, smart power sensors and various intelligent sensors, transmitter .
digital sensor includes a circuit for adjusting and processing signals and a network communication interface. They are usually made in module form, including sensors, DSPs (digital signal processors), DSCs (digital signal controllers) or ASICs (specific purpose integrated circuits), and are also made in a system package or system chip. There are usually three types of electronic components used to drive digital outputs: mechanical relays, transistor and bidirectional FET devices.
Intelligent sensor refers to a sensor with anthropomorphic intelligence characteristics or functions developed by using artificial intelligence technologies such as hardware softening, software integration, virtual reality, and soft measurement. It is also an active sensing system with independent detection and signal processing and conversion capabilities, self-testing and communication functions. A typical representative of
intelligent sensor is a high-performance intelligent industrial transmitter. , such as Japan Yokogawa Electric's EJA series intelligent transmitter, ABB's MV2000T series multi-function differential pressure/pressure transmitter, Rosemount's 3095MV multi-parameter mass flow transmitter, uses silicon resonant sensor, composite microsilicon solid-state sensor and high-precision capacitive sensor as sensitive components, with an accuracy of 0.1075%, with high stability and reliability, and no zero adjustment is required within ten years.
5. Sensors' strong environmental adaptability technology
We know that from automobiles to industry, from medical care to aerospace, from home appliances to testing and measurement, sensors are everywhere, and many industry applications have high requirements for the environmental adaptability of sensors. For example, a magnetoresistive sensor produced by a German company, which was used in the Mars rover " courage " and " opportunity " in 2004, can work normally within the temperature range of +270℃ to -133℃.
Sensor products have strong environmental adaptability tests including electrical safety experiments, failure analysis experiments, corrosive gas experiments, environmental performance experiments, material experiments, etc. .
The advancement of sensor packaging materials and technology has made the sensor's environmental adaptability stronger and stronger.
Metal-based composite material package (AI/Si Cp). realizes the physical performance design of the material by changing the type, arrangement of the reinforcement body, or changing the alloy composition of the substrate, or changing the heat treatment process; or change the interface bonding status between the substrate and the reinforcement body by changing the heat treatment process, thereby affecting the thermal performance of the material. This type of material has a low thermal expansion coefficient, which can not only match the thermal expansion coefficient of electronic component material, but also has high thermal conductivity and low density.
plastic packaging More than 90% of epoxy resin is used, which has the advantages of large-scale production and reliability comparable to metal or ceramic materials. vulcanized epoxy resin also has the characteristics of faster curing speed, lower curing temperature and hygroscopicity, higher moisture resistance and heat resistance.
ceramic packaging is to install one or more chips on the ceramic base plate or tube base with adhesive or solder , bond with the ceramic metal pattern layer by flip-fitting welding, and then seal the package, while providing a suitable electrical connection .
ceramics have high Young's modulus, high insulation performance and excellent high-frequency characteristics. They have good reliability, plasticity and easy to seal. Their linear expansion coefficient is very similar to that of electronic components, stable chemical properties and high thermal conductivity. They are used in multi-chip components, soldering arrays and other packaging.
6, wireless sensor network technology
wireless sensor network (WSN), is a multi-hop self-organized network system composed of a large number of static or mobile sensors with perception, wireless communication and computing capabilities, and can independently complete designated tasks according to the environment.
A large number of sensors form a distributed and intelligent information processing system through the network. They cooperate to monitor, perceive, collect and analyze events, phenomena and environments in the network coverage area from multiple perspectives and in multiple modes in real time, obtain rich and high-resolution information, and process and transmit this information to the observer.
Sensor, perception object and observer constitute three elements of the wireless sensor network. Wireless Sensor Network (WSN) includes sensor units, controllers and wireless communication modules, which realize functions such as data acquisition, short-range communication, data calculation and long-range wireless communication.
WSN integrates sensor technology, embedded operating system technology, distributed information processing technology , wireless communication technology, energy collection technology, low power consumption technology, multi-hop ad hoc network routing protocol, positioning technology, time synchronization technology, data fusion and data management technology, information security technology , network transmission technology, the key is to overcome node resource limitations (energy supply, computing and communication capabilities, storage space, etc.) and meet the requirements of sensor network scalability and fault tolerance.
This technology was rated as the top ten emerging technologies that have had a profound impact on human future life by the "Technology Review" magazine of the Massachusetts Institute of Technology (MIThings 2).
7, sensor digital communication bus technology
field bus technology is an emerging control technology that integrates computer technology, communication technology, integrated circuit technology and intelligent sensing technology. It is a digital, serial, multi-point communication data bus installed in the field device in the manufacturing and process area and the automatic control device in the control room. It is a fully digital, open, two-way transmission, multi-branch, and multi-station communication system, and is an integration of the field communication network and the control system.
▲Simplified diagram of intelligent sensing technology based on fieldbus
Fieldbus 's key sign is to support all digital communication , establish a high-reliability data communication line at the control site, realize data communication between various intelligent sensors and between intelligent sensors and the master controller, and turn a single dispersed intelligent sensor into network node .
Fieldbus intelligent sensor needs the following functions: use a bus to transmit information, with multiple computing, data processing and control functions, thereby reducing the burden on the host; replace 4-20mA analog signal transmission, realize the digitization of the transmitted signal, and enhance the anti-interference ability of the signal; adopt a unified network protocol to become a node of the FCS, realizing information exchange between the sensor and the actuator; the system can verify, configure, and test it to improve the reliability of the system; the interface is standardized, with plug-and-play characteristics.
fieldbus intelligent sensor is the mainstream instrument of the future industrial process control system .
8. Sensor application technology
Sensor application technology refers to the general term for various technologies that apply sensors to downstream devices and scenarios. Single sensors often cannot play their due role.
These technologies include: signal processing and interface technology; noise reduction and anti-interference technology; display and adjustment instruments; measurement and error processing; sensor selection and installation adjustment technology; detection technology of mechanical quantities such as displacement, force, torque, load, speed, acceleration, etc.; detection technology of process quantities such as temperature, pressure, flow, and level; humidity detection and gas analysis technology; detection, imaging and safety prevention technology; intelligent and automatic testing technology; installation technology of proximity sensor , pressure sensor, and induction synchronizer; infrared, ultrasonic , microwave detection anti-theft alarm installation technology, etc.
For consumer applications, the main technical difficulty of transmitting sensor fusion is how to control the size of the product , reasonably test the performance of each sensor, control the yield rate of the entire chip and reduce costs.
For sensor fusion in the fields of industry, military industry, automobile, medical care, etc., we must also consider how to ensure the accuracy and reliability in various working conditions of , and use the fusion feature to achieve compensation correction between sensors, etc. The internal noise of the sensor circuit includes circuit board electromagnetic component interference, low frequency, high frequency heat, semiconductor device shred transistor, resistor , integrated circuit noise, etc., and external interference includes power supply, ground , long-line signal transmission, space electromagnetic wave , etc.
Therefore, in the circuit design, it is necessary to reasonably select low-noise semiconductor components according to different working frequencies, and select the appropriate amplification circuit according to different working frequency bands and parameters.
Conclusion
More than 90% of my country's mid-to-high-end sensors need to be imported, and sensing technology has become one of the key boredom areas that my country urgently needs to solve. Although the sensor is small, it is behind it that leverages trillion-level markets such as industrial automation , robots, autonomous driving, Internet of Things, etc. , which is a key technology field that truly affects the national economy and people's livelihood! The eight key common technologies of sensors in the article are important cornerstones for the future development of sensing technology. Through these technical directions, we will seize the dominance of industrial development and narrow the gap between my country and foreign sensor technology.
But at the same time, we should pay more attention to the disconnection between technology and industry in my country's sensor industry, that is, technology research and development is in universities and research institutes, and the implementation of the sensor industry is the vast number of small and medium-sized sensor enterprises. How to combine the technology in the laboratory with the vast number of small and medium-sized sensor enterprises to do a good job in technological industrialization is equally important as the research and development of sensor technology.
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