A smartphone contains hundreds of sensors: CMOS image sensors for photography, ambient light sensors for detecting environmental brightness, geomagnetic sensors and gyroscopes for navigation, and so on. It is thanks to these sensors that various applications on a smartphone can function smoothly, making it a portable smart device that integrates work, life, and entertainment, bringing about tremendous changes in people's lifestyles. Visible and infrared photoelectric sensors on Fengyun satellites can acquire atmospheric information day and night, accurately predicting the weather. Sensors even operate on the moon and Mars, helping humanity explore the mysteries of the universe.
More acute and powerful than human senses
Sensors are the "eyes" of information systems. Like human eyes, ears, and skin, they perceive the surrounding environment, helping us understand the diverse world around us. The difference lies in the fact that sensors are far more sensitive and powerful than human senses. The diversity of information contained in the objective world far exceeds the capabilities of our senses. Human eyes cannot observe infrared and ultraviolet radiation, ears cannot hear infrasound and ultrasound, and we cannot perceive the invisible yet constantly influencing magnetic fields. Sensors can "sense" all this information beyond the reach of our senses.
With the development of productivity, humanity increasingly needs to perceive the world in all aspects. In 1821, scientists developed the world's first sensor—a temperature sensor—by utilizing the principle that materials generate voltage due to temperature differences. Initially, people directly used physical effects such as light, heat, electricity, force, and magnetism to prepare various sensors. These sensors were large, had low sensitivity, and were inconvenient to use. In the 1970s, integrated sensors emerged, which integrated the sensitive element and signal circuit into a single design, such as thermocouple sensors, Hall effect sensors, and photosensitive sensors. These sensors are composed of solid-state components such as semiconductors, dielectrics, and magnetic materials, and output analog signals. Starting in the late 20th century, digital sensors developed rapidly, achieving digital signal output through "analog-to-digital" conversion modules. Digital sensors integrate intelligent processing units, which can automatically collect and process data and automatically adjust operating parameters according to the environment. The photosensitive element in a digital camera is a representative product of this technology.
Without sensors, there is no digitalization and intelligentization.
Digitalization is the quantification of the attributes of things and the expression of them as abstract results using numbers. With the help of modern information technology, people can store, process, and disseminate various digital information. Sensors can convert the various information contained in things into electrical signals, and then use digital-to-analog converters to express these electrical signals digitally, making them an effective tool for digitalization. When you take a photo or video with your phone, the photosensor converts the received light intensity signal into an electrical signal, then expresses and stores it digitally according to certain rules, ultimately forming the image on the phone screen.
Digitalization relies on sensors to acquire information. Digital systems need to process massive amounts of information that cannot be obtained manually or with traditional equipment alone. Sensors, however, can acquire this information in real-time, efficiently, accurately, and quickly, leading to urban big data, weather big data, medical big data, agricultural big data, and so on. Using various sensors, people can hold remote meetings, take online courses, make payments via QR code, and even sell goods via live streaming, thus developing the digital economy. The various technologies involved in the digital economy, such as cloud computing, the Internet of Things, artificial intelligence, and 5G communication, are all closely related to sensors.
Without sensors, there is no digitalization or intelligentization. Sensors are the first line of defense in intelligent systems, and their level determines the level of the intelligent system and its instruments and equipment. Sensor technology has become a research frontier in the field of high-end information devices internationally, playing an irreplaceable role in fields such as artificial intelligence, smart cities, 5G communications, aerospace, and life sciences. For example, a car is equipped with more than 100 sensors, including pressure, temperature, position, sound, light, and electricity sensors, which are processed by the onboard computer to help the driver make judgments. Intelligent analysis of data reduces the difficulty of driving, making cars safer and easier to drive. Furthermore, self-driving cars acquire road information in real time through sensors, and once obstacles are detected, they can avoid them in time through intelligent analysis. High-rise buildings, bridges, tunnels, and other structures in cities also need to be monitored for safety in real time through sensors such as video, temperature, pressure, and smoke sensors. When the data is aggregated, the intelligent system will analyze it in time and condense a small amount of key information for users to make decisions. Even in the future, human senses can be enhanced with the help of sensors to build intelligent systems.
If we compare intelligent systems to "people," then sensors are like those sensory organs. Different types of sensors perceive the surrounding environment and transmit data to the system for calculation, enabling real-time analysis, judgment, and response. With the deepening of digitalization and intelligentization, the applications of various sensors have greatly expanded, playing a significant role in creating a better life for humanity.
A smartphone contains hundreds of sensors: CMOS image sensors for photography, ambient light sensors for detecting environmental brightness, geomagnetic sensors and gyroscopes for navigation, and so on. It is thanks to these sensors that various applications on a smartphone can function smoothly, making it a portable smart device that integrates work, life, and entertainment, bringing about tremendous changes in people's lifestyles. Visible and infrared photoelectric sensors on Fengyun satellites can acquire atmospheric information day and night, accurately predicting the weather. Sensors even operate on the moon and Mars, helping humanity explore the mysteries of the universe.
More acute and powerful than human senses
Sensors are the "eyes" of information systems. Like human eyes, ears, and skin, they perceive the surrounding environment, helping us understand the diverse world around us. The difference lies in the fact that sensors are far more sensitive and powerful than human senses. The diversity of information contained in the objective world far exceeds the capabilities of our senses. Human eyes cannot observe infrared and ultraviolet radiation, ears cannot hear infrasound and ultrasound, and we cannot perceive the invisible yet constantly influencing magnetic fields. Sensors can "sense" all this information beyond the reach of our senses.
With the development of productivity, humanity increasingly needs to perceive the world in all aspects. In 1821, scientists developed the world's first sensor—a temperature sensor—by utilizing the principle that materials generate voltage due to temperature differences. Initially, people directly used physical effects such as light, heat, electricity, force, and magnetism to prepare various sensors. These sensors were large, had low sensitivity, and were inconvenient to use. In the 1970s, integrated sensors emerged, which integrated the sensitive element and signal circuit into a single design, such as thermocouple sensors, Hall effect sensors, and photosensitive sensors. These sensors are composed of solid-state components such as semiconductors, dielectrics, and magnetic materials, and output analog signals. Starting in the late 20th century, digital sensors developed rapidly, achieving digital signal output through "analog-to-digital" conversion modules. Digital sensors integrate intelligent processing units, which can automatically collect and process data and automatically adjust operating parameters according to the environment. The photosensitive element in a digital camera is a representative product of this technology.
In general, sensors work on the principle that the electrical properties of certain materials change with environmental factors. For example, platinum has different resistivity at different temperatures, silicon's resistance decreases under visible light, and quartz develops surface charges under pressure. Utilizing the relationship between resistance and temperature, temperature sensors can be fabricated. Further, by adding heat-insulating structures to the sensitive element and based on the relationship between the temperature change of the sensitive element and infrared radiation energy, infrared sensors can be created. Building upon this, non-contact temperature sensors can be manufactured based on the relationship between target temperature and infrared radiation energy. The forehead thermometer, familiar to many for measuring body temperature, utilizes this principle. Leveraging a wealth of physical and chemical effects, a variety of powerful sensors have been developed, including "electronic noses" with sensitivity 1000 times higher than a dog's nose that can "smell" gas molecules, and infrared cameras that can observe objects in the dark.
Without sensors, there is no digitalization and intelligentization.
Digitalization is the quantification of the attributes of things and the expression of them as abstract results using numbers. With the help of modern information technology, people can store, process, and disseminate various digital information. Sensors can convert the various information contained in things into electrical signals, and then use digital-to-analog converters to express these electrical signals digitally, making them an effective tool for digitalization. When you take a photo or video with your phone, the photosensor converts the received light intensity signal into an electrical signal, then expresses and stores it digitally according to certain rules, ultimately forming the image on the phone screen.
Digitalization relies on sensors to acquire information. Digital systems need to process massive amounts of information that cannot be obtained manually or with traditional equipment alone. Sensors, however, can acquire this information in real-time, efficiently, accurately, and quickly, leading to urban big data, weather big data, medical big data, agricultural big data, and so on. Using various sensors, people can hold remote meetings, take online courses, make payments via QR code, and even sell goods via live streaming, thus developing the digital economy. The various technologies involved in the digital economy, such as cloud computing, the Internet of Things, artificial intelligence, and 5G communication, are all closely related to sensors.
Without sensors, there is no digitalization or intelligentization. Sensors are the first line of defense in intelligent systems, and their level determines the level of the intelligent system and its instruments and equipment. Sensor technology has become a research frontier in the field of high-end information devices internationally, playing an irreplaceable role in fields such as artificial intelligence, smart cities, 5G communications, aerospace, and life sciences. For example, a car is equipped with more than 100 sensors, including pressure, temperature, position, sound, light, and electricity sensors, which are processed by the onboard computer to help the driver make judgments. Intelligent analysis of data reduces the difficulty of driving, making cars safer and easier to drive. Furthermore, self-driving cars acquire road information in real time through sensors, and once obstacles are detected, they can avoid them in time through intelligent analysis. High-rise buildings, bridges, tunnels, and other structures in cities also need to be monitored for safety in real time through sensors such as video, temperature, pressure, and smoke sensors. When the data is aggregated, the intelligent system will analyze it in time and condense a small amount of key information for users to make decisions. Even in the future, human senses can be enhanced with the help of sensors to build intelligent systems.
Smart sensors open up new application scenarios
Currently, various sensors are undergoing further performance improvements and cost reductions, evolving towards digitalization, intelligence, miniaturization, green and low-carbon technologies, and wearable applications, exhibiting a booming development trend. Among them, the research and development of intelligent sensors, flexible sensors, and sensors based on new principles are of representative significance and are expected to shape new work and lifestyles.
The development of intelligent sensors is a significant trend. Leveraging intelligent sensing technology, people have designed and manufactured various sensing units and microsystems with the functions of acquiring, storing, and analyzing information, achieving low-cost, high-precision information collection. Intelligent sensors are widely used in robotics, autonomous driving, intelligent manufacturing, and quantitative motion monitoring, and can also be used to develop non-invasive or minimally invasive health monitoring devices. The continuously variable blood glucose meter (CVG) that has become popular in recent years is a good example. Diabetic patients have a flexible sensor painlessly implanted in their body; the sensor measures blood glucose levels every 5 minutes and transmits the data to a mobile application. Patients can observe changes in their blood glucose curves and adjust their blood sugar levels promptly through diet and exercise; some patients have even been able to discontinue medication and insulin treatment as a result. Furthermore, researchers are also developing biodegradable electronic devices to allow intelligent sensors to better contribute to a low-carbon, environmentally friendly lifestyle.
Developing flexible sensors is another trend. Many applications require sensors to be fabricated on flexible substrate materials, possessing characteristics such as transparency, flexibility, stretchability, bendability (even foldability), portability, and wearability. Currently, commonly used sensing materials for flexible sensors include carbon-based materials (carbon black, carbon nanotubes, and graphene, etc.), metal nanomaterials (metal nanowires, metal nanoparticles, etc.), polymers, and protein fibers. For example, a cross-linked supramolecular polymer thin-film electrode material with stretchability, tear resistance, and self-healing capabilities can be used to manufacture next-generation wearable and implantable flexible electronic devices. Combining multifunctional flexible sensors with flexible printed circuits can create "smart bands" that can be worn on different parts of the body to monitor and analyze physiological information in real time, helping people, especially those with sensory impairments, understand their health status.
New sensor principles are constantly emerging. In the field of basic research, new laws are being discovered, and people are using these new scientific understandings to fabricate sensors. At the same time, technological advancements are also placing new demands on basic research. In everyday life, people want to improve the performance parameters of cameras, such as pixels, sensitivity, and speed; in high-speed experiments, streak cameras capable of recording femtosecond-scale information are needed; in quantum communication, photodetectors with sensitivity reaching single-photon levels are required; in aerospace technology, the detection of high-speed moving objects and cold targets is needed, and so on. This requires scientists to further explore the physical world, discover new phenomena and laws, and improve sensor performance.
Smart sensors open up new application scenarios
Currently, various sensors are undergoing further performance improvements and cost reductions, evolving towards digitalization, intelligence, miniaturization, green and low-carbon technologies, and wearable applications, exhibiting a booming development trend. Among them, the research and development of intelligent sensors, flexible sensors, and sensors based on new principles are of representative significance and are expected to shape new work and lifestyles.
The development of intelligent sensors is a significant trend. Leveraging intelligent sensing technology, people have designed and manufactured various sensing units and microsystems with the functions of acquiring, storing, and analyzing information, achieving low-cost, high-precision information collection. Intelligent sensors are widely used in robotics, autonomous driving, intelligent manufacturing, and quantitative motion monitoring, and can also be used to develop non-invasive or minimally invasive health monitoring devices. The continuously variable blood glucose meter (CVG) that has become popular in recent years is a good example. Diabetic patients have a flexible sensor painlessly implanted in their body; the sensor measures blood glucose levels every 5 minutes and transmits the data to a mobile application. Patients can observe changes in their blood glucose curves and adjust their blood sugar levels promptly through diet and exercise; some patients have even been able to discontinue medication and insulin treatment as a result. Furthermore, researchers are also developing biodegradable electronic devices to allow intelligent sensors to better contribute to a low-carbon, environmentally friendly lifestyle.
Developing flexible sensors is another trend. Many applications require sensors to be fabricated on flexible substrate materials, possessing characteristics such as transparency, flexibility, stretchability, bendability (even foldability), portability, and wearability. Currently, commonly used sensing materials for flexible sensors include carbon-based materials (carbon black, carbon nanotubes, and graphene, etc.), metal nanomaterials (metal nanowires, metal nanoparticles, etc.), polymers, and protein fibers. For example, a cross-linked supramolecular polymer thin-film electrode material with stretchability, tear resistance, and self-healing capabilities can be used to manufacture next-generation wearable and implantable flexible electronic devices. Combining multifunctional flexible sensors with flexible printed circuits can create "smart bands" that can be worn on different parts of the body to monitor and analyze physiological information in real time, helping people, especially those with sensory impairments, understand their health status.
New sensor principles are constantly emerging. In the field of basic research, new laws are being discovered, and people are using these new scientific understandings to fabricate sensors. At the same time, technological advancements are also placing new demands on basic research. In everyday life, people want to improve the performance parameters of cameras, such as pixels, sensitivity, and speed; in high-speed experiments, streak cameras capable of recording femtosecond-scale information are needed; in quantum communication, photodetectors with sensitivity reaching single-photon levels are required; in aerospace technology, the detection of high-speed moving objects and cold targets is needed, and so on. This requires scientists to further explore the physical world, discover new phenomena and laws, and improve sensor performance.
Sensor technology also has wide applications in environmental protection and resource management. By deploying sensor networks, we can monitor environmental information such as air pollution and water quality changes in real time, and take timely measures to protect the environment. Furthermore, the energy-saving advantages of sensors bring new possibilities to resource management. In the energy sector, smart sensors can monitor energy consumption in real time, optimize energy allocation, and achieve efficient energy use. Such applications not only help reduce resource waste but also help reduce adverse environmental impacts.
With the widespread application of sensor technology, we also face several security and privacy issues. The vast amounts of data generated by sensors need to be properly protected to prevent misuse or malicious attacks. Especially in the era of the Internet of Things (IoT), the connection between sensors and networks requires enhanced security measures to ensure the secure transmission and storage of data. Furthermore, we need to regulate the use and sharing of sensor data to ensure that users' privacy rights are fully protected.
The explosive growth of sensor technology will drive the arrival of the intelligent era, bringing immense convenience and innovation to our lives. The integration of sensors with artificial intelligence, automation, and other technologies will expand the boundaries of technology, creating a smarter future world. However, the accompanying security and privacy issues also require our serious attention. Let us actively explore the applications of sensor technology and contribute our efforts to the development of the intelligent era! Let us look forward to and witness together the bright future brought about by sensor technology!
In general, sensors work on the principle that the electrical properties of certain materials change with environmental factors. For example, platinum has different resistivity at different temperatures, silicon's resistance decreases under visible light, and quartz develops surface charges under pressure. Utilizing the relationship between resistance and temperature, temperature sensors can be fabricated. Further, by adding heat-insulating structures to the sensitive element and based on the relationship between the temperature change of the sensitive element and infrared radiation energy, infrared sensors can be created. Building upon this, non-contact temperature sensors can be manufactured based on the relationship between target temperature and infrared radiation energy. The forehead thermometer, familiar to many for measuring body temperature, utilizes this principle. Leveraging a wealth of physical and chemical effects, a variety of powerful sensors have been developed, including "electronic noses" with sensitivity 1000 times higher than a dog's nose that can "smell" gas molecules, and infrared cameras that can observe objects in the dark.
