The status quo and development trend of sensors and detection instruments

In recent years, sensors are in the stage of transition from traditional to new sensors. The new sensors are characterized by miniaturization, digitization, intelligence, multi-functionalization, systematization, and networking. They not only promote the transformation of traditional industries, but also lead to the establishment of new industrial and military revolutions. They are the new economic growth points in the 21st century. . In the process of industrialization of sensor production, China should not relax in the introduction of foreign technology and independent innovation. In the introduction of foreign advanced technology, it can improve its own technology, but also meet the needs of the domestic market, forming a sensor production industry scale. The importance of sensors and measuring instruments Industrial equipment will encounter various mechanical and geometrical quantities in the manufacturing process and in the overall performance test. Some industrial equipments are often required to detect or monitor some mechanical quantities and power during operation. These mechanical quantities include displacement, velocity, acceleration, force, torque, power, pressure, flow, temperature, hardness, density, temperature, specific gravity, and viscosity. Geometrical quantities include length, angle, shape, position, surface roughness, and surface waveforms. These are all physical quantities. Actually in the production, life, and scientific experimentation of people, there will be chemical quantities and biomass (including medicine). All of this, from the point of view of the signal, needs to be converted into electrical signals by sensors, Can be converted into optical signals, and then the signal transmission, processing, storage, display, control ... ... from the information point of view, these signals together with sound and image information are the source of information, so sensors and detection instruments, measurement Instrumentation is an important part of the three parts of information science technology (information acquisition, information transmission, and information processing).

In modern industrial equipment, sensors and measuring instruments are an indispensable part of the reason, but also from the following two aspects: the traditional industrial equipment such as adding the necessary sensors, equipped with precision measuring components (accessories), then Its function and accuracy can be improved, user-friendly operation and maintenance, security level can also be improved, equipment can be added value, industrial equipment as part of the automation system control or as part of the automation system, must be able to and three parts of the automation system (detection, control , Execution) is compatible or provides an interface to integrate it into an organic whole, whether it is a stand-alone automation or as part of a large-scale automation device, so that the use of the industrial equipment to expand. In summary, adding sensors and measuring instruments, measuring instruments or providing interfaces as industrial equipment itself is a necessary condition for the upgrading of traditional equipment. The sensor is a device that converts non-electrical energy into electrical signals. In the case of analog circuits, the detection instrument generally includes sensors, sampling devices and detection amplifiers (for anti-interference processing and signal transmission), and of course, power supply and on-site. Display part (optional), the electrical signal is generally divided into two kinds of continuous and discrete. Actually, it can also be divided into analog quantity, switch quantity, pulse quantity, etc. The analog signal transmission adopts unified signal (4~20mADC, etc.). In the digitization process, the detection instrument changes greatly. After several stages, ASIC specific integrated circuits are used more recently, and sensors and microprocessors and network interfaces are encapsulated in one device to complete information acquisition, processing, transmission, storage, and the like. Features. Often referred to as a transmitter in the automation instrument, such as temperature transmitters, pressure transmitters. Because sensors are used in all walks of life, coupled with the rapid development of household appliances, automobiles, and information industries over the years, the demand for sensors has greatly increased. Therefore, the sensor manufacturing industry has developed rapidly and has formed an independent industry, which has driven industrial equipment. In particular, the development of semiconductors and equipment manufacturing industry, so China must pay special attention to the sensor industry.

There are many kinds of sensor products, many scientific principles, and technology intensive. They have diversity, marginality, comprehensiveness, and artistry. They require multidisciplinary and multi-technology cooperation. Although they have high additional benefits, their prices are not high, so It is difficult to promote the development of the sensor industry. The current state of sensors and detection instruments There are a wide variety of sensor products. The main products used in the process industry are temperature sensors, pressure sensors, weight sensors, flow sensors, liquid level sensors, oxygen sensors, various force sensors, and gas sensors. , Analytical instruments, etc., used in the machinery industry are: switching type proximity / positioning sensors, safety switches and other safety sensors, rotary encoders, visual sensors, speed sensors, acceleration sensors.

At present, domestic sensors are divided into 10 categories, 24 sub-categories, and 6000 varieties. And there are more domestic varieties, such as about 17,000 kinds of sensors in the United States, so the field of developing sensor varieties in China is very broad. The market for sensors in China has continued to grow in recent years, with a growth rate of more than 15%. Sales in 2003 were RMB 18.6 billion, up 32.9% year-on-year; and the non-military sensor market in the world was USD 32.5 billion in 1998, with an average growth rate of 9%. It is expected to increase to 50.6 billion U.S. dollars in 2008. In 2003, China's four major areas of sensor applications were industrial and automotive electronics, communications and electronic products, and consumer electronics products, with industrial and automotive electronics accounting for 33.5% of the market. Due to the reform and opening up, China’s huge market has attracted companies from various countries such as Siemens, Yokogawa, Honeywell, Omron, Bonner and others, which has brought great convenience to end users and industrial equipment manufacturers. Although there are developments in the production of domestic sensors and detection instruments, this is far from keeping up with the requirements of the situation. The scale of sensor production and R&D in various countries is continuously expanding. The United States has about 1,300 manufacturers that produce and develop sensors, more than 100 institutes and institutions, and Japan has 800 manufacturers. In recent years, China has established a national key laboratory for sensor technology, a micro/nano national key laboratory and other R&D bases, and initially established a sensor and sensor industry. In 2000, the total output exceeded 1.3 billion. At present, there are 1,688 sensors manufacturing in China. And research and development companies, which have engaged in MEMS development and production of more than 50, to the "Tenth Five-year" period, the total annual output of sensitive components and sensors has reached 2 billion.

China has also embarked on a new path in participating in the international sensor market competition. For example, the Sensor National Research Center of the Shenyang Instrument Science Research Institute has exported 400,000 force sensor chips to the United States. Sensor technology includes sensitive mechanisms, sensitive materials, process equipment and measurement technology. There are about 30 kinds of technologies. With the development of microelectronics technology, sensor technology has developed rapidly. The research and development force in China still requires a lot of investment. In particular, it is necessary to strengthen the development of sensors with independent intellectual property rights, the transformation of scientific research results, and the industrialization of sensor production. The imminent problem is that in the case of mass production, the performance of the sensor product (mainly stability and reliability) should be controlled, so that the qualified rate is high, and advanced manufacturing processes and process equipment with high automation levels are needed. Our country should Develop dedicated process equipment to work hard to solve the "bottleneck" problem of sensor production industrialization; In the application of sensors, especially the application of new sensors, has not been vigorously promoted, reform and opening up has created favorable conditions, a variety of industrial equipment applications Advanced sensors, which expands the sensor market, have also given impetus to the industrialization of new sensor production in China.

In the process of industrialization of sensor production, China should take into account both the introduction of foreign technology and independent innovation. In the introduction of foreign advanced technology, it can improve its own technology, but also meet the needs of the domestic market, forming a sensor production industry scale. For example, the EJX multivariable transmitter recently released by Yokogawa is an example that can consider the introduction of technology. Its high accuracy (0.025%), high degree of intelligence, the use of fieldbus technology, due to the ability to put mass flow, medium pressure and Various variables and information, such as conduit blockage, diagnosis, steam heat tracing diagnosis, and orifice wear, are transmitted to the central control room via the field bus; they are very beneficial to ensure production and provide equipment maintenance information and ensure safe operation. This new type of transmission The development of the device is in line with the reform of the integration of the automation system's management and control. Only when the source of information is strong and the information is abundant, can the informationization better promote the development of productivity.

In addition, it has a vast market because it is used in a large number of industries such as petrochemicals, metallurgy, and electricity. Trends in the development of sensors and instrumentation In recent years, sensors are in the development stage of transition from traditional to new sensors. The new sensors are characterized by miniaturization, digitization, intelligence, multi-functionalization, systemization, and networking. They not only promote the transformation of traditional industries, but also lead to the establishment of new industrial and military revolutions. They are the new economic growth points in the 21st century. .

Miniaturization is based on Micro-Electro-Mechanical System (MEMS) technology and has been successfully applied to form silicon pressure sensors (such as the EJX transmitter mentioned above) on silicon devices. Micro-electro-mechanical processing technologies include bulk micro-machining technology, surface micro-machining technology, L1GA technology (X-ray deep lithography, micro-electroforming and micro-replication technology), laser micro-machining technology and micro-encapsulation technology. The development of MEMS has raised the level of miniaturization, intelligence, multi-functionality and reliability of sensors to a new level. Sensors and measuring instruments, based on microelectronics technology, built-in microprocessors, or micro-sensors and microprocessors and related integrated circuits (operational amplifiers, A/D, D/A, memory, network communication interface circuits) Such as packaged together to complete the digital, intelligent, networked, systematic. In terms of networkization, currently it mainly refers to the use of multiple fieldbuses and Ethernet (Internet). This is based on the needs of various industries, and one or more of them are selected. The most popular ones in recent years are FF, Profibus, CAN, and LonWorks. , AS-I, Interbus, TCP/IP, etc. In addition to MEMS, the development of new sensors also depends on new sensitive materials, sensitive components and nanotechnology, such as a new generation of fiber optic sensors, superconducting sensors, focal plane display infrared detectors, biosensors, nanosensors, new quantum sensors, micro-gyro , networked sensors, smart sensors, fuzzy sensors, multi-sensors, etc.

Multi-sensor data fusion technology is forming hot spots. It was formed in the 1980s. It differs from general signal processing and also differs from single or multiple sensor monitoring and measurement. It is based on measurement results based on multiple sensors. High-level integrated decision-making process. In view of the miniaturization and intelligentization of sensor technology, based on information acquisition, a variety of functions are further integrated to achieve integration, which is an inevitable trend. Multi-sensor data fusion technology also promote? ? Summarized as follows: the local data resources provided by multiple sensors of the same type or different types distributed in different positions are integrated and analyzed by computer technology to eliminate possible redundancy and contradiction between multi-sensor information and complement each other. Reducing its uncertainty and obtaining a consistent explanation and description of the measured object, thereby improving the rapidity and correctness of system decision-making, planning and response, and enabling the system to obtain fuller information. Its information fusion appears at different levels of information, including data layer (pixel layer) fusion, feature layer fusion, decision layer (evidence layer) fusion. Because it has the following advantages over single sensor information, namely fault tolerance, complementarity, real-time, and economy, it is gradually applied. In addition to military applications, the application field also applies to automation technology, robotics, marine surveillance, seismic observation, construction, air traffic control, medical diagnosis, and remote sensing technology.