Sensors, communications, and computers are known as the three pillars of modern information technology and the foundation of the Internet of Things. Their applications involve various areas of the national economy and national defense research. They are one of the basic and strategic industries of the national economy and directly affect national defense security, Economic security and social security. In modern control systems, the sensor is located at the interface between the test object and the test system, and can directly or indirectly contact the test object. It is the "window" for information input and the only functional device for data information acquisition, which directly affects and determines The function and performance of the system are good and bad, and many control systems cannot achieve the function due to obstacles in data collection. In layman's terms, if the computer is likened to the "brain" of human beings and the "nervous system" is used to communicate, then the sensors are "features" and "skin", and they are responsible for "perceiving" all parameters and any data of the environment. In particular, the current Internet of Things, big data, cloud computing technologies, and various technology implementations in smart cities that have attracted international attention are particularly dependent on sensor technology.
Development history and status at home and abroad
In the early 1970s, developed countries in the western countries vigorously developed computer and communication technologies, neglecting the development of sensor technology, which resulted in the development of the "brain" and the slowness of the "five senses". The sensor industry was relatively bleak. In the early 1980s, the United States, Japan, Germany, France, Britain and other countries have successively established the policy of accelerating the development of sensor technology. As a key technology involving scientific and technological progress, economic development and national security, they have been included in long-term development plans and key plans. . Investment in human and material resources, rapid development at an annual growth rate of 10% -30%, has made significant breakthroughs in process technology and products, formed a leading technological advantage, and occupied major international markets. It also adopted strict confidentiality regulations to block and control technology, and banned technology exports, especially against China.
Japan ranked first in "Technology Notable for the Next Decade" in 1979; it ranked 14th among the 20 key military technologies announced by the U.S. Department of Defense in 1985; "Star Wars" plan, European " The "Eureka" plan, the "Soviet Spaceflight" plan of the former Soviet Union, Britain, France, Germany and other countries in the development plan of high-tech fields have listed sensors as a key development technology, and their research results and manufacturing processes and equipment are included in the core of the country technology. The United States believes that computer technology is the core, sensitive technology and optoelectronic technology are the key and focus, and new materials and microelectronic technology are the support and foundation. The combination of communications and computers, as well as the integration of diversification and new technologies, represent the development direction of American information technology. In the "National Key Technology" report released by the US government in April 1991, 22 key technologies in 6 areas were identified. These include sensors and signal processing, as well as information technology-related material technologies and processing technologies. In the 2003 US Business Week "Future Technology Development Report", the sensor is listed as one of the top 10 new technologies that will affect and change the world in the 21st century. Forbes believes that at present, even in the next few decades, the top 10 technology products that affect and change the world's economic structure and people's lifestyles are listed as sensors. The National Science Development Foundation believes that "personal computers in the 1980s simplified computing to the fingertips of people; the Internet technology in the 1990s made people's needs for information global through the Internet; the major change in this century is: The physical world is connected, and given it an electronic nervous system, so that it has a life that can sense information, and the core that can bear this task is the sensor. " The annual budget is about 6.9 billion U.S. dollars, which is used for sensor basic technology and application research, which is called "Sensor Revolution" (ie: sensor revolution).
At present, there are no international standards and norms for formulating international standards, and no authoritative sensor standard type has been developed. Its sensitive mechanisms, sensitive materials, use functions, and application fields are intertwined and deeply integrated. It is difficult to clarify. The debate over the division of standards in various countries and industries has never stagnated, and each has its own opinions and arguments, which has led to confusion, variety and structure of product names Complex conditions such as complexity and different parameters can only be divided into large categories such as simple physical sensors, chemical sensors, and biosensors.
For example, physical sensors are: sound, force, light, magnetism, temperature, humidity, electricity, radiation, etc .; chemical sensors are: various gas sensitivity, pH value of acid and alkali, ionization, polarization, chemical adsorption, electrochemical reaction And other phenomena; biosensors include: enzyme electrodes and mediator bioelectricity and so on. However, materials, mechanisms, parameters, and models in physical, chemical, and biosensors often penetrate and fuse with each other. The intersection of technology and technology is common, such as force sensitivity, position, liquid level, energy consumption, speed, heat sensitivity, and acceleration. , Ray radiation, vibration, humidity sensitivity, magnetic sensitivity, gas sensitivity, vacuum degree, biological and other sensors in function, piezoelectric effect, magnetostrictive, thermoelectric, photoelectric, magnetoelectric effect, electrochemical reaction, thermal sensitivity, field effect , Piezoelectric, optical, acoustic channels, etc., cause and effect in the product use and formation process are entangled with each other, can neither be divided into physical or chemical categories, it is difficult to strictly divide.
Commonly used sensors are classified and named in the following types:
(1) According to the conversion principle, it can be divided into physical sensors, chemical sensors and biosensors.
(2) According to the detection information of the sensor, it can be divided into acoustic, light, heat, force, magnetic, gas, humidity, pressure, ion and radiation.
(3) According to the power supply method, it can be divided into active or passive sensors.
(4) According to its output signal, it can be divided into analog output, digital digital output and switching sensor.
（5) According to the sensors used materials can be divided into: semiconductor materials; crystalline materials; ceramic materials; organic composite materials; metal materials; polymer materials; superconducting materials; optical fiber materials; nano materials and other sensors.
(6) According to energy conversion, it can be divided into energy conversion type sensors and energy control type sensors.
(7) According to its manufacturing technology, it can be divided into mechanical processing technology; composite and integrated technology; thin film, thick film technology; ceramic sintering technology; MEMS technology; electrochemical technology and other sensors.
There are more than 26,000 types of sensor products worldwide. China already has about 14,000 types, most of which are conventional types and varieties. More than 7,000 products can be commercialized, and they are used in medical, scientific research, microbiological, chemical analysis and other special varieties. There are still shortages and gaps, and there is a large space for technological innovation.
Common basic processes and three major technological innovation trends
As we all know, due to different sensitive mechanisms and sensitive materials, coupled with the characteristics of industrial site environment, usage scenarios, and complexity requirements of the tested medium and personalized parameters, structure, etc., the sensor has been in a multi-variety and small-batch production state for a long time, combined with process technology Due to the decentralization, complexity, and expensive equipment, the industry calls its production process "manufacturing industrial crafts." Engineers and technicians from various countries have started long-term technological development and innovation in terms of product technology standardization, performance normalization, function integration, structural standardization, and industrialization of process equipment and tooling fixtures. A large number of technical achievements with different characteristics and features.
In the field of Silicon Valley sensors in the United States, innovations in various sensor products with different packaging structures based on MEMS process technology and based on the needs of different industries and functions have continued for nearly 25 years. The type of sensor products has been continuously expanded in application fields and has been widely recognized and accepted by various industries. As Mr. Dennis, the founder of Silicon Valley MEMS process technology, said: "For more than 20 years, Silicon Valley sensor products have been packaged in different structural forms around MEMS chips based on silicon-based materials and market application requirements in different industries. Product Competition and Innovation. " Therefore, MEMS process technology is the common basic process technology of various types of sensors, and is called the source of sensor innovation by the industry. At present, MEMS mature processes are 4 inches, 6 inches, 8 inches, and 12 inches. With the upgrading and continuous upgrading of semiconductor planar processes, the maturity of process equipment and devices has increased, and prices have continued to decline. Innovation and development, the maturity of the process has also been continuously enhanced. The products involve and are widely used in physical, chemical, and biological sensors. The applications in sound, light, heat, force, magnetic, gas, humidity, pressure, and ion sensors have matured. Not only improves the industrialization ability, reduces the product cost, but also greatly improves the reliability, stability, and consistency of the product, which greatly improves the dispersion and dispersion of the product, which can be standardized and standardized packaging and Production has played an important role in batch and large-scale production. In 2011, the U.S. industry believed that the MEMS process had matured and could be widely promoted and established. The sensor industry had established and formed two major innovations and breakthroughs in MEMS process technology and applications:
The first is the innovation of sensitive mechanisms and technological breakthroughs. Improve the basic theory and application level of MEMS process technology in materials and process structures, such as in crystalline and amorphous, various semiconductor materials; Process technology innovation has greatly improved the basic level of industrialization such as miniaturization, low cost, complex type and integration of product production.
The second is to improve the level of intelligence and application innovation. Innovations and breakthroughs have been formed in multifunctional integration, modular architecture, embedded capabilities, and networked interfaces. It has greatly improved the contradiction between production and use, which has been difficult to connect, built bridges and technology channels for manufacturing and market applications, and broke through the long-term technical barriers and development bottlenecks formed by the industry in production and application. At the same time, it has also improved the ability of product independent selection and application design in various industries, greatly stimulating application demand and expanding market space.
At the same time, the United States also identified three core technologies and innovation trends for sensor intelligence:
1. MEMS process technology: In the miniaturization, low power consumption, low cost, multi-material composite, multi-parameter fusion; large-scale integrated process technology and equipment, micron and sub-micron high-precision control technology, flexible production process technology, and iterative upgrade Innovation.
2. Wireless network technology: In order to adapt to the promotion and application of various Internet of Things (sensor network) technologies, wireless networked sensor products and technological innovations under the industrial Internet, artificial intelligence technology, mobile intelligent terminals, and 5G technology standards. Use mobile (mobile phones, cars, boats, airplanes, etc.) or fixed objects (machine tools, buildings, shopping malls, homes, mountains, forests, etc.) as platforms and intelligent nodes for installing and applying sensors to achieve embedded, multifunctional composite and integration, modules Collaborative innovations such as intelligent architecture, networked interfaces, etc., to meet the needs for intelligent, "unmanned" management and control of all objects.
3. Micro-energy acquisition technology: During the indoor and outdoor use of sensor intelligent nodes, especially in the field, the power supply problem has always been a major obstacle to the promotion and application of various fields. The collection and acquisition of micro-energy such as wind, light, and electromagnetic energy in the natural world is called "micro-energy capture technology", which will provide another direction for future technological innovation for sensors.
From the perspective of the development of the US sensor industry, there are several characteristics: First, work on common basic technologies, and focus on innovative applications of new technologies and processes to continuously improve quality. The second is to emphasize sensor network, intelligent node technology, energy capture technology and collaborative innovation. Third, the core technology has the shadow of government control, support, funding and promotion. The fourth is the obvious leading and leading action in the application field. Such as military industry, equipment manufacturing, logistics, ecological environment monitoring (forest prevention and control), mobile medicine, smart home, etc.
Industrialized Ecosystem and Environmental Construction
With the help of common basic technologies and processes, establishing a production system with flexible production, standardized processes, and standardized products, looking for supporting markets for products, and completely changing the islanding and fragmentation of technology and markets are the key to sensor industrialization. According to the MEMS process technology and product market application characteristics, 7 types of products, including temperature-sensitive, sound-sensitive, force-sensitive, light-sensitive, gas-sensitive, magnetic, and frequency, meet the technical characteristics of industrialization and market scale requirements, and can realize industrial-scale production.
In addition, the acoustic sensors represented by silicon microphones have formed ten mainstream characteristic brand products and businesses (including AAC and Goertek domestic enterprises) at home and abroad, and have achieved industrial-scale production; temperature and humidity sensors The United States, Germany, Switzerland, Japan, China and other countries have large-scale production capacity. In the future development, temperature and humidity will be compounded in other physical quantity sensors. For example, force and magnetic sensors can detect temperature and humidity parameters at the same time; the frequency includes RF radio frequency Products with similar common technologies like millimeter wave and millimeter wave, but with large differences in parameters, functions and applications, can be industrialized in the same manufacturer. In particular, it has explosive growth in applications such as mobile phones, intelligent transportation, and biosensing, which has great temptation. 95% of RF devices are still dominated by European and American manufacturers, and not even an Asian manufacturer has entered. In order to break the industry monopoly phenomenon, this will become the focus of future technological innovation and competition.
Compared with foreign countries, the slow development of China's sensor industry is mainly due to the gap in understanding! The sensor is biased and one-sided, and lacks a high level of national strategic understanding. Because the sensors belong to different industries and departments, there is multiple management, it is difficult to reach consensus on development, management chaos, and lack of policy support have led to the fragmentation of the industry and the products cannot be serialized; more than 95% of more than 1,200 enterprises belong to small and micro enterprises. On the one hand, it lacks sufficient manpower, material resources, and technical conditions and other resource allocation, and the industrialization base is weak; on the other hand, the market entry threshold is too high, and the corresponding application development and technological innovation capabilities are lacking. The overall product technology level and parameter performance indicators In particular, the reliability and stability indicators are 1 to 2 orders of magnitude lower than similar foreign products, which cannot meet the market's requirements for corporate qualifications and supporting capabilities. The third is the lack of leading companies leading and industry-driven, the lack of international brands, market influence, competitive advantages and basic research capabilities, leading to less than 3% of specialized companies in the industry; most of the core chips rely on imports, almost 100% of high-end products import. The overall technological level is 10 to 15 years behind advanced foreign countries.
In view of the current situation of domestic and foreign industries, industry characteristics and existing problems, and the combination of sensor technology and process characteristics, the industry looks forward to gathering more than dozens of domestic and foreign sensor professional companies and research institutes in economic and technological advantages and developed regions to form products with Technological process features and industrial scale advantages, as well as industrial clusters or bases with international market influence, form an international sensor characteristic industry with annual sales of more than 100 billion yuan (US $ 15 billion) and an annual growth rate of more than 20% Park. Form an industrial chain structure (industrial ecology) with sensitive components as the core, intelligent, networked, modular and other integrated applications as the main innovation, and the Internet of Things and smart cities as the application goals. Use and serve the six-dimensional integrated ecological environment to achieve industrialized cluster development, and form a "dual-ecological" industrial chain of sensors in China. It has an international sensor industrial park with obvious industrial characteristics and prominent geographical advantages-the "sensor valley".
Author Guo Yuansheng, deputy director of the Central Science and Technology Commission of the Jiu San Society, and vice chairman of the China Sensor and Internet of Things Industry Alliance