Analysis on the development and application status of magnetic sensors at home and abroad

Magnetic sensor Sensor is an important part of sensor products. With the development of magnetic sensor technology in China, its product types and quality will be further developed and improved, and it will soon be possible to enter the large-scale and wide-ranging application fields such as automobiles and civil instruments. Domestic current sensors, gauss meters and other products have recently begun to enter the international market, and the gap with foreign products is rapidly narrowing. 1. Development characteristics of magnetic sensors 1. Application of integrated circuit technology. Apply silicon integrated circuit technology to magnetic sensors to make integrated magnetic sensors. 2. The successful development of InSb thin film technology has led to a sharp increase in the production capacity of Hall devices and a significant reduction in costs. 3. Strong magnetic alloy films are widely used. Various magnetoresistive devices have appeared and are widely used. 4. Research and development of giant magnetoresistive multilayer films. The high sensitivity and high stability of the new device have attracted great attention from scientific and technological personnel who are developing high-density recording disk read heads. 5. Application of amorphous alloy materials. The application of matching with basic devices has greatly improved the performance of magnetic sensors. 6. Development and application of III-V semiconductor heterostructure materials. Through epitaxial technology, heterogeneous structures are formed to improve the performance of magnetic sensitive devices. 2. The current situation of foreign magnetic sensors 1. Common types of foreign magnetic sensors In terms of market share, the main types of foreign magnetic sensors are still Hall elements and magnetoresistive elements. The recent giant magnetoresistive elements also have good development space. 2. Representative manufacturers of external magnetic sensors: · Hall elements: Asahi Kasei of Japan; Toshiba of Japan; Honeywell of the United States; Allogro of the United States. · Magnetoresistive devices: Sony of Japan; PHILIPS of the Netherlands. 3. Application of foreign magnetic sensors The biggest feature of the application of magnetic sensors is contactless measurement. · Hall elements: magnetic field measurement, used as detection probes for Gauss meters (Tesla meters). Current detection, used as primary elements of current sensors/transmitters. Brushless DC motors, used to detect rotor position and provide excitation signals. Speed/revolutions measurement of integrated switch-type Hall devices. · Strong magnetic thin film magnetoresistive devices: displacement sensors, mainly linear long-distance displacement measurement of magnetic scales. Angular displacement sensors, mainly used for rotation angle measurement, are widely used in the automotive manufacturing industry. Pulse signaling sensors are mainly used for flow detection and speed/revolution measurement, such as signaling sensors for electronic water meters and flow meters. ·Semiconductor magnetoresistive devices: mainly InSb magnetoresistive devices Weak magnetic field detection, mainly used for counterfeit banknote identification Pulse measurement, mainly used for speed/revolution measurement III. The current status of domestic magnetic sensors 1. Common types and characteristics of domestic magnetic sensors At present, after more than 30 years of development, domestic magnetic sensors have been developed. In terms of the research and development of basic devices, except for the gap in the giant magnetoresistance period, other commonly used magnetic sensors such as Hall elements and magnetoresistive elements have reached the same level as similar foreign products. The types of domestic magnetic sensor devices used in the market are also comparable to those of foreign products, still Hall elements and magnetoresistive elements. 2. Representative manufacturers of domestic magnetic sensor devices ·Hall elements: Semiconductor Institute of Chinese Academy of Sciences, Shenyang Institute of Instrument Science, Nanjing Zhongxu Microelectronics Company. ·Magnetoresistance devices: Shenyang Institute of Instrument Science (Huibo Sibinis Company) 3. Application of magnetic sensors in China ·Current sensors: There are 20 to 30 companies of different sizes in China, including Shenyang Instrument Science Research Institute (Sibinis Company) and Southwest Automation Institute, which are producing and selling current sensors/transmitters, and the market competition is already fierce. This field is the earliest, most popular and most mature field for the application of magnetic sensors in China. ·DC brushless motor field: InSb Hall elements are mainly used for DC brushless motor rotor position detection and provide excitation signals for stator coil current commutation. The current annual demand is hundreds of millions. The price is only about RMB 0.3. This field is the field with the largest consumption of magnetic sensors, but industrial production has not yet been formed in China. ·Flow measurement field: Low-power thin-film magnetic magnetoresistive devices used for flow signal sensors such as electronic water meters, electronic gas meters, and flow meters. Recently, this product was produced by Huibo Sibinis Sensing Technology Co., Ltd. of Shenyang Instrument Science Institute, and the market space is considerable. This field is the most promising emerging application field for magnetic sensors in China, and is currently in the market growth stage. ·Special measuring instruments: Gaussmeter, used for magnetic field detection, is widely used in the production and application of magnetic materials. It is produced by several domestic companies such as Shenyang Instrument Institute Sibinis Company and Beijing Normal University. Among them, Sibinis's Gaussmeter has been exported to the United States in batches. In addition, domestic magnetic sensors are also used in the fields of speed/revolution measurement and counterfeit banknote identification, but they have not formed a scale. Professor Sun Rentao mentioned that it is a great pity that domestic magnetic sensors have not entered the field of automobile production. 4. The gap between domestic and foreign magnetic sensors 1. Small production scale and high cost. 2. Poor stability and reliability of some components. 3. There are few practical applications and large-scale fields, especially in the automotive field, which is still blank. 4. Slow transformation of scientific research results, poor matching of production conditions, and lack of capital. Conclusion: "We cannot deny that there is a gap between domestic magnetic sensors and foreign magnetic sensors in terms of product types, product quality and application fields, but we have also seen the momentum and determination of domestic magnetic sensors to enter the international market." Professor Sun said, "We have reason to believe in our own products and our own scientific and technological workers who have worked tirelessly for the development of magnetic sensors!" Related concepts · Sensitive element: refers to the part of the sensor that can directly sense or respond to the measured value. · Converter (element): refers to the part of the sensor that can convert the measured value sensed or responded by the sensitive element into an electrical signal suitable for transmission or measurement. Usually, people are accustomed to calling sensitive elements "sensors"; sensors equipped with converters are called transducers. In foreign countries, the division is not very clear. · Magnetic sensor: a device or device that can receive magnetic signals and convert them into usable output signals according to certain rules. Magnetic sensors have gradually developed with the progress of magnetic measuring instruments. Among the many magnetic measuring methods, most of them convert magnetic field information into electrical signals for measurement.