Anti halo glass: the "eyes" that pierce through the night
2024-06-11
Imagine how we can see the road clearly and distinguish objects on a dark, dark night without light? There is a material called anti halo glass at China National Building Materials Science Research Institute Co., Ltd. (hereinafter referred to as China National Building Materials Institute), which allows people to clearly see the environment and objects inside the room in a dark room where they cannot see their fingers. The anti glare glass is transparent in the middle and has a black edge, commonly known as the "cow's eye window", and is the main material for the optical input window of low light night vision devices. Its performance has a significant impact on the photoelectric conversion quantum efficiency, imaging quality, and working life of low light night vision devices. Recently, the "Anti Halo Glass Series Products" developed by China National Building Materials Institute for many years have been selected as the eighth batch of single champion products in the manufacturing industry by the Ministry of Industry and Information Technology. Jia Jinsheng, General Manager of China National Building Materials Institute Beijing Branch, told Science and Technology Daily reporters: "The anti halo glass team has continuously made breakthroughs, promoting the development of low light night vision and related weak signal detection technology in China." Overcoming difficulties and improving imaging level. Recently, the reporter visited the anti halo glass production line of China National Building Materials Institute. I saw workers working in an orderly manner with the help of machinery and equipment to polish, polish, and inspect the anti glare glass. The anti glare glass has a small area and a diameter between 25 millimeters and 90 millimeters, but it is difficult to make. Liu Hui, Deputy Director of the R&D Center of the Beijing Branch of China National Building Materials Institute, told reporters that this small piece of glass has gone through more than 20 years of research and development, and an important achievement achieved during this process is the glass blackening technology. In the 1990s, the main optical input window materials for low light night vision devices shifted from low transmittance fiber panel materials to high transmittance glass materials. However, high transmittance glass materials are accompanied by the problem of difficult to eliminate stray light Liu Hui introduced that the "stepped" structure of window materials exacerbates the complexity of the problem of stray light, seriously affecting the overall imaging quality, and glass blackening technology can effectively solve the problem of stray light. The anti glare glass has two distinct zones: a transparent center area and a black outer area. To eliminate stray light, the project team initially thought of a "separate and then combined" approach. They drew inspiration from more mature special fiber drawing techniques and made transparent glass and black glass into glass rods and glass tubes respectively, and then fused them at high temperatures. But after a period of experimentation, the team found that the ability of glass to eliminate stray light was significantly insufficient. In response to this, the team adjusted their research and development approach and re designed and developed from the perspective of "combining and then dividing", that is, presenting different colors in different areas on a piece of glass to have corresponding functions. Liu Hui introduced that the project team conducted systematic research on glass formulation, melting and molding, secondary treatment, and other aspects according to the concept of "combining and then dividing", and ultimately invented glass blackening technology in more than 100 days. "Glass blackening technology is like implementing a black and white transformation 'magic' on a whole piece of glass. By adjusting the microstructure and related process control of the glass, it ultimately forms a glass with a black external partition and a pure and transparent central area." Liu Hui said that glass blackening technology achieves the performance characteristics of high transmittance and high absorption in different areas on the same glass substrate. In addition, the project team also developed a glass melting furnace and determined relevant process parameters through repeated experiments and finding patterns, overcoming technologies such as high-quality and uniform melting and forming of high viscosity glass. In 2003, the anti glare glass project team successfully delivered the first batch of products. Compared with traditional anti halo technology, glass blackening technology creates anti halo glass with higher photoelectric conversion quantum efficiency and imaging quality, injecting new impetus into the development of low light night vision devices in China. Breaking through bottlenecks and improving production quality. In 2012, the market demand for anti glare glass rapidly increased. At the same time, users have significantly increased their requirements for the performance of anti glare glass, but the production capacity of anti glare glass production lines is seriously insufficient. The main reason for this problem is the unstable efficiency of the production line. The process technology of the production line is not high, and the production operations of each process are extremely unstable, resulting in a low yield rate. In 2014, a French customer ordered 2000 pieces of anti glare glass products. But after testing the products, most of them showed scratches and edge breakage, and the final customer only took 400 pieces. Under the leadership of the chief craftsman, the project team has taken root in the workshop, overcoming blockages and bottlenecks in one process after another, innovating and optimizing production processes, and making every effort to improve product performance indicators. Taking polishing as an example. The project team strictly controlled the selection of materials, tested polishing powders from almost all manufacturers on the market, and re prepared and processed them. "If the polishing powder becomes hard, it can easily cause polishing scratches, and if it becomes soft, it cannot be polished. Therefore, we carry out multiple processes such as soaking, boiling, and standing for the polishing powder." Liu Hui said that the team finally developed a hydrothermal process to improve the dispersion and uniformity of the polishing powder, optimize the hardness and particle size of the polishing powder, and solve the problem of surface smoothness of anti halo glass. According to the process control requirements of "striving for excellence", the project team has successively broken through a series of key core technologies such as precision machining of irregular optical components and performance evaluation. At the same time, the team has increased investment in automation and intelligent production technology and equipment during the production process, greatly improving the performance of anti halo glass products and meeting the production capacity of user units. Liu Hui introduced: "In 2023, the annual production capacity of anti halo glass reached 500000 pieces, an increase of 70 times compared to 2012, and domestic and foreign customers were promoted to enter the company for product inspection according to AQL sampling standards, with a product qualification rate of over 99.98%, approaching the level of 'exemption from inspection'." In June 2023, the China Optical Engineering Society organized an evaluation of the achievements of anti halo glass technology and products, and the expert group unanimously believed that its technical achievements were difficult and innovative, with independent intellectual property rights, core technology was independently controllable, and solved the problem of "bottleneck" of key materials. The overall technology reached a leading domestic and international level. ". For over 20 years, the anti halo glass team of China National Building Materials Institute has achieved breakthroughs and industrialization in material design, key technologies, and complete equipment for anti halo glass. Anti halo glass has obtained more than 20 national authorized invention patents, as well as multiple scientific and technological awards such as the Second Prize of Building Materials Science and Technology Award and the Second Prize of Science and Technology Progress of the Chinese Society for Materials Research. "In the future, anti halo glass will play an increasingly important role in medical diagnosis and treatment, information display, intelligent wearability, ultraviolet detection, high-energy physics, and other fields." Jia Jinsheng said, "We will continue to promote the research and industrialization of glass functional materials such as anti halo glass, and use materials to create a better world." (Xinhua News Agency)
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