English
1、 Introduction: The demand for technological upgrading in the optical thin film industry
Optical thin films, as the core foundational materials of optoelectronic technology, are widely used in fields such as display, communication, energy, and healthcare. With the rapid development of 5G communication, flexible display, and laser technology, traditional optical film production processes are facing three major challenges: the contradiction between high-precision optical performance requirements and insufficient process stability, the strict requirements of high-power laser systems for film damage resistance thresholds, and the urgent constraints of environmental regulations on the greening of production processes. This article will systematically analyze a new optical thin film production process that integrates material design, nanomanufacturing, and intelligent control, and explore its technical principles, key innovations, and industrial application prospects.
2、 The bottleneck of traditional craftsmanship and the technological breakthrough of new craftsmanship
（1） The limitations of traditional craftsmanship
1. The uniformity problem of physical vapor deposition (PVD)
Although magnetron sputtering can achieve high-density film layers, the thickness uniformity error during large-area deposition can reach ± 5%, which affects the consistency of optical components. The adhesion of the evaporated coating is insufficient, which limits its application in high-frequency vibration environments.
2. High temperature limitations of chemical vapor deposition (CVD)
Hot CVD requires a reaction temperature above 800 ℃, resulting in deformation of the substrate material; Although plasma enhanced CVD (PECVD) reduces temperature, the complex precursor gas ratio can easily introduce impurities.
3. Efficiency bottleneck of post-processing technology
Traditional annealing takes several hours and is difficult to precisely control grain size, which affects the electrical and optical properties of the film.
（2） Core innovation of new technology
1. Multi field coupled sedimentation technology
By combining magnetron sputtering with ion beam assisted deposition (IAD) and dynamically adjusting the sputtering power and ion beam energy, the film density was increased to 99.8% and the surface roughness was reduced to below 0.5nm. For example, Shanghai Institute of Optics and Fine Mechanics adopts dual ion beam sputtering technology, which optimizes the ion oxygen concentration to reduce the absorption loss of SiO ? thin films to 1.4ppm, breaking the 10 fold limit of traditional processes.
2. Nanostructured design and self-assembly technology
Introducing aerosol assisted CVD (AACVD) and utilizing ultrasonic atomization of precursor solution to form nanoscale particles, which self assemble into ordered microstructures on the substrate surface. This technology reduces the average reflectivity of the anti reflective film from 3% to 0.5% while maintaining a transmittance of over 98%.
3. Digital process control platform
Based on machine learning algorithms, a process parameter prediction model is established and integrated with a real-time spectral monitoring system to achieve a deposition rate control accuracy of ± 0.1nm/s and a reduction in film thickness uniformity error to ± 1%. For example, Jiangsu Pioneer Microelectronics' patented process achieves large angle anti reflection in the 1510-1575nm wavelength band through the coordinated control of an intermediate frequency power supply and an RF ion source, and the incident angle response range is increased to ± 60 .
3、 Technical principles and implementation paths of new processes
（1） Innovation in Material Systems
1. Design of composite dielectric materials
Developing high refractive index Ta ? O ? - SiO ? nanocomposites, by adjusting the volume ratio of the two materials, the refractive index can be continuously adjusted between 1.46-2.2, meeting the design requirements of broadband filter films.
2. Metal dielectric multilayer film structure
By using silver silicon dioxide alternating deposition technology, a 99.9% reflectivity is achieved in the visible light band, and the lifespan of the film layer is extended to more than 10 years through an aluminum oxide protective layer.
（2） Key process steps
1. Substrate pretreatment
Introducing atmospheric pressure plasma cleaning technology to remove organic matter from the substrate surface below 100 ℃, improving the adhesion of the film layer to 5N/cm (ASTM D3359 standard).
2. Gradient membrane deposition
By changing the sputtering gas flow rate ratio layer by layer, an anti reflection film with gradually changing refractive index was prepared, effectively suppressing interface reflection and covering a bandwidth of 300-2500nm.
3. Laser annealing post-treatment
Using pulsed laser annealing technology, the crystallization process is completed within 100 nanoseconds, controlling the grain size of the thin film within 10-50nm and improving its electrical properties by 30%.
（3） Intelligent production system
1. Real time optimization of process parameters
Deploy a fiber Bragg grating sensor network to real-time collect 50+parameters such as temperature, pressure, sputtering power, etc. Predict film performance through a digital twin model and dynamically adjust process parameters.
2. Defect detection and closed-loop control
Integrated AI visual inspection system for online recognition of surface defects (such as pinholes and particles) on film layers, with a detection accuracy of 0.5 μ m, triggering an automatic compensation mechanism.
4、 Application verification and industrialization case of new technology
（1） Display field: ultra-thin flexible polarizer
Anhui Wanwei has successfully prepared an anhydrous corrugated film with a thickness of 50 μ m by optimizing the casting process parameters of PVA optical film and combining stress control during heat treatment. The film has a light transmittance of 92% and a haze of<1%, meeting the high reliability requirements of foldable screen smartphones.
（2） Laser technology: high-power anti damage film
The TiO ? - SiO ? multilayer high reflectivity film prepared by ion beam sputtering technology has a reflectivity of 99.99% at a wavelength of 1064nm and a laser damage threshold of 15J/cm ². It is applied in laser nuclear fusion devices.
（3） Energy sector: Photovoltaic anti reflective film
The nano porous SiO ? film prepared by the sol gel method has an average reflectivity of<2% in the 400-1100nm band, which improves the efficiency of photovoltaic modules by 4.2%, and has realized the large-scale production of 10 million square meters annually.
5、 Future Development Trends and Challenges
1. Greening of materials
Develop bio based precursor materials, such as plant-based cellulose derivatives, to reduce carbon emissions during the production process.
2. Device integration
Explore the integrated manufacturing of optical thin films, sensors, and integrated circuits to promote the development of micro optical systems.
3. Extreme environmental adaptability
Develop thin film materials with a wide temperature range of -200 ℃ to+500 ℃ to meet the needs of special scenarios such as aerospace and deep-sea exploration.
conclusion
The new optical film production process has broken through the performance bottleneck of traditional technology through the deep integration of material innovation, process optimization, and intelligent control. With the continuous demand in fields such as 5G, artificial intelligence, and new energy, this process will drive the optical thin film industry to upgrade towards higher precision, lower cost, and more environmentally friendly directions, providing core support for the leapfrog development of optoelectronic technology.
