In the fields of optical display, lighting, etc., the transmittance of PC optical film directly affects the visual effect and performance of the product. PC optical film with high transmittance can reduce light loss and make the picture clearer and brighter, so it is of great significance to study the technology of improving transmittance and surface treatment process.
The transmittance of PC optical film is restricted by many factors. First of all, the purity of raw materials. If there are impurities, color particles or uneven molecular weight distribution in polycarbonate (PC) raw materials, it will cause light to scatter and absorb when it propagates in the film, reducing the transmittance. Secondly, the control of process parameters in the production process is crucial, such as extrusion temperature, stretching rate, cooling rate, etc. If not properly controlled, crystal points, bubbles or internal stress will be generated inside the film material, interfering with light transmission. In addition, the flatness, roughness and presence of scratches on the surface of the film material will also affect the refraction and reflection of light, and then affect the transmittance.
Selecting high-purity, optical-grade polycarbonate raw materials is the basis for improving the transmittance of PC optical film. Optical-grade PC raw materials have extremely low impurity content and narrow molecular weight distribution, which can effectively reduce the scattering and absorption of light. At the same time, adding suitable optical additives, such as UV absorbers, antioxidants, etc., to the raw materials can not only improve the weather resistance and stability of the film, but also avoid the negative impact of the color or impurities of the additives themselves on the transmittance. In addition, through the blending modification technology, PC is blended with other polymers with high transmittance to improve the optical properties of PC optical film and further increase the transmittance.
Optimizing the production process is a key link in improving the transmittance of PC optical film. During the extrusion molding process, the extrusion temperature and screw speed are accurately controlled to ensure that the raw materials are fully melted and mixed evenly, and to avoid decomposition or poor plasticization of the raw materials due to excessively high or low temperatures, resulting in crystal points and bubbles. During the stretching process, the stretching ratio and stretching speed are reasonably adjusted to arrange the molecular chains in an orderly manner, reduce internal stress, and improve the optical uniformity of the film. The cooling stage adopts a fast and uniform cooling method to prevent the film from deforming and generating internal stress due to uneven temperature during the cooling process, thereby ensuring the stability of the transmittance.
The surface treatment process has a significant impact on the transmittance of PC optical film. One of the common surface treatment methods is coating technology. By coating a layer of high-transmittance, low-refractive-index coating on the surface of the film material, the reflection loss of light on the film surface can be reduced and the transmittance can be improved. For example, coating an anti-reflective coating can reduce the reflectivity of the film surface to less than 1%, greatly improving the transmittance effect. In addition, the use of nanoimprinting technology to prepare microstructures on the film surface, such as microprisms and microlenses, can change the propagation direction of light, improve the utilization rate of light, and further enhance the transmittance. At the same time, polishing the surface of the film material to reduce the surface roughness and reduce the diffuse reflection of light can also effectively improve the transmittance.
After the production of pc optical film is completed, the post-processing process can also affect the transmittance. Annealing is a commonly used post-processing method. By heat treating the film material at a certain temperature, the internal residual stress is eliminated and the arrangement of the molecular chain is improved, thereby improving the optical properties and transmittance of the film material. In addition, cleaning the film material to remove impurities such as dust and oil on the surface to avoid the interference of impurities on light transmission can also help maintain and improve the transmittance.
Establishing a sound testing and quality control system is an important means to ensure the stability of the transmittance of pc optical film. High-precision optical testing equipment, such as transmittance tester and haze meter, is used to monitor and accurately measure the transmittance, haze and other optical properties of the film in real time. During the production process, multiple quality control points are set up to strictly inspect raw materials, semi-finished products and finished products to promptly discover and solve problems that affect transmittance. Through data analysis and process optimization, the production process is continuously improved to ensure that the transmittance of pc optical film is always maintained at a high level.
With the continuous development of optical technology, the transmittance improvement technology and surface treatment process of pc optical film will continue to innovate. In the future, the research and development and application of new optical materials will provide new ways to improve transmittance, such as developing polycarbonate modified materials with higher transmittance and stability. At the same time, intelligent and automated production processes will further improve the accuracy and controllability of the production process and reduce the impact of human factors on transmittance. In terms of surface treatment, the application of advanced technologies such as nanotechnology and self-assembly technology is expected to achieve more efficient and precise surface structure design and coating preparation, bringing new breakthroughs in improving the transmittance of PC optical film.
