Simulation And Experimental Research On Technology Of Continue Injection Direct Rolling For Polymer Optical Plate

"Larger" and "Thinner" has always been two major trends in LCD panel development. Optical polymer plate is an important component of backlight module. Due to the difficulty of forming the surface micro structure and other reasons, LCD panel development is facing obstacle. Problems like small size, low productivity are very common in the current various production process. Technology of "Continuous Injection Direct Rolling(CIDR)" in the optical polymer sheet studied in this paper is based on technology of "injection compression" and "micro hot embossing". It not only has low demand for extrusion equipment, higher microstructure replication rate, and small stress in the product but also can achieve continuous production of large-size and high efficiency.In this paper, we study PMMA light guide plate of 300 mm width, 0.4mm thick and has a continuous triangle Micro Grooves surface. First, CIDR process is divided into three rolling model to have simulation analysis, including the injection-rolling nozzle flow channel, rolling region and micro-structure forming. The injection-rolling nozzle flow channel is designed to combined flow channel as "coat hanger – fishtail". In this paper, we use ICEM CFD to structured meshing so that the mesh quality of the flat seam at the outlet can be guaranteed, and optimize the location and geometry of junction of hangers and fishtail to achieve CIDR process requirements. In the process of rolling, materials transformation of "molten state-high elastic state- glass state" is completed, Take the corresponding interval ratio of the three states at the Rolling Zone as objects, We explore the influence of injection temperature, roll temperature and rolling speed on melt. Research show that rolling speed exert the most significant impact on the interval ratio. Microstructure molding studies of CIDR surface can be divided into filling and embossing processes, research on effect of injection pressure, roller temperature changes, depth of the microstructure to microstructure filling capacity, and embossing analysis of incomplete filling microstructure. The research results show that the filling process on forming quality is more critical. Through comprehensive analysis, we conclude that the rolling speed range is 2- 2.5mm/s, the temperature of the roller is 90 – 70?, and the melt injection temperature is about 230?. Finally, CIDR experiments were done. In the process of experiment, It was found that the rolling speed adjustable range is very small, the optimum rolling speed is the maximum curvature of the curve of relationship between the rolling speed and the rolling force. Combined with simulation analysis, we confirmed that it has a direct relationship between the rolling force and rolling material state transition in rolling. In the detection of microstructure surface, it presents three forms, "Shrinkage" "swelling" and "tear-type". The study found the state of "Shrinkage" is the result of in sufficient impression, "swelling" is due to incomplete filling, and the cooling rate difference between out-rolling roll and products lead to the "tear-type". Optical performance testing of products shows its maximum birefringence of about 90 nm, which indicates the internal stress is small.