变模温注压成型对超薄导光板品质的探析与实践

超薄导光板高速高压注射成型具有残余应力集中、厚度不均、微特征转写效果差等缺陷。简述了导光板注射成型缺陷原因,重点分析了注压成型工艺对超薄导光板残余应力、厚度均匀性、微特征转写性的影响,并根据导光板设计要求选择最佳工艺方案进行实验,结果显示,与注射工艺相比,注压工艺使导光板样本点应力集中均值从9.46 MPa降为7.98 MPa、厚度均匀性均值从0.428 mm降为0.391 mm、微特征高度均值从0.022 mm提升为0.038 8 mm,导光板综合性能显著提高。鉴于微特征转写性是导光板光学性能的关键因素,且其受模温影响显著,进一步将变模温技术与注压工艺相结合,使微特征高度均值进一步从0.038 8 mm提升至0.039 4 mm,更加接近设计值0.04 mm。

Analysis and Practice on Quality of Ultra-Thin Light Guide Plate by Dynamic Mold Temperature Injection Compression Molding

The high-speed and high-pressure injection molding of ultra-thin light guide plate has the defects of residual stress concentration,uneven thickness,poor micro-feature transcribability.The reasons for the defects in the injection molding of the light guide plate were briefly described and the influence of the injection compression molding process on the residual stress,thickness uniformity and micro-feature transcribability of the ultra-thin light guide plate was emphatically analyzed.According to the design requirements of the light guide plate,the best technology scheme was selected for experiments.The results show that compared with the injection molding process,at the sample points of the light guide plate by the injection molding process,the average stress concentration was reduced from 9.46 MPa to 7.98 MPa,the average thickness uniformity decreased from 0.428 mm to 0.391 mm,the average micro feature height increased from 0.022 mm to 0.0388 mm,the comprehensive performance of the light guide plate improved significantly.In view of the fact that the micro-feature transcribability is the key factor of the optical performance of the light guide plate,and it is significantly affected by the mold temperature,dynamic mold temperature technology with the injection compression molding is further combined,so that the average value of the micro-feature height is further increased from 0.0388 mm to 0.0394 mm,which is closer to the design value of 0.04 mm.