等温等效替代热压印法成型超薄导光板的工艺分析

Analyses on Forming Process of Ultrathin Light Guide Plate by Isothermal Equivalent Substitution Hot Embossing

针对超薄导光板微结构模具难加工的问题,结合等温热压印法,提出了一种新型的"等效替代"压印工艺,即通过控制成型工艺参数来降低微结构复制高度,实现了在基片上成型出小于模具微结构尺寸的等效结构,突破了热压印过程中模具微结构完全等大复制的思想禁锢,降低了微结构模具加工难度,从而革新了高质量超薄导光板的成型工艺。以聚甲基丙烯酸甲酯(PMMA)为基片,设计具体实验,加工0.25 mm厚的导光板,验证这一方法的可行性。实验结果表明,这种新型的"等效替代"压印工艺不仅可以降低模具的制造难度和加工成本,而且可以大大改善超薄导光板的性能,与等温热压印工艺相比均匀度提高了23%,整个成型时间缩短到了20 s。

Aiming at the problem that the ultra-thin light guide micro-die is difficult to process, combined with the isothermal hot stamping method, a new “equivalent substitution” imprinting process is proposed, which is to reduce the microstructure replication height by controlling the molding process parameters. The equivalent structure smaller than the microstructure of the mold is formed on the substrate, which breaks through the idea of completely replicating the microstructure of the mold during the hot stamping process, reduces the difficulty of processing the microstructure mold, and thus innovates the high quality super forming process of a thin light guide plate. The specific experiment was designed with polymethyl methacrylate (PMMA) as the substrate, and the 0.25 mm thick light guide plate was processed to verify the feasibility of this method. The experimental results show that this new “equivalent substitution” imprint process can not only reduce the manufacturing difficulty and processing cost of the mold, but also greatly improve the performance of the ultra-thin light guide plate. Compared with the thermostatic upper and lower mold differential thermal imprint process, the uniformity was increased by 23% and the overall molding time was shortened to 20 s.