This research first indicates the melt front delay of wedge-shaped lightguiding plate of
backlight module on micro injection molding. This research fabricated the patterns of mold insert of
lightguiding plate by photo etching process. The micro-facture of lightguiding plate was
manufactured by micro injection molding. The lightguiding plate of backlight module was used for
the PMMA material. The single parameter method was used to discuss the flatness and replication
properties for different processing parameters (mold temperature, melt temperature, packing
pressure, packing time and injection pressure). The results show that there are melt front delays due
to the slow injection velocity, the low temperature induced by the little effect of shear heating, the
high viscosity, the large flow resistance and the slow flow velocity. The mold temperature is the
most important factor for the flatness and the replication of micro-feature of liughtguiding plate.
Lower mold temperature induces better flatness properties. The surface roughness of micro-facture
of lightguiding plate is 8.8 nm on micro injection molding for this work.