We propose a recessed pyramid microstructure (PYM) to be used on the base of the light guide as micro-optical components to replace the conventional diffuser dot made by direct etching on the steel stamper. The PYM is made by microelectromechanical systems technology, which uses a silicon wafer for the original PYM mold, which is replicated on a Ni micromold using the electroforming method. An effective optical design tool is used to find the optimal PYM distribution integrating the random microstructure generation scheme based on the molecular dynamics method into optical commercial software. The scanning electron microscopy images show intact PYMs can be produced on the Si micromold and then replicated fully on the Ni micromold by the electroforming process. An intact PYM on the base of the light guide can then be produced by injection molding, completing the transformation of the Ni micromold for use in the light guide. The luminance measurement of a 2.4-in. backlight module with four LEDs shows an average luminance of 4769 nit with 86.3% uniformity for the PYM on the base of light guide, 10% higher than that of the diffuser dot microstructure.