Optimization of hybrid LED package system for energy saving based on micro machining technology and taguchi method

A new concept, ‘hybrid LED package system (HLP system)’, is proposed as a simpler LED manufacturing process that unifies two steps of the process, the package step and the module step. Moreover, the HLP system can increase optical efficiency by virtue of its integrated optical pattern. A square pyramidal pattern was selected as the basic shape of the pattern of the HLP system. Four shape parameters of the HLP system were selected for optimizing the system. Nine cases of optical simulations organized according to the Taguchi method were performed using LightTools, and the optimum values of the parameters were determined by an SN ratio analysis. Using the optimum values, 28% higher illuminance and 32% higher luminance were predicted simultaneosly compared to the values without the integrated optical pattern. The optimum square pyramidal pattern was machined on a metal mold using an ultra-fine planer and a 90 degree angle diamond tool which would be used as a mold for manufacturing the optimized integrated optical pattern of the HLP system. The exact shape of the square pyramidal pattern with a height of 25 µm and a 90 degree angle was obtained. This study verified that the micro machined mold for manufacturing an optimized integrated optical pattern could be machined accurately, and finally the HLP system with the integrated optical pattern had higher uniform and brighter light distribution.