Simplified LED packaging technology for a new freeform lens

White LED (Light Emitting Diode) is a blue light excitation by Gan yellow phosphor, finally through the application of blue and yellow light are obtained by mixing white light. Phosphor coating is one of the key technologies in LED packaging. The optical properties of the final LED are determined by the effect of phosphor coating. The fluorescent powder conformal coating can realize the uniform thickness of the phosphor powder layer, which can greatly improve the spatial uniformity of the final light output. In order to achieve this ideal phosphor coating method, the major LED packaging companies and research institutions have developed a variety of processes.

In 973 countries and 863 projects under the support of Professor Luo Xiaobing and Professor Liu Sheng in the Wuhan National Laboratory for Optoelectronics (chips) MOEM (MOEMS) research team, through combining the characteristics of phosphor conformal coating, combined with the design method of uniform illumination, designed a new type of freeform lens. The new lens through the inner surface of the powder to achieve conformal coating, through the outer surface of the control light, can achieve the same time, the powder coating and uniform illumination. By this method, the traditional LED packaging technology is simplified, the operation is simple, and it is easy to be applied to the mass production of LED.

The research results have been published in Optics Express (Vol.20, No.13, pp.13727-13737, 2012).