Fabrication of adjustable-morphology lens based on electrohydrodynamic for high-power light-emitting diodes

Advanced lens fabricating techniques are urgently required for the development of light-emitting diode (LED) packaging. In this study, a method of fabricating LED lenses was proposed based on electrohydrodynamics (EHD). In this method of fabricating lenses, the normal stress on the air-liquid interface was induced and adjusted by an electric field applied around liquid lens material. By controlling this interface stress, the lenses could be tailored into the desired morphologies. Three kinds of typical lens morphologies, namely cone, ellipse and asymmetric, were fabricated by varying the electric field type. Moreover, the detailed characteristics of each of the morphologies were significantly and accurately regulated. As a result of varying the lens morphology, the light intensity distributions (LIDs) of the LED modules changed obviously. The strongest light intensity increased up to 39% and its occurring view angle varied from 0° to 48°. Meanwhile, the light efficiency of the lenses fabricated in the presented method was examined. The results showed that the light efficiency sacrifice was less than 2%.