Light‐diffusing materials for LED illumination applications: Comparing the effectiveness of two typical light‐diffusing agents

Abstract

ABSTRACTLight‐diffusing materials (LDMs) are the primary lampshade materials used for indoor light‐emitting diode (LED) illumination. In this work, two varieties of typical LDMs filled with acrylic or silicone diffusing agents were fabricated via a twin‐screw extruder, and the influences of the particle size, refractive index and light‐diffusing surface area of the light‐diffusing agents on the properties of the LDMs, including their light‐diffusing properties, thermal stability and mechanical properties, were explored in depth. The results indicated that both acrylic and silicone light‐diffusing agents can be dispersed evenly in a polycarbonate (PC) matrix. The light‐diffusing surface area and refractive index are the main factors that influence the diffusing properties of LDMs. Compared with the silicone LDM, the acrylic LDM exhibited higher transmittance but poorer thermal stability and impact strength, making this material suitable for a rapid injection molding process to form half‐sphere covers that combine high haze and transmittance for LED light bulbs. Silicone LDMs exhibit good stability and impact strength, favoring a slow single‐screw extrusion molding process to prepare tubular or panel covers for tubular LED lamps and panel lamps. In this study, a method for producing LDMs with both high transmittance and high haze is reported. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42923.