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

Abstract

Light-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.

Flexible transparent projection screen of polycarbonate matrix integrated with functionalized alumina particles

“…Since the refractive index of Al 2 O 3 filler is different from that of PC, the refractive index and hence the diffuse reflection capacity for PC films with increased Al 2 O 3 content, which resulted into a significantly enhanced projecting performance. 14,18,42 Owing to the increasing content and wide distribution of Al 2 O 3 particles, the incident light reflection among them becomes more apparent. When the particle concentration therein increases to a certain extent, although sacrificed their transmittance (Figure 6), the reflectivity of PC films increased dramatically.…”

“…16 As it is difficult to obtain expected projection behavior with pure polymers, compositing approach, namely, introducing heterogeneous fillers in polymer, have received much attention in the production of TPS films. [17][18][19] Up till now, a variety of fillers, particularly, inorganic nanoparticles including some oxides such as Al 2 O 3 , SiO 2 , TiO 2 , CeO 2 , ZnO, ITO, ATO and ferric oxide, semiconductors such as CdS, PbS, CdTe and CdSe, minerals such as clays and CaCO 3 , and metals/alloys such as Au, Ag, Cu, Ge and Fe, have been incorporated in polymer matrices. 20 Besides the filler content, the optical performance of the composites was largely determined by the properties of nanoparticles, such as particle granule, light scattering ability, refractive index and so on.…”

PMMA@TiO2@SiO2 Composite Microsphere with Sufficiently High Light Transmittance and Haze for Promising Application in Optical Diffusion Film

“…It is well-known that the diffusion effect of a diffusion film is primarily dependent on the diffusion particles in its diffusion layer. Poly­(methyl methacrylate) (PMMA) is commonly used for preparing diffusion particles because of its good transparency as well as strong corrosion resistance. − More importantly, PMMA microspheres as diffusion particles also have good diffusion effects. However, some defects (e.g., poor heat resistance, poor solvent resistance, difficult control of scattering effects, etc.)…”

Preparation of PP/PC light‐diffusing materials with UV‐shielding property

“…Meanwhile, interfacial scattering occurs due to the refractive index difference between particles and the matrix. [14][15][16] In comparison, Organic particles are more commonly used. In order to achieve better optical properties, some studies focus on the structural design of light diffusers.…”

“…Organic particles, such as crosslinked polymethyl methacrylate microspheres (PMMA), silicone microspheres (SMS) and polystyrene microspheres (PS), generally have high transmittance, which enables part of the incident light directly pass through. Meanwhile, interfacial scattering occurs due to the refractive index difference between particles and the matrix 14–16 . In comparison, Organic particles are more commonly used.…”