Wacker has released two new HRI silicones for encapsulating high-performance LEDs. LUMISIL® 590 and LUMISIL® 591 are highly transparent, addition-curing silicone elastomers with a refractive index of 1.53, which means they rank among the high-refractive-index (HRI) encapsulants. Such grades are particularly suitable for manufacturing highly efficient LEDs. The HRI silicone protects the sensitive LED chip against mechanical influences and corrosive gases. At the same time, the silicone’s high refractive index enables optimum light efficiency. The products withstand high operating temperatures and strong light radiation without yellowing. This makes them ideal for manufacturing LEDs with high light efficiency.
The new HRI silicones are easy to process, heat-resistant and absolutely tack-free after curing. They also exhibit optimized flow and crosslinking characteristics. With a viscosity of the mix of 2,000 and 2,500 mPa*s respectively, they enable efficient, cost-effective processing. Both products are suitable for encapsulating the LED chip via contact-free dispensing processes. LUMISIL® 590 and LUMISIL® 591 form cured rubber grades of varying hardness.