Munich-based chemical company Wacker developed Lumisil 590 and Lumisil 591, new encapsulants for light emitting diodes (LED) and optical components.
The compounds are made of highly transparent silicone elastomers with a high refractive index. The products withstand high operating temperatures and strong light radiation without yellowing. That makes them ideal for manufacturing LEDs with high light efficiency. They also protect the LED chip against corrosive gases, which greatly extends the component’s service life. The silicone encapsulation compounds can be processed in industrial metering processes such as dispensing.
Lumisil 590 and Lumisil 591 protect the LED chip against environmental influences. Corrosive gases such as hydrogen sulfide can damage the LED chip and reduce its performance.
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. With a hardness of Shore A 65,
Lumisil 590 is relatively soft, whereas Lumisil 591 is formulated to be significantly harder at Shore D 40.