LED Materials

Protection

Silicones have a long history of use as protective materials for semiconductor devices. Their optical clarity and stability make them particularly useful for use on high brightness LEDs. Optical grade silicones are currently being used in commercial production of LED devices. Silicone elastomers are well known for their stress-relieving nature and can be useful here. Silicone gels offer even greater stress relief. 

Light Extraction

When applied as encapsulants surrounding LED chips, silicones increase light extraction by more closely matching the refractive index of the chip surface.  Silicones can be formulated with a range of refractive indices to optimize the optical and lifetime performance of the LED assembly. 

Forming Lenses - Optical Parts Fabrication

Silicone resins are being used commercially to form HBLED lenses. Silicones are well adapted to precision molding applications. Micrometer sized features can be replicated on the lens surface for benefits in directing light output for various LED applications. Silicones have been molded using a variety of molding techniques such as injection molding, casting/cavity molding and others. The optimal molding process conditions are often different from traditional thermoplastics. Dow Corning can provide engineering assistance to optimize molding processes for high volume manufacturing of silicone lenses. 

Thermal Management

An increasingly important use of silicones is for thermal management. By using special fillers, very low thermal resistance can be achieved while maintaining low stress properties. You can find out more about our thermal materials by visiting the Thermal Interface Materials section.