Optimum Encapsulation

WACKER has responded to growing demand for LED encapsulants by developing a portfolio of four new specialty silicones. These encapsulation compounds are tailored to a variety of LED grades and their associated manufacturing processes. As a result, it is possible to increase the luminous efficacy of LEDs and make them more cost-efficient to produce.

A sample LED encapsulated in silicone is taken for quality-control purposes and placed in a test dish.

Light-emitting diodes – LEDs – are becoming ever more powerful and efficient. Nowadays, white LEDs can generate well over 100 lumens from one watt of electrical power. Such luminous efficacy values far exceed those of any traditional lamps. White light-emitting diodes have been increasingly replacing conventional luminaires for several years now – and the market is growing at a correspondingly fast pace. According to a Boston Consulting Group study, six out of every ten luminaires retailed in 2020 will be LEDs. And for professional luminaires, the share will be as high as 80 percent.

“Our materials are intended to increase the lifetime of LEDs, as well as maximizing their luminous efficacy.”

Dr. Jeong-Han Kim Head of the Center of Electronics Excellence

Yet LED-based lighting is still relatively expensive, with the industry making every effort to further improve cost efficiency – and thereby offer its customers more lumens per dollar. “Strategies include optimizing the LED technology, faster production techniques and using materials that increase the lifetime of LEDs, as well as maximizing their luminous efficacy,” says Dr. Jeong-Han Kim, head of the Center of Electronics Excellence (COEE) in Seoul. COEE is a corporate R&D facility where the silicones made by WACKER are customized to meet the demands of the East Asian electronics and lighting sectors.

At the heart of an LED is the light emitting semiconductor chip, which is encapsulated to protect it and to optimize outcoupling. The encapsulant used for this purpose often also serves as a carrier for the luminescent pigments that are used to tune the color of the emitted light. The encapsulant influences both the production cycle time and the quality of the LED.