As new and improved electronic materials hit the market each year, and the technologies for building new and improved high refractive index silicone also improves, the applications for this technology grow accordingly. High refractive index silicone encapsulants are used in the electronic materials manufacturing of LEDs. The higher the refractive index of the silicone encapsulating material, the brighter the LED light.
The applications of LEDs are many and are expanding constantly, fueled by the improvements in brightness, low gas permeability, thermal stability and laser resistance. Specific applications include TV backlighting and general lighting, traffic and other kinds of signal lighting. High refractive index silicone is perfect for applications in which long-term reliability is a basic requirement, like automotive lighting and as power semiconductor lighting.
A Better LED
Better, brighter and more reliable LEDs are entering the electronic materials market at an increasing pace because of the technologies available for silicone encapsulants and production. Silicone is the material of choice for encapsulating high power Light Emitting Diodes because of their reliability under qualification stresses. Harsh conditions have previously been a major deterrent for silicone encapsulants and therefore LEDs to become widespread in their applications. Now, however, high refractive index silicone that is also able to withstand stresses promises to extent the use of powerful LEDs in the electronics materials market.
Silicone for LED
There are several qualities that manufacturers look for in a silicone for high power LEDs. One is the ability of the silicone to remain non-yellowing. Another is how it acts under stresses like heat. Ideally, the silicone is non warping and fully heat resistant in temperatures up to 180 degrees Celsius, or 356 degrees Fahrenheit. That allows the LED to be used in a great variety of applications. Another desired quality is excellent transparency into high frequency ranges. This is essential in creating high refractive index silicone that can have many and broad applications.
Another desired trait in the silicone for LEDs is low ionic impurity. Ionic contamination has a very negative impact on the lifetime of semiconductors and electronic devices in general. In fact, when it comes to long term reliability, the ionic purity of polymeric materials that are in contact with the active chip surface is key. As the uses for super bright and long lasting LEDs continues to grow, industry will funnel more time and resources towards improving the refractive index of silicone and its reliability.