Large-format advertising displays and LED panels are made from a multitude of individual RGB LEDs, often up to several million. Each RGB LED contains one red, one green and one blue light-emitting chip. Individual control of each chip makes it possible to mix the emissions spectra and produce a wide range of colors. The LEDs are encapsulated with a protective temperature-resistant silicone potting compound. The tackiness of the silicone surface can cause problems during manufacturing and subsequent use of the displays.
The LEDs are assembled on the corresponding PCBs using the wave soldering process. Tin residues in the solder bath are often deposited on the tacky surface of the LED's silicone encapsulant, resulting in a high scrappage rate. External impurities such as dust can also build up on the display during its life time, resulting in significant soiling. Furthermore, the tacky surface of the silicone material often causes problems during the pick-and-place process, for example individual LEDs may stick to one another or to the placement tool, which disrupts the assembly process.
Using PlasmaPlus® technology, Plasmatreat has succeeded in applying an anti-adhesive, wafer-thin vitreous coating to the silicone. This coating effectively protects against contamination during manufacturing, optimizes handling during the pick-and-place process and prevents soiling during subsequent use.