Parylene Coating Blog by Diamond-MT

Conformal Coatings for LED Applications

Posted by Sean Horn on Wed, Oct 30, 2013 @ 07:58 AM

From front to back, LEDs are improved by conformal coatings. Whether the coating is improving the LED's color accuracy, protecting it from damage or keeping the electronics functioning well, conformal coating of LED electronics extends the suitability of LED technology. Here are the top six ways that conformal coating and LEDs go well together

1. UV Resistance

Many types of LEDs are sensitive to the ultraviolet radiation that comes off of the sun. Over time, these LEDs gradually yellow and experience reduced light output. While some conformal coatings do not protect LEDs from UV, others like special types of Parylene, block the light and its yellowing effects. Conformal coating of LED electronics that are outside can help to make the displays last longer while maintaining the vivid colors that LEDs are known for.

2. Moisture-Resistance

Putting LEDs outside means exposing them to the extremes of the elements. Among other risks is damage from exposure to water. Silicone conformal coatings can be applied relatively thickly, providing a large margin of error to prevent water from reaching and damaging the LEDs and the circuitry that drives them.  Parylene coatings have also been shown to have a high degree of success preventing moisture damage to LEDs.  

3. Chemical Protection

Providing a conformal coating for LED's can also protect them from chemicals. Urethane conformal coatings and parylene both protect LEDs from the solvents that they can be exposed to in automotive applications. At the same time, the salt protection that coating provide aren't just valuable for outdoor facing LEDs. They're also useful for products like consumer electronics that will be used in close proximity to the human body and the sweat and other byproducts that it can produce. 

4. Optical Clarity 

Many conformal coatings are optically transparent to visible and, in some case, invisible light. This means that they can add protection to LED displays without the risk of glare or distortion that can come with adding a cover glass over them. At the same time, they're also usually relatively light and thin. A truly conformal coating over LED electronics, like the kind that parylene offers, is also  completely uniform, minimizing the risk of any distortion or refraction of the light. 

5. Electrical Insulation

Many conformal coatings are also excellent dielectrics. When conformal coatings are applied to the backside of LED electronics, they seal the components off from each other. This helps to reduce the risk of any short circuits occurring when parts shift or when conductive materials fall on the PC board.

6. Tin Whisker Management

Unfortunately, some connections are prone to the formation of tin whiskers. These are small conductive bridges of tin that gradually grow out of tin-coated surfaces and can cause short circuits. One of the best ways to manage them is through the use of conformal coatings. Conformal coating of LED electronics with compounds like urethane solves the problem in two ways. First, they hold back the growth of whiskers and encapsulate any growth in a dielectric barrier. Second, even if the whisker can pierce the coating, it will end up running into a conformal coating barrier on the other side, instead of contacting a bare conductor.

As LEDs continue to go into places that were never envisioned, conformal coating for LED electronics will continue to be important. To learn more about how conformal coatings can help your company use LEDs in new places and to get a free quote to estimate the cost of using coatings in your product, contact us.

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Tags: parylene, silicone conformal coating, parylene for LEDs