LED protection - a designer's guide

Louise Smyth

The LED market must surely represent one of the fastest growing sectors within the electronics industry and LEDs are now utilised in all types of lighting, signage and domestic appliance products. LEDs offer many advantages over traditional lighting in the form of adaptability, lifetime, design and efficiency and represent a real alternative to halogen, incandescent and fluorescent lighting systems for both interior and exterior applications. Ultimately, LED bulbs offer an exceptionally long life time, converting the majority of energy to light and thus minimising the heat given off.

Specially designed and formulated chemical products are widely used in the electronics industry for a vast array of applications. Whether it is during PCB manufacture or for the protection of components or complete devices, such products have become an essential factor in ensuring the performance and quality of electronic devices.  Specifically in LED applications such products can be used to assist Design Engineers in protecting LED systems in a variety of conditions, including the installation of lighting designs in corrosive environments, for example. Due to the design freedom that LEDs offer, applications are becoming more diverse and challenging and as such, aesthetic results must be achieved in conjunction with the consideration of reliability and lifetime of the product. In addition, specialist chemical products can also be used as part of the design for cosmetic reasons as well as helping to provide key functional improvements.

The environment that the LEDs and associated electronic components are used in will have an effect on the type of product required to protect the system. Environmental challenges can be in the form of corrosive environments; when high humidity, salt mist or corrosive gases are present, for example. Due to the potential variety of LED applications it is also possible that UV exposure, water immersion or chemical exposure may make up part of the operating environment. The end use application must therefore be fully understood to ensure the correct protection media is applied.

Where protection directly over the LED is required there are a number of points that must be considered. The clarity of the material applied is crucial to ensuring the maximum utilisation of light output from the LED. In addition, any potential changes to the colour temperature, clarity of the material or light output of the LED during operation must also be considered. Protection can be offered in the form of conformal coatings or encapsulation resins, with the choice between the two being determined by the severity of the operating environment and the desired aesthetic effect.

Whether choosing a protective material for the individual LEDs or the entire unit design it is clear that the operating environment must be considered. With applications becoming more and more diverse, the number of challenges is increasing. By the correct selection and application of protection compounds, it is also possible to use LED arrays in a wide range of products and when combined with efficient thermal management it is possible to achieve consistent quality and appearance whilst improving the lifetime of LED devices. More information from Electrolube