Electronic devices, such as, but not limited to, printed circuit boards (“PCBs) populated with light emitting diodes (“LEDs”) or chip-on-board (“COB”) LEDs, are typically required to include a material with high dielectric strength to electrically isolate the electronic device from the substrate on which it is mounted. However, these devices also require high performance thermal interfaces for effectively conducting heat away from the device during operation. Dielectric materials typically have poor thermal properties, and thermal interface materials typically have poor dielectric properties. One solution is to use two distinct layers—a dielectric layer on top of a thermal interface layer. This dual layer configuration, however, results in a significant reduction in thermal performance.
Another solution, shown in the COB system 100 in FIGS. 1 and 2, is to use a commercially available material that has been designed for the purpose of combining dielectric strength and thermal conductivity. Exemplary materials include, but are not limited to, silicone- and fiberglass-based thermally conductive insulator pads (e.g., Sil-Pad, manufactured by the Bergquist Company or Cho-Therm, manufactured by Parker Hannifin Corporation), acrylic-based thermal interface pads (e.g., 5589H, manufactured by 3M Company), and coated graphite sheets (e.g., HITHERM, manufactured by GrafTech International Holdings, Inc.). In such an embodiment, the thermal interface 110 is a homogeneous material that is mounted on a substrate 120. The electronic device 130 is, in turn, mounted onto the thermal interface. The thermal interface includes dielectric properties to electrically isolate the electronic device from the substrate. In addition, it has thermal conductivity properties to transfer heat generated by the electronic device to the substrate, which acts as a heat sink. While the homogeneous thermal interface materials provide an acceptable combination of dielectric and thermal conductivity properties, they fall short of the performance of materials designed to provide only one of these properties.