High-Power Light-Emitting Diodes Package With Phase Change Material

We report the fabrication and charaterization of high-power light-emitting diodes (LEDs) package with phase change material. Paraffin wax with melting point of 49.6 °C was inserted between the LED die and silicone encapsulant. The phase changing of embedded wax in a working LED is observed by studying its output flux and junction temperature. With a driving current density of 443 mA/mm$^{\mathrm {\mathbf {2}}}$ , LED sample demonstrates a decreasing of junction temperature by 19 °C and an increasing of light flux by 25% with the insertion of 6-mg paraffin wax. Optical and thermal simulations are employed to analyze the improved performance of LED package. Higher thermal conductivity of paraffin wax compared with silicone resin is considered to be reason for LED's reduced junction temperature. The high refractive index of paraffin wax is considered to be the dominant mechanism of LEDs enhanced emission.