Performance Comparison of InGaN-Based Phosphor Converted and AlGaInP-Based Red Light-Emitting Diode Packages for Vehicle Rear Fog Lamps

Abstract

We investigated the electrical and optical properties of chip LED and phosphor-converted red LED (pcR-LED) packages for a vehicle rear fog lamp application. The chip LED package had a lower forward voltage, narrower electroluminescence spectrum, and a larger view angle than the pcR-LED package. At 85 °C under 700 mA, the pcR-LED package emitted 26.8% more luminous flux than the chip LED package. After 1000 temperature cycles (−40 to +125 °C), the chip LED packages exhibited a 7.83% maintenance rate variance, whereas the pcR-LED packages showed a 2.78% change. Furthermore, after 1000 h under relative humidity conditions of 85 °C/85% both the samples demonstrated an average maintenance rate >98.66%. At 85 °C under 700 mA, it was demonstrated that the pcR-LED package exhibited a 48.9% lower thermal resistance (junction to package) than the chip LED package. Also for the chip LED package, the temperatures were 58.6 °C at the central region and 61.9 °C at its periphery, whereas the pcR-LED package had temperatures of 70.5 °C at the center and 55.8 °C at the periphery. Unlike the chip LED package, neither current nor temperature significantly affected the CIE coordinates of the pcR-LED packages.