A Decade of Gains in LED Packaging Technologies as Captured in LM-80 Data

The Illuminating Engineering Society (IES) standard LM-80, which has been in use for more than 10 years, and its companion projection model, TM-21 provide the lighting industry with a standard way to convey information on the luminous flux maintenance of LEDs. LM-80-15 added chromaticity maintenance to the parameters that can be tracked with this standard procedure. The analysis described in this work is based on an examination of nearly 500 LM-80 data sets, spanning the time frame 2011-2019, that were provided by major LED manufacturers. Details on the information provided by LM-80 and how this data can be used to track changes in LED technology are a focus of this work. Data for polymer-based and ceramic-based LED packaging platforms are used to compare products made before 2015 to products made in 2019. Then, this evaluation shifts to LM-80 data for the current generation of chip-on-board and chip-scale packages. An emphasis is placed on the impact of junction temperature and forward current on parametric failure modes of LED packages (e.g., luminous flux and chromaticity maintenance) and how these modes have changed over time based on data in LM-80 reports and TM-21 models.