ANSI/IES-LM-85-23: A Productive Collaboration During COVID Produces 100X-Improved Measurement Technique
IES LM-85, Approved Method: Optical and Electrical Measurements of LED Sources is the IES standard that applies to LED component measurements. 1 LM-85-23 covers the same topics as its predecessor, LM-85-14, but it is a substantial rewrite that improves the methods in LM-85-14 and adds several new testing methods, including two that are based upon a novel technique, previously considered a proprietary trade secret, that increases measurement accuracy by roughly 100X.
LM-85 also now truly ties optical measurements to junction temperature, TJ, eliminating a significant error source present in many LED measurements. Using the updated and new LM-85 methods, LED measurements will now be more consistent when performed at different laboratories.
Temperature-referenced measurements will also give product designers something they haven’t had before: accurate LED-output-vs-temperature data. Using this data, designers can create LED products with improved thermal optimization. These products promise to be more efficient, less costly, and more reliable.
LM-85-23 came about because of a unique collaboration that occurred during the COVID pandemic. With most of the world locked down, the scientists and engineers (from Australia, Germany, Japan, and USA) in charge of LM-85 worked overtime to refine the standard; the resulting document will likely be considered a breakthrough in the field. This article provides an overview of LM-85’s innovative methods and details the history of the document’s development.
