ANSI/IES LM-85, Approved Method: Optical and Electrical Measurements of LED Sources, is the IES standard that applies to LED component measurements. ANSI/IES 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.
