LED - Technical Notes

LEDs are sustainable, eco-friendly, efficient, and safe lighting solutions that deliver multiple benefits to the users.   One of the benefits of LED is its long lifetime. Because they have no movable parts  or filaments tht may break, LED’s can have long lifetime. LEDs generally do not fail by burning out but will slowly reduce in light output over time; as solid state devices they will continue to operate even after 100,000 hours, continuing to use electrical power even if they produce very little useful light. LEDs, however, follow a different method for measuring life expectancy called lumen maintenance. What is lumen maintenance? Lumen maintenance is an approach of measuring the light output (lumens) of a brand new light source and comparing that with its light output after a certain period of time. L70 and L50 are examples of lumen maintenance – benchmarks for when 70% or 50% of a lamp or fixture's total light output remains. What is L70? It is rated lumen-maint...

All light sources degrade over time or most just “burn out”. LEDs, on the other hand, do not burn out but continue to degrade – eventually beyond useful light output, which is typically recognized as 70% of initial luminous flux (L70). Recognizing the need for an industry standard that would also help users evaluate LED products, in 2008 the Illuminating Engineering Society of North America (IES) published LM-80. Note, however that while LM-80 provides a standard method for testing lumen maintenance, it does not provide guidance or recommendations for predicting or extrapolating maintenance beyond the duration of these measurements. LM-80 is a standard that defines how the lumen output and colour shift of LEDs should be measured over time and at different temperatures. The full name of the latest version of this standard is “IES LM-80-20 Approved Method: Measuring Luminous Flux and Color Maintenance of LED Packages, Arrays and Modules”. LM80 Test LM-80 is important to lighting de...