LEDLuminaireReliabilityandLifetimeDiscussion.pptVIP

What is color shift for a luminaire? For our discussion, “color shift” is what happens over TIME It does NOT mean initial variation in color from one luminaire to another or from one batch to another Orange Green Blue Pink What are some of the causes for color shift in luminaires? Aging (for example, UV exposure may cause plastics to change color) Operating conditions (contaminants in the atmosphere may cause luminaire changes) Light engines may shift color over time (different engines shift color differently) Maintenance issues may cause the luminaires to look different over time (“wrong” parts installed) Nearly all light engines havesome type of “color shift” Metal Halide lamps are notorious for color shift Incandescent bulbs color shift when dimmed Linear Fluorescents may not color shift “much” however, improper maintenance practices can cause obvious luminaire color shift over time LEDs use a technology that will shift color over time Why does color shift with LED-based luminaires need attention? The causes of color shift with LEDs are not well understood or communicated Caliper testing shows color shift with LED-based luminaires is real and can be so great as to constitute a “failure” to an end user This creates a potential for trouble Our group identified four challenges Describing color shift Projecting color shift Identifying design impact on color shift Testing for color shift Describing color shift How can we make description of color shift consumer “friendly”? Too Hard Too Simple Projecting color shift Our group could not identify any team that is trying use that data to project color shift over an extended period of time (50,000 or more hours) Identifying designimpact on color shift Remember, the color shift in the final luminaire may be not be due to an LED color shift Examples include: Different optics and designs age differently Different environmental operating conditions may cause different shifts over time Different luminaire desig