Why Are Streetlights Turning Purple? In Depth Analysis and Fix

Have you noticed weird colored purple or blue LED streetlights where you live? In this teardown we take apart a streetlight that has shown significant color shift to blue, and diagnose what has gone wrong as well as propose a possible fix (without complicated and costly replacement). Comparison to a new, good streetlight and analysis of the differences at the LED level are performed. Major findings include: -LED phosphor layer has physically removed (delaminated) from the LED die, causing increase in blue light output and reduction in down-converted colors (white). -Significant loss of useful light output (illuminance) for failed LED lights -Adding remote phosphor layer can improve color point and useful light output -Color rendering with broken light is very poor. Adding remote phosphor can significantly improve CRI. Thanks to collaborator Matthew Bertram for all his help on this project! Useful tools I use in my teardowns… Mini screwdriver set for electronics: https://amzn.to/423lvoH Heat gun: https://amzn.to/4hNdE4v Loupe magnifier: https://amzn.to/3FGFJ00 Microscope: https://amzn.to/4l3SG4a UV LED: https://amzn.to/4hJMT0M Blue light blocking glasses: https://amzn.to/4j5MG9f Nitrile gloves: https://amzn.to/4kXVcZP Cut-resistant gloves: https://amzn.to/4j5JsCF Multimeter: https://amzn.to/4j7LZwh iFixIt heat pad and tools: https://amzn.to/4iNVBN2 Digital calipers: https://amzn.to/4iNWFAw Digital film micrometer: https://amzn.to/4camdoW USB Spectrometer: https://www.avantes.com/products/spec... Epoxy for coating LEDs with phosphor: https://amzn.to/4iITxWt LED Inside article: https://inside.lighting/news/24-05/he... LED Systems Reliability Consortium video with in-depth analysis of LED failures:    • Causes of Excess Color Changes in Streetli...   USA Today article: https://www.usatoday.com/story/news/n... Some of the links above are affiliate links — I may earn a small commission (at no cost to you) if you choose to buy through them. In fact, it's an easy way for you to support this channel! As an Amazon Associate, I earn from qualifying purchases.