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Homework Help: About LEDs technical question - very hard to solve

  1. Oct 7, 2012 #1
    In a COB product with FR-4 substrate, blue light chip excites yellow phosphor to form white light.
    Why is room temperature aging attenuation higher than 85 degree/85% RH aging attenuation?
    (After 1000h lighting, Attr=7% while Att85=1%)

    (If you have further questions about how I do the experiment, ask me here)
  2. jcsd
  3. Oct 7, 2012 #2
    I'd suppose heat heals some damage. For instance when hot electrons are injected into insulators, heat helps the electrons flow back.
  4. Oct 7, 2012 #3
    Good thought!
    I was thinking whether high temperature and humidity affects phosphor and colloid so that the possibility of attenuation caused by phosphor might be lowered.
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