Title page for etd-0702109-231045


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URN etd-0702109-231045
Author Ying-Jyun Lin
Author's Email Address tattoochilli@hotmail.com
Statistics This thesis had been viewed 5369 times. Download 19 times.
Department Electro-Optical Engineering
Year 2008
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title A Study on Optical Properties of High Color-Rendering
Index for Nitride Phosphor Mixture in White-Light LEDs
Date of Defense 2009-06-08
Page Count 85
Keyword
  • color rendering index
  • white ligh
  • nitride
  • phosphor
  • Light Emitting Diode
  • Abstract This paper tries to explore the phosphor optical characteristics through reliability tests using white light emitting diodes (WLEDs) with a high color rendering index
    (CRI ,Ra>90). Based on light mixing principles and considering the high CRI, three color-coded powders were mixed separately with silicone into a phosphor, and then
    bottomed with blue chips into WLEDs. The three powders were oxide nitride (red), YAG (yellow), and silicate (green).
    Two kinds of samples were fabricated – phosphor and emitters similar to commercial products. Both cool-white (CCT=5650~7000K, lumen efficiency>60 lum/w.) and
    warm-white (CCT=2850~3250K, lumen efficiency>50 lum/w.) samples passed the Bin Code distribution process and brightness measurement. The results indicate better
    lumen efficiency than previously published research.
    After the three kinds of mono-colored phosphors were created, .we implemented the reliability test in which three CREE standards were chosen. These standards were (1)
    high temperature with high humidity test (60℃ , 90% humidity) in operating and non-operating condition; (2) thermal shock test (-40℃ ~125℃ ); (3) life time test.
    The thermal shock test showed the decaying power of intensity for red, yellow, and green phosphors were 11.7%, 17.5%, and 19.3% respectively. These results demonstrate that the red phosphor has the best thermal resistance. However, after the high temperature with high humidity tests, the decaying power of intensity for red,yellow, and green phosphor were 15.7%, 10.1% and 6.4% correspondingly. These results show that the green phosphor has best aqua resistance. In the life time test of
    emitters, the decaying power of intensity for the cool-white emitter was 3.2%, while the warm-white emitter showed 4.2%. As such, cool-white emitters were concluded to
    have better reliability than warm-white emitters.
    Advisory Committee
  • Jiang-Jhen Lin - chair
  • Mei-Ying Chang - co-chair
  • Chao-Sheng Wang - co-chair
  • Yi-Jhong Huang - co-chair
  • Wood-Hi Cheng - advisor
  • Files
  • etd-0702109-231045.pdf
  • indicate in-campus access in a year and off_campus not accessible
    Date of Submission 2009-07-02

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