• Laser & Optoelectronics Progress
  • Vol. 56, Issue 8, 082301 (2019)
Xuyan Lan, Xin Yang, Shichen Su, and Yong Zhang*
Author Affiliations
  • Institute of Optoelectronic Materials and Technology, South China Normal University, Guangzhou, Guangdong 510631, China
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    DOI: 10.3788/LOP56.082301 Cite this Article Set citation alerts
    Xuyan Lan, Xin Yang, Shichen Su, Yong Zhang. Effects of Current and Temperature Stress on Reliability of LED Bulbs[J]. Laser & Optoelectronics Progress, 2019, 56(8): 082301 Copy Citation Text show less
    Emission spectrum of LED bulbs and photograph of LED light source module
    Fig. 1. Emission spectrum of LED bulbs and photograph of LED light source module
    Luminous flux maintenance of LED bulbs under different currents at room temperature
    Fig. 2. Luminous flux maintenance of LED bulbs under different currents at room temperature
    Performances of LED bulbs versus aging time under different currents at room temperature. (a) Chromaticity coordinates; (b) color temperature; (c) color rendering index; (d) emission intensity ratio between yellow phosphor and blue chip
    Fig. 3. Performances of LED bulbs versus aging time under different currents at room temperature. (a) Chromaticity coordinates; (b) color temperature; (c) color rendering index; (d) emission intensity ratio between yellow phosphor and blue chip
    Aging effects of light source module of LED bulbs under different currents at room temperature. (a) Appearance; (b) infrared thermal imaging; (c) substrate of driving power
    Fig. 4. Aging effects of light source module of LED bulbs under different currents at room temperature. (a) Appearance; (b) infrared thermal imaging; (c) substrate of driving power
    I-V characteristics of chips aged under different currents at room temperature
    Fig. 5. I-V characteristics of chips aged under different currents at room temperature
    Characteristics of LED bulbs under different currents at 55 ℃. (a) Luminous flux maintenance; (b) chromaticity coordinates; (c) color temperature; (d) color rendering index
    Fig. 6. Characteristics of LED bulbs under different currents at 55 ℃. (a) Luminous flux maintenance; (b) chromaticity coordinates; (c) color temperature; (d) color rendering index
    Effect of joint temperature-current stress on characteristic of LED bulbs. (a) Emission intensity ratio between yellow phosphor and blue chip; (b) I-V curves of chips and substrate of driving power
    Fig. 7. Effect of joint temperature-current stress on characteristic of LED bulbs. (a) Emission intensity ratio between yellow phosphor and blue chip; (b) I-V curves of chips and substrate of driving power
    Effect of joint temperature-current stress on characteristics of LED bulbs at 55 ℃ temperature. (a) Aging photographs of light source modules and spectral changes; (b) infrared thermal distributions of light source modules
    Fig. 8. Effect of joint temperature-current stress on characteristics of LED bulbs at 55 ℃ temperature. (a) Aging photographs of light source modules and spectral changes; (b) infrared thermal distributions of light source modules
    Temperature /℃Current /mADecay luminescence ratio /%Time /hτLifetime /h
    252508667204599316404
    25300823120158025636
    25350861632111103963
    254508693661892208
    Table 1. Aging lifetimes under different current stresses
    CurrentI0 /mACurrentIt /mAFittingvalue nLifetime /h
    3003502.297189
    3004502.317217
    3504502.337185
    Table 2. Fitted power exponent n and predicted normal working lifetime of LED device