Lumen degradation and chromaticity shift in glass and silicone based high-power phosphor-converted white-emitting diodes under thermal tests

Overdriving reliability of chip scale packaged LEDs: Quantitatively analyzing the impact of component

“…Although the reliability of white LEDs has been attracted great interest by many research groups [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], there is limited report on the reliability of CSP LEDs under overdriving current. In fact, identification of the failure modes, especially quantitative analysis the impact of each component on the CSP LEDs, is essential for further improving CSP technology.…”

“…Fan et al [12,31,32] analyzed thermal, optical and electrical performance of LEDs with experiment and simulation after a high temperature accelerated degradation test. Cheng et al [13] presented lumen degradation and chromaticity shift in glass and silicone based high-power LEDs under accelerated thermal tests. Most of their studies indicate that the blue die and the phosphor layer are the critical factors to determine the reliability of LEDs.…”

Thermal Aging Performance Analyses of High Color Rendering Index of Glass-Based Phosphor-Converted White-Light-Emitting Diode

“…Dynamic color control is achievable by electronically adjusting the driving current of each LED individually. High quantum efficiency is also an advantage of the multiple LEDs technique because no Stokes shift due to photonic energy down-conversion [8][9] . However, costs of multiple LEDs technique are much higher than the other techniques, therefore multiple LEDs technique is only used in some specialized applications.…”

“…However, usually less than 70, low color rendering index (CRI) of the WLEDs is not acceptable for general interior illumination and some special lighting including medical applications and architectural lighting. To achieve high color rendering properties, multi-phosphors such as red/yellow and orange/yellow in the color conversion layer is essential [8] . Multi-phosphor-doped silicone as the color conversion layer of the high-CRI WLED has been demonstrated [14][15] , but the poor thermal stability of the silicone matrix has been weakening the superiority for high-luminance lighting applications [3,9,11] .…”

P.72: Glass‐based Color Conversion Multilayer for White Light‐emitting‐diodes and its Angular Color Performance

“…Development of new glass-based carriers for phosphors in high power WLEDs is consequently critical to the applications where absolute reliability is required, since glass-based materials usually exhibit a better thermal stability than polymer-based materials. The novel glass phosphors with high thermal stability have been demonstrated recently [4,5]. Stable chromaticity characteristics of the glass phosphors have been shown even under a thermal aging condition up to 350 ℃ [6].…”