Optimization Studies of Two-Phosphor-Coated White Light-Emitting Diodes

Three-hump InGaN-based white light-emitting diodes (LEDs) precoated with traditional yellow/green phosphors and red-emitting quantum dots (QDs), have been numerically investigated. Under variations of eight correlated color temperatures (CCTs), three wavelengths, two bandwidths, and two peak heights, optimal results of luminous efficacy radiation (LER) and color rendering index (CRI) are identified and retained through filtering off billions of unqualified candidates. These results include LER = 390 lm/W and CRI = 90 [chromaticity difference (Duv)<;0.0054] at CCT = 3000 K. In addition, our photometric and colorimetric sensitivity studies provide the dependence of LER, CRI, CCT, and Duv on LED spectral parameters affected by operating temperatures. Finally, we have discovered that higher instabilities may be induced for cool white LEDs (CCT = 6500 K) than for warm white LEDs (CCT = 3000 K) within the analysis of CCT versus spectral parameters.

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