Utilization of far-red LED to minimize blue light hazard for dynamic semiconductor lighting

ABSTRACT

The blue light hazard (BLH) and luminous efficacy of a source (${\eta }_V$) are associated with the photobiological safety and energy saving of light-emitting diodes (LEDs), respectively. In this study, we used genetic algorithm (GA) to optimize the BLH, ${\eta }_V$, and color rendering parameters of five-chip hybrid white LEDs. Based on the optimal results, we used five-chip LEDs to obtain the hybrid white light. Their peak wavelengths were 461.5 (blue), 523.9 (green), 588.2 (orange), 643.3 (red), and 694.2 nm (far-red), respectively. In practice, the blue light hazard efficiency of radiation (BLHER) of the hybrid white light was less than 0.10, which was lower than half of the most common light sources. The ${\eta }_V$ ranged from 51.6 to 115.6 lm/W at correlated color temperature (CCT) from 2700 to 6500 K. On average, the CIE general color rendering index (Ra), CIE special color rendering index for the ninth deep red test sample (R9), ANSI/IES TM-30 color fidelity index (Rf), and color gamut index (Rg) of hybrid white light were 91.3, 87.8, 83.3, and 96.7, respectively. The melanopic efficacy of luminous radiation ($K_{mel,V}$) was tunable in the range of 0.60 to 1.35 mW/lm. These results demonstrated that we used far-red LEDs to fabricate white light with low BLH and relatively high efficiency.

KEYWORDS:

• Blue light hazard
• luminous efficacy
• light-emitting diode
• multi-chip color mixing

Disclosure statement

No potential conflicts of interest were reported by the authors.

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Additional information

Funding

This work was supported by the National Key Research and Development Program (2017YFB0403100); National Natural Science Foundation of China 61927806,62174004 (62174004, 61927806); Science and Technology Major Project of Guangdong Province (2016B010111001); Guangdong Basic and Applied Basic Research Foundation (2020B1515120020); Science and Technology Planning Project of Henan Province (161100210200).