Wide Range CCT Laser-Based Illuminant With High Efficiency and Excellent Optical Performances

A wide range correlated color temperature (CCT) white light laser-based illuminant (LBI) consisting of dual blue laser diodes (LDs), yellow phosphor color converters and red LDs has been proposed. In addition to the conventional 455 nm blue LDs-pumped phosphor color converters, another blue LD is utilized for the adjustment of CCT and improvement of the color rendering index (CRI). Considering systematic manipulation of the power ratio of LDs and peak wavelength of tuning blue LDs from 440 nm to 480 nm, different combinations of spectral power distributions of LBIs were simulated. It shows that an optimized 465 nm tuning blue LD is employed to achieve a balance between optical performances and blue light hazard efficiency of radiation (BLHER). The first practical LBI comprised of Y3Al5O12:Ce
$^{\mathrm {3+{}}}$
(YAG:Ce
$^{3+}$
) phosphor color converters and three monochromatic LDs of 455 nm, 465 nm and 635 nm was fabricated based on the stated simulations. In good agreement with the simulation results, the LBI has simultaneously achieved an excellent CRI beyond 85, a high luminous flux of approximately 2000 lm and a high luminous efficiency of radiation (LER) of over 300 lm/W at the fairly wide CCT range of 3300 K to 6000 K. The low BLHER was consistently below 0.237. The circadian action factor (CAF) was between 0.36 and 0.83, and its tunability was 2.31 above the CCT range, which favors the entrainment of circadian rhythm. Therefore, this work demonstrates a promising method for providing high-quality and human-oriented white light sources in applications requiring great brightness.