Open AccessAccurate control of chromaticity and spectra by feedback phosphor-coating
Author(s) -
Mei-Tan Wang,
Jung-Min Huang
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.011576
Subject(s) - phosphor , chromaticity , color rendering index , optics , materials science , coating , color temperature , luminous efficacy , superposition principle , optoelectronics , spectral line , light emitting diode , luminous flux , wavelength , physics , nanotechnology , layer (electronics) , light source , quantum mechanics , astronomy
The chromaticity coordinates and spectra of phosphor-converted LEDs are demonstrated to be well controlled in this study. Through the feedback coating method of stacked yellow, green, and red phosphor layers, the color rendering index (CRI), correlated color temperature (CCT), and spectra are determined to match precisely the desired target. In addition, the reabsorption effect is strongly influenced by the order of stacked phosphor layers and the selected excitation wavelength of phosphors. The degree of reabsorption will modify the original spectra and cause a mismatch between the experimental measurement and the simulation based on the linear superposition of blue light and phosphor-emitted light. This feedback coating method offers an easy approach towards optimized spectra, which can offer the highest luminous efficacy of radiation with excellent color-rendering properties.