title: Excellent color rendering indexes of multi-package white LEDs.
abstract: This study introduces multi-package white light-emitting diodes (LEDs) system with the ability to realize high luminous efficacy and an excellent color rendering index (CRI, R a) using the R B,M A B,M G B,M C B (R B,M A B,M G B,M denoted as a long-pass dichroic filter (LPDF)-capped, monochromatic red, amber and green phosphor converted-LED (pc-LED) pumped by a blue LED chip, and C B denoted as a cyan and blue mixed pc-LED pumped by a blue LED) system. The luminous efficacy and color rendering index (CRI) of multi-package white LED systems are compared while changing the concentration of the cyan phosphor used in the paste of a cyan-blue LED package and the driving current of individual LEDs in multi-package white LEDs at correlated color temperatures (CCTs) ranging from 6,500 K (cold white) to 2,700 K (warm white) using a set of eight CCTs as specified by the American National Standards Institute (ANSI) standard number C78.377-2008. A R B,M A B,M G B,M C B white LED system provides high luminous efficacy (≥ 96 lm/W) and a color rendering index (≥ 91) encompassing the complete CCT range. We also compare the optical properties of the R B,M A B,M G B,M C B system with those of the R B,M A B,M G B,M B and RAGB (red, amber, green, and blue semiconductor-type narrow-spectrum-band LEDs) systems. It can be expected that the cyan color added to a blue LED in multi-package white LEDs based on LPDF-capped, phosphor-converted monochromatic LEDs will meet the needs of the high-quality, highly efficient, full-color white LED lighting market in the near future.
authors.affiliation: Department of Chemistry, Kookmin University, Seoul 136-702, South Korea.
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Oh
authors.forename: Su Ji
authors.initials: SJ
authors.lastname: Yang
authors.forename: Yeon-Goog
authors.initials: YG
authors.lastname: Sung
authors.forename: Y R
authors.initials: YR
authors.lastname: Do
mesh_terms: D003116:Color; D003124:Colorimetry / Q000295:instrumentation*; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008029:Lighting / Q000295:instrumentation*; D012666:Semiconductors