title: Design of vertically-stacked polychromatic light-emitting diodes.
abstract: A new design for a polychromatic light-emitting diode (LED) is proposed and demonstrated. LED chips of the primary colors are physically stacked on top of each other. Light emitted from each layer of the stack passes through each other, and thus is mixed naturally without additional optics. As a color-tunable device, a wide range of colors can be generated, making it suitable for display purposes. As a phosphor-free white light LED, luminous efficacy of 30 lm/watt was achieved.
authors.affiliation: Department of Electrical and Electronic Engineering, Semiconductor Display and Lighting Laboratory, The University of Hong Kong, Hong Kong.
authors.forename: K N
authors.initials: KN
authors.lastname: Hui
authors.forename: X H
authors.initials: XH
authors.lastname: Wang
authors.forename: Z L
authors.initials: ZL
authors.lastname: Li
authors.forename: P T
authors.initials: PT
authors.lastname: Lai
authors.forename: H W
authors.initials: HW
authors.lastname: Choi
mesh_terms: D003116:Color; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008029:Lighting / Q000295:instrumentation*; D055096:Optical Devices; D015203:Reproducibility of Results; D012666:Semiconductors; D012680:Sensitivity and Specificity