title: A novel randomly textured phosphor structure for highly efficient white light-emitting diodes.
abstract: We have successfully demonstrated the enhanced luminous flux and lumen efficiency in white light-emitting diodes by the randomly textured phosphor structure. The textured phosphor structure was fabricated by a simple imprinting technique, which does not need an expensive dry-etching machine or a complex patterned definition. The textured phosphor structure increases luminous flux by 5.4% and 2.5% at a driving current of 120 mA, compared with the flat phosphor and half-spherical lens structures, respectively. The increment was due to the scattering of textured surface and also the phosphor particles, leading to the enhancement of utilization efficiency of blue light. Furthermore, the textured phosphor structure has a larger view angle at the full width at half maximum (87°) than the reference LEDs.
authors.affiliation: Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, 300, Taiwan. hckuo@faculty.nctu.edu.tw.
authors.forename: Hsin Chu
authors.initials: HC
authors.lastname: Chen
authors.forename: Kuo Ju
authors.initials: KJ
authors.lastname: Chen
authors.forename: Chao Hsun
authors.initials: CH
authors.lastname: Wang
authors.forename: Chien Chung
authors.initials: CC
authors.lastname: Lin
authors.forename: Chia Chi
authors.initials: CC
authors.lastname: Yeh
authors.forename: Hsin Han
authors.initials: HH
authors.lastname: Tsai
authors.forename: Min Hsiung
authors.initials: MH
authors.lastname: Shih
authors.forename: Hao Chung
authors.initials: HC
authors.lastname: Kuo
authors.forename: Tien Chang
authors.initials: TC
authors.lastname: Lu