A novel randomly textured phosphor structure for highly efficient white light-emitting diodes
1 Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, 300, Taiwan
2 Institute of Photonic System, National Chiao Tung University, 301 Gaofa 3rd Rd., Guiren Township, Tainan County, 711, Taiwan
3 Research Center for Applied Sciences, Academia Sinica 128 Academia Rd., Sec 2 Nankang, Taipei, 115, Taiwan
Nanoscale Research Letters 2012, 7:188 doi:10.1186/1556-276X-7-188Published: 16 March 2012
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.