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Open Access Nano Express

A novel randomly textured phosphor structure for highly efficient white light-emitting diodes

Hsin Chu Chen1, Kuo Ju Chen1, Chao Hsun Wang1, Chien Chung Lin2, Chia Chi Yeh1, Hsin Han Tsai1, Min Hsiung Shih13, Hao Chung Kuo1* and Tien Chang Lu1

Author affiliations

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

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Citation and License

Nanoscale Research Letters 2012, 7:188  doi:10.1186/1556-276X-7-188

Published: 16 March 2012

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.

Keywords:
white light-emitting diodes; imprinting; phosphor; texture; package