Browsing by Author "Chen, Kuo Ju"

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A novel randomly textured phosphor structure for highly efficient white light-emitting diodes
(2012-03-16)
Chen, Hsin Chu
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Chen, Kuo Ju
;
Wang, Chao Hsun
;
Lin, Chien Chung
;
Yeh, Chia Chi
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 (87A degrees) than the reference LEDs.
Enhanced performance of nitride-based ultraviolet vertical-injection light-emitting diodes by non-insulation current blocking layer and textured surface
(2014-12-29)
Chiang, Yen Chih
;
Lin, Bing Cheng
;
Chen, Kuo Ju
;
Lin, Chien Chung
;
Lee, Po Tsung
For the purpose of light extraction and efficiency enhancement, the nitride-based ultraviolet vertical-injection light-emitting diodes (UV-VLEDs) with non-insulation current blocking layer (n-CBL) and optimized textured surface were fabricated. The optical and electrical characteristics were investigated in this n-CBL UV-VLED. Furthermore, the efficiency of optimized structure was improved by 5 similar to 6 times compared to our reference.