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Crystals 2018, 8(12), 472;

Square Column Structure of High Efficiency, Reliable, Uniformly Flexible LED Devices

Department of Photonics & Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
Institute of Photonic System, College of Photonics, National Chiao Tung University, Tainan 711, Taiwan
Fok Ying Tung Research Institute, Hong Kong University of Science and Technology, Hong Kong, China
Authors to whom correspondence should be addressed.
Received: 2 December 2018 / Accepted: 13 December 2018 / Published: 16 December 2018
(This article belongs to the Special Issue GaN-Based Optoelectronic Materials and Light Emitting Devices)
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This study demonstrates that flexible white LEDs, doped with diffusion particles and with a square column structure, have excellent luminosity, uniformity, and bending reliability. This large area (5 cm × 5 cm) square column flexible device had a smaller thickness (2 mm), and enhancements in both luminous efficiency (29.5%) and uniformity (44.6%) compared to the characteristics of the 6 mm reference sample. Optimization of the reflective layer coating for the square column, flexible white LED was achieved with a higher luminous efficiency (171 lm/w) and uniformity (92%). We designed a novel lightning bolt electrode to improve reliability and bendability. After the bending test, the blue flexible LED had a lower bending diameter (10 mm) but more bending circles (increased to 2000 times. View Full-Text
Keywords: optics; light emitting diodes; flexible optics; light emitting diodes; flexible

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Lin, C.-H.; Pai, Y.-M.; Kang, C.-Y.; Lin, H.-Y.; Lee, C.-F.; Chen, X.-Y.; Tu, H.-H.; Yang, J.-J.; Chen, C.-H.; Lin, C.-C.; Lee, P.-T.; Sher, C.-W.; Kuo, H.-C. Square Column Structure of High Efficiency, Reliable, Uniformly Flexible LED Devices. Crystals 2018, 8, 472.

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