Browsing by Author "Chen, Huang-Ming"

Now showing 1 - 8 of 8

Effective optimization and analysis of white LED properties by using nano-honeycomb patterned phosphor film
(2016-08-22)
Lin, Huang-Yu
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Wang, Sheng-Wen
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Lin, Chien-Chung
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Tu, Zong-Yi
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Lee, Po-Tsung
This study presents an approach for patterning a polydimethylsiloxane (PDMS) phosphor film with a photonic crystal nano-honeycomb structure on a blue chip package. A phosphor film with a nano-honeycomb structure was patterned and transferred using a nanosphere and used for fabricating remote white light-emitting diodes (w-LEDs). The angular correlated color temperature deviation of the remote phosphor LED could be improved by varying nano-honeycomb structure pitches (450, 750, and 1150 nm). In particular, w-LED samples with excellent color uniformity (Delta CCT ranging from 940 to 440 K) were fabricated from 750-nm w-LED samples with nano-honeycomb-patterned tops. (C) 2016 Optical Society of America
Fabrication of Flexible White Light-Emitting Diodes from Photoluminescent Polymer Materials with Excellent Color Quality
(2017-10-11)
Lin, Huang-Yu
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Sher, Chin-Wei
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Lin, Chih-Hao
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Tu, Hsien-Hao
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Chen, Xin Yin
This study developed flexible light-emitting diodes (LEDs) with warm white and neutral white light. A simple ultraviolet flip-chip sticking process was adopted for the pumping source and combined with polymer and quantum dot (QD) films technology to yield white light. The polymer-blended flexible LEDs exhibited higher luminous efficiency than the QD-blended flexible LEDs. Moreover, the polymer-blended LEDs, achieved excellent color-rendering index (CRI) values (Ra = 96 and R9 = 96), with high reliability, demonstrating high suitability for special applications like accent, down, or retrofit lights in the future. In places such as a museum, kitchen, or surgery room, its high R9 and high CRI characteristics can provide high-quality services.
Improvement of light quality by DBR structure in white LED
(2015-02-09)
Lin, Huang-Yu
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Chen, Kuo-Ju
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Wang, Sheng-Wen
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Lin, Chien-Chung
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Wang, Kuan-Yu
This study demonstrates the application of DBR structure into the remote phosphor structure to improve the angular correlated color temperature (CCT) deviation in white light-emitting diodes (WLEDs). In the experiment, the LED device with DBR structure yielded a higher luminous efficiency than a conventional structure. The CCT deviation can be improved from 1758K to 280K in a range of -70 to 70 degree and the luminous flux increases more than 10% due to the enhancement of the light extraction of the blue light. Moreover, the reflectance of the different DBR structures is analyzed with different angles to reveal the reasons of such improvements. As the result, this LED device with DBR structure shows the great potential to use as the next generation lighting source. (C) 2014 Optical Society of America
Improvement of light quality by ZrO2 film of chip on glass structure white LED
(2016-01-25)
Lin, Huang-Yu
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Ye, Zhi-Ting
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Lin, Chien-Chung
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Chen, Kuo-Ju
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Tu, Hsien-Hao
A novel combination of blue LED chips, transparent glass substrates and phosphors with PDMS thin film is demonstrated. The flip-chip bonding technology is applied to facilitate this design. The ZrO2 nanoparticles are also doped into the PDMS film to increase light scattering. The resultant luminous efficiency shows an 11% enhancement when compared to the regular COG device. The variation of correlated color temperature of such devices is also reduced to 132K. In addition to these changes, the surface temperature is reduced from 121 degrees C to 104 degrees C due to good thermal dissipation brought by ZrO2 nanoparticles. (C) 2015 Optical Society of America
ITO-free inverted polymer solar cell on metal substrate with top-illumination
(2014-01-01)
Chen, En-Chen
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Tsai, Pei-Ting
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Tsai, Chia-Ying
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Chang, Jung-Hao
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Huang, Zheng-Yu
High-performance polymer solar cells are conventionally fabricated on the rigid and costly indium-tin-oxide (ITO) glass substrates, which are incompatible with the roll-to-roll process with low cost. This study shows that polymer solar cells can be made on ITO-free flexible stainless steel with only a moderate compromise in power conversion efficiency. A blend of poly (3-hexylthiophene) (P3HT) and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) was used as the active material for the inverted structure. The bottom electrode was an alloy of Al and Au spontaneously formed from a bi-layer during thermal annealing of the active layer. This alloy had a low work function of 3.9 eV, and a high resistance to oxide formation throughout the entire process. Semi-transparent Ag was used as the top electrode. These solar cells on stainless steel had an efficiency of 2.6%. The majority of the loss came from the top electrode transmission at approximately 60%. This all-metal approach makes roll-to-roll polymer cell fabrication possible. (C) 2013 Elsevier B.V. All rights reserved.
Laser-patterned Array with Aerosol-jet Printing Quantum-dots for Novel White Light Source
(2016)
Wang, Sheng-Wen
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Lin, Huang-Yu
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Lin, Chien-Chung
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Kao, Tsung Sheng
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Chen, Kuo-Ju
Through the laser-ablation and aerosol-jet printing techniques, a novel photoluminescent quantum-dots device with microscale patterns has been demonstrated as a white-light emitting source with stable emission at different driving currents and larger color productivity domain.
Pulsed-laser micropatterned quantum-dot array for white light source
(2016-03-23)
Wang, Sheng-Wen
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Lin, Huang-Yu
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Lin, Chien-Chung
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Kao, Tsung Sheng
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Chen, Kuo-Ju
In this study, a novel photoluminescent quantum dots device with laser-processed microscale patterns has been demonstrated to be used as a white light emitting source. The pulsed laser ablation technique was employed to directly fabricate microscale square holes with nano-ripple structures onto the sapphire substrate of a flip-chip blue light-emitting diode, confining sprayed quantum dots into well-defined areas and eliminating the coffee ring effect. The electroluminescence characterizations showed that the white light emission from the developed photoluminescent quantum-dot light-emitting diode exhibits stable emission at different driving currents. With a flexibility of controlling the quantum dots proportions in the patterned square holes, our developed white-light emitting source not only can be employed in the display applications with color triangle enlarged by 47% compared with the NTSC standard, but also provide the great potential in future lighting industry with the correlated color temperature continuously changed in a wide range.
Resonant-enhanced full-color emission of quantum-dot-based micro LED display technology
(2015-12-14)
Han, Hau-Vei
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Lin, Huang-Yu
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Lin, Chien-Chung
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Chong, Wing-Cheung
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Li, Jie-Ru
Colloidal quantum dots which can emit red, green, and blue colors are incorporated with a micro-LED array to demonstrate a feasible choice for future display technology. The pitch of the micro-LED array is 40 mu m, which is sufficient for high-resolution screen applications. The method that was used to spray the quantum dots in such tight space is called Aerosol Jet technology which uses atomizer and gas flow control to obtain uniform and controlled narrow spots. The ultra-violet LEDs are used in the array to excite the red, green and blue quantum dots on the top surface. To increase the utilization of the UV photons, a layer of distributed Bragg reflector was laid down on the device to reflect most of the leaked UV photons back to the quantum dot layers. With this mechanism, the enhanced luminous flux is 194% (blue), 173% (green) and 183% (red) more than that of the samples without the reflector. The luminous efficacy of radiation (LER) was measured under various currents and a value of 165 lm/Watt was recorded. (C)2015 Optical Society of America