scholarly journals New paradigm of multi-chip white LEDs: combination of an InGaN blue LED and full down-converted phosphor-converted LEDs

2011 ◽  
Vol 19 (S3) ◽  
pp. A270 ◽  
Author(s):  
Ji Hye Oh ◽  
Jeong Rok Oh ◽  
Hoo Keun Park ◽  
Yeon-Goog Sung ◽  
Young Rag Do
Keyword(s):  
Blue Led ◽  
2012 ◽  
Vol 717-720 ◽  
pp. 87-92
Author(s):  
Mikael Syväjärvi ◽  
Rositza Yakimova ◽  
Motoaki Iwaya ◽  
Tetsuya Takeuchi ◽  
Isamu Akasaki ◽  
...  

The LED technology started to developed many years ago with red light emitting diodes. To achieve the blue LED, novel growth technologies and process steps were explored, and made it possible to demonstrate efficient blue LED performance from nitrides. The efficiency was further developed and blue LEDs were commercially introduced in the 1990’s. The white LED became possible by the use of the blue LED and a phosphor that converts a part of the blue light to other colors in the visible range to combine into white light. However, even today there are limitations in the phosphor-based white LED technology, in particular for general lighting, and new solutions should be explored to speed the pace when white LEDs will be able to make substantial energy savings. In this paper we overview gallium nitride materials evolution and growth concepts for LEDs. We describe the fluorescent silicon carbide material prepared by a novel growth technology for a new type of white LED in general lighting with pure white light. This paper introduces an interesting research in fundamental growth and optical properties of light emitting silicon carbide.


RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4448-4453 ◽  
Author(s):  
Panlai Li ◽  
Zhijun Wang ◽  
Qinglin Guo ◽  
Zhiping Yang

Warm white LEDs were fabricated by combining a 432 nm blue LED with a single-phase white emitting phosphor Ca4Y6O(SiO4)6:Eu2+, Mn2+.


2010 ◽  
Vol 43 (39) ◽  
pp. 395103 ◽  
Author(s):  
Vengala Rao Bandi ◽  
M Jayasimhadri ◽  
Junho jeong ◽  
Kiwan Jang ◽  
Ho Sueb Lee ◽  
...  
Keyword(s):  
Blue Led ◽  

2016 ◽  
Vol 4 (42) ◽  
pp. 9968-9975 ◽  
Author(s):  
Xiao-Jun Wang ◽  
Shiro Funahashi ◽  
Takashi Takeda ◽  
Takayuki Suehiro ◽  
Naoto Hirosaki ◽  
...  

A novel orange-yellow-emitting Ca1.62Eu0.38Si5O3N6 phosphor was discovered by a single-particle-diagnosis approach for UV, or blue LED driven white-LEDs.


Nanophotonics ◽  
2013 ◽  
Vol 2 (1) ◽  
pp. 57-81 ◽  
Author(s):  
Talha Erdem ◽  
Hilmi Volkan Demir

AbstractColloidal nanocrystals of semiconductor quantum dots (QDs) are gaining prominence among the optoelectronic materials in the photonics industry. Among their many applications, their use in artificial lighting and displays has attracted special attention thanks to their high efficiency and narrow emission band, enabling spectral purity and fine tunability. By employing QDs in color-conversion LEDs, it is possible to simultaneously accomplish successful color rendition of the illuminated objects together with a good spectral overlap between the emission spectrum of the device and the sensitivity of the human eye, in addition to a warm white color, in contrast to other conventional sources such as incandescent and fluorescent lamps, and phosphor-based LEDs, which cannot achieve all of these properties at the same time. In this review, we summarize the color science of QDs for lighting and displays, and present the recent developments in QD-integrated LEDs and display research. First, we start with a general introduction to color science, photometry, and radiometry. After presenting an overview of QDs, we continue with the spectral designs of QD-integrated white LEDs that have led to efficient lighting for indoor and outdoor applications. Subsequently, we discuss QD color-conversion LEDs and displays as proof-of-concept applications – a new paradigm in artificial lighting and displays. Finally, we conclude with a summary of research opportunities and challenges along with a future outlook.


2012 ◽  
Vol 512 (1) ◽  
pp. 264-269 ◽  
Author(s):  
Vengala Rao Bandi ◽  
Bhaskar Kumar Grandhe ◽  
Kiwan Jang ◽  
Ho-Sueb Lee ◽  
Dong-Soo Shin ◽  
...  

2021 ◽  
Vol 50 (8) ◽  
pp. 3044-3059
Author(s):  
Malini Abraham ◽  
Arup K. Kunti ◽  
Thejas K.K. ◽  
Nuño Amador-Mendez ◽  
Noëlle Gogneau ◽  
...  

The bright red emitting (Li, Mg)3RbGe8O18:Mn4+ nanophosphors significantly enhanced the colour rendering of a white-LED based on blue-LED chip and YAG:Ce3+ phosphor.


2004 ◽  
Vol 449-452 ◽  
pp. 953-956
Author(s):  
J.K. Park ◽  
Chang Hoi Kim ◽  
Kyung Joo Choi ◽  
H.D. Park ◽  
Se Young Choi

We have synthesized a Eu2+-activated Sr2SiO4yellow phosphor and investigated an attempt to develop white LEDs by combining it with a GaN blue LED chip. Two distinct emission bands from the GaN-based LED and the Sr2SiO4:Eu phosphor are clearly observed at 400 nm and at around 550 nm, respectively. These two emission bands combine to give a spectrum that appears white to the naked eye. Our results show that GaN (400 nm chip)-based Sr2SiO4:Eu exhibits a better luminous efficiency than that of the industrially available product InGaN (460 nm chip)-based YAG:Ce.


2020 ◽  
Vol 28 (2) ◽  
pp. 29-34
Author(s):  
Bożena Matysiak

AbstractThe impact of light quality generated by light-emitting diodes (LEDs) on the adventitious root formation and cuttings’ quality of rose hip ‘Konstancin’ under controlled conditions in multilevel growth chamber without access to natural light and in the greenhouse was evaluated. In the growth chamber, the lighting was provided by a combination of red and blue LED arrays and white LED tubes, while in the greenhouse, red and blue LED lights were used as a supplement to natural light. The number of rooted cuttings under both growth conditions was not affected by the light conditions generated by LEDs. However, light quality showed significant effects on the biomass production and development of adventitious roots, with the most stimulating red light generated by LEDs. In the growth chamber, the root biomass of the cuttings illuminated with white LEDs supplemented with red LEDs was on average 2.2 times higher than of the cuttings illuminated with white LEDs only. A similar reaction was noted under greenhouse conditions. Supplementation of natural light with red LEDs resulted in 1.7 times increase of the fresh biomass of roots. Both in the growth chamber and in the greenhouse, illumination with red LEDs promoted axillary bud outgrowth. LED lamps can be used in the production of high-quality rose cuttings, both in greenhouses as a complement to natural light and in multilevel rooms as a sole-source lighting for plants.


2015 ◽  
Vol 3 (28) ◽  
pp. 7356-7362 ◽  
Author(s):  
Naoyuki Komuro ◽  
Masayoshi Mikami ◽  
Paul J. Saines ◽  
Katsuhiro Akimoto ◽  
Anthony K. Cheetham

The deep red phosphor Sr4(PO4)2O:Eu2+, which has an excitation peak around 450 nm for blue LED applications, is reported.


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