Colour-enhanced light emitting diode light with high gamut area for retail lighting

2015 ◽  
Vol 49 (3) ◽  
pp. 329-342 ◽  
Author(s):  
XF Feng ◽  
W Xu ◽  
QY Han ◽  
SD Zhang
Keyword(s):  
Light Source ◽  
Light Emitting Diodes ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Broad Band ◽  
Area Index ◽  
Light Emitting ◽  
High Preference ◽  
Colour Rendering ◽  
Colour Appearance

Light emitting diodes with high colour quality were investigated to enhance colour appearance and improve observers' preference for the illuminated objects. The spectral power distributions of the light emitting diodes were optimised by changing the ratios of the narrow band red, green and blue light emitting diodes, and the phosphor-converted broad-band light emitting diode to get the desired colour rendering index and high gamut area index. The influence of the light emitting diode light on different coloured fabrics was investigated. The experimental results and the statistical analysis show that by optimising the red, green, blue components the light emitting diode light can affect the colour appearance of the illuminated fabrics positively and make the fabrics appear more vivid and saturated due to the high gamut area index. Observers indicate a high preference for the colours whose saturations are enhanced. The results reveal that the colour-enhanced light emitting diode light source can better highlight products and improve visual impression over the ceramic metal halide lamp and the phosphor-converted light emitting diode light source.

scholarly journals Influences of Spectral Power Distribution on Circadian Energy, Visual Comfort and Work Performance

2021 ◽  
Vol 13 (9) ◽  
pp. 4852
Author(s):  
Jack Ngarambe ◽  
Inhan Kim ◽  
Geun Young Yun
Keyword(s):  
Light Source ◽  
Power Distribution ◽  
Work Performance ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Essential Element ◽  
Visual Comfort ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Spectral Power Distribution

Spectral power distribution (SPD) is an essential element that has considerable implications on circadian energy and the perception of lit environments. The present study assessed the potential influences of SPD on energy consumption (i.e., considering circadian energy), visual comfort, work performance and mood. Two lighting conditions based on light-emitting diode (LED) and organic light-emitting diode (OLED) were used as proxies for SPDs of different spectral content: dominant peak wavelength of 455 nm (LED) and 618 nm (OLED). Using measured photometric values, the circadian light (CL), melatonin suppression (MS), and circadian efficacy (CE) of the two lighting sources were estimated via a circadian-phototransduction model and compared. Additionally, twenty-six participants were asked to evaluate the said lit environments subjectively in terms of visual comfort and self-reported work performance. Regarding circadian lighting and the associated energy implications, the LED light source induced higher biological actions with relatively less energy than the OLED light source. For visual comfort, OLED lighting-based conditions were preferred to LED lighting-based conditions, while the opposite was true when considering work performance and mood. The current study adds to the on-going debate regarding human-centric lighting, particularly considering the role of SPD in energy-efficient and circadian lighting practices.

scholarly journals Colour-Encoded Electroluminescent White Light-emitting Diode Enabled by Perovskite-Cu-In-S Quantum Composites

2021 ◽  
Author(s):  
Seung-Bum Cho ◽  
Jung Inn Sohn ◽  
Sang-Seok Lee ◽  
Seung-Gyun Moon ◽  
Bo Hou ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Light Source ◽  
White Light ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Large Area ◽  
Solution Processed ◽  
Light Emitting ◽  
Ambient Lighting ◽  
White Light Emitting Diodes

Solution-processed quantum dot (QD) white light-emitting diodes (WLEDs) have received much attention as a viable light source in the next-generation large-area ambient lighting, flexible photonics and full-colour display backlighting technologies....

Photocrystallography – design and methodology for the use of a light-emitting diode device

2010 ◽  
Vol 43 (2) ◽  
pp. 337-340 ◽  
Author(s):  
Simon K. Brayshaw ◽  
Jason W. Knight ◽  
Paul R. Raithby ◽  
Teresa L. Savarese ◽  
Stefanie Schiffers ◽  
...  
Keyword(s):  
Single Crystal ◽  
Light Source ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Experimental Methodology ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
X Ray ◽  
Led Array

With the increase in interest in photocrystallographic experiments, the use of light-emitting diodes (LEDs) provides an alternative, low-budget light source (by comparison to lasers) and allows photocrystallographic experiments to be carried out readily. Here the design of an LED array device suitable for use in single-crystal X-ray diffraction experiments is reported, and the experimental methodology used for determining the structures of metastable species is described.

Design and Investigation of H-Shaped Patch Antenna Integrated with Light Emitting Diodes

2015 ◽  
Vol 781 ◽  
pp. 106-109 ◽  
Author(s):  
S.N. Kamarudin ◽  
M.T. Ali ◽  
S. Subahir ◽  
A.A. Azlan ◽  
S. Muhamud-Kayat ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Light Source ◽  
Patch Antenna ◽  
Microstrip Antenna ◽  
Return Loss ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Integration Process ◽  
Light Emitting ◽  
Integrated Antenna

The limitations in the applications of microstrip antenna lead to wastage in the form of space and functionality. In order to overcome the wastage of space and functionality of the microstrip antenna, the new idea is to make one single device of microstrip antenna which has two application at the same time where it can operates as antenna and the function as lighting source is proposed. Light Emitting Diode (LED) has been chosen as the light source since the characteristic and the structure of the LED are suitable for the integration process. Hence, this paper presents an investigation on the characteristic of an H-shaped patch antenna integrated with Light Emitting Diodes (LEDs).The proposed integrated antenna has been designed and simulated by using Computer Simulation Technology (CST) Microwave Studio Software. It has been fabricated and measured to investigate the performance of the antenna in terms of return loss. The results confirms that the antenna can operate at 2.4 GHz and it works well as an illumination.

scholarly journals Embryonic development of fully biocompatible organic light-emitting diodes

2021 ◽  
Author(s):  
Bruno F.E. Matarese
Keyword(s):  
Light Source ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Device Structure ◽  
Light Emitting ◽  
Organic Light ◽  
Biological Environment

Prototype fully biocompatible organic light-emitting diodes are investigated, with a view to creating a suitable and high-performance light source as a medical implant device. A selection of organic LED materials that have potential suitability for the biological environment are examined. First, the biocompatibility of selected OLED materials was evaluated by the study of cell adhesion and cytotoxicity of HeLa cells cultured on the candidate materials. Thus it was possible to design a device structure composed entirely of biocompatible materials. Second, the characterization of the electroluminescence properties of the prototype OLED is shown and its limitation evaluated. Third, the aqueous stability of the fully biocompatible light source is examined. There is strong evidence that fully biocompatible and stable light-emitting implant devices can be easily constructed. This is the first time a fully biocompatible organic light-emitting diode, albeit embryonic, is reported, with the hope that it may lead to further research to optimize the device performance. Some suggestions on suitable device properties towards in vivo transition are provided.

Assessing glare, Part 4: Generic models predicting discomfort glare of light-emitting diodes

2017 ◽  
Vol 50 (5) ◽  
pp. 739-756 ◽  
Author(s):  
Y Yang ◽  
MR Luo ◽  
WJ Huang
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Human Vision ◽  
Appearance Model ◽  
Generic Model ◽  
Light Emitting ◽  
Generic Models ◽  
Discomfort Glare ◽  
Colour Appearance

Two generic models to predict the influence of the luminance uniformity and spectral power distribution of light-emitting diode luminaires on discomfort glare were developed. One model was an extension of the empirical Unified Glare Rating, the other was based on a colour appearance model for unrelated colours. A new experiment was carried out to verify the performance of the generic models. There were twelve glare sources, having three types of luminance uniformity and four spectral power distributions. The results showed both generic models outperformed Unified Glare Rating but gave similar performance to each other. The generic model based on the colour appearance model bridges the gap between glare perception and human vision theory.

Comparison of the effects of operating microscopes with light emitting diode and halogen light source on the eye: a rabbit study

2021 ◽  
pp. 1-7
Author(s):  
Bahri Aydın ◽  
Armagan Ozgur ◽  
Huseyin Baran Ozdemir ◽  
Pınar Uyar Gocun ◽  
Mehmet Arda Inan ◽  
...  
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Halogen Light ◽  
Halogen Light Source

Light source with light emitting diodes. Determination of limited frequencies and of the crest factor of illuminance meters and luminance meters

1989 ◽  
Vol 20 (5) ◽  
pp. 205-217
Author(s):  
J Deforges ◽  
P Garcia ◽  
J Bastie ◽  
F Marandet ◽  
J Bernard ◽  
...  
Keyword(s):  
Light Source ◽  
Light Emitting Diodes ◽  
Crest Factor ◽  
Light Emitting

Ab Initio Two-sites Occupancy and Broadband Near-Infrared Emission of Cr3+ in Li2MgZrO4

2021 ◽  
Author(s):  
Xue Zhou ◽  
Jinmeng Xiang ◽  
Jiming Zheng ◽  
Xiaoqi Zhao ◽  
Hao Suo ◽  
...  
Keyword(s):  
Plant Growth ◽  
Ab Initio ◽  
Light Source ◽  
Near Infrared ◽  
Broad Band ◽  
Infrared Emission ◽  
Night Vision ◽  
Light Emitting ◽  
Non Destructive ◽  
Near Infrared Emission

Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) light source have great potential in non-destructive detection, promoting plant growth and night vision applications, while the discovery of a broad-band NIR phosphor still...

scholarly journals Unravelling the electron injection/transport mechanism in organic light-emitting diodes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tsubasa Sasaki ◽  
Munehiro Hasegawa ◽  
Kaito Inagaki ◽  
Hirokazu Ito ◽  
Kazuma Suzuki ◽  
...  
Keyword(s):  
Work Function ◽  
Transport Mechanism ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Electron Injection ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Materials Used

AbstractAlthough significant progress has been made in the development of light-emitting materials for organic light-emitting diodes along with the elucidation of emission mechanisms, the electron injection/transport mechanism remains unclear, and the materials used for electron injection/transport have been basically unchanged for more than 20 years. Here, we unravelled the electron injection/transport mechanism by tuning the work function near the cathode to about 2.0 eV using a superbase. This extremely low-work function cathode allows direct electron injection into various materials, and it was found that organic materials can transport electrons independently of their molecular structure. On the basis of these findings, we have realised a simply structured blue organic light-emitting diode with an operational lifetime of more than 1,000,000 hours. Unravelling the electron injection/transport mechanism, as reported in this paper, not only greatly increases the choice of materials to be used for devices, but also allows simple device structures.

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