CQD-LEDs with High Colour Rendering Index

2020 ◽  
Author(s):  
Yuxian Yan ◽  
Doudou Zhang ◽  
Luqiao Yin ◽  
Jianhua Zhang
Keyword(s):  
Colour Rendering

Analysis of Characteristics of LED Lamps with T8 Bulb by Various Manufacturers

2019 ◽  
pp. 82-87
Author(s):  
Nina P. Nestyorkina ◽  
Olga Yu. Kovalenko ◽  
Yulia A. Zhuravlyova
Keyword(s):  
Supply Voltage ◽  
Luminous Flux ◽  
Supply Network ◽  
Operational Characteristics ◽  
Nominal Voltage ◽  
Electric Parameters ◽  
The Moment ◽  
Colour Rendering

The article analyses the operational characteristics of 10W LED lamps with T8 bulb manufactured by ASD (Russia), Smartbuy (Taiwan), and VOLPE (PRC) and 18W FL with T8 bulb manufactured by PHILIPS (Poland) including the dependence of these lamps on the supply voltage. The results of measurements show that: a) the period of stabilisation of electric parameters and luminous flux of LED lamps does not cause discomfort of illumination unlike the said FL, the luminous flux of which at the moment of switching on is 70 % of the nominal value, which is reached after 13 minutes; b) with nominal voltage of supply network, the value of luminous flux of 10W ASD LED-T8R-STD LED lamp (Russia) is 6 % less than the declared one, and that of Smartbuy SBL-T8-10-64K-A (Taiwan) and VOLPE LED-T8-10W/DW/G13/FR/FIX/N (PRC) is even less; c) the general colour rendering index of all studied LED lamps is less than the declared one (72 instead of 80); d) the flicker index of all studied LED lamps does not exceed the declared value of 5 %; e) the characteristics of LED lamps almost do not depend on changes of the supply voltage within the range of ±10 %. The recommendations regarding the application of the studied LED lamps are given.

scholarly journals Full-frame and high-contrast smart windows from halide-exchanged perovskites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
You Liu ◽  
Jungan Wang ◽  
Fangfang Wang ◽  
Zhengchun Cheng ◽  
Yinyu Fang ◽  
...  
Keyword(s):  
Contrast Ratio ◽  
High Contrast ◽  
Smart Window ◽  
Frame Size ◽  
Smart Windows ◽  
Ideal Solutions ◽  
Ion Gel ◽  
And Control ◽  
Colour Rendering ◽  
Perovskite Photovoltaic

AbstractWindow glazing plays an essential role to modulate indoor light and heat transmission, which is a prospect to save the energy cost in buildings. The latest photovoltachromic technology has been regarded as one of the most ideal solutions, however, to achieve full-frame size (100% active area) and high-contrast ratio (>30% variable in visible wavelength) for smart window applicability is still a challenge. Here we report a photovoltachromic device combining full-transparent perovskite photovoltaic and ion-gel based electrochromic components in a vertical tandem architecture without any intermediated electrode. Most importantly, by accurately adjusting the halide-exchanging period, this photovoltachromic module can realize a high pristine transmittance up to 76%. Moreover, it possesses excellent colour-rendering index to 96, wide contrast ratio (>30%) on average visible transmittance (400-780 nm), and a self-adaptable transmittance adjustment and control indoor brightness and temperature automatically depending on different solar irradiances.

scholarly journals Towards the Optimum Light Source Spectrum

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Andrew Chalmers ◽  
Snjezana Soltic
Keyword(s):  
Light Source ◽  
Large Scale ◽  
Source Spectrum ◽  
Light Sources ◽  
Luminous Efficacy ◽  
Light Emitting ◽  
Spectral Bands ◽  
Good Energy ◽  
Lighting Systems ◽  
Colour Rendering

This paper is concerned with designing light source spectra for optimum luminous efficacy and colour rendering. We demonstrate that it is possible to design light sources that can provide both good colour rendering and high luminous efficacy by combining the outputs of a number of narrowband spectral constituents. Also, the achievable results depend on the numbers and wavelengths of the different spectral bands utilized in the mixture. Practical realization of these concepts has been demonstrated in this pilot study which combines a number of simulations with tests using real LEDs (light emitting diodes). Such sources are capable of providing highly efficient lighting systems with good energy conservation potential. Further research is underway to investigate the practicalities of our proposals in relation to large-scale light source production.

Research Note: LED chip-on-board packaging technology for strict colour tolerance

2017 ◽  
Vol 49 (8) ◽  
pp. 1052-1057
Author(s):  
J Zhang ◽  
P Ge ◽  
Z Zhou ◽  
D Liu ◽  
H Wang ◽  
...  
Keyword(s):  
Research Note ◽  
Luminous Efficacy ◽  
Packaging Technology ◽  
Colour Temperature ◽  
Colour Rendering ◽  
Method Show

In the field of LED packaging, people usually pay more attention to colour temperature, luminous efficacy and colour rendering than colour tolerance. This paper focuses on how to meet strict colour tolerances in the process of chip-on-board packaging. The McAdam ellipses are used to explain the meaning of colour tolerance. A method based on adjusting the amount of phosphor glue and the proportions of different phosphors it contains is described. Measurements on samples packaged according to this method show that it makes it possible to meet strict colour tolerance requirements.

A Monolithic White-Light LED Based on GaN Doped with Be

2014 ◽  
Vol 93 ◽  
pp. 264-269 ◽  
Author(s):  
Henryk Teisseyre ◽  
Michal Bockowski ◽  
Toby David Young ◽  
Szymon Grzanka ◽  
Yaroslav Zhydachevskii ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
White Light ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Yellow Emission ◽  
Bulk Crystals ◽  
Light Emitting ◽  
Type Conductivity ◽  
P Type ◽  
Colour Rendering

In this communication, the use of gallium nitride doped with beryllium as an efficient converter for white light emitting diode is proposed. Until now beryllium in this material was mostly studied as a potential p-type dopant. Unfortunately, the realization of p-type conductivity in such a way seems impossible. However, due to a very intensive yellow emission, bulk crystals doped with beryllium can be used as light converters. In this communication, it is demonstrated that realisation of such diode is possible and realisation of a colour rendering index is close to that necessary for white light emission.

VISUAL EFFECTS OF OBJECTS UNDER METAMERISM WITH MULTI-SPECTRAL LIGHT SOURCE

2021 ◽  
Author(s):  
Y.M. Li ◽  
H. Fan ◽  
C.H. Lin ◽  
J.U. Chong ◽  
T.X. Lee
Keyword(s):  
Light Source ◽  
Positive Relationship ◽  
Target Object ◽  
Visual Effects ◽  
Colour Temperature ◽  
Lighting Conditions ◽  
The Future ◽  
Convenience Sampling ◽  
Colour Rendering

This study attempts to simulate the metamerism colour, and the guava was used as the target object. We design four sets of metamers with a correlated colour temperature of 4000K and an illuminance of 750lux. The light source was simulated in the LED cube. The subjects with convenience sampling observed the visual effects, including look delicious, colourful, and colour rendering of guava under metamerism, then analysed its relationship with CRI and CQS. The results showed that colour rendering and visual effects are not a positive relationship, and the effect of CQS is closer to the visual effects of the subjects. The results of this study can be used as a reference for light source lighting designers as a basis for improving lighting conditions. In the future, we can collect databases for the different objects with an optimized multi-spectral light source.

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