Discomfort Glare Caused by R/G/B/W Four-Color Light Emitting Diode Sources

2019 ◽  
Vol 56 (13) ◽  
pp. 132301
Author(s):  
田会娟 Huijuan Tian ◽  
郝甜甜 Tiantian Hao ◽  
关涛 Tao Guan ◽  
胡阳 Yang Hu ◽  
蔡敏鹏 Minpeng Cai ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Light Emitting ◽  
Discomfort Glare

The effectiveness of light-emitting diode lighting for providing circadian stimulus in office spaces while minimizing energy use

2019 ◽  
Vol 52 (2) ◽  
pp. 167-188 ◽  
Author(s):  
C Jarboe ◽  
J Snyder ◽  
MG Figueiro
Keyword(s):  
Energy Use ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Visual Performance ◽  
Luminous Intensity ◽  
Light Emitting ◽  
Lighting Conditions ◽  
Office Space ◽  
Discomfort Glare ◽  
Architectural Lighting

Architectural lighting has traditionally addressed visual performance and horizontal illuminance on the work plane, later focussing on energy efficiency, while only recently paying particular regard to human health outcomes. The present study evaluated the effectiveness of several light-emitting diode lighting strategies for delivering circadian stimulus to occupants of a typical office space while minimizing energy use. The study employed photometric simulations in a typical open-office space, delivering a criterion circadian stimulus of 0.3 to calculation points modelled at the simulated occupants’ eye level. Six luminaire types, two luminous intensity distributions, six spectral power distributions and two horizontal illuminances were evaluated, resulting in 144 unique lighting conditions. Additionally, the study calculated the discomfort glare for selected luminaires with the highest total lumen output, smallest aperture and direct-only luminous intensity distributions at the higher of the two horizontal illuminances (500 lx). The most impactful strategy involved supplementing common overhead lighting with a desktop luminaire delivering light directly to the simulated office occupants’ eyes, which provided greater circadian stimulus and used less energy than overhead luminaires that were capable of delivering the criterion circadian stimulus of 0.3.

Discomfort glare caused by white LEDs having different spectral power distributions

2017 ◽  
Vol 50 (6) ◽  
pp. 921-936 ◽  
Author(s):  
WJ Huang ◽  
Y Yang ◽  
M Ronnier Luo
Keyword(s):  
White Light ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
White Leds ◽  
Significant Difference ◽  
Discomfort Glare ◽  
Led Lights ◽  
Green Leds

This paper describes an experiment to investigate discomfort glare caused by white light-emitting diode (LED) lights having different spectral power distributions. It included two groups: a ‘Metamerism’ group and a ‘correlated colour temperatures (CCT)’ group. In the former group, it was found that white lights at 7000 K constructed from different blue LEDs and the same red and green LEDs gave about the same glare perception. In the latter group, there was a significant difference in glare perception between white lights having different CCTs. Finally, glare models, including unified glare rating (UGR) and the newly derived QUGRspd, and mUGRspd models, were tested using the data from the experiment. All of them gave quite accurate predictions of the data.

Response to White Light Emitting Diode Aviation Signal Lights Varying in Correlated Color Temperature

2019 ◽  
Vol 2673 (3) ◽  
pp. 667-675 ◽  
Author(s):  
John D. Bullough ◽  
Yi-wei Liu
Keyword(s):  
Light Emitting Diode ◽  
Color Temperature ◽  
Light Sources ◽  
White Led ◽  
Low Light ◽  
Light Emitting ◽  
Light Levels ◽  
Relative Brightness ◽  
Discomfort Glare ◽  
Source Spectra

Airfield lighting for runways and taxiways is currently undergoing a transition from filament-based incandescent sources to light emitting diodes (LEDs). Although models to assess the relative brightness, discomfort glare, and peripheral detectability of signal lights such as those used for aviation exist, their applicability to white LED airfield lighting has not been verified independently. A series of three experiments was conducted to compare white LED sources, having correlated color temperatures of 2,700 K and 5,900 K, in terms of their relative brightness, discomfort glare, and peripheral detectability. The perceived brightness and discomfort glare from the light sources closely matched predictions from the published models, demonstrating the usefulness of these models at characterizing these responses in airfield lighting. In the case of peripheral detectability, there was little to no difference in how quickly the two LEDs were perceived at low light levels, suggesting that there is no need to consider spectral differences between light source spectra for this response when the intensities are similar to those used in the present study.

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.

Synchronization of Chaotic Quantum Dot Light Emitting Diodes under Optical Feedback Effect

2020 ◽  
pp. 144-148
Keyword(s):  
Quantum Dot ◽  
Delay Time ◽  
Chaos Synchronization ◽  
Optical Feedback ◽  
Light Emitting Diode ◽  
Feedback Effect ◽  
Complete Synchronization ◽  
Light Emitting ◽  
Coupling Methods ◽  
Coupling Parameters

Chaos synchronization of delayed quantum dot light emitting diode has been studied theortetically which are coupled via the unidirectional and bidirectional. at synchronization of chaotic, The dynamics is identical with delayed optical feedback for those coupling methods. Depending on the coupling parameters and delay time the system exhibits complete synchronization, . Under proper conditions, the receiver quantum dot light emitting diode can be satisfactorily synchronized with the transmitter quantum dot light emitting diode due to the optical feedback effect.

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