A new rationale for setting light source luminous efficacy requirements

2016 ◽  
Vol 50 (3) ◽  
pp. 340-359 ◽  
Author(s):  
MS Rea ◽  
A Bierman
Keyword(s):  
Spectral Sensitivity ◽  
Ad Hoc ◽  
Light Output ◽  
Luminous Efficiency ◽  
Light Sources ◽  
Human Retina ◽  
Efficiency Function ◽  
Luminous Efficacy ◽  
Long Wavelength ◽  
Short Wavelength Light

The photopic luminous efficiency function (V(λ)) is used internationally for the definition of light output from electric light sources (lumens) and thereby for regulating minimum luminous efficacy requirements (lumens per watt) for the manufacture and sale of light sources. V(λ) has, however, a long-wavelength spectral bias with respect to the overall spectral sensitivity of the human retina. When used in luminous efficacy regulations, the long-wavelength spectral bias of V(λ) effectively penalizes many of the benefits expected from lighting that can be provided by short-wavelength light (e.g. scene brightness, colour rendering, circadian regulation and off-axis detection). Regulators must use ad hoc reductions to luminous efficacy requirements for ‘cool’ light sources to ensure that lighting benefits can be provided to society. These reductions would be unnecessary if a luminous efficiency function representing the overall spectral sensitivity of the human retina were used instead of V(λ) in luminous efficacy regulations. The universal luminous efficiency function (U(λ)) is proposed as a replacement. Utilization of U(λ) would obviate ad hoc adjustments to regulations for ‘cool’ light sources, minimize wasted electric power imposed by regulations based upon V(λ), and perhaps most importantly, encourage manufacturers to produce light sources that efficiently provide multiple benefits to users.

Road Luminaire’ Mesoptic Luminous Efficiency Analysis

2011 ◽  
Vol 71-78 ◽  
pp. 4918-4922
Author(s):  
Ke Huang ◽  
Ji Weng ◽  
Ying Kui Hu
Keyword(s):  
Luminance Level ◽  
Efficiency Analysis ◽  
Luminous Efficiency ◽  
Light Sources ◽  
Efficiency Function ◽  
Photopic Vision

Four kinds of traffic lighting sources HPS, MH, LED and EDL are widely used in roads and tunnels, the luminance at this place almost in the range of 1-10 cd/m2, which is the mesoptic vision. The mesoptic luminous efficiency can be calculated from photopic vision spectral luminous efficiency function. The results indicate that HPS’s luminous efficiency increased with improve of adaptation brightness, while the rest three kinds of light sources’ luminous efficiency reduced. At the same luminance level, HPS, MH, LED and EDL’s mesoptic luminous efficiency reduced in turn.

Properties of Light Sources under Mesopic Vision

2011 ◽  
Vol 308-310 ◽  
pp. 228-231
Author(s):  
Yong Yang ◽  
Lei Wang ◽  
Wei Li
Keyword(s):  
Visual Perception ◽  
Luminous Efficiency ◽  
Light Sources ◽  
Human Visual Perception ◽  
Efficiency Function ◽  
White Leds ◽  
Mesopic Vision ◽  
Vision Condition ◽  
Background Brightness

The mesopic vision theory is used to study illumination properties of series of light sources, through the test of luminous spectrum and derivation based on the MOVE model, the results show that spectral luminous efficiency function Vmes(λ) is between traditional V(λ) and V′(λ) when the background brightness under mesopic vision condition, and the function of Vmes(λ) is changed with the different of light sources and background brightness. Based on human visual perception, the mesopic vision equivalent brightness can be calculated, which of HPS is lower than test brightness corrected by V(λ), but white LEDs and FL show opposite phenomena, and the different value between mesopic and photopic brightness presents reduce trend with rising of background brightness.

Equivalent Brightness Fitting Calculation Method about White LEDs

2011 ◽  
Vol 121-126 ◽  
pp. 2721-2725
Author(s):  
Yong Yang ◽  
Lei Wang ◽  
Chuan Zheng Zhu
Keyword(s):  
Relative Strength ◽  
Luminous Efficiency ◽  
Color Temperature ◽  
Light Sources ◽  
White Led ◽  
Excellent Correlation ◽  
Efficiency Function ◽  
White Leds ◽  
Mesopic Vision ◽  
Brightness Curve

White LEDs can show different correlated color temperature (abbreviated as CCT) by adjusting the luminous spectrum peak distribution and relative strength. Recent research results indicate that spectral luminous efficiency function of mesopic vision Vmes(λ) and equivalent brightness are associated with luminous spectra of light sources. A series of white LEDs with different CCT are tested and calculated, it shows white LED with higher CCT has higher mesopic vision equivalent brightness, although the brightness are identical when the tester corrected by traditional photopic vision spectral luminous efficiency V(λ). From the equivalent brightness curve fitting, the curve can be described as a polynomial function, for it excellent correlation, the more value of equivalent brightness could be calculated without complex derivation.

Green Innovation Design Based on TRIZ Theory

2011 ◽  
Vol 308-310 ◽  
pp. 373-379 ◽  
Author(s):  
Zhi Feng Liu ◽  
Yang Gao ◽  
Lei Zhang ◽  
Di Hu
Keyword(s):  
Visual Perception ◽  
Luminous Efficiency ◽  
Light Sources ◽  
Green Innovation ◽  
Human Visual Perception ◽  
Efficiency Function ◽  
White Leds ◽  
Mesopic Vision ◽  
Vision Condition ◽  
Background Brightness

The mesopic vision theory is used to study illumination properties of series of light sources, through the test of luminous spectrum and derivation based on the MOVE model, the results show that spectral luminous efficiency function Vmes(λ) is between traditional V(λ) and V′(λ) when the background brightness under mesopic vision condition, and the function of Vmes(λ) is changed with the different of light sources and background brightness. Based on human visual perception, the mesopic vision equivalent brightness can be calculated, which of HPS is lower than test brightness corrected by V(λ), but white LEDs and FL show opposite phenomena, and the different value between mesopic and photopic brightness presents reduce trend with rising of background brightness.

scholarly journals Photocatalytic techniques to prevent and combat healthcare associated infections

2019 ◽  
Vol 111 ◽  
pp. 04046
Author(s):  
Răzvan Bucureşteanu ◽  
Roxana Apetrei ◽  
Monica Ioniţă ◽  
Ludmila-Otilia Cinteză ◽  
Lia-Mara Diţu ◽  
...  
Keyword(s):  
Light Output ◽  
Antimicrobial Effect ◽  
Light Sources ◽  
Healthcare Associated Infections ◽  
Excitation Light ◽  
Disinfection Process ◽  
Type Semiconductor ◽  
Healthcare Associated ◽  
Areas Of Interest ◽  
Air Circulation

An ever-increasing rate of morbidity and mortality caused by healthcare associated infections is reported annually. Air circulation mediates contact with microbial contaminated aerosols and represents a major risk of transmitting healthcare associated infections. We propose a revolutionary technique for the protection of interior surfaces based on a photocatalytic composition with doped TiO2 or ZnO type semiconductor metal oxides which exert antimicrobial effect. In principle, there is an activation of the photocatalytic coating with light from the normal lighting apparatus, which may incorporate one or more sources of photocatalytic excitation light. By studying the air circulation in the hospital, it is possible to design light fixtures with specific design of light distribution, in order to perform the disinfection of the air and surfaces and to amplify the antimicrobial effect. The disinfection process does not affect patients or healthcare professionals, it can be done in their presence and has a continuous, controllable effect. Photocatalytic paint in combination with a prototype luminaire with a precise spectrum light sources, light output and a light intensity distribution curve relative to the shape and dimensions of the rooms, shows that the proposed method may represent a successful alternative to classical methods of disinfection in hospitals. This technique can also be used in other areas of interest.

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.

Manufacture and Evaluation of Light Emitting Diode Package Substrate Using Flexible Printed Circuit Board

2015 ◽  
Vol 15 (10) ◽  
pp. 7578-7581
Author(s):  
Jung-Kab Park ◽  
Jin-Ha Shin ◽  
Mun-Gi Jung ◽  
Tomabechi Shigehisa ◽  
Hwa-Sun Park ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Light Emitting Diode ◽  
Thermal Conductance ◽  
Polyimide Film ◽  
Luminous Efficiency ◽  
Circuit Board ◽  
Light Sources ◽  
Thermal Shock Test ◽  
Light Emitting ◽  
Au Electrode

Unlike other light sources such as fluorescent lamps and incandescent bulbs, light-emitting diodes (LED) convert 70∼80% of energy into heat. If the heat produced an LED chip is not effectively released, its luminous efficiency and lifespan are reduced. Therefore, as a method effectively release heat, an LED PKG substrate containing a heat-releasing material with excellent thermal conductance was fabricated, and its thermal resistance and luminous efficiency were analyzed. In this experiment, a thin polyimide film with excellent ductility was used to fabricate the LED PKG substrate. A 35-μm-thick Cu foil with excellent thermal conductance was subjected to high temperature and pressure and attached to both sides of the polyimide film. By electroplating Ag or Au, which has excellent thermal conductance, for us as the electrode and heat-releasing material, LED PKG substrate was fabricated with a thickness of approximately 170 μm. (−40 °C → RT → 120 °C). The results revealed that the LED PKG substrate having a Ag electrode with excellent thermal conductance had an excellent thermal resistance of approximately 4.2 °C/W (Au electrode: 5.6 °C/W). The luminous flux after 100 cycles in the thermal shock test was reduced by approximately 0.09% (Au electrode: 2.77%), indicating that the LED PKG substrate had excellent thermal resistance without any mechanical and material defects in a rapid-temperature-changing environment. The advantages and excellent thermal resistance can be exploited in cellular phones and LCD panels, and heat-releasing problems in thin panels be solved.

scholarly journals Luminous Efficacy of LED White Light Sources

2016 ◽  
Vol 16 (06) ◽  
pp. 64-74
Author(s):  
V Pavlov ◽  
V Pyasetskiy ◽  
A Horohorov ◽  
A Shirankov
Keyword(s):  
White Light ◽  
Light Sources ◽  
Luminous Efficacy

ENERGY EFFICIENT LIGHTING OF PUBLIC PREMISES

2021 ◽  
pp. 54-56
Author(s):  
E. A. Kuznetsov ◽  
N. P. Nesterkina ◽  
Yu. A. Zhuravleva ◽  
S. A. Mikaeva
Keyword(s):  
Educational Institution ◽  
Light Output ◽  
Light Flux ◽  
High Energy ◽  
Educational Institutions ◽  
Energy Costs ◽  
Light Sources ◽  
Fluorescent Lamps ◽  
High Level ◽  
Incandescent Lamps

The article provides a technical and economic comparison of costs when covering 10 classrooms of a general educational institution with LED and fluorescent lamps for a period of 10 years. The main advantage of led light sources is the high level of light output compared to traditional light sources. Replacing incandescent lamps and gas-discharge ICS with led ICS can significantly reduce energy costs. Currently, led ICS are increasingly replacing traditional ICS due to their high energy efficiency and safety. For comparison, luminescent lamps LVO04-4x14-031 and LED lamps DVO12-45-003 produced by JSC “Ardatovsky lighting plant” with a comparable light flux and light distribution were selected. The number of lamps in the 65 m2 auditorium was chosen based on the normalized illumination of 500 Lux on a horizontal work surface (0.8 m). The calculation of the number of lamps that meet all the requirements for lighting in General and higher educational institutions was carried out in the DiaLux 4.13 program. According to preliminary calculations, lighting with led lamps will reduce energy costs over 10 years by 2.16 times compared to fluorescent lamps. The maximum expenses are spent on the purchase of new led lamps. This is mainly due to the higher price of led lighting devices compared to fluorescent ones.

scholarly journals Circadian Potency Spectrum with Extended Exposure to Polychromatic White LED Light under Workplace Conditions

2020 ◽  
Vol 35 (4) ◽  
pp. 405-415 ◽  
Author(s):  
Martin Moore-Ede ◽  
Anneke Heitmann ◽  
Rainer Guttkuhn
Keyword(s):  
Spectral Sensitivity ◽  
White Light ◽  
Light Exposure ◽  
Human Subjects ◽  
Light Sources ◽  
Led Light ◽  
Light Spectra ◽  
Timing System ◽  
Circadian Timing System ◽  
Spectral Sensitivity Curve

Electric light has enabled humans to conquer the night, but light exposure at night can disrupt the circadian timing system and is associated with a diverse range of health disorders. To provide adequate lighting for visual tasks without disrupting the human circadian timing system, a precise definition of circadian spectral sensitivity is required. Prior attempts to define the circadian spectral sensitivity curve have used short (≤90-min) monochromatic light exposures in dark-adapted human subjects or in vitro dark-adapted isolated retina or melanopsin. Several lines of evidence suggest that these dark-adapted circadian spectral sensitivity curves, in addition to 430- to 499-nm (blue) wavelength sensitivity, may include transient 400- to 429-nm (violet) and 500- to 560-nm (green) components mediated by cone- and rod-originated extrinsic inputs to intrinsically photosensitive retinal ganglion cells (ipRGCs), which decay over the first 2 h of extended light exposure. To test the hypothesis that the human circadian spectral sensitivity in light-adapted conditions may have a narrower, predominantly blue, sensitivity, we used 12-h continuous exposures of light-adapted healthy human subjects to 6 polychromatic white light-emitting diode (LED) light sources with diverse spectral power distributions at recommended workplace levels of illumination (540 lux) to determine their effect on the area under curve of the overnight (2000–0800 h) salivary melatonin. We derived a narrow steady-state human Circadian Potency spectral sensitivity curve with a peak at 477 nm and a full-width half-maximum of 438 to 493 nm. This light-adapted Circadian Potency spectral sensitivity permits the development of spectrally engineered LED light sources to minimize circadian disruption and address the health risks of light exposure at night in our 24/7 society, by alternating between daytime circadian stimulatory white light spectra and nocturnal circadian protective white light spectra.

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