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.

Study on the Highway Tunnel Lighting with Spectrum Superposition

2012 ◽  
Vol 512-515 ◽  
pp. 2713-2717
Author(s):  
Yong Yang ◽  
Wen Yuan Han ◽  
Lei Wang
Keyword(s):  
Luminous Efficiency ◽  
Light Sources ◽  
White Led ◽  
Peak Wavelength ◽  
Mesopic Vision ◽  
Photopic Vision ◽  
Highway Tunnel ◽  
Vision Condition ◽  
The Difference

The lighting level of highway tunnel is usually under mesopic vision condition, but the traditional luminance and illuminance test are corrected by photopic vision spectral luminous efficiency. According to the difference of spectral luminous efficiency between photopic and mesopic, the lighting with different peak wavelength would provide various ratios of radiation / photometric flux. Four kinds of narrowband light sources with the same tested flux were stacked up in white LED and HPS respectively, through equivalent brightness calculation, the most efficient spectral wavelength were obtained under mesopic condition.

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.

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.

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.

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.

Evaluation Index Study of Students’ Physiological Rhythm Effects under Fluorescent Lamp and LED

2012 ◽  
Vol 433-440 ◽  
pp. 4757-4764 ◽  
Author(s):  
Yong Hong Yan ◽  
Tang G. Lee ◽  
Yang Guan ◽  
Xiang De Liu
Keyword(s):  
Luminance Level ◽  
Evaluation Index ◽  
Light Sources ◽  
Fluorescent Lamp ◽  
Colour Temperature ◽  
Learning Efficiency ◽  
Fluorescent Lamps ◽  
Comprehensive Index ◽  
Index Study ◽  
Typical Colour

The influence of artificial classroom light source’s colour temperature to students’ learning efficiency and physiology rhythm is the focus of this study. An experiment compares a subjects’ learning efficiency, asthenopia and brain fag under different luminance level of three typical colour temperatures from T5 fluorescent lamps and LED. Using comprehensive index ε and norm identification Ψ for quantitative evaluation and testing under different lighting environments, we determined the best colour temperature of two experimental light sources. We also determined the best combinations of illuminance value and the colour temperature that should be avoided in classroom lighting. Experiment shows that spectrum difference obviously effects comprehensive index ε and norm identification Ψ. For learning efficiency and health of people, there need to be improvement in the spectrum of fluorescent lamps and LEDs

scholarly journals Application of Virtual Display Technology of LCD Backlight Spectrum Optimization Algorithm Based on Linear Programming

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yuan Cui ◽  
Zhuyang Chen ◽  
Cheng Huang ◽  
Qian Gao
Keyword(s):  
Linear Programming ◽  
Optimization Algorithm ◽  
Programming Model ◽  
Research Process ◽  
Luminous Efficiency ◽  
Light Sources ◽  
Theoretical Maximum ◽  
Display Technology ◽  
Spectrum Optimization ◽  
Light Efficiency

In order to make the color of image display more realistic, optimize the use of energy, and improve the light efficiency of the module through reasonable spectral distribution, this paper proposes a backlight spectral optimization algorithm based on linear programming. With the goal of maximizing the backlight luminous efficiency, the theoretical maximum of the luminous efficiency of the backlight spectrum can be achieved by constructing a linear programming model. The research process is to obtain the optimal distribution of transmittance spectrum by linear programming method on the premise of ensuring the color gamut standard of display system. The results show that the light efficiency can be increased to 335.5 lm/W, while the original light efficiency of the system is less than 150 lm/W. With the goal of maximizing the light efficiency, light sources with narrow bandwidths such as lasers and quantum dot materials can be used to simulate and reconstruct these characteristic wavelengths. There will be easier to approach the ideal optimization spectrum and achieve the theoretical maximum luminous efficiency of 610.8 lm/W.

Sign in / Sign up

Export Citation Format

Share Document