A simple design of uniform LED illumination using catadioptric collimator and freeform lenslet array

2021 ◽  
pp. 147715352110524
Author(s):  
DT Vu ◽  
H Vu ◽  
S Shin ◽  
NM Kieu ◽  
TQ Tien ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Light Emitting Diode ◽  
Optical Path Length ◽  
Light Emitting ◽  
Simple Strategy ◽  
Area Of Interest ◽  
Lenslet Array ◽  
Freeform Optics ◽  
Receiver Plane ◽  
Indoor Lighting

We introduce a compact lenslet array principle that takes advantage of freeform optics to deploy a light distributor, beneficial for highly efficient, inexpensive, low energy consumption light-emitting diode (LED) lighting system. We outline here a simple strategy for designing the freeform lens that makes use of an array of the identical plano-convex lenslet. The light is redistributed from such lenslet, hinging on the principle of optical path length conservation, and then delivered to the receiver plane. The superimposing of such illumination area from every lenslet occurs on the receiver plane, in which the non-uniform illumination area located in the boundary should have the same dimension as the size of the freeform lenslet array. Such an area, insofar, is negligible due to their small size, which is the crux of our design, representing a large departure from the former implementations. Based on simulations that assess light performance, the proposed design exhibited the compatibility for multiple radiation geometries and off-axis lighting without concern for the initial radiation pattern of the source. As simulated, the LED light source integrated with such proposed freeform lenslet array revealed high luminous efficiency and uniformity within the illumination area of interest were above 70% and 85%, respectively. Such novel design was then experimentally demonstrated to possess a uniformity of 75% at hand, which was close to the simulation results. Also, proposed indoor lighting was implemented in comparison with the commercial LED downlight and LED panel, whereby the energy consumption, number of luminaires and illumination performance were assessed to show the advantage of our simplified model.

scholarly journals Comparative Study of Four TiO2-Based Photocatalysts to Degrade 2,4-D in a Semi-Passive System

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 621 ◽  
Author(s):  
Gisoo Heydari ◽  
Jordan Hollman ◽  
Gopal Achari ◽  
Cooper Langford
Keyword(s):  
Energy Consumption ◽  
Degradation Rate ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Dichlorophenoxyacetic Acid ◽  
Light Emitting ◽  
Glass Spheres ◽  
Degradation Rate Constant ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Mode Energy

In this study, the relative efficiency of four forms of supported titanium dioxide (TiO2) as a photocatalyst to degrade 2,4-dichlorophenoxyacetic acid (2,4-D) in Killex®, a commercially available herbicide was studied. Coated glass spheres, anodized plate, anodized mesh, and electro-photocatalysis using the anodized mesh were evaluated under an ultraviolet – light-emitting diode (UV-LED) light source at λ = 365 nm in a semi-passive mode. Energy consumption of the system was used to compare the efficiency of the photocatalysts. The results showed both photospheres and mesh consumed approximately 80 J/cm3 energy followed by electro-photocatalysis (112.2 J/cm3), and the anodized plate (114.5 J/cm3). Although electro-photocatalysis showed the fastest degradation rate (K = 5.04 mg L−1 h−1), its energy consumption was at the same level as the anodized plate with a lower degradation rate constant of 3.07 mg L−1 h−1. The results demonstrated that three-dimensional nanotubes of TiO2 surrounding the mesh provide superior degradation compared to one-dimensional arrays on the planar surface of the anodized plate. With limited broad-scale comparative studies between varieties of different TiO2 supports, this study provides a comparative analysis of relative degradation efficiencies between the four photocatalytic configurations.

scholarly journals Development of Light-obscuration-type Smoke Meter Using Visible Light of Single Wavelength

2020 ◽  
Vol 20 (1) ◽  
pp. 211-216
Author(s):  
Jongjin Jung
Keyword(s):  
Visible Light ◽  
Light Emitting Diode ◽  
Optical Path Length ◽  
Optical Path ◽  
Smoke Detector ◽  
Silicon Photodiode ◽  
High Brightness ◽  
Light Emitting ◽  
Light Obscuration ◽  
Photo Sensor

In this study, we developed a light-obscuration-type smoke meter using visible light of a single wavelength. This could replace smoke meters that use selenium photocells and tungsten lamps, which are standard domestic equipment. A high-brightness light emitting diode was used as a light source, and a silicon photodiode was used as a photo sensor. An effective optical path length of 500 mm was developed in accordance with ISO 7240-7 and UL 268 regulations. To compare and evaluate the developed lightobscuration-type smoke meter, a smoke detector sensitivity tester with automatic smoke concentration control and maintenance was developed. Compared to standard light-obscuration-type smoke meters that use selenium photocells, it was confirmed that our smoke meter performs to an equivalent standard.

scholarly journals Comparison of Intracanopy Light-emitting Diode Towers and Overhead High-pressure Sodium Lamps for Supplemental Lighting of Greenhouse-grown Tomatoes

2013 ◽  
Vol 23 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Celina Gómez ◽  
Robert C. Morrow ◽  
C. Michael Bourget ◽  
Gioia D. Massa ◽  
Cary A. Mitchell
Keyword(s):  
High Pressure ◽  
Energy Consumption ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Significant Proportion ◽  
Fruit Production ◽  
Light Sources ◽  
Node Number ◽  
Light Emitting ◽  
Supplemental Lighting

Electric supplemental lighting can account for a significant proportion of total greenhouse energy costs. Thus, the objectives of this study were to compare high-wire tomato (Solanum lycopersicum) production with and without supplemental lighting and to evaluate two different lighting positions + light sources [traditional high-pressure sodium (HPS) overhead lighting (OHL) lamps vs. light-emitting diode (LED) intracanopy lighting (ICL) towers] on several production and energy-consumption parameters for two commercial tomato cultivars. Results indicated that regardless of the lighting position + source, supplemental lighting induced early fruit production and increased node number, fruit number (FN), and total fruit fresh weight (FW) for both cultivars compared with unsupplemented controls for a winter-to-summer production period. Furthermore, no productivity differences were measured between the two supplemental lighting treatments. The energy-consumption metrics indicated that the electrical conversion efficiency for light-emitting intracanopy lighting (LED-ICL) into fruit biomass was 75% higher than that for HPS-OHL. Thus, the lighting cost per average fruit grown under the HPS-OHL lamps was 403% more than that of using LED-ICL towers. Although no increase in yield was measured using LED-ICL, significant energy savings for lighting occurred without compromising fruit yield.

Indoor Lighting Workplaces

2021 ◽  
pp. 243-258
Author(s):  
David Baeza Moyano ◽  
Roberto Alonso González Lezcano
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Working Environment ◽  
Office Work ◽  
Light Emitting ◽  
Spectral Power Distribution ◽  
Indoor Lighting ◽  
New Criteria

Office work has so far been carried out in company buildings and was largely based on the use of paper on a horizontal surface. Due to multiple reasons, more workers are working in their homes with electronic devices. As a result, both the working environment and personal tools are changing. Since the discovery about 20 years ago of the non-visual ways of light absorption, it was known that apart from the image forming effects (IF) of light from which the criteria for correct lighting have been developed, non-image forming effects (NIF) of light exist. The discovery of NIF has enhanced researcher belief in the importance of daylighting and has raised new criteria to be taken into account for proper interior lighting. Due to all the factors mentioned above, the parameters to be met by a luminaire and its environment for proper lighting of the workstation have been modified and expanded. The rapid advance in the development of new light-emitting diode (LED) luminaires with which the spectral power distribution (SPD) can be practically created opens the door to a genuine technological revolution comparable to the invention of electric lighting around 150 years ago. The authors of this study will review the latest published studies on the importance of light in our lives, IF and NIF effects of light, the parameters which from these effects are suggested to be taken into account for a correct indoor lighting, the regulations in force on indoor lighting workplaces, and proposals to improve indoor lighting and therefore the quality of life of workers.

A Study on Energy Saving and Light Pollution of LED Advertising Signs

2011 ◽  
Vol 121-126 ◽  
pp. 2979-2984 ◽  
Author(s):  
Chen Ying Ho ◽  
Hsien Te Lin ◽  
Kuang Yu Huang
Keyword(s):  
Energy Consumption ◽  
Urban Areas ◽  
Light Emitting Diode ◽  
Outdoor Environment ◽  
Light Pollution ◽  
Light Emitting ◽  
Full Color ◽  
Average Luminance ◽  
Color Screens ◽  
Color Screen

Lighting advertising signs not only play an important role in outdoor lighting environment in Taiwan, but also become the main factor of energy consumption in urban areas at night. Light-emitting diode (LED) has been gradually used in advertising signs due to its advantages. However, in order to be conspicuous and legible in the daytime, signs that are excessively bright may result in considerable light pollution and energy waste at nighttime. Therefore, this research aims to measure the luminance of LED signs and traditional internally lighted signs, and analyze the light trespass from each signage. Based on the research results, the energy consumption from a LED full color screen is 12 times more than a traditional internally lighted sign per day. Statistically, all kinds of LED signs are much higher than traditional internally lighted signs in the percentage of excessive brightness and average luminance value. As for the light trespass, since the vertical illuminance on facade facing the signs increases with the increase of the sign area or the decrease of the distance between the sign and the facade, the vertical illuminance on facade facing the signs would exceed the limit of CIE even if the luminance of the signs achieves the standard of CIE in terms of the general conditions in Taiwan. This happens to LED full color screens in particular and thus results in considerable obtrusive light. To sum up, in order to reduce unnecessary energy consumption and improve the nighttime lighting quality for outdoor environment, this research recommends the luminance limitation for light dimming of LED advertising signs should refer to the zoning, time period, and sign area.

Hybrid daylight/light-emitting diode illumination system for indoor lighting

2014 ◽  
Vol 53 (9) ◽  
pp. 1869 ◽  
Author(s):  
Aiming Ge ◽  
Peng Qiu ◽  
Jinlin Cai ◽  
Wei Wang ◽  
Junwei Wang
Keyword(s):  
Light Emitting Diode ◽  
Light Emitting ◽  
Illumination System ◽  
Indoor Lighting

scholarly journals Benzene and NOx photocatalytic assisted removal using indoor lighting conditions

2021 ◽  
Author(s):  
David Maria Tobaldi ◽  
Dana Dvoranová ◽  
Luc Lajaunie ◽  
Kristina Czikhardtová ◽  
Bruno Figueiredo ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Light Emitting Diode ◽  
Human Beings ◽  
Negative Consequences ◽  
Light Emitting ◽  
Lighting Conditions ◽  
Indoor Lighting

Modern life-style is creating an indoor generation: human beings spend approximately 90% of their time indoors, almost 70% of which is at home – this trend is now exacerbated by the lockdowns/restrictions imposed due to the COVID-19 pandemic. That large amount of time spent indoors may have negative consequences on health and well-being. Indeed, poor indoor air quality is linked to a condition known as sick building syndrome. Therefore, breathing the freshest air possible it is of outmost importance. Still, due to reduced ventilation rates, indoor air quality can be considerably worse than outdoor. HVAC, air filtration systems and a well-ventilated space are a partial answer. However, these approaches involve only a physical removal. Photocatalytic mineralisation of pollutants into non-hazardous, or at least less dangerous compounds, is a more viable solution for their removal. Titanium dioxide, the archetype photocatalytic material, needs UVA light to be “activated”. However, modern household light emitting diode lamps irradiate only in the visible region of the solar spectrum. In this short-communication, we show that the surface of titanium dioxide nanoparticles modified with copper oxide(s) and graphene shows promise as a viable way to remove gaseous pollutants (benzene and NOx) by using a common light emitting diode bulb, mimicking real indoor lighting conditions. Titanium dioxide, modified with 1 mol% CuxO and 1 wt% graphene, proved to have a stable photocatalytic degradation rate, three times higher than that of unmodified titania. Materials produced in this research work are thus strong candidates for offering a safer indoor environment.

scholarly journals Design and Implementation of a radio controlled led lighting system

2016 ◽  
Vol 10 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Ádám Bálint ◽  
József Sárosi
Keyword(s):  
Radio Frequency ◽  
Light Emitting Diode ◽  
Lighting System ◽  
Light Emitting ◽  
Led Lighting ◽  
Led Light ◽  
Design And Implementation ◽  
Technological Advances ◽  
History Of ◽  
Indoor Lighting

Technological advances allow us to control LED (Light Emitting Diode) lighting at home, in the office it can even allow us to change the intensity of the light and this is just the beginning of what the future holds for us. In this study an LED internal lighting fixture of our own design will be presented focusing on each step in its design. Firstly, the features, types and history of LEDs will be presented, next the products available in market that are required for the completion of the device. Finally, the design and implementation as well as the radio frequency controlled LED indoor lighting fixture will be shown.

Design of the Light-Emitting Diode Vehicle Projector Headlamp System without Shield

2013 ◽  
Vol 284-287 ◽  
pp. 2723-2728 ◽  
Author(s):  
Chi Chang Hsieh ◽  
Yan Huei Li
Keyword(s):  
International Economic ◽  
Energy Consumption ◽  
Light Emitting Diode ◽  
Small Dimension ◽  
Low Energy ◽  
Light Emitting ◽  
Light Pattern ◽  
Economic Commission ◽  
Low Energy Consumption ◽  
Critical Components

The light-emitting diode (LED) has been applied extensively to various kinds of applications according to the advantages of its small dimension, low energy consumption and strong reliability. The projector headlamp system proposed in this study was composed of four main critical components including focused LED, asymmetric metal-based plate, freeform surface and condenser lens. It was designed, developed and simulated under low energy consumption to save more energy. Only five 3-Watt focused LEDs without a shield or baffle inside the projector headlamp system was designed to provide the low-beam cutoff in order to meet the requirements of international Economic Commission for Europe (ECE) R112 regulation. Eventually, the prototype of this LED vehicle projector headlamp system was also fabricated to perform the correct light pattern.

scholarly journals Analysis of the Real Energy Consumption of Energy Saving Lamps

2020 ◽  
Vol 10 (23) ◽  
pp. 8446
Author(s):  
Manuel Ángel Graña-López ◽  
Almudena Filgueira-Vizoso ◽  
Laura Castro-Santos ◽  
Ana Isabel García-Diez
Keyword(s):  
Energy Consumption ◽  
Compensation Effect ◽  
Light Emitting Diode ◽  
Low Energy ◽  
Fluorescent Light ◽  
Negative Effects ◽  
Light Emitting ◽  
The Real ◽  
Low Energy Consumption ◽  
Working Together

Light emitting diode (LED) and compact fluorescent light (CFL) lamps are widely used because they are associated with low energy consumption and a reduced environmental impact. In the present paper, a study of the real consumption of these devices has been carried out. To do this, the active, reactive, distortion and apparent power and electrical efficiency for various lamps have been measured and calculated. The distortions produced in the network provoke the consumed energy to be in the order of 50–75% higher than that which appears in the commercial characteristics. This situation means that for its operation, it is necessary to generate and distribute an amount of energy much higher than that which is declared as the consumption of these lamps, and so far, this amount of energy is neither quantified nor invoiced. Additionally, groups of lamps have also been studied to check whether, when working together on the same network, there is a compensation phenomenon that reduces the negative effects of individual lamps. We have found that this compensation effect does not occur for the type of devices evaluated.

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