The technical possibilities of losses reduction in the LED optical systems

Różowicz, A.; Leśko, M.; Wachta, H.

doi:10.1109/lumenv.2016.7745534

Cited by 6 publications

(6 citation statements)

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“…η extraction = number o f photons emitted into f ree space per second number o f photons emitted f rom active region per second (5) Finally, the optical efficiency η o , also known as radiant efficiency, is defined as:…”

Section: The Effect Of Junction Temperature On the Lighting Parameters Of A Single Led Sourcementioning

confidence: 99%

“…Seven measuring channels were installed on the heat sink and MCPCB, with a temperature sensor in the form of a K-type thermocouple. The LED panel measuring points were located as follows: on the upper base in the central part of the heat sink ( 1), on the central fin of the heat sink (2), on the fin protrusion above the central LED source (3), on the fin protrusion above the outer LED source (4), on the lower base of heat sink (5), on MCPCB at a distance of 1 mm from the central LED source (6) and on MCPCB at a distance of 1 mm from the outer LED source (7) (Figure 9).…”

Section: Thermal Modeling Of the Led Panelmentioning

confidence: 99%

“…LED light sources are also equipped with advanced lens optics, in order to group of light sources [1][2][3]. LED light sources are also equipped with advanced lens optics, in order to obtain the maximum amount of LED light transmitted by the optical system for the purpose of energy savings, savings in terms of energy consumption, and the cost of electricity bills [4,5]. Electrical light sources are responsible for an energy consumption of around 1/6 to 1/5 of the worldwide electricity production, and the use of semiconductor light sources reduces energy consumption and significantly reduces carbon dioxide emissions into the atmosphere [5,6].…”

Section: Introductionmentioning

confidence: 99%

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Modeling of Selected Lighting Parameters of LED Panel

et al. 2020

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Semiconductor light sources are currently the fastest growing and most energy efficient group of light sources used in lighting technology. Their lighting parameters, such as luminous flux, correlated color temperature and color rendering index depend on the value of the forward current, as well as the temperature of the junction. LED source manufacturers usually specify, in data sheets, the effect of junction temperature and forward current on the luminous flux for individual light sources. The difficulty, however, is the correct determination of temperature and then lighting parameters, by simulation methods for multi-source lighting systems. Determining the junction temperature which affects lighting parameters is particulary important in the case of LED panels and luminaires, where thermally coupled LED sources shaping the output lighting parameters are in close proximity to each other. Additionally, other factors influencing the temperature distribution of sources, such as the design and geometry of the cooling system, the design of the printed circuit and thermal interface material used, should be considered. The article is a continuation of the publication in this journal where the influence of factors influencing the temperature distribution of the LED panel is presented. The purpose of the research in this article was to confirm the possibility of using CFD (Computational Fluid Dynamics) software, as well as to determine the accuracy of the results obtained in the temperature analysis of the multi-source LED panel, and in determining the output lighting parameters of the LED panel based on it. In this article, based on previously published research, a LED panel model with a cooling system was made, and then the CFD software determined the junction temperature of all light sources. The determined temperature of the LED sources constituted the basis for determining the output lighting parameters of the panel: luminous flux, color temperature and color rendering index. The simulation results were verified by real measurements on the constructed LED panel prototype. The LED panel temperature difference between the simulation results and the real results on the prototype did not exceed 5%. Moreover, the error of lighting parameters between the simulation results obtained and the results on the LED panel prototype in the worst case was 4.36%, which proves the validity and accuracy of simulation studies.

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Section: The Effect Of Junction Temperature On the Lighting Parameters Of A Single Led Sourcementioning

confidence: 99%

Section: Thermal Modeling Of the Led Panelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling of Selected Lighting Parameters of LED Panel

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“…The specific nature of both spatial distribution of light and formation of the luminous surface of high-power electroluminescent sources means that they cannot be effectively used in the same luminaires as the discharge sources; thus, it is necessary to design new constructions where multi-source matrices are used [2][3][4]. Thanks to small dimensions of LED sources, it has become possible to limit dimensions of luminaires, which is associated with the widespread use of optical lens systems replacing reflector systems wherever it is desirable [5,6]. However, in some situations, the use of reflectors is necessary because of the expected lighting effect.…”

Section: Introductionmentioning

confidence: 99%

Adaptive Luminaire with Variable Luminous Intensity Distribution

et al. 2020

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The field of indoor lighting covers a wide range of lighting uses with varying requirements for lighting conditions to be satisfied by properly selected lighting equipment. The need to frequently change the arrangement of useable areas entails the necessity to adapt the lighting to new requirements. A good solution for reducing costs and saving time is a luminaire adjusting the luminous flux and spatial luminous intensity distribution in a wide range. The authors present the concept of an adaptive luminaire and its construction assumptions. In addition, the results of studies on the development of the concept are shown together with conditions and limitations that influenced the construction of the luminaire. The analysis of the surface of the moveable reflector is presented, and the results of testing the luminaire prototype are compared with the results of simulation tests.

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“…At that time, in the field of lighting technology, floodlighting and measuring technology [3][4][5], we were facing an actual revolution. The methods of design and analysis of optical systems were also changing [6][7][8][9]. The construction and specificity of light distribution in the light sources themselves in general applications has also changed considerably [10].…”

Section: Introductionmentioning

confidence: 99%

Bulletin of the Polish Academy of Sciences: Technical Sciences

Słomiński¹

2019

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Designing, optimizing and analyzing optical systems as part of the implementation process into production of modern luminaires require using advanced simulation and computational methods. The progressive miniaturization of LED (light emitting diode) chips and growth in maximum luminance values, achieving up to 10 8 cd/m 2 , require constructing very accurate geometries of reflector and lens systems producing complex luminous intensity distributions while reducing discomfort glare levels. Currently, the design process cannot function without advanced simulation methods. Today's simulation methods in the lighting technology offer very good results as far as relatively large conventional light sources such as halogen lamps, metal halide lamps and high pressure sodium lamps are concerned. Unfortunately, they often fail in the case of chip-on-board LED light sources whose luminous surface dimensions are increasingly often contained inside a cube of the side length below 1mm. With the high sensitivity of such small chips and lenses with dimensions ranging from a just a few to between 10 and 20 mm, which is presented in this paper, modern luminance distribution measurement methods, luminance modelling and ray tracing methods should be used to minimize any errors arising from incorrectly projecting the design in the final physical model. Also, very importantly, focus should be directed towards reducing a chance of making a mistake while collimating the position of the light source inside the optical system. The paper presents a novel simulation calculation method enriched with an analysis of optical system sensitivity to a light source position. The results of simulation calculations are compared with the results of laboratory measurements for corresponding systems.

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The technical possibilities of losses reduction in the LED optical systems

Cited by 6 publications

References 2 publications

Modeling of Selected Lighting Parameters of LED Panel

Modeling of Selected Lighting Parameters of LED Panel

Adaptive Luminaire with Variable Luminous Intensity Distribution

Bulletin of the Polish Academy of Sciences: Technical Sciences

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