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- 2018
- sodium lighting system
- modeling
- radiation curves
- LED lighting system
- software goniophotometer
- upper half-space
- light-emitting diode (LED)
- bulb's replacement
- lighting parameters at the workplace
- light sources for household
- Electrical Engineering and Automation
- VSB-TU Ostrava
- Poznan University of Technology
- Central Institute for Labour Protection - National Research Institute
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On the Blue Emitting Phosphor Na <sub/>3</sub> RbMg <sub/>7</sub> (PO <sub/>4</sub> ) <sub/>6</sub> :Eu <sup>2+</sup> Showing Ultra High Thermal Stability
摘要： This work concerns a novel blue emitting LED phosphor activated by Eu2+. It turned out that this luminescent material can be efficiently pumped by near UV or UV-A radiation sources while it exhibits a high quantum yield for a doping level between 0.3 and 3.0%. More impressively, the material has a very high quenching temperature T1/2 and will thus be applicable on-chip in high power phosphor converted LEDs or even in laser diodes. The emission and thermal stability is almost identical to that of BAM:Eu2+ while the absorption band is broader and reaches into the near UV range. Therefore, Na3RbMg7(PO4)6:Eu2+ is a promising candidate as a blue emitter in high CRI full conversion LEDs. To investigate the site preference of Eu2+, DFT and Ligand Field Theory based calculations were performed to successfully predict the emission spectrum. An unusual decay behavior was observed at low temperatures and the underlying mechanism involving spin-forbidden transitions of Eu2+ is discussed.
关键词： high thermal stability,solid state lighting,Eu2+ luminescence,near UV LED,high CRI,decay time,Blue photoluminescence
更新于2025-11-21 11:18:25
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Near-Infrared-Laser-Driven Robust Glass-Ceramic-Based Upconverted Solid-State-Lighting
摘要： Laser lighting, generally consisting of blue laser and downconversion phosphors, is considered to be the next promising illumination to replace traditional LED lighting. However, the irradiation of high-power blue laser will inevitably cause significant thermal attack, which puts forward high demand on phosphor converters as well as device architecture. In this work, a proof-of-concept prototype of near-infrared laser-driven upconversion solid-state-lighting is proposed. Robust lanthanide doped α/β-NaYF4 embedded glass ceramics are developed as upconverted color converters and routine 980 nm laser is used as pumping source for its relatively low thermal effect and a perfect resonance with Yb3+ sensitizers. Stable and bright upconversion white light is indeed produced by coupling Yb/Tm/Er doped α-NaYF4 glass ceramic with 980 nm laser but the luminous efficiency and energy efficiency are only 0.3 lm/W and 0.12%, respectively, owing to low Er doping concentration. As an alternative, a stacking structure of Yb/Tm doped glass ceramics and Yb/Er doped one is designed as color converter to improve luminous efficiency up to 1.0 lm/W and energy efficiency of 0.5% under a laser power density of 275 W/cm2. It is believed that this research will provide a new idea for laser lighting and open the application field of glass ceramics.
关键词： upconversion,lanthanide ions,optical materials,glass ceramics,laser lighting
更新于2025-11-20 15:33:11
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Lead Halide Post-Perovskite-Type Chains for High-Efficiency White-Light Emission
摘要： Hybrid metal halides containing perovskite layers have recently shown great potential for applications in solar cells and light-emitting diodes. Such compounds exhibit quantum confinement effects leading to tunable optical and electronic properties. Thus, broadband white-light emission has been observed from diverse metal halides and, owing to high color rendering index, high thermal stability, and low-temperature solution processability, these materials have attracted interest for application in solid-state lighting. However, the reported quantum yields for white photoluminescence (PLQY) remain low (i.e., in the range 0.5–9%) and no approach has shown to successfully increase the intensity of this emission. Here, it is demonstrated that the quantum efficiencies of hybrid metal halides can be greatly enhanced if they contain a polymorph of the [PbX4]2? perovskite-type layers: the [PbX4]2? post-perovskite-type chains showing a PLQY of 45%. Different piperazines lead to a hybrid lead halide with either perovskite layers or post-perovskite chains influencing strongly the presence of self-trapped states for excitons. It is anticipated that this family of hybrid lead halide materials could enhance all the properties requiring the stabilization of trapped excitons.
关键词： trapped excitons,solid-state lighting,post-perovskite,photoluminescence
更新于2025-11-14 15:16:37
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Correlations among lighting quality metrics for interior lighting
摘要： Correlations between selected lighting quality metrics derived from the spectrum were computed and interpreted for a representative set of interior light source spectra. Metrics of brightness and the melanopic effect were strongly correlated with each other but not with the metrics of colour quality. Results can be used to establish a two-dimensional diagram with criterion values to ensure the general user acceptance of a lighting system. This diagram can be extended in the future by further metrics describing light intensity and spatial and temporal distributions. Relationships between lighting quality metrics and colorimetric quantities as well as photoreceptor signal values are also shown.
关键词： lighting quality metrics,spectral design,correlations,human-centric lighting,interior lighting
更新于2025-09-23 15:23:52
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[IEEE 2018 Seventh Balkan Conference on Lighting (BalkanLight) - Varna (2018.9.20-2018.9.22)] 2018 Seventh Balkan Conference on Lighting (BalkanLight) - Color space distribution of luminaire for dynamic ?tunable white" lighting at different color temperatures
摘要： In this paper are presented the experimental results from the study of light and color distributions of specially constructed luminaire for dynamic "tunable white" lighting. They would be the base for the following study in the field of lighting effects on human health and wellbeing - Human Centric Lighting (HCL).
关键词： color,changing of color temperature,human centric lighting,LED lighting sources,dimming process of lighting
更新于2025-09-23 15:23:52
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[IEEE 2018 Seventh Balkan Conference on Lighting (BalkanLight) - Varna (2018.9.20-2018.9.22)] 2018 Seventh Balkan Conference on Lighting (BalkanLight) - Good Practices for Efficient Industrial Lighting
摘要： The paper presents for realization of energy efficient industrial lighting. A real industrial plant is taken in consideration and comparison is made between the existing and designed lighting systems in terms of energy efficiency, estimated by means of Lighting Energy Numerical Indicator (LENI). The opportunity for maximum use of daylight is also considered and analyzed in details.
关键词： industrial lighting,daylighting,efficient industrial lighting
更新于2025-09-23 15:23:52
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[IEEE 2018 5th International Conference on Advanced Informatics: Concept Theory and Applications (ICAICTA) - Krabi (2018.8.14-2018.8.17)] 2018 5th International Conference on Advanced Informatics: Concept Theory and Applications (ICAICTA) - The Experimental Set of Light Distribution Analysis by LabView Application
摘要： This research presents experimental set of distribution light. Light illuminance is displayed by LabView application. The set was tested by four types of lamp (CFL), incandescent, E27 LED (Light Emitting Diode), T8 tubular fluorescent (FL). The 3 types of luminaire are used for testing. They consisted of down light, high bay and fluorescent reflector. The black close room was 1.5x1.5x1.5 m in size. It was constructed by steel and plywood. The center floor of the room is installed by LDR (Light Dependent Resistor). It was used for measuring the illuminance. LabView application was applied to display value on computer screen. The stepping motor was installed to rotate the lamp. It was controlled by LabView through DAQ 6008 interface card. It was rotated from -90o to 90o. The control set consisted of interface card, motor drive and power supply. They were contained in the insulation box outside of the test room. From the experimental result, the LDR illuminance meter can measure illuminance with 4.52% average error. The light distribution curve from experiment set is correspondent with theory.
关键词： LabView,LDR,illuminance,lighting system,light distribution
更新于2025-09-23 15:23:52
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Spectral Optimization to Minimize Light Absorbed by Artwork
摘要： Light is needed to appreciate artwork, but visible radiation causes damage by photochemical action. Photons trigger photochemical action only when they are absorbed by the object. Damage to sensitive materials can be reduced by optimizing the spectrum of a light source to the reflectance factor of a museum artifact. Absorption minimization approaches can be utilized to quantify and optimize typically conflicting parameters, such as damage due to light absorption, color quality of artwork, and energy consumption. In this project, seven narrowband light emitting diodes (LEDs) are optimized using a multi-objective genetic algorithm to reduce light absorption and energy consumption, while maintaining the color appearance of five paints (blue, green, yellow, orange, red). Results indicate that optimized test spectra can reduce light absorption between 18% and 48%, without causing perceptible color or hue shifts in the paintings. Parallel to absorption, energy consumption is almost halved for all of the paints (between 42% and 48%). Optimizing the light source spectrum can aid in conservation of art collections in museums by reducing damage caused by optical radiation while preserving color fidelity.
关键词： color perception,LED sources and systems,Art conservation,museum lighting,color rendition
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - An Automatic Sun Tracking System for Fiber Optic Lighting
摘要： An automatic sun tracking system for fiber optic lighting is proposed. Using STC89C52RC microcontroller as the core controller, together with the steering gear to control the system daylighting, the system is able to trigger the sun tracking system and auxiliary lighting system automatically for overheating protection and brightness adjustment. A practical sun tracking system with hardware and software is implemented and validated by experiments.
关键词： steering gear,sensor,sun tracking system,Fiber optic lighting
更新于2025-09-23 15:23:52
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Smart Lighting Systems as a Demand Response Solution for Future Smart Grids
摘要： Massive deployment of distributed and intermittent renewable energy sources cause instability in the power system because of the mismatch between the power generation and load consumption. In order to solve this problem, smart loads embedded with modern power electronic converters and communication devices are being developed. They are able to communicate with the utility and perform automatic demand response. In this paper, we propose a smart light-emitting diode (LED) driver for lighting. This smart LED driver adjusts its electricity usage in response to the utility without the expense of human visual comfort. To achieve this goal, a new control method is developed and a typical rate of change of LED power is determined through conducting a series of visual assessments with interviewees. An experimental smart LED driver is built to validate the new control method. Experimental report from the visual assessments has confirmed that the proposed control method can significantly reduce the light flickering caused by change of LED power.
关键词： Smart lighting,demand response,renewable energy,smart grid
更新于2025-09-23 15:23:52