Degradation of Photometric Characteristics of Phosphor Layers in LED Based Airfield Lights

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60162694%3AG43__%2F26%3A00563914" target="_blank" >RIV/60162694:G43__/26:00563914 - isvavai.cz</a>

Výsledek na webu

<a href="https://mailchi.mp/e640636bd6ed/ieee-dasc-2024-know-before-you-go?e=%5bUNIQID%5d" target="_blank" >https://mailchi.mp/e640636bd6ed/ieee-dasc-2024-know-before-you-go?e=%5bUNIQID%5d</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1109/DASC62030.2024.10748720" target="_blank" >10.1109/DASC62030.2024.10748720</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Degradation of Photometric Characteristics of Phosphor Layers in LED Based Airfield Lights

Popis výsledku v původním jazyce

Airfield lighting system is one of the most important parts of every airport. Lighting aids individually present various types of navigation information during the final part of approaching maneuver such as runway edge, course line, glidepath angle, touch-down zone, and many others. These aids are important for visual as well as instrument approaches and the automatization in aeronautics does not exclude them, rather opposite. The requirements for airfield lighting on CAT II, III runways are much stricter in comparison to visual runways. This results in using more airfield lights, it means more light sources and higher power requirements. In the recent past whole lighting were built on incandescent light bulbs that placed high demands on energy resources as well as the solution for individual lights powering required unconventional solutions such as serial loops to maintain the same luminance values of lights of the same significance. The use of LED technology brought different approach to powering of airfield lighting. Special types of LED drivers are used for maximum energy efficiency and LED light sources emits the light in non-incandescent way. LED technology reduced the energy requirements to approximately one-third to one-fifth in general and significantly increased service life of every airfield light. As for emitting colors, LED based lights do not need colors filters they do not need filters causing light flux losses as well as keeping the light color defined by aviation regulations as the coordinates in the chromaticity diagram is easier. However, LED technology also suffers from some negative features. LEDs are more sensitive to instability in the power supply, some colors of the light spectrum are difficult to obtain in PN transition of diode. Special technologies of phosphors must be consequently used. Despite these challenges the LED technology currently remains the most promising way to emit the light by airfield systems. This article touches on one of the most significant disadvantages of LED technology, the need to transpose the light spectrum of excitation source to the desired color or colors via phosphor. As the phosphor is chemical, itconsequently brings the problems with degradation the photometric characteristics of LED phosphor layers during operation. The article shows basic characteristics of the most used phosphors in airfield lights, ways of their excitation supported by measurement of every phosphor in simulated operating conditions on typical airfield. The following measurements present increasing or decreasing the LEDs photometric characteristics depending on operating temperatures and humidities of phosphors layers using the most spread phosphors such as Yttrium Aluminum Garnet (YAG) phosphor powders, Nitride phosphors or Zinc Sulfide based phosphors. As the second parts, the paper deals with the long-term stability of phosphors layers which mostly depends on their filler properties. Typical filler for LED technology based on silicones is tested for changes in photometric properties. The testing energy source, 405 nm laser diode working almost in ultraviolet part of light spectrum, is used as the excitation source, where the radiation dose delivered into the phosphor powder filler is relatively easy to define. All the photometric characteristic changes are graphically presented in the paper.

Název v anglickém jazyce

Degradation of Photometric Characteristics of Phosphor Layers in LED Based Airfield Lights

Popis výsledku anglicky

Airfield lighting system is one of the most important parts of every airport. Lighting aids individually present various types of navigation information during the final part of approaching maneuver such as runway edge, course line, glidepath angle, touch-down zone, and many others. These aids are important for visual as well as instrument approaches and the automatization in aeronautics does not exclude them, rather opposite. The requirements for airfield lighting on CAT II, III runways are much stricter in comparison to visual runways. This results in using more airfield lights, it means more light sources and higher power requirements. In the recent past whole lighting were built on incandescent light bulbs that placed high demands on energy resources as well as the solution for individual lights powering required unconventional solutions such as serial loops to maintain the same luminance values of lights of the same significance. The use of LED technology brought different approach to powering of airfield lighting. Special types of LED drivers are used for maximum energy efficiency and LED light sources emits the light in non-incandescent way. LED technology reduced the energy requirements to approximately one-third to one-fifth in general and significantly increased service life of every airfield light. As for emitting colors, LED based lights do not need colors filters they do not need filters causing light flux losses as well as keeping the light color defined by aviation regulations as the coordinates in the chromaticity diagram is easier. However, LED technology also suffers from some negative features. LEDs are more sensitive to instability in the power supply, some colors of the light spectrum are difficult to obtain in PN transition of diode. Special technologies of phosphors must be consequently used. Despite these challenges the LED technology currently remains the most promising way to emit the light by airfield systems. This article touches on one of the most significant disadvantages of LED technology, the need to transpose the light spectrum of excitation source to the desired color or colors via phosphor. As the phosphor is chemical, itconsequently brings the problems with degradation the photometric characteristics of LED phosphor layers during operation. The article shows basic characteristics of the most used phosphors in airfield lights, ways of their excitation supported by measurement of every phosphor in simulated operating conditions on typical airfield. The following measurements present increasing or decreasing the LEDs photometric characteristics depending on operating temperatures and humidities of phosphors layers using the most spread phosphors such as Yttrium Aluminum Garnet (YAG) phosphor powders, Nitride phosphors or Zinc Sulfide based phosphors. As the second parts, the paper deals with the long-term stability of phosphors layers which mostly depends on their filler properties. Typical filler for LED technology based on silicones is tested for changes in photometric properties. The testing energy source, 405 nm laser diode working almost in ultraviolet part of light spectrum, is used as the excitation source, where the radiation dose delivered into the phosphor powder filler is relatively easy to define. All the photometric characteristic changes are graphically presented in the paper.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20200 - Electrical engineering, Electronic engineering, Information engineering

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

DASC 2024 CONFERENCE PROCEEDINGS

ISBN

979-8-3503-4961-0

ISSN

—

e-ISSN

—

Počet stran výsledku

7

Strana od-do

3231

Název nakladatele

—

Místo vydání

Piscataway, NJ 08855-1331 USA

Místo konání akce

San Diego, CA, USA

Datum konání akce

29. 9. 2024

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

001453360400022