Electroluminescent diodes have become increasingly popular on outdoor billboards for the last few years, all over the world. Digital billboards with electroluminescent diodes are large, have high luminance and display dynamically changing images. Billboards located near streets are a potential threat to traffic safety. The paper presents requirements for such billboards, the results and analysis of measurements of selected billboards located in Poznań, Poland, as well as conclusions and recommendations for large size billboards with light emitting diodes located in the vicinity of roads and intersections.
Currently used electronic components (LED, processors, CCD matrices) are distinct for their increasingly dense packing of active elements and, consequently, higher heat loss power per a single element. The arising thermal barrier restricts the functionality and further development of components in their present-day form. Cooling systems (natural or forced types, including water cooling systems) sometimes fail to come up to the required standard. The paper discusses a concept whereby the operation of standard cooling systems is supported by incorporation of Peltier elements. A heat flow analysis is presented for systems containing: an electronic element -Peltier element -radiator, complete with a study of cooling efficiency and elements facilitating the process of design of such combined systems. Also, experimental data from tests examining the process of cooling in sample systems will be provided.
Various kinds of media are used for outdoor advertising purposes. One such medium comprises large electronic billboards with light-emitting diodes (LED) as the source of light. Such novel advertising devices' photometric parameters are different than in the media used so far and consequently impact road traffi c participants in a different manner. Digital billboards with electroluminescent diodes are large, have high luminance, and display dynamically changing images. Billboards located near streets are a potential threat to traffi c safety. The paper presents requirements for such billboards, the results and analysis of measurements of selected billboards located in Poznań, Poland, as well as conclusions and recommendations for large-sized billboards with LED located in the vicinity of roads and intersections.
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