From LED die to a lighting system: Performance improvement in LED lighting by means of thermal management and smart control: Dissertation

Eveliina Juntunen

    Research output: ThesisDissertationCollection of Articles


    Light-emitting diodes (LEDs) are solid-state light sources increasingly used in general illumination. Advanced properties, such as energy efficiency and long lifetime, are promoting LED replacement over traditional lamp-based solutions. Features like small size and ease of control are also appreciated among the lighting community. Smart lighting with advanced control has attracted particular attention recently due to the increased energy savings via added intelligence. Besides the environmental reasons, the economic impact of LED lighting technology development is significant, with solid growth predicted for the energy-efficient lighting market. This thesis addresses high-power LED lighting technology development at four different levels. At the component, module and luminaire levels, the research concentrates on thermal management, which is considered one of the main factors for reliability and performance. The research focus is on reducing the thermal resistance of the high-power LED structure. This is achieved with thermal vias through the insulation layer of the substrate under the heat source. As a result, a total thermal resistance reduction of 10-55% is shown in comparison with commercial substrate technologies. Energy efficiency is considered the measure of the achievements at the luminaire and system levels. The topic is studied with a pedestrian street lighting installation in a real use environment. Case examples of dimming the street lighting according to natural light levels and pedestrian presence revealed power savings of more than 40% with smart control.
    Original languageEnglish
    QualificationDoctor Degree
    Awarding Institution
    • University of Oulu
    • Jantunen, Heli, Supervisor, External person
    Award date24 Oct 2014
    Place of PublicationEspoo
    Print ISBNs978-951-38-8152-8
    Electronic ISBNs978-951-38-8153-5
    Publication statusPublished - 2014
    MoE publication typeG5 Doctoral dissertation (article)


    • LED lighting
    • street lighting
    • thermal resistance
    • thermal via
    • smart control
    • energy savings


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