Defence of doctoral thesis in the field of Measurement Science and Technology, M.Sc. Janne Askola

Opponent: Vicedirector Técnico, Dr. Joaquín Campos-Acosta, Instituto de Óptica Daza de Valdés (IO-CSIC), Spain
Custos: Professor Erkki Ikonen, Aalto University School of Electrical Engineering, Department of Signal Processing and Acoustics

The defence will be organised via remote technology (Zoom). Link to the defence

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The doctoral thesis will be publicly displayed 10 days before the defence in the Aaltodoc publication archive of Aalto University.
Doctoral theses in the School of Electrical Engineering: https://aaltodoc.aalto.fi/handle/123456789/53

Press release:

In optical metrology, the phase out of the incandescent lamps and the adoption of LED based lighting has introduced changes that bring both challenges and advantages in calibration activities. The measurement procedures in use have been not been developed for the LED based sources, and therefore the research for updating the procedures is important.

In this thesis, various advancements in LED photometry have been pursued. The finding of the effect of nitrogen gas purging through optical aperture on the effective aperture area is one step in adopting the LED based primary photometric measurements with decreased uncertainties. Additionally, the ageing studies of LED based street luminaires, retrofitted LED lamps and OLED panels, each present the opportunities and challenges in the era of moving towards LED based lighting.

Contact information of doctoral candidate: