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Semaine du Cerveau

Published on March 13, 2017

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 European funded projects 

Circadian Metrology - PI : Claude Gronfier


The European 2020 Strategy is pursuing the overall objective of saving 20% of the Union’s primary energy consumption by 2020. This is possible when for instance energy efficiency of innovative lighting is enhanced, by improving product quality and assuring longer lifetime. Initial commercial first generation SSL products, based on LED technology, suffered from reduced light quality and variable performance. At first, the development of basic metrology for SSL (ENG05 “Metrology for Solid State Lighting”) has
led to considerable improvements towards the reliable measurement of SSL performance. The gradual maturing of SSL technology has led to a steady increase in product quality and enhanced efficiency, but demands an advanced metrology framework. This JRP will strengthen the metrological framework for novel SSL, notably OLEDs/OLED arrays and pulsed SSL. This JRP will make a first step towards meeting metrological needs for nanostructured and flexible LED systems.

SSL technology is developing continuously and new types of SSL products frequently appear on the market, notably OLED and flexible LED, phosphor-free LEDs and pulsed LED systems. These products have distinct characteristics, which have to be taken into account in the measurement procedure to avoid measurement errors.
Measurement solutions have to be developed to deal with large area and curved light emitting surfaces (e.g.OLED and flexible SSL). Metrics and validated measurement procedures have to be developed to cover safety and health aspects. To drive novel SSLs new electronic circuits are developed. Electrical characterisation has to keep pace with these developments. The need for reliable methods for lifetime determination is broadly felt. Endusers are not ready to pay for unproven/unlabelled highly priced products. Lifetime is an important factor to determine accurately, because it not only governs the long-term quality experience of users, but it also underpins economic models for lamp replacement. User confidence may be damaged by faulty lifetime estimates and uptake will suffer. Since metrology for SSL covers a wide set of parameters, some related to optical output, some to electrical aspects, some to reliability and some to perception and safety, a broad expertise is indispensable. Only through the cooperation of NMIs and academic partners with complementary knowledge and facilities will this JRP succeed strengthening the metrological framework for SSL and create the expected impact.

For further information, click here.

Claude Gronfier

My research focuses on how light synchronizes physiology, including the circadian timing system, to the 24h day in humans.  My projects investigate the mechanisms involved in non-visual photoreception, the effects of light on physiological functions (alertness, cognition, mood), and how light could be used/designed to treat circadian, mood, vigilance, and sleep disorders, in shiftwork and pathological conditions (Ocular diseases, neurodegenerative ...

Selected Publications of Team members :