ʵ

News

LEDs change laboratory measurements of light

Measurements of LED lighting become more reliable when 90-years old reference spectrum of incandescent lamps is complemented with a new reference spectrum of white LEDs.
Kuvassa oleva LED-standardivalonlähde kehitettiin EMPIR PhotoLED -projektissa ja siinä käytetyt valkoiset LEDit on valittu uuden valkoisen spektrin eli CIE reference spectrum L41:n mukaisesti. Kuva: Tuomas Poikonen / VTT
LED-based light source developed in PhotoLED project. The LED chips have been selected to produce a spectrum of light resembling the new reference spectrum CIE L41. Photo: Tuomas Poikonen / VTT

International Commission on Illumination (CIE) has published Technical Report CIE 251:2023 LED Reference Spectrum for Photometer Calibration, related to laboratory measurements of LED lighting. Dr. Tuomas Poikonen from VTT MIKES chaired the technical committee TC 2-90 that produced the report as a collaboration of 29 members from 16 countries. The work was initiated 10 years ago by Professor Erkki Ikonen from Aalto University when it became evident that significant improvements on measurements of LED lighting can be achieved, if the old reference spectrum of incandescent lamp calibrations is complemented with a new reference spectrum of white LEDs. 

Poikonen says that ”the technical report CIE 251:2023 will serve industry as a guideline for laboratory measurements. The new reference spectrum will be used for calibration of photometers that are needed for measurements of LED lighting.”

”Better tests and measurements finally improve the quality of luminaires sold to consumers. We demonstrated that white LED reference spectrum in calibration of photometers produces lower uncertainty in lighting measurements of LED luminaires.  In addition, we observed that the same reference spectrum works well also in measurements of day light and fluorescent lamps,” he continues.

Photometer is a measurement device to quantify the amount of light observed by a standardized human eye. Measurement of photometric characteristics of luminaires and lighting systems is an important stage in all product development.

”Consumers have already changed incandescent lamps to LED lamps. After global adoption of the LED reference spectrum, measurement equipment manufacturers can start producing dedicated LED light sources for calibration laboratories”, professor Ikonen adds.

”Photometers will be calibrated in the future using LED light sources also in our laboratory at Aalto University.  It is important for the reliability of measurements that a smooth transition is ensured for customer photometer calibrations when changing from incandescent based reference spectrum to LED based reference spectrum,” he continues. 

An international research group led by Poikonen studied 1500 different types of LED lamps to reach statistically meaningful results for the definition of the reference spectrum. Part of the results of Technical Report CIE 251:2023 has been produced in the EU funded PhotoLED project ()

Introduction of the Technical Report CIE 251:2023 .

Further information:

Dr. Tuomas Poikonen
VTT
tuomas.poikonen@vtt.fi
phone +358 50 5904 070

Professor Erkki Ikonen
Aalto University and VTT
erkki.ikonen@aalto.fi
phone +358 50 5502 283

  • Updated:
  • Published:
Share
URL copied!

Read more news

Research & Art Published:

Soil Laboratory Exhibition – Exploring the Dialogue Between Human and the Earth in Utsjoki

Soil Laboratory explores the relationship between humans and the earth as a living landscape through ceramic practices in Utsjoki.
Three people walking in winter next to a sign that says 'Aalto University' with snow-covered trees and buildings in the background.
Research & Art Published:

The Finnish Cultural Foundation awarded grants for science and art

A total of 15 individuals or groups from Aalto University received grants
Aerial view of a tram on a curved track surrounded by trees and buildings in a cityscape on a sunny day.
Awards and Recognition, Cooperation, Research & Art Published:

Environmental Structure of the Year 2025 Award goes to Kalasatama-Pasila tramway

The award is given in recognition of meritorious design and implementation of the built environment. Experts from Aalto University developed sustainability solutions for the project.
A blue figure holds two red, abstract creatures against a yellow background.
Aalto Magazine Published:

Five things everyone should know about creativity

Creativity is not the preserve of artists or a rare innate talent but a human capacity we all share – and one that can be measured, developed, and led for. The two-year Creative Leap project explored how creativity shows up in everyday life and work and how it connects to companies’ financial results. Here are five key takeaways.