Simplified evaluation of blue light hazard

The rapidly increasing significance of modern solid-state lighting technology in our daily environment poses important safety aspects with regard to photobiological safety and blue light hazard. The current international standard IEC 62471 contains the appropriate guidelines for the evaluation of lamps and lamp systems. Because it places extremely strict requirements on measuring equipment and procedures, supplementary practical evaluation methods have been introduced with Technical Report IEC TR 62778.

On this basis, Instrument Systems has developed a fast and practical measuring system for the evaluation of LEDs in excess of 360 nm. The new TOP 150-BLH telescopic optical probe is based on the proven TOP 200 telescopic optical probe, although it has only one aperture with a diameter of 7 mm. The aperture is positioned at the same height as the objective lens and corresponds to the reference level. A measuring spot over 2.2 mm is set via an internal aperture for test objects at a distance of 200 mm. This can be easily positioned by means of an internal alignment camera.

A direct spectral radiance measurement can be made in conjunction with a calibrated CAS 140 D spectroradiometer and the accompanying SpecWin Pro analysis software. For effective evaluation of the blue light hazard the IEC 62471 standard prescribes a weighting factor by which the spectral measurement data must be multiplied. This function covers the wavelength range between 300 und 700 nm and has a maximum of 435 to 440 nm. In this range, blue light can cause photochemical damage to the retina. Independently of the radiation density L_B and the calculated maximum exposure time t_max measured with the blue light hazard function, the analysis software classifies the light sources according to the four risk groups specified by the standard. Due to the simple measurement set-up, rapid and long-term stable measurements are also possible in production applications.

https://www.instrumentsystems.com/…

Trade fair notice:
Light+Building 2020, Booth 8.0 F60, 8–13 March 2020, Frankfurt / Germany