Flicker, even when it is not being perceived, is an issue in all lighting sources and can have negative effects on our health. Ultimately, it compromises the quality of the emitted light. For lighting manufacturers it is important to be able to certify this requirement in advance until a universal standard is adopted. These topics have been discussed in a dedicated meeting titled “Optical flicker in LED lighting” held by UL (Underwriters Laboratories) in its headquarters of Burago Molgora, in Lombardy, Italy.

The meeting was opened by the keynote speech of Laura Bellia, professor of Environmental Physics of the department of industrial engineering of the University “Federico II” in Naples who provided an accurate definition of flicker and of the parameters used for the determination of this annoying phenomenon. Bellia also discussed the state-of-the-art research regarding the effects of flicker on human body. It is a complex mechanism that concerns our eyes and the neurological responses of our body. The field is still under study, but it will supply ever more precise data, since the large-scale distribution of LEDs is a relevantly recent phenomena.

Walter Parmiani from UL illustrated the method used by UL to measure the flickering effect in different lighting fixtures and the issuance of the “Low Optical Flicker” mark. The need for the new service offered by the certification company stems from the belief that this parameter is an important element for determining the quality of lighting with regards to the health and comfort of users, in addition to providing companies with the possibility to qualify their products with certified and reliable technical data.

The point of view of manufacturers was presented by Giorgio Sottsass from Disano illuminazione, the first company in Italy to have its products certified with the “Low Optical Flicker” mark. Sottsass highlighted how Disano has been committed to controlling this parameter for several years, in line with the search for quality that has always characterised the Milan-based lighting company. In LED sources, in fact, flicker is present in a greater extent compared to traditional sources and, says Sottsass, it is important for manufacturers to have a standard reference. The development of standards is slower compared to technological and market evolution; this explains the importance for users to have a certification delivered by an independent body that can help them choose a tested and safe product. Flicker is a technical definition that in reality concerns a vast range of sectors. An example of this is the connection between lighting and video surveillance. Today, surveillance cameras are an essential tool to prevent or fight crime, but inadequate lighting or an excessive level of flicker can compromise the quality of videos. Similar examples can be made in many other sectors, considering the many functions of lighting both outdoors and indoors.

Overall, the meeting provided many points of further discussion not only regarding the importance of a specific factor like flicker, but also the role that regulations and certifications can have on a market where technology evolves at fast speed and where it is increasingly important to have safe criteria for defining the quality of a product.