In February 2023, Nichia started a blog with the 1st post titled "Nichia's contribution to a realization of a mercury-free society" and for nearly a year, Nichia has been introducing examples of LED/LD replacement for mercury lamps in various fields. Maybe it was surprising to readers to find out that mercury lamps are still used in various applications in modern society. This includes fluorescent lamps, high-pressure sodium lamps (HPS) used in street lights and greenhouse lighting, low-pressure mercury lamps used in disinfection applications, high-pressure mercury short arc lamps in semiconductor photolithography, liquid crystal displays (LCDs) and printed circuit boards (PCBs), medium-pressure mercury lamps used in paint curing and ultra-high-pressure mercury lamps used in projector applications. At the same time, Nichia believes that readers have also realized that new solid-state light sources such as LEDs and LDs are emerging as effective mercury-free alternative technologies.

Both LEDs and LDs are new technologies that are still growing and evolving. Around 2015 / 2016 when the current RoHS exemption was being considered, it was recognized that LEDs and LDs were insufficient as alternative technologies. However, 7-8 years have passed since then, the performance of LEDs and LDs have improved significantly, and it is now possible to use them in many fields and applications. Furthermore, due to their high-power conversion efficiency, they are expected to contribute not only to mercury-free but also the realization of a carbon neutral society. Therefore, it is expected that these technologies will continue to evolve and develop further and become indispensable to modern society. Nichia, that attempts to encourage the adoption of LEDs/LDs in various fields, also feels that once a new technology has appeared, it is natural that new technologies and products will emerge because of these influences. For example, in the curing of paints, various paints that had been optimized over the years to match the output and wavelength of mercury lamps have now been adapted to the output and wavelength of UV LEDs, following the commercialization of UV LEDs and the progress of their replacement of mercury lamps. Subsequently, the improved characteristics of UV LEDs, combined with the development of UV LEDs with various wavelengths, have led to a further reduction in the time required for curing and a significant reduction in the amount of power input. This is just one example, but it reminds Nichia that technological progress accelerates by involving the surrounding environment.

It is fun to imagine how much more progress will be seen in 2027, when many of the current exemptions will have expired, including peripheral technologies, and how many applications will have replaced mercury lamps. Of course, Nichia, as a leader of LED/LD technology, has a great responsibility to achieve the realization of a mercury-free society. Nichia will continue to make efforts to eliminate all exemptions related to mercury-containing lamps by 2027.

The blog on "Nichia's contribution to a realization of a mercury-free society" will take a little break after today's post. Although Nichia will stop this monthly series, Nichia will continue to introduce new case studies of LED and LD adoption in this blog space.