NICHIA, the world’s largest LED manufacturer and inventor of the high-brightness blue and white LED, has launched a high density UV-C LED that can help target the inactivation and sterilization of various bacteria and viruses. The new NCSU434B UV-C LED is only 3.5×3.5-mm and offers a high radiant flux of 62 mW operating from 350 mA. Nichia has also documented the germicidal efficacy.
The ultraviolet (UV) performance in the germicidal UV-C band (100–280 nm) has been documented to deactivate including SARs-CoV-2 virus that causes COVID-19. The LED is suitable for usage in water, near-surface, and air disinfection systems, and is commercially available immediately.
Nichia considers both high radiant flux and lifetime as critical in the evolution of its LEDs and ultimately in effective germicidal dosage. Reports are that Nichia only releases a UVC LED that with minimum 10,000-hour reliability at L70 and at realistically high temperatures. Still, the company has pushed both radiant flux and wall plug efficiency (WPE) consistently at 280 nm.
Nichia’s previously best performing UV-C LED has been the NCSU334B LED. The 6.8×6.8-mm device was announced at the end of 2020, capable of delivering 70 mW from a drive current of 350 mW. Some at the time labeled the product a high-power device based on the old categorization criteria of LED components by drive current and wattage.
What’s clear is that Nichia has driven performance on all vectors in the prior nine months. The NCSU434B nearly matches the NCSU334B in radiant flux in a much smaller package. Both product families have a relatively high (compared to visible-light LEDs) forward voltage in the 5.5–6V range.
The smaller package will be a critical factor. With the NCSU434B, system designers will be able to pack the LEDs much more closely together to maximize virucidal power in smaller form factors. That compact form will enable the broad application targets mentioned earlier.
Nichia has been among the more aggressive UV-C LED manufacturers in documenting the germicidal efficacy of its products. Earlier this year, the company challenged the UV-C sector to deliver complete details of UV-C LED performance with Swenson authoring a column in the March issue of LEDs magazine.
Using NCSU434B Hitachi Zosen Corporation and Professor Jiro Yasuda of the National Research Center for the Control and Prevention of Infectious Diseases/Institute of Tropical Medicine, Nagasaki University conducted various inactivation experiments (Figure 1) on airborn microdroplets of a new coronavirus (Alpha strain and British mutant strain). In a one-pass test, results confirmed that a dosage of ~1mJ/cm2 reduced the infection titer to less than 1/10 (virus survival rate 4.5%), thus indicating positive and effective results against these new coronaviruses.
Professor Yasuda commented that since the inactivation mechanism of deep ultraviolet light is based on direct denaturation of viral RNA, equally effective results can be expected against new mutant coronavirus strains beyond the British strain, including the currently rampant Delta strain.
