The Germicidal Experiment Process and Results of NICHIA Exposure at 280nm

 NICHIA Corporation (Headquarters: Anan City, Tokushima; President: Hiroyoshi Ogawa; hereinafter “Nichia”) announces confirmation through experimentation of the inactivation effect (99.99%) of NICHIA’s 280nm deep UV LEDs on the novel coronavirus SARS-CoV-2.

1.Summary of the experimental results

This experiment was carried out by Professor Masako Nomaguchi and Assistant Professor Takaaki Koma of Tokushima University Graduate School of Biomedical Sciences.

Experimental environment (reconstruction) irradiation conditions : irradiation distance 50mm, irradiance 1.7mW/cm2

Experimental results : the inactivation effect of Novel Coronavirus was confirmed to be 99.99% after 30 seconds of deep ultraviolet irradiation.

Irradiation time	Inactivation effect
30 seconds	99.99%
10 seconds	98.42%
5 seconds	93.28%

Table 1. Inactivation effect by irradiation time (reference values)

The Efficacy Assessment of Disinfecting Substances Alternative to Alcohol for Use Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) (Ministry of Economy, Trade and Industry) has judged virucidal efficacy of disinfecting substances against SARS-CoV-2 on the basis of the criterion set at a 99.99% or more reduction in viral titer.

The virucidal effect of handwashing and hand sanitizers, recommended as measures to control infectious diseases, is reported to be

• about 99% when washing hands with running water for 15 seconds

• 99.99% when using commonly-available alcohol-based hand sanitizer (containing 77–81% ethanol) for 30 seconds.

However, to get a better cleaning effect, hands must be thoroughly rubbed when washing with water. When using alcohol disinfection, sufficient amounts of alcohol are required to contact the object being sterilized, which takes time and effort.

According to the experimental results of deep ultraviolet ray, we know that it can easily achieve high sterilization effect in a shorter time.

We found that deep 280nm UVC UV LEDs may have a high virucidal effect while saving time and effort.

2. Virucidal power

Sterilization by deep 280nm Ultraviolet LEDs involves the following two factors:

• Wavelength: The difference in the virucidal effect according to wavelength shows that a wavelength of 260 nm exhibits the highest virucidal effect (100%).

• Optical output power: Higher optical output power (radiant flux) of LEDs is favorable.

Sterilization power is obtained by multiplying the virucidal effect according to wavelength by optical output power.

While the life span of the 265nm LED is expected to be approximately 2,000 hours, that of the 280nm LED is expected to be approximately 20,000 hours, or roughly 10 times as long as that of the 265nm LED.

The shorter the wavelength of light emitted from UV LEDs meanslower performance, such as output and lifespan.Therefore, the power conversion efficiency (i.e. wall-plug efficiency or WPE) of the UV LED also declines sharply. Conversely, NICHIA NCSU334B 280nm UVC LEDs can present higher output and longer lifespans.

In addition, the putative life of 280nm is about 20000 hours, while 265nm is estimated to be about 2000 hours, so 280nm is about 10 times longer. Ultraviolet LEDs have the characteristics that : when the wavelength is short, the performance such as light power and life will be reduced, and the photoelectric conversion efficiency will also be very low. This feature results in a high output power of 280nm and long life. Therefore, in consideration of higher bactericidal capacity and longevity, the wavelength of 280nm was adopted for this inactivation experiment.

3.Contribution of pilot products

NICHIA has contributed additional prototype hand-held UV irradiation devices that were made for the inactivation experiment to Tokushima Prefecture (20 units) and Tokushima University (30 units). This rechargeable, portable device can be easily used for sanitizing common spaces and surfaces where alcohol-based solution cannot be used.

NCSU334B
6.8x6.8x2.12
Wavelength	280nm
Radiant flux	70mW
Current	350mA
Forward voltage	5.5V
WPE	3.6%

This device is equipped with 12pcs deep 280nm Ultraviolet UV LEDs NCSU334B  at intervals of 25 mm These LEDs offer the industry’s highest radiant flux, 70mW (typical value), and WPE, 3.6%, at the peak wavelength of 280nm (typical value) (according to NICHIA research).

NICHIA will continue to devote itself to the development of high power deep ultraviolet LED with stronger bactericidal ability in the future, in order to overcome Novel Coronavirus, and hope that this deep ultraviolet LED is used in all kinds of products, also can bring you some help in daily life.

References

1) The Journal of the Japanese Association for Infectious Diseases, 80:496-500, 2006.

2) J. Antibact. Antifung. Agents, Vol.48, No.9, pp.477-480 (2020).

3) JIS Z8811-1968

4）from NICHIA Corporation News

12 Inches Cutting Scratches Transport Fixed Silicon Disk Iron Ring Frame Special For Blue Film

 Stainless Steel 12’’ Wafer Ring Metal Film Frame is selection of materials through SGS certification, high bending strength, high hardness, can bear high load, high wear, corrosive media. 12 inches Blue Film Attachment Wafer Ring is with strong hardness, resistance to bending, good stickiness, durability.

Product information for Stainless Steel Wafer Chip Rings :

Brand : DSXUV

Name : wafer chip ring

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Applications of 12’’ Disco Wafer Frame Ring :

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Why Is NICHIA UV LED Fond Of 280nm?

 On December 29, in the expert said, UV LED wind direction jointly held by the expert said 2020 annual meeting · deep ultraviolet LED special summit forum, Mr. Hu Jun, deputy manager of Japan and Asia shared the "280nm sterilization solution and NICHIA UV LED products" keynote speech.

Hu Jun, vice manager of NICHIA, pointed out that NICHIA focused on the development of 280nm UVC LED and improve the optical power, and in 2019 successfully launched the wavelength of 280nm, power of 55mW UVC LED -- NVSU334A. In September 2020, NICHIA launched an upgraded version of 280nm 70mW UVC LED with an external quantum efficiency of 3.6%, while similar UV LED products on the market are usually 265nm.

So, why in a variety of UVC bands, NICHIA chose 280nm as a sterilization solution? Mr. Hu Jun made the scene to answer.

Mr. Hu Jun said that UV sterilization and other comparison, there are many advantages, but in the daily life scene or industrial scene, the use of UV sterilization is not very popular. And even in the sterilization method, the Minamata Convention requires the elimination of mercury, but mercury lamp utilization rate is higher than UV LED. This is because LEDs are not efficient enough to replace all mercury lamps used in everyday life and industry. Therefore, this is a problem facing LED enterprises together.

Therefore, for all LED enterprises, improving efficiency is a top priority. NICHIA chose 280nm as the UVC sterilization product, and it is the only one band, no other band. The reason why NICHIA chose 280nm is that its product development believes that higher conversion efficiency can be achieved at 280nm. The current mass-produced product has an efficiency of 3-4% and a very long life.

Through comparison and verification, the sterilization efficiency of 265nm UVC LED is 95% under the same condition of using 3W power. But the efficiency of 265nm UVC Ultraviolet LED light is not very high. So the power output is not high, which is 50mW. However, the killing efficiency of 280nm UVC LED Light Bead is 60%, which is lower than that of 265nm UVC LED. But it has higher efficiency and higher power output, which can reach 100mW. A simple calculation can be made based on the above data. The output power of 280nm UVC LED is 100mW multiplied by 60% of the sterilization efficiency to get 60 points. The output power of 265nm UVC UV LED Lamp is 50mW multiplied by 95% of the sterilization efficiency to get 48 points. This means that 280nm UVC Ultraviolet LEDs use less power to kill the same bacteria.

In addition, another advantage of 280nm UVC LEDs is that they last longer than 265nm UVC Ultraviolet LED Lights. For example, NICHIA NCSU334B UVC LED product maintains a 92% performance maintenance rate after 5000 hours of use. The 265nm UVC LED light beads dropped to 67% at the same time. From the user’s point of view, users want longer and more reliable products, not frequent replacement.

Therefore, NICHIA chose 280nm band as UVC LED Sterilization Lamp products, together with the industry, is committed to solving the pain point of low efficiency of UVC LED, effectively popularize the healthy and pollu-free sterilization program of UVC LED.