Chapter 177
Happy New Year! The beginning of 2022 seemed to be restless because of SARS-Cov-2 Omicron variant and heavy snowfall in Japan. Extreme weather has become an annual event, and there is no waiting for prevention of global warming. At the end of 2021, we hurriedly announced a new product for deep UV LED sterilization lighting. The effect of the vaccine is limited, and the number of infected people has reached a record high overseas, so we prepared to use it as a preventive measure. Vaccines are a defense against viruses that are taken up by the body, but if they can be neutralized before they enter the body, it is better. As you know, bacteria and viruses can be inactivated by light in the deep ultraviolet region, but it is meaningless unless the irradiation method and the time required for inactivation are properly controlled. The 222 nm which is safe to be exposed for the human body and deep ultraviolet LEDs 275 nm are attracting attention as a sterilizing light source to replace conventional UV (low voltage mercury) lamps due to the influence of restrictions on the use of mercury. Therefore, I thought that it was necessary to understand the characteristics of each light and apply it correctly. With the cooperation of Dr. Shuichi Nishimura, Virus Center, Sendai Medical Center, National Hospital Organization, we asked them to evaluate the inactivating effect of the excimer lamp at 222 nm and the deep UV LED at 275 nm compared with 254 nm UV lamp on the pseudo-SARS-Cov-2 coronavirus OC43. In the prediction before the test, 254nm was advantageous, and it was unclear which effect was higher at 222nm or 275nm, but the result was that the inactivating effect was higher in the order of 275nm, 254nm, 222nm. Details will be published in a paper soon, but we were skeptical of this result. The reason is that the maximum absorption band of nucleic acids that make up DNA and RNA is around 254 nm, so it was expected that the closer it is to 254 nm, the more advantageous it is, regardless of the type of virus. The general interpretation is that the absorption of ultraviolet light alters the protein and makes it impossible to transmit genetic information. 222 nm and 275 nm deviate from 254 nm to about 30 nm short wave and 20 nm long wave, respectively. However, the result was that 275nm exceeded 254nm. As a matter of course, the amount of irradiation energy (Illuminance x Time, unit Joule) is adjusted to be equal and unified so as not to be unfair. The distance from the light source to the virus is 50 cm, which is a condition close to the practical environment such as medical sites, and it is not a test in an unrealistic environment that is often seen in inactivation evaluation with chemicals. There is no point in testing in an environment that is harmful to the human body. The evaluation team was not inductive but neutral in a professional position, and the result was advantageous for our deep UV LED sterilization lighting. Since it is an LED, we are thoroughly designing energy saving, long life, and safety design that does not irradiate with the function of the sensor when there is a person. There is a mechanism that can reliably and safely repel viruses. This year, along with the development of microUV-LED, which is expected as a next-generation display, we would like to make efforts to enlighten and popularize deep UV LED lighting so that it can be widely applied. We look forward to your continued support and encouragement this year as well.
This year we will focus on Micro UV-LED and Sterilization lighting.
January 5th, 2022
New Year Greetings
