Current Optics and Photonics

Optical Society of Korea (한국광학회)
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Bactericidal Effect of a 275-nm UV-C LED Sterilizer for Escalator Handrails: Optimization of Optical Structure and Evaluation of Sterilization of Six Bacterial Strains

  • Kim, Jong-Oh (Printed Electronics Technology Research Center, Pukyong National University) ;
  • Jeong, Geum-Jae (Department of Food Science and Technology, Pukyong National University) ;
  • Son, Eun-Ik (Department of Food Science and Technology, Pukyong National University) ;
  • Jo, Du-Min (Department of Food Science and Technology, Pukyong National University) ;
  • Kim, Myung-Sub (ACRO Co.) ;
  • Chun, Dong-Hae (ACRO Co.) ;
  • Kim, Young-Mog (Department of Food Science and Technology, Pukyong National University) ;
  • Ryu, Uh-Chan (Interdisciplinary Program of LED and Solid-State Lighting Engineering, Pukyong National University)
  • Received : 2021.10.19
  • Accepted : 2022.02.08
  • Published : 2022.04.25
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Abstract

In the pasteurization of escalator handrails using ultraviolet (UV) sterilizers, a combination of light distribution and escalator speed has priority over other important factors. Furthermore, since part of the escalator handrail has a curved structure, proper design is needed to improve the sterilization rate on the surfaces touched by users. In this paper, two types of sterilizers satisfying these conditions are manufactured with 275-nm UV-C LEDs, after modeling the three-dimensional (3D) structure of an escalator handrail and simulating optical distributions of UV-C irradiation on the handrail's surface according to light-emitting diode (LED) positions and reflector variations in the sterilizers. Pasteurization experiments with the UV-C LED sterilizers are conducted on six types of gram-positive and gram-negative bacteria, with exposure times of 0.2, 5, and 15 s at an actual installation distance of 20 mm. The sterilization rates for the gram-positive bacteria are 10.63% to 27.94% at 0.2 s, 89.44% to 96.30% at 5 s, and 99.64% to 99.88% at 15 s. Those for the gram-negative bacteria are 57.70% to 77.63% at 0.2 s, 98.90% to 99.49% at 5 s, and 99.88% to 99.99% at 15 s. The power consumption of the UV-C LED sterilizer is about 8 W, which can be supplied by a self-generation module instead of an external power supply.

Keywords

Acknowledgement

The author would like to thank Dr. Jae-Pil Kim of the Korea Photonics Technology Institute (KOPTI) for the information on the LED phosphors and the Korean government for the testing facilities provided by the Transfer Program of Idle and Underused Research Facilities and Equipment.

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