Urban Solutions & Sustainability

Germicidal UV-C LED Technology

Ray Optics Solution for the Safe and Efficient Usage of Germicidal UV-C LED Technology

In the new normal, people resume economic and daily activities with enhanced safety measures. One important safety measure is the regular surface disinfection in public space to prevent coronavirus spread. Surfaces could be contaminated when the infected person speaks, coughs, or sneezes without covering his/her mouth. Another person could be infected by touching the contaminated surface and then eating food or rubbing eyes. Conventional surface disinfection by chemical spraying or surface wiping is labour-intensive, thus it is imperative to develop a safe and effective non-contact sanitizing solution to prevent the spread of viruses or bacteria on surfaces in the public space, such as food court, office, public transport and aircraft cabin, etc.

Lack of Implementation Guideline for UV-C Technology

Germicidal lamps with ultraviolet C (UV-C) light sources are considered as an effective non-contact solution for killing a wide range of microbial and viruses including coronavirus thanks to the coincidence of UV-C radiation (100nm-280nm) with the absorption peaks of DNA and RNA (260nm). A popular choice of germicidal lamps is a mercury lamp, however, it poses environmental and health risks due to potential mercury leakage. More recently, the germicidal lamp with UV-C LED light sources emerges as an environmentally friendly, compact, low-cost and durable germicidal solution. Despite the superior merits, the adoption of UV-C technology is held back by eye and skin risks. To address the gap in implementation guidelines, we aim to develop a validated guide through optical simulation for the safe deployment, and efficient design of the germicidal UV-C LED technology. 

IHPC In-house Ray Optics Solution

The IHPC in-house ray optics solution is developed based on a physically accurate and geometrically flexible ray-tracing technique accelerated by parallel computing. It can model a point UV-C LED light source and an array of point sources and generate irradiance distribution on 2D cut-planes and the entire 3D scene with clearly defined safe and effective zones.

IHPC benchmarked the solution against commercial software and an analytical solution using an off-the-shelf UV-C LED point light source. All results are well agreed.


  • Output irradiance mapping on 2D cut planes and over the entire 3D scene
  • Output safe and effective zones on 2D cut planes and over the entire 3D scene
  • High computational efficiency and scalability with efficient parallel computing
  • Cross-platform compatibility
  • High physical accuracy with ray tracing technology
  • Define a single UV-C LED point light source and an array of point sources
  • Handle complex 3D geometry

The Science Behind

The ray optics solution describes the UV-C LED light source based on its radiant profile and spatial arrangement, models the energy propagation in light rays following the approximation of geometrical optics,  and projects the irradiance distribution onto the surfaces of the ambient operating area taking into consideration shadows cast by nearby objects. The exposure areas can be demarcated into safe, buffer, and effective zones through this and earlier determination of germicidal irradiance power levels. Moreover, it can be applied to derive the germicidal exposure time for different strands of viruses and bacteria based on respective UV-C efficacy data and UV-C LED light sources’ specifications.

Industry Applications

The proposed ray optics solution serves as a validated guide for the safe deployment and efficient design of germicidal UV-C LED solutions in public places, such as food courts, offices, aircraft cabins, and public transport. It also acts as a safety guide for on-site engineers to test and maintain UV-C LED equipment. Furthermore, it is important to optimise the UV-C LED system at the early stage for the appropriate choice of the power, shape, arrangement, and height of the UV-C LED light sources to design the LED modules’ movement pace and time of exposure for efficient disinfection. Besides, we can also extend the solution to other applications such as water purification, toilet cleaning system, etc.

For more info or collaboration opportunities, please write to enquiry@ihpc.a-star.edu.sg