Excimer lamps

Ray tracing

Ray tracing for optimized surface treatment with light

The irradiation of surfaces with light is a common procedure in surface technology. It can be used, for example, to clean or activate surfaces before the adhesive bonding or coating process. Currently, there is also great interest in the disinfection of surfaces with UV light. In order to design and optimally configure irradiation systems, researchers at Fraunhofer IFAM simulate light distribution and intensity with an algorithm that has recently gained publicity for its application in 3D computer graphics: ray tracing.

Ray tracing: Intensity distribution on a light profile
© Fraunhofer IFAM
Ray tracing: Intensity distribution on a light profile

Simulating light in a computer-aided model

Ray tracing is not only about imaging the illuminated space. The ray tracing algorithm also allows conclusions about the intensity distribution of light. For the development of 3D computer games, this means that the illumination of 3D objects and shadow casts can be represented extremely realistically. Meanwhile, surface technology makes use of this technology by calculating the distribution of light intensity in three-dimensional space using volume emitters, complex lamp arrangements or component geometries. Irradiation arrangements can thus be optimized and the necessary irradiation doses can be calculated precisely.

Simulation of VUV pretreatment processes for adhesive bonding and coating

In industrial bonding and coating processes like varnishing, VUV light sources are often used to pretreat surfaces for cleaning or activation. In order to optimally design the required irradiation systems, the experts at Fraunhofer IFAM simulate these VUV pretreatment processes using ray tracing technology.

Excimer lamps or low-pressure mercury lamps are represented as volume emitters. Material parameters such as absorption cross-sections at oxygen-containing working atmospheres and transparent materials can be taken into account as well as the reflection properties of used surfaces. As a result, process parameters such as irradiation duration or velocity speed can be predicted from the irradiances.

Simulation of a parcel lock with UV light for disinfection of parcel surfaces
© Fraunhofer IFAM
Simulation of a parcel lock with UV light for disinfection of parcel surfaces

Design of UV irradiation systems for the disinfection of surfaces

Currently, Fraunhofer IFAM evaluates the possibilities of disinfecting surfaces with UV light against viruses (also Corona or Covid-19 viruses) and bacteria. One can think of the disinfection of masks, but also of an application in hospitals, for example to disinfect incoming or outgoing packages and goods.

For the design of such UV irradiation systems, radiation at 254 nm of a mercury lamp is needed. With knowledge of the doses required to inactivate the viruses, ray tracing can be used to determine

Surface technology is a core competence of the Fraunhofer IFAM. The working group »VUV Technology« of Dr. Christopher Dölle researches the use of light sources in surface treatment. In the department »Plasma Technology and Surfaces« the group has comprehensive know-how and the latest technologies for surface treatment at its disposal. The fields of application range from automotive engineering to aircraft manufacturing and medical technology.