Development of a gonioreflectometer

Purpose and goal

Within the project an automated gonioreflectometer has been developed which will supplement the existing activities at the national laboratory and enable better and more relevant evaluations of advanced coatings and other distinct surfaces. The overall objective of the project, to strengthen the activities in the field of reflectometry at the Swedish national laboratory for photometry and radiometry at RISE AB by development of a cost-effective measuring system for characterization of BRDF, has been fulfilled.

Expected results and effects

The developed gonioreflectometer shows good potential to offer fast evaluations of BRDF with acceptable precision for most applications. The system has an initial dynamic range of 5 decades, variable bandwidth and a spectral range of about 300 - 900 nm. After additional characterization, we expect to be able to offer traceable evaluations of BRDF to interested parties. Also, the capacity to evaluate BRDF and related quantities increase the possibilities to participate in larger international projects in the field.

Planned approach and implementation

An initial study to evaluate the method, measurement geometries and the construction of the measurement system based largely on already existing equipment has been carried out. It was concluded that some modifications were needed in order to reach the desired performance but based on a double monochromator, a rotational stage for sample and detector, a LDLS (Laser Driven Light Source) and a limited amount of other components (optical and mechanical) a fully functional gonioreflectometer with accompanying measurement and steering software was constructed.