Stray light is a major source of interference in many applications involving photodiodes and photodiode arrays. It increases the signal background and thus negatively affects the sensitivity of detectors and their signal-to-noise ratio. Traditional suppression measures such as inserting apertures or blackening surfaces are often incompatible with the requirements of miniaturized systems.
The research project “SOS – Stray Light Suppression in Optical Sensor Assemblies” was launched with the aim of simulating and recording the formation and influence of stray light in miniaturized sensor assemblies and finding and evaluating methods for suppressing it. The figure shows a test vehicle consisting of a structured photodiode with a daylight filter and based on an assembly from a turbidity sensor. A particular challenge with miniaturized sensor systems is that individual components have to fulfill multiple functions. For example, a surface optimized for optical purposes must also serve as a contact partner for bonding. Measures to suppress stray light must therefore meet all requirements and boundary conditions applicable to the system. For this reason, another focus of the research is the compatibility of various suppression measures with joining processes and the sensor materials used.
The research and development work described was funded by the German Federal Ministry for Economic Affairs and Energy (BMWE) as part of the research project “Stray Light Suppression in Optical Sensor Assemblies” (SOS).
Funding code: 49MF202457
