Optical Design and Instrumentation

Optical measurement techniques are used in a lot of everyday applications, including CD/DVD players and burglar alarms. Several optical technologies are playing an increasing role in industrial non-destructive characterisation of surfaces and materials.

By combining appropriate optical detectors, wavelengths and algorithms, it is possible to identify material types, compute concentration of gases and chemicals in mixtures, monitor colours, measure temperature, control film thickness, etc. Such methods are traditionally used in laboratory instruments, but are just recently gaining ground as online production tools, even in harsh environments. These advances are based on new detectors combined with powerful computers for advanced signal processing. In many industrial applications, existing systems that are suited can not be found. Often a simpler custom design performs better than an advanced, commercial system.

Knowledge on illumination and spectroscopy are often necessary when designing and optimising a custom system. The department combines optical design with signal processing to build complete sensor systems, using custom design or off-the-shelf components as necessary. In-house competence on data analysis, electronics and machine vision is often necessary components of a project. For example, a machine sorting beverage cartons and all common types of plastic from continuous waste streams by infrared spectroscopy was developed for the Norwegian company Titech Visionsort (previously Titech Autosort). The machine is now sold to waste-sorting plants in Europe, Japan and USA. The technology has been improved such that all paper not suited for de-inking can be removed automatically.

Application examples:

• NIR spectrometers for plastic recycling
• IR spectrometers for gas analysis
• Visible light/NIR spectrometers for return paper sorting
• Optical systems for bottle recycling machines
• Optical systems for high speed bar code scanners
• Optical systems for transflection spectrometric scanners
• DOE based spectrometers
• Grating spectrometers
• Illumination optics for computer vision
• Custom optics for computer vision