Wavelength Mapping
Precision imaging systems in web inspection use multi-wavelength light to convert physical depth or position into a color spectrum. Through spectral encoding, each point in the physical space or along the optical axis is associated with a specific wavelength of light. This approach allows a sensor to capture multi-dimensional surface data using a single-point detector or a linear spectrometer.
It avoids the need for mechanical scanning in the vertical direction.
Thickness Profiling
In the production of multi-layer packaging films, measuring the thickness of individual co-extruded barrier layers is necessary for quality control. Applying spectral encoding allows the inspection system to measure the interference of light reflected from each layer interface simultaneously. The resulting spectral return contains a frequency pattern that corresponds directly to the thickness of each layer.
This technique can resolve thin coatings of adhesive or polymer down to the sub-micron level on a fast-moving web. It provides a continuous profile of the material structure without slowing down the winding machinery. This data allows immediate adjustment of the extrusion dies to prevent material waste.
High-Speed Acquisition
Because the physical information is carried by the wavelengths of light, the system does not require moving focus stages. This static design makes the sensor highly resistant to mechanical vibration and wear. It is ideal for the harsh environments found in commercial laminating and coating facilities.
