Davinor LayerGauge is a gauging system for off-line structure analysis of transparent or semi-transparent multilayer materials. It has been specifically designed for measuring plastic materials with barrier layer construction as well as polymer coatings on transparent or non-transparent surfaces.

      The LayerGauge operates by directing a light beam through the multilayer film sample and measuring the weak reflections from the boundaries between the different layers. This technique - interferometry - uses ordinary white light and it can be used to measure extremely small distances.

      A narrow light beam is directed into the material to be measured. Given that the layers to be measured are: A) transparent to the white light and B) have slight differences between the refractive indices of the adjacent layers, the layer interfaces cause light reflections.

      Davinor LayerGauge detects the light reflections, and, by a special optical and electronic arrangement, converts these reflections into an electronic sensor signal. The reflections cause sharp and intense peaks to the measured detector signal.

      Each of these signal peaks represents the location of the corresponding layer-interface. The separation of the adjacent peaks indicates the optical thickness of the layer. To get the actual thickness, the optical thickness must be divided by the refractive index of the material:

  The optical arrangement of the Davinor LayerGauge resembles the traditional Michelson’s White Light Interferometer. In actual operation, the mirror moves back and forth continuously while the computer of the instrument automatically analyses the sensor signal and calculates the layer thickness using the refractive indices of the respective layers.

  Calibration of the LayerGauge is an automatic software driven process. Traceability conforms to the national measurement standard. Film manufacturers who utilize the LayerGauge can document the quality of their products and provide quality certificates compatible with any quality system.

      The measurement technique applied in LayerGauge sets some limitations on materials to be measured and also on conditions for successful measurement and reliable results. The following is a description of the most important characteristics required for this measurement method.

  In order for a material to be measured with LayerGauge, some amount of light must penetrate it. No information can be gained beyond an opaque part of sample. Therefore layers of a multilayer film or polymer coating on non-transparent...

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