Thin organic coatings and multilayer films
Measuring the thickness distribution of thin transparent coatings on transparent materials is a challenge, especially as an in-line process control technique. The challenge becomes greater the thinner the layers or the more similar the refractive indices are.
This challenge arises, for example, with
- sub-micron organic coatings (lacquer, adhesive etc.) on polymer films
- impregnations such as siliconization on polymer films or on paper
- components of multilayer co-extrudes films
- organic coatings on components, e.g. lubricants, release agents
Using fluorescence dyes can help to face this challenge.