Method to determine properties of a coating on a transparent film, method for manufacturing a capacitor film and device to determine properties of a coating on a transparent film

A method for manufacturing a capacitor film, the method comprising:

• forming a coating of a metal on a transparent film;
• moving the transparent film with the coating on a path that passes between a light source and a sensor;
• illuminating, by the light source, the coating on the transparent film;
• detecting, by the sensor, an intensity of transmitted light from the light source, wherein the light source performs a sweep in a frequency of emitted light;
• determining, by a processor, a wavelength that is optimal with respect to a material of the coating based on the intensity of the transmitted light over a frequency range of the sweep, wherein the wavelength is an optimal wavelength when an attenuation coefficient of the material is maximal or when, in case the coating comprises at least two different materials, a difference in the attenuation coefficient of the two materials is maximal for the wavelength;
• calculating, by the processor, a composition of the coating on the transparent film based on the detected intensity of the transmitted light;
• and
• adapting formation of the coating of the metal on the transparent film based on calculating the composition of the coating,
• wherein the coating on the transparent film is the capacitor film.

A device comprising:

• a light source configured to:
• illuminate a coating on a transparent film, wherein the coating is a metallization;
• and
• perform a sweep in a frequency of emitted light;
• a sensor configured to detect transmitted light intensity through the coating on the transparent film;
• and
• a processor configured to:
• determine a wavelength that is optimal with respect to a material of the coating based on the intensity of the transmitted light over a frequency range of the sweep, wherein the wavelength is an optimal wavelength when an attenuation coefficient of the material is maximal or when, in case the coating comprises at least two different materials, a difference in the attenuation coefficient of the two materials is maximal for the wavelength;
• and
• calculate a composition of the coating on the transparent film based on the detected intensity of the transmitted light which depends on the wavelength of the transmitted light.