MESSVERFAHREN UND FOTOMETERANORDNUNG FUER DIE HERSTELLUNG VON VIELFACH-SCHICHTSYSTEMEN

The production on transparent substrates of multiple-coating systems is measured by continuously determining the transmission and/ or reflection of highly refractive and slightly refractive coatings respectively applied to at least two glass test plates, as 5a. At least one of the coatings has a thickness of an integral multiple of ???/4 where ??? is the wavelength of the light 7, and at least one further coating has a thickness deviating from an integral multiple. Photo-receivers 12, 15 with monochrometers 11, 14 measure the proportion of the light reflected and/or transmitted by each test plate. Analysing circuit 24 recognises extreme values and data- processor 26 produces, via means 31, an adjustable control signal, prior to the application of the further coating, switching the monochrometer(s) to a wavelength at which the further coating produces an extreme value upon reaching its final thickness, and controls via output 28 a device for interrupting the coating process.