Engineer's Office for Applied Spectroscopy

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Bullet-Blue.gif (925 bytes) Technology Features
Optical method:  non-contact, non-destructive. no Beta radiation, no calibration required!
Fast measurement and film thickness evaluation - within milliseconds!
Wide thickness measurement range, up to ~ 0.1 to 150 micrometer ( 0.004 to 6 mil )
High accuracy:  typically better 0.005 micrometer over the entire range
Simultaneous determination of double-layers possible
Motion bridge controlled measurement on web coaters possible

  Download Application Note: 

Bullet-Blue.gif (925 bytes) Application Examples
Protective Lacquer Coatings

Click on the image

Film thickness measurement of dry or even wet lacquer coatings, with the possibility of a simultaneous two-layer measurement. Our technology is used by the world's leading manufacturers of Automobile Headlights and Compact-Discs. The picture shows a 3D film thickness profile of the protective lacquer of a standard commercial Compact-Disc in the range of 9-13 microns.

Vapor Deposition (e.g. Parylene) and Photo Resist Layers

Click on the image

The highly precise technology of our thickness gauges determine the film thickness of even sub-micron layer structures. The picture shows a 3D film thickness profile of a 10 mm diamond layer on silicon in the thickness range of 800-1000 nanometers.

Web Coating of Wrapping Foils and other

Click on the image

The film thickness profiles of web produced or coated foils can be determined in cross- and/or machine-direction by using a scanning bridge and our film thickness gauges. This permits an intermediate feedback for your process and production control. The picture shows a schematic setup for film thickness measurement on a web coating or foil machine.

Bullet-Blue.gif (925 bytes) Measurement Method Principles

A commonly well-known effect, which occurs for example with soap bubbles or on a thin oil film on water, is used for the determination of the film thickness. You can see many colors which change according to the layer thickness, e.g. when the soap bubble is blown up. Also check out this Soap Bubble Web site for some nice pictures and more detailed explanation of this effect!

These "colors at thin layers" are based on the interference phenomenon, i.e. on the superposition of light waves, which have been reflected at the front and back side of the layer (at two boundaries with different optical densities).

The Interference Model
The interference model

The undisturbed superposition of the two reflected light rays 1 and 2 leads to periodical amplifications and extinction in the spectrum of a white continuum light source (such as a halogen spectral lamp as a pseudo white-light source).

Since the superposition of the two light rays is not purely additive, a so-called interference occurs. The figure at the right shows the interference spectrum of a 1 m layer (chart on top) and 2 m layer (chart at bottom).

Examples of Interference Spectra
Examples of interference spectra

Bullet-Blue.gif (925 bytes) Film Thickness Gauge and Measurement Setup

The interference spectra of thin transparent or semi-transparent layers are measured and analyzed by our TranSpec and TranSpec Lite Film Thickness Gauges, as shown in the schematic figure right beside. The sample is illuminated through a bifurcated fiber optics cable, which is connected to the spectrometer and a halogen lamp. The reflected interference spectrum is guided back to the spectrometer, where the spectrum is analyzed and the film thickness is computed.

TranSpec Lite Film Thickness GaugeTranSpec Process Spectrometer for Film Thickness
           TranSpec Lite film thickness gauge                  TranSpec process spectrometer

Gauge Setup for Film Thickness Measurement
Film thickness measurement setup

This Website was edited last on January 7, 2019

Copyright 1998-2019 by Thomas Fuchs, Engineer's Office for Applied Spectroscopy, Germany


  Ing.-Buero Thomas Fuchs

Street Address: 

  Bischof-Fischer-Str. 108

Zip and City:

  73430 Aalen - Germany

Phone Number:

  +49  (0)7361 - 97 53 28 0

Fax Number:

  +49  (0)7361 - 97 53 28 5



  DE 167178636

WEEE-Reg. No.:

  DE 93698084