What is chromatic confocal ?

Fruits of more than fifteen years of research and development by our engineers, STIL optical sensors offer the best of technology in response to the most demanding needs in terms of non-contact dimensional measurements.

Based on an innovative optical principle which uses the chromatic coding of space (invented and patented by STIL), our sensors allow users to perform measurements on nearly any kind of materials with exceptional accuracy.

STIL sensors find applications in most sectors of industry, may it be it high precision instruments in metrology or research laboratories, or as quality control tools on production lines.

Designed for use in industrial environments, the different ranges of STIL sensors will appeal to integrators for their easy interfacing with measurement and inspection machines, thanks to the dynamic link libraries (DLL) provided with each instrument.

Optical principle

Our optical sensors are based on the highly innovative Confocal Chromatic Imaging principle (STIL patent).

An incident white light pinhole is imaged through a chromatic objective into a continuum of monochromatic images along the Z-Axis, thus providing a «color coding» along the optical axis.


This backscattered beam passes through a filtering pinhole into a spectrograph, which determines the wavelength has been perfectly focused on the object, and then accurately determine its position in the measuring field.

Confocal Chromatic Imaging gives access to reliable, accurate and reproducible dimensional measurements with extremely high resolution.

What is Spectral Confocal Interferometry ?

The measurement accuracy in non-contact profilometric techniques is generally limited by mechanical vibrations and by positional inaccuracies of the micro-scanning table. In order to free the measurement from these environmental perturbations, STIL has developed a new vibration insensitive interferometric method. With this new type of interferometric system, the potential sub-nanometric accuracy of interferometric microscopy is effective.

Spectral Confocal Interferometry principle

STIL interferometric method is based on Spectroscopic Analysis of White Light Interferograms (SAWLI).

It consists in analyzing the interference signal observed on a spectrometer in order to measure the air gap thickness between reference plate and sample. The originality of the developed system lies in the fixation of the reference plate on the inspected target. As reference plate and sample are fixed together, the mechanical vibrations do not affect the measurements.

Moreover, this sensor can be used for measuring transparent films that are too thin to allow Chromatic Confocal technology to be used. Minimum measurable thickness is 0.4μm.

Legal Notice


Domaine Saint Hilaire, 595 Rue Pierre Berthier, 13855 Aix-en-Provence cedex 3 - +33 (0)4 42 39 66 51

Domaine Saint Hilaire

595 Rue Pierre Berthier

13855 Aix-en-Provence cedex 3

+33 (0)4 42 39 66 51