Non-contact surface topography measurements
Principle
Optosurf interferometric measurement system is based on Michelson’s interferometer principle (interferences between a reference mirror and the sample’s surface).
The sample is lighted up by a filtered white light source. 50% of the beam is sent on a reference surface (mirror) thanks to a separative slide. The other part lights up the sample’s surface. Reflected beams from the mirror and the sample are combined on the separative surface and interfere.
Height differences between the sample and the reference create a interference pattern related to the sample’s surface.
OPTOSURF’s principle
Those Height differences are recorded and numerically processed so as to reconstruct the surface ( 100 µm²).
Many processings are available : surface characterization, roughness parameters calculation, distances and heights measurements, 3D and 2D representations, …. This system is particularly dedicated to extra-polished surfaces.
Equipement
OPTOSURF measurements station
| Microscope |
Nikon, Leica |
| Light source |
Halogen lamp 100 Watts |
| Detector |
High resolution CCD detector |
| Format |
1384x1036 Pixel |
| Z resolution |
< 0,1 nm |
| Acquisition time |
3-30 sec |
| Filters |
20 nm &120 nm |
ALTISURF 500 measurements station
Principle
A light beam from an halogen lamp (polychromatic white light) passes through an optic fiber and goes to a passive probe. This passive probe has a chromatic aberration lens that divides the beam into monochromatic wavelengths on a z range (300 µm or 3mm, as a function of the probe). As a function of the surface’s relief, some wavelengths are reflected, other don’t. Reflected wavelengths are then interpreted in terms of height.
Technical characteristics
 Acquisition maximum speed : 10 mm.s-1
Probes : 300 µm (resolution 0,01 µm) & 3 mm (resolution 0,1 µm)
Accuracy : < 0,1 µm / 50 mm
Measurements up to an angle of 43°
Surface treatment processing
Surface state characterization
Normalised 2D and 3D roughness parameters calculations
Distances, heights, angles and thickness measurements
Volume measurements (peaks or valleys)
2D and 3D surface representation
Applications : surface characterization on all types of supports, tribology, coatings control, defects propagation (ex : cracks, scratches,…), surface planeness, manufacturing control, etc. |
