White Light Interferometry (WLI) Testing Technique
White Light Interferometry (WLI) provides quantitative surface topography information from all solid materials.
The resolution of the measurements are ~0.5µm in the lateral (X, Y) plane and ~1nm in the height (Z) plane. This allows microfeatures and large scale topographic variations to be monitored in detail.
Surface metrology data is presented in the form of pseudo-color height maps, 3D images, line profiles and surface roughness parameters (e.g. Ra, Rz).
- Height maps, 3D images and movies to illustrate the surface topography
- Profilometry - Measurement of feature heights / depths on the nm - mm scale using line profiles
- Surface roughness parameters - including Sa - mean surface roughness; Sp - highest peak of the surface; Sv - deepest valley; Sy - total height between highest peak and deepest hole; Sz - mean of distance between the five highest peaks and five deepest holes
- Measurement of transparent film thickness in the 0.2µm - 50µm range.
Typical applications
- Characterization of surface defects, stains and residues on metals, glasses and polymers
- Measurement of coating film thickness and uniformity on arterial stents
- Monitoring the effect of acid erosion on human tooth enamel
- Measurement of wear scars in tribological studies.
Typical industries using White Light Interferometry
- Healthcare
- Medical Devices
- Printing
- Packaging
- Semiconductors
- Electronics
- Aerospace
- Automotive
WLI - At a Glance
- Information: Quantitative surface topography and roughness parameters
- Area Analysed: From ~100mm x 100mm to ~60µm x 80µm
- Film Thickness: transparent films from ~200nm - ~50µm thick
- Imaging: Yes
- Image Resolution: ~0.5µm in X,Y; 1nm in Z
- Data Output: Height maps, line profiles, 3D images and movies