The robust μsurf sensor technology is based on the CMP technology (Confocal-Multi-Pinhole) of NanoFocus. Within seconds, topography, roughness and layer thickness in the micro and nanometer ranges are acquired.
Functional principle of the µsurf technology
The NanoFocus confocal microscope comprises an LED light source, a rotating multi-pinhole disc, an objective lens with a piezo drive and a CCD camera.
The LED source is focused through the multi-pinhole disc (MPD) and the objective lens on to the sample surface, which reflects the light. The reflected light is reduced by the pinhole of the MPD to that part which is in focus, and this falls on the CCD camera.
An image from a conventional optical microscope contains sharp and blurred detail. In contrast, in the confocal image, the blurred detail (unfocused) is filtered out by the operation of the multi-pinhole-disc. Only light from the focal plane reaches the CCD camera. Thus the confocal microsocope is capable of high resolution in the nanometer range.
Each confocal image is a horizontal slice through the topography of the sample. Capturing the images at different focal heights produces a stack of such images, achieved by the confocal microscope through precise vertical displacement of the objective lens by means of a piezo drive. 200 to 400 confocal images are generally captured within a few seconds, after which the software reconstructs an exact three-dimensional height image from the stack of confocal images.
The µsurf technology has many advantages in characterizing technical surfaces in the micrometer and nanometer range.
Contrary to the SEM (x,y), μsurf offers the data in true 3-dimensional coordinates (x,y,z). Only this quantitative data makes an exact analysis of 3D surface parameters possible, delivering a larger range of information about the surface texture. No previous sample preparation is required for measurements with the μsurf systems.
In many industry sectors the standard measurement methods is tactile scanning. An independent third party study performed by the National Institute of Standards and Technology (NIST) shows that the μsurf technology achieves the highest correlation (99 %) to tactile systems. Additionally, differences in the hardness of the material to be examined are irrelevant because the systems operates without contact and destruction of the surface.
Benefits at a glance
- Patented and developed by NanoFocus
- Fast data aquisition
- Height resolution in the nanometer range
- Robust and higly precise
- No sample preparation
- Real 3D data
- Independent of material propoerties like color, relectivity or hardness
- Measurements conform to DIN