The Analytical Instrumentation Facility (AIF) at NC State has recently installed the Keyence VKx1100, a Confocal Laser Scanning Microscope (CLSM). This microscope combines optical microscopy with laser profilometry, making it possible to obtain high resolution optical images and subsequently measure profile and surface roughness. It can be used for almost any type of material and is especially suited to measure surface features and roughness of samples which traditional stylus profilometry would not be feasible.

Instrument Features

  • 404 nm violet laser profiler, (Spatial resolution: 150 nm, lateral resolution: 5 nm)
  • 5x, 10x, 20x, 50x, and 150x objective lenses, capable of up to 28,800x magnification
  • Motorized XY Stage for sample navigation and automated image stitching

Advantages of Laser Profilometry

  • Higher depth of field than other light microscopy
  • No physical contact with sample
  • Faster measurement over larger areas in comparison to AFM or stylus profilometry
  • Virtually no limit on sample types

Recent Examples

Metals. The CAMAL group at NC State fabricates and conducts research on 3D printed metals. Characterizing these surfaces (roughness, topography) through AFM or other profilometry is challenging – most AFM tips or stylus profilometers would quickly wear or break if attempted.  The Keyence VKx1100 is ideally suited for helping compare surface roughness quickly and visualize surfaces in 3D for samples like this.

Surface roughness and topographic measurement of 3D printed metal

Textiles. Fibrous materials are typically challenging to other profilometry due to their movement during measurement; since the laser is not a physical probe, it is well-suited for imaging and analyzing textile surfaces. Example 2 shows roughness before and after applying conductive ink to knit fabric. Example 3 shows the profile of a calendared bond region in nonwovens.

Roughness measurement on knit fabrics before and after applying conductive ink

                               Profile of a calendared bond region in nonwovens

Microelectronics. The motorized stage on the Keyence VKx1100 allows for stitching together large areas at high magnification. The picture on the left is of a 1cmx1cm area on a microelectronic chip with a variety of patterns using the 20x objective lens on the Keyence VKx1100.  The entirety of these images can be analyzed for roughness measurement and step profiles (right). Profiling an area this large would take hours with AFM or stylus profilometry, however, the laser profiler combined with the motorized stage makes it possible in a matter of minutes.

                      Profiles of microelectronic chip with a variety of patterns