Advanced Optical Microscopy


Optical microscopy is used across a vast array of industries. Due to its accessibility, it is often the first step in observing unknown characteristics of a surface. Tool capabilities and level of data quality, however, are greatly influenced by the specific instrument used. While many people have used an optical microscope at some point, many are unfamiliar with the benefits offered by a modern digital microscope equipped with cutting-edge technology.

Covalent offers a diverse set of advanced optical microscopy capabilities. High depth of field optics, coupled with the ability to make a composite of images at different focal planes, enable fully focused imaging across the whole field of view, even with large differences in feature height. Large objective working distances also allow for imaging of recessed features that would be impossible to access with more traditional microscopes. Additionally, greater control on illumination modes such as brightfield, darkfield, or mixed lighting, as well as polarization or even directional lighting, results in exceptional images that can reveal important surface features otherwise not observable. Image stitching allows for imaging large areas with the resolution afforded by higher magnification.


High-end digital microscopes are used in various applications across multiple industries. Below are some common advanced optical microscopy applications:

  • Critical dimensions on printed circuit boards & high-resolution imaging of PCB components
  • Defect inspection for thin films on glass substrates
  • Cross-sectional imaging of semiconductor structures such as vias and layer thickness
  • Metallographic samples
  • Transparent and biological samples


  • High resolution imaging
  • Dimensions, angles, curvature
  • Rapid imaging and analysis for high throughput
  • Multi-mode illumination for enhanced feature contrast
  • Transmission optical microscopy
  • Particle size analysis & statistical characterization
  • Grain size analysis
  • Contamination and defect detection
  • Approximate 3D scale (especially helpful in determining if our in-house profilometry options might provide additional, valuable information)

Example images from Digital Microscopy

Grain Size & Count on Keyence VHX-S660E

Large depth of field on 35-degree tilt angle (Keyence VHX-S660E)

Particle Size Analysis on Keyence VHX-S660E

Digital Microscopy Instruments

Keyence VHX-S660E Digital Microscope

This microscope offers all of the advanced capabilities described above and boasts magnification choices ranging from 20x to 2,000x (19.05 mm to 190 um field of view). Additionally, the objective can be tilted around the sample, enabling different imaging angles inaccessible for most tools. This instrument is particularly capable of automated imaging and analysis of similar parts, making measurements of large batches of samples feasible. It is also noteworthy that both the hardware and the software for this microscope are exceptionally user-friendly – because we offer our customers the opportunity to receive training and subsequent external user status on many of our tools, this instrument’s ease of use makes it especially attractive for customers looking for a way to further reduce costs for larger projects.