Pattern Projection with Focus Detection
Typically, software used on optical instruments can have difficulties determining what is in focus and what is out of focus. The accuracy of the optics may limit how effectively the focal plane can be resolved.
By using advanced optics to project a sharp pattern that will only be in focus at a precise distance, the software and optics are able to determine what is in the focal plane more easily and with greater accuracy.This also allows for more flexibility in measuring transparent samples as the projection will only be in focus on a real surface.
This combination technique is slightly more complicated than focus detection but it provides more accurate measurements and simpler software detection.
Micropillars for self-cleaning surfaces analyzed using Zeta 3D optical profiler
Pattern projection with focus detection is generally faster than the other scanning techniques because only Z motion is required. This method also improves height resolution to be comparable or better than scanning techniques. Pattern projection with focus detection is the essence of the Zeta 3D optical profiler ZDot focusing technology.
Comparison to White Light Interferometry
Zeta 3D optical profiler vs WLI