Optical Profilometer Training

Field of View and Numerical Aperture

Field of View

The Field of View (FoV) is the diameter of the circle of light that you see when looking into a microscope. The higher your magnification, the smaller the microscope field of view will be.

The benefits a microscope objective

The imaging system of the Nexview 3D is a microscope objective, which gives the two-fold benefit of:

  • higher magnification for small features;
  • measurement of rough and sloped surfaces due to higher numerical aperture.
Field of View, Working Distance, and Numerical Aperture
Field of View, Working Distance, Focal Plane, Numerical Aperture

Numerical Aperture (NA)

In optics, the numerical aperture(NA) characterizes the range of angles over which the system can accept or emit light. When the light hits a surface which is highly sloped, it can be reflected to not return up the optical system, and nothing will be detected. This means that higher NA objectives can measure steeper slopes.

Numerical aperture acceptance angle
Numerical aperture acceptance angle