Meaning
Optical metrology provides height data through the axial dispersion of a broadband light source. Chromatic confocal profilometry works by mapping different wavelengths to specific focal distances along the vertical axis, allowing the system to identify surface height based on the color of the light reflected back to the sensor. This technique distinguishes topography without physical contact on surfaces ranging from transparent films to opaque metals.
Optical Interference
White light passes through a series of lenses designed to create severe longitudinal chromatic aberration. The instrument gathers only the light wavelength that focuses exactly on the sample surface through a pinhole aperture, while blocking all other spectral components. High vertical resolution results from this strict spatial and spectral filtering.
Dimensional Control
Lens manufacturers apply this technology during the inspection of high-curvature polymer surfaces. The process captures deviation from the target radius during the molding cycle, ensuring that the profile meets the required optical tolerance for the final part. Production variance causes rapid shifts in focal point data, which indicates potential cooling instability or improper resin pressure within the cavity.
Sensor Calibration
Frequent validation against certified optical flats maintains the accuracy of the height map. Errors appear when the spectral response of the detector drifts or the internal light source loses intensity at the edge of the visible spectrum. Reliable measurements depend on the stable relationship between the wavelength shift and the physical movement of the objective lens relative to the subject.
